Revised Draft: WHO guidelines on good herbal … Do not distribute without permission from WHO R-Draft WHO guidelines for comments, March 2017 - - WHO guidelines on good herbal processing

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- WHO guidelines on good herbal processing practices (GHPP) for herbal medicines -

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1 WHO/SDS/TCM 2

R-Draft WHO guidelines for comments 3 March 2017 4

Distribution: Restricted 5

Revised Draft: 6

WHO guidelines on good herbal processing practices (GHPP) 7

for herbal medicines 8

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REVISED DRAFT FOR COMMENTS 10

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Please address any comments on this revised draft WHO guidelines by 31 May 2017, to:

Ms Yukiko Maruyama, Scientist, Traditional and Complementary Medicine, Service Delivery and

Safety Department, World Health Organization, 1211 Geneva 27, Switzerland, at the email address

below:

E-mail: [email protected]

12 Traditional and Complementary Medicine (TCM) 13

Service Delivery and Safety Department (SDS) 14

World Health Organization (WHO) 15 16

TITLE: R-Draft: WHO guidelines on good herbal processing practices (GHPP) for herbal medicines – 17 Revised draft for comments, March 2017 18

19 © World Health Organization 2017 20 21 All rights reserved. 22 23 This revised draft is intended for a restricted audience only, i.e. the individuals and organizations having received this revised 24 draft. The draft may not be reviewed, abstracted, quoted, reproduced, transmitted, distributed, translated or adapted, in part or 25 in whole, in any form or by any means outside these individuals and organizations (including the organizations’ concerned 26 staff and member organizations) without the permission of WHO. The revised draft should not be displayed on any web site. 27 28 Please send any request for permission to: 29 30 Ms Yukiko Maruyama, Scientist, Traditional and Complementary Medicine, Service Delivery and Safety Department, World 31 Health Organization, 1211 Geneva 27, Switzerland. E-mail: [email protected] 32 33 The designations employed and the presentation of the material in this draft do not imply the expression of any opinion 34 whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or 35 of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate 36 border lines for which there may not yet be full agreement. 37 38 The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or 39 recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and 40 omissions excepted, the names of proprietary products are distinguished by initial capital letters. 41 42 The World Health Organization does not warrant that the information contained in this draft is complete and correct and shall 43 not be liable for any damages incurred as a result of its use. 44

mailto:[email protected]



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SCHEDULE FOR THE PROPOSED ADOPTION PROCESS OF DRAFTDOCUMENT: 45

WHO GUIDELINES FOR GOOD HERBAL PROCESSING PRACTICES FOR HERBAL 46

MEDICINES 47

Need for a WHO technical guidance on processing to produce herbal

materials, and to produce herbal preparations for quality control of herbal

medicines at different stages of their production, was stated during the

WHO informal meeting on methodologies for quality control of finished

herbal products (Ottawa, Canada) as a recommendation to WHO for

development/action.

July 2001

Reported to the 37th session of the WHO Expert Committee on

Specifications for Pharmaceutical Preparations (ECSPP), Geneva, on the

output of the WHO informal meeting (July 2001) and informed the

Committee that WHO planned to develop new technical guidelines on

processing of herbal medicines; the Committee noted the proposal.

22-26 October 2001

Needs for good processing practices for herbal medicines were also stated

during the International Conferences of Drug Regulatory Authorities

(ICDRAs)

Hong Kong SAR, China,

November 2002

Madrid, Spain, February 2004

Drafting of the proposal on the development of WHO guiding document

on good processing practices for medicinal plant materials

2003

Obtained WHO’s internal approval in developing a WHO guiding

document on good processing practices for medicinal plant materials

(title: tentative)

November 2003

Identification, collection, collation and compilation of technical

information and reference materials for formulating draft synopsis and

annotated content table

2008

Development of concept paper on scope and background as well as the

document development plan

2008

Further identification, collection, collation and compilation of technical

information and reference materials for revising draft synopsis and

annotated content table.

2012

Revision of draft concept paper on scope and background as well as the

document development plan

2012 – 2013

Revision and elaboration of the draft synopsis and content table for

drafting the first working draft guidelines

2012 – 2013

Meeting proposal development and search for potential host of the

meeting (2nd WHO consultation on quality control of herbal medicines) 2012 – 2013

Further collection and collation of technical information and reference

materials for the preparation of the first working draft guidelines

2013 – 2014

Formulating the first working draft WHO guidelines on good processing

practices for herbal medicines

2014

Formation of initial drafting group 2014

Reported on the progress to the 49th session of the WHO ECSPP,

Geneva, October 2014

October 2014



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Distribution of the first working draft WHO guidelines to the participants

of the 2nd WHO consultation on quality control of herbal medicines for

discussion at the 2nd WHO consultation meeting

October – November 2014

Reported on the progress to the 37th Annual meetings of national centres

participating in the WHO international drug monitoring programme,

Tianjin, China, October 2014

October 2014

At the 2nd WHO consultation meeting held in Hong Kong SAR, China, in

November 2014, the first working draft WHO guidelines on good

processing practices for herbal medicines were reviewed and discussed;

and the objectives, scope and proposed contents were discussed

intensively, and agreed. The draft synopsis and table of content of the

proposed guidelines were further refined and agreed; it was also agreed to

revise the first working draft WHO guidelines based on the discussion

and agreed guidelines’ objectives, scope, and contents at the 2nd WHO

consultation meeting.

17-19 November 2014

Reported on the progress of the guidelines development at the 7th annual

meeting of International Regulatory Cooperation for Herbal Medicines

(IRCH), Lisbon, Portugal, December 2014

December 2014

Further identification, collection and collation of relevant technical

information for revision of the first working draft guidelines

2015 – 2016

Revision of the first working draft WHO guidelines 2015 – 2016

Reported on the progress at the 8th annual meeting of IRCH, Riyadh,

Saudi Arabia, December 2015

8-10 December 2015

Formulation of the draft WHO guidelines on good herbal processing

practices for herbal medicines for a global review

2016

Reported on the progress to the 51st session of the WHO ECSPP, Geneva,

October 2016

17-21 October 2016

Reported on the progress at the 9th annual meeting of IRCH, New Delhi,

India, November 2016

9-11 November 2016

First global review on the draft WHO guidelines on good herbal

processing practices for herbal medicines

December 2016 – February

2017

Meeting proposal development and search for potential host of the

meeting (3rd WHO consultation on quality control of herbal medicines) December 2016 – February

2017

Compilation of comments received and revision of the draft February – March 2017

The second global review on the revised draft April – May 2017

Compilation of comments received and revision of the revised draft (to

form the 2nd revised draft)

June – July 2017

Review and discussion of feedback received on the 2nd revised draft at

the 3rd WHO consultation on quality control of herbal medicines, Hong

Kong SAR, China, September 2017

4-6 September 2017

Finalization of the manuscript based on the discussion at the 3rd WHO

consultation meeting

September 2017

Update to the 10th annual meeting of IRCH, Bonn, Germany, September

2017

11-13 September 2017

Update to the 52nd session of the WHO ECSPP, Geneva, October 2017

October 2017

Any follow-up action, as needed



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Table of Contents 48 49

1. INTRODUCTION…………………………………………………………………...………………7 50 1.1 Background of guidelines development………………………………………………...…7 51 1.2 Scope………………………………………………………………...…………………….952 1.2.1 Processing of herbs into herbal materials……………………………………...….9 53 1.2.2 Processing of herbal materials into herbal preparations……………………..……9 54 1.2.3 Processing of herbal materials or herbal preparations into herbal dosage forms..10 55 1.3 Objectives of guidelines………………………………………………………...……..…10 56 1.4 Definitions of terms………………………………………………..…….…………….…11 57 1.4.1 Terms relating to herbal medicines…………………………………..….………11 58 1.4.2 Terms related to herbal processing practices……………………….……….…..1359 1.4.3 Terms relating to quality control……………………………………………..….13 60 61 2. GOOD HERBAL PROCESSING PRACTICES FOR THE PRODUCTION OF HERBAL 62

MATERIALS…………………………………………………………………………………...….15 63 2.1 General information………………………………………………………………….…..15 64 2.2 Purposes and functions of processing……………………………………………….…...16 65 2.3 Processing techniques and procedures……………………………………………….…..17 66 2.3.1 Preparation of harvested/collected medicinal plant part for processing………..17 67 2.3.2 Primary processing procedures………………………...………………..………18 68 2.3.2.1 Sorting………………………………………………………………18 69 2.3.2.2 Washing………………………………………………..……………19 70 2.3.2.3 Parboiling (Blanching) ……………………………………………..19 71 2.3.2.4 Leaching…………………………………………………….………19 72 2.3.2.5 Drying…………………………………………………….…………19 73 2.3.3 Secondary processing procedures………………………………….……………20 74 2.3.3.1 Cutting, sectioning, and comminution……...………………….……21 75 2.3.3.2 Aging/Sweating…………………………………………………….21 76 2.3.3.3 Baking/Roasting……………………………………………………22 77 2.3.3.4 Boiling/Steaming………………………………………………….22 78 2.3.3.5 Stir-frying…………………………………………………………22 79 2.3.3.6 Fumigation …………………………………………………….……23 80 2.3.3.7 Irradiation………………………………………………………….23 81 2.3.3.8 Selection of processing method ………...…..………………….……23 82 2.3.3.9 Temperature………………………………………………....………23 83 2.3.3.10 Duration of procedure/treatment………….………………………..24 84 2.3.3.11 Use of adjuvants…………………………………….……...………..24 85 2.3.4 Special processing procedures………………………..……………….…………24 86 2.3.4.1 Detoxification…………………….………………..………………..24 87 2.3.4.2 Modification of therapeutic properties……….…………...…………25 88 2.3.4.3 Use of adjuvants……………………………..………………………25 89 2.3.5 Documentation………………….…………………….…………………………25 90

91 3. GOOD HERBAL PROCESSING PRACTICES FOR THE PRODUCTION OF HERBAL 92

PREPARATIONS………………………………………………………………………………….26 93 3.1 General information…………………………………….……..……………………….26 94 3.1.1 Preparation of herbal materials for processing……………………………..……27 95 3.2 Processing techniques and procedures…………………………………………..……….27 96 3.2.1 Extraction…………………………………..……….…………………...………27 97 3.2.1.1 Common methods of extraction……………………………….…...27 98



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3.2.1.2 Steps involved in the extraction of herbs and herbal materials…..….29 99 3.2.1.3 Common herbal preparations prepared by extraction………...……..30 100 3.2.1.4 Factors influencing extraction of herbal materials……….……….…31 101 3.2.1.5 Selection of extraction methods…………………………………….31 102 3.2.1.6 Extraction conditions and procedures………………………….……31 103 3.2.2 Distillation……………………………………..…………….…………………33 104 3.2.2.1 Distillation procedures……………………………….……………33 105 3.2.3 Fractionation and purification…………………………………………...………34 106 3.2.3.1 Liquid-liquid partition……………………………………….………34 107 3.2.3.2 Chromatography………………………………………………….….34 108 3.2.3.3 Fractionation and purification procedures………………….……….34 109 3.2.4 Concentration and drying…….………………………………………………….35 110 3.2.4.1 Concentration and drying procedures……………………………….35 111 3.2.5 Fermentation……………………………………………………….……….……35 112 3.2.5.1 Fermentation procedures…………………………………….………36 113 3.2.6 Powdering………………………………………………………………………..36 114 3.2.6.1 Powdering procedures………………………………………….…36 115 3.3 Documentation………………………………………..……………………….………....36 116 117 4. GOOD HERBAL PROCESSING PRACTICES FOR THE PRODUCTION OF HERBAL 118

DOSAGE FORMS…………………………………………...……………………………….……37 119 4.1 General information………………………………………………………….………..…37 120 4.2 Processing techniques and procedures…………………………………………………...37 121 4.2.1 Liquid herbal dosage forms…………………………………….…………..…....38 122 4.2.1.1 Fludiextracts…………………………………………………………38 123 4.2.1.2 Infusions……………………………………………………………38 124 4.2.1.3 Decoctions…………………………………………………………38 125 4.2.1.4 Liquid (fluid) extracts……………………………………..…………38 126 4.2.1.5 Tinctures…………………………………………………………….38 127 4.2.1.6 Syrups……………………………………………………………….38 128 4.2.1.7 Oral emulsions………………………………………………….……38 129 4.2.2 Solid herbal dosage forms……………..…………………….………………..…38 130 4.2.2.1 Herbal tea bags………………………………………………………38 131 4.2.2.2 Plant powders………………………………………………………..38 132 4.2.2.3 Powdered extracts…………………………………………………..38 133 4.2.2.4 Granules……………………………………………………………..39 134 4.2.2.5 Pills…………………………………………………………………39 135 4.2.2.6 Capsules…………………………………………………………….39 136 4.2.2.7 Tablets………………………………………………………………39 137 4.2.2.8 Lozenges……………………………………………………………39 138 4.2.3 Other herbal dosage forms…………………………………………………….39 139 4.2.3.1 Ointments/creams……………………………………………………39 140 4.2.3.2 Inhalations……………………………………………………...……39 141 4.2.3.3 Plasters and patches…………………………………………….……39 142 4.2.3.4 Aromatic waters……………………………………………………..40 143 4.2.3.5 Gel capsules………………………………………………...……….40 144 145 5. T E C H N I C A L I S S U E S S U P P O R T I N G G O O D H E R B A L P R O C E S S I N G 146

PRACTICES…………………………………………………….…………………………….……40 147 5.1 Processing facilities………………………………………………………………….…...40 148 5.2 Packaging and labelling……………………………………………………………….…40 149



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5.3 Storage and transportation……………………………………………………….…….…41 150 5.4 Equipment………………………………………………………………………….….…42 151 5.5 Quality assurance and quality control…………………………………………….……...42 152 5.6 Documentation……………………………………………………………….……..……43 153 5.7 Personnel……………………………………….…………………….……………….….43 154 5.7.1 General…………………………………….…………….……………………….43 155 5.7.2 Health, hygiene and sanitation…………………………………….……………..43 156

157 6. OTHER RELEVANT ISSUES………………………………………………………….………….44 158 6.1 Ethical and legal considerations……………………………………………….…………44 159 6.2 Research, research training and information sharing……………………………….……44 160 6.3 Adoption of good herbal processing practices………………….…………….………….45 161 6.4 Intellectual property rights and benefits-sharing……………………...………….………45 162 6.5 Threatened and endangered species……………………………………………………...45 163

164 7. REFERENCES……………………………………………………………………………….….....45 165 166 Annex 1: Example of a model format of good herbal processing practices monograph/SOP protocol to 167

produce a herbal material………………………….…..………………………..………..…47 168 169 Annex 2: Example of a model format of good herbal processing practices monograph/SOP protocol to 170

produce a herbal preparation…..…………..…………………………………………….…..50 171 172 Annex 3: Example of general rules for preparations/monographs of herbal preparations and herbal 173

dosage forms …………………………………………………………………………….…53 174 175 Annex 4: Processing facilities…………………….…..………………………………………..…….59 176



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1. INTRODUCTION 177

178

1.1 Background of guidelines development 179

180 Needs 181

Over the past three decades, there has been a constant, and at times, exponential growth in 182

global interest in the use of herbal medicines. This increase in popularity and usage of herbal 183

medicines is evidenced by the global market which also experienced similar growth. Herbal 184

medicines, including not only finished herbal products but also their starting materials for 185

production, such as medicinal plants, herbal materials, and herbal preparations, are moving 186

into the international commerce and the global trade arena, which indicates increased 187

economic value and importance. When adverse events are reported to the regulatory 188

authorities in relation to the use of herbal products, a large portion of them are attributable to 189

poor quality of products, which may involve a variety of factors, including those due to 190

natural (e.g. source material) and human (e.g. manufacturing/processing) factors. Hence, the 191

safety and quality of herbal medicines at every stage of its production process, have become a 192

major concern to health authorities, healthcare providers, the herbal industries and the public. 193

194

The safety and efficacy of herbal medicines largely depend on their quality. Unlike other 195

pharmaceutical products, which are formulated from single molecule chemicals produced 196

synthetically or by isolation from natural source materials employing reproducible methods, 197

herbal medicines consist of simple processed herbs or finished herbal products prepared from 198

source materials containing a multiplicity of chemical constituents, the quality and quantity of 199

which can vary from batch to batch due to intrinsic and extrinsic factors. Consequently, the 200

quality of finished herbal products is greatly influenced by the quality of the raw materials 201

and the intermediates; and the requirements and methods for quality control of finished herbal 202

products, particularly for mixed herbal preparations, are far more complex than those 203

employed for single molecule chemical drugs. 204

205

A number of World Health Assembly (WHA) resolutions relating to traditional medicine has 206

requested WHO to provide technical support to develop methodology to monitor or ensure the 207

quality, efficacy and safety of herbal medicines. The International Conferences of Drug 208

Regulatory Authorities (ICDRAs), and annual meetings of International Regulatory 209

Cooperation for Herbal Medicines (IRCH), as well as the Meetings of the National Centres 210

Participating in the WHO International Drug Monitoring Programme have also requested 211

WHO to develop and continuously update the technical guidelines on quality, safety, and 212

efficacy of herbal medicines. 213

214

Process and context 215

Participants of the WHO Informal Meeting on Methodologies for Quality Control of Finished 216

Herbal Products (held in Ottawa, Canada, July 2001) looked at the overall picture of herbal 217

medicines: from raw materials to the distribution and supply of finished herbal products, 218

including key steps where quality control is required. 219

220



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One of the main recommendations of the meeting was that WHO should prepare a series of 221

technical guidelines and documents covering quality control issues (from raw materials to 222

finished herbal products), as well as to update other existing documents. 223

224

Following the meeting’s recommendations, and as a part of the implementation of relevant 225

WHO strategies (notably, WHO traditional medicine strategies and WHO medicines 226

strategies) and WHA resolutions, WHO, since then, undertook the development of four new 227

guidelines and to update other existing documents in order to provide technical guidance for 228

quality control required at key steps in the production of herbal medicines to support Member 229

States in their efforts to ensure the quality of herbal medicines. These cover: 230

231

WHO guidelines on good agricultural and collection practices (GACP) for medicinal 232

plants (published in 2003) [WHO, 2003a]; 233

WHO guidelines on assessing quality of herbal medicines with reference to contaminants 234

and residues (published in 2007) [WHO, 2007b]; 235

WHO guidelines for selecting marker substances of herbal origin for quality control of 236

herbal medicines (in press) [WHO, 2017]; and 237

WHO guidelines on good herbal processing practices (GHPP) for herbal medicines 238

(present document). 239

240

WHO has also updated two key technical guiding documents: 241

242

WHO guidelines on good manufacturing practices (GMP) for herbal medicines (published 243

in 2007) [WHO, 2007a]; and 244

Quality control methods for herbal materials (published in 2011) [WHO, 2011], which 245

includes the WHO good practices for pharmaceutical quality control laboratories as an 246

annex. 247

248

GACP for medicinal plants are only the first step in quality assurance. The next important 249

phase involves the GHPP of herbal materials. The processed materials are herbal materials or 250

herbal preparations, which may be used as a starting source material for the GMP production 251

of finished herbal products, or directly employed as herbal medicines in various herbal dosage 252

forms. For this reason, GHPP for herbal medicines is integrally linked to GACP for 253

medicinal plants and GMP for herbal medicines in the quality assurance and control of herbal 254

medicines. 255

256

The present guidelines are intended to complement, and should be read in conjunction with, 257

those guidelines provided in WHO guidelines on GACP for medicinal plants [WHO, 2003a] 258

and WHO guidelines on GMP for herbal medicines [WHO, 2007b]. Altogether, the present 259

guidelines plus the above-mentioned three new and two updated WHO guidelines form the 260

core technical guidance for the overall quality assurance and control of herbal medicines. 261

262

Preparation of the guidelines 263

The original title suggested for these guidelines was “Good processing practices for herbal 264

materials”. In November 2014, WHO convened the second WHO consultation on quality 265

control of herbal medicines with financial support of Department of Health of Hong Kong 266



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SAR, China, in Hong Kong SAR, during which the working draft guidelines were reviewed 267

and discussed, and the objectives, scope and proposed contents were discussed and agreed. 268

First draft guidelines were revised through global review process. 269

270

1.2 Scope 271 272

Processing refers to the unique procedures of preparing herbal materials, herbal preparations 273

and herbal dosage forms for therapeutic applications. The process concerns ensuring the 274

quality of the herbal materials, herbal preparations and herbal dosage forms produced. The 275

safety and efficacy are strictly related to the intrinsic properties of the herbal materials. 276

277

These guidelines will provide technical guidance on good processing practices in the: 278

(1) processing of herbs into herbal materials; 279

(2) processing of herbal materials into herbal preparations; and 280

(3) processing of herbal materials or herbal preparations into herbal dosage forms. 281

282

In the case of processing herbs into herbal materials, the “primary” process is involved; 283

whereas in the case of processing of herbal materials into herbal preparations, “secondary” or 284

“special” processes are involved. On the other hand, for processing herbal materials or herbal 285

preparations into herbal dosage forms, the processing procedures involve the good practice of 286

the preparation or GMP for the production. 287

288

An outline of the major processes and examples of procedures are given below. 289

290

1.2.1 Processing of herbs into herbal materials 291

292 Primary processing encompasses the immediate post-harvest treatments accorded to herbs 293

obtained from cultivation or by wild crafting or field collection intended to free them from 294

foreign matters, untargeted plant materials and other contaminants, and includes, for example, 295

the procedures of sorting (garbling), washing, drying, cooling and freezing, where 296

appropriate. Primary processing is applied to herbs in the preparation of herbal materials. 297

298

1.2.2 Processing of herbal materials into herbal preparations 299

300 Secondary processing is the next step concerned with converting the primary processed herbs 301

(herbal materials) into herbal preparations by various additional procedures, including, for 302

example, cutting, sectioning, comminution (fragmentation), aging/sweating; baking/roasting; 303

boiling/steaming; and stir-frying. 304

305

Secondary processing may also involve special processing, an extension, in which a 306

specialized method is employed to treat selected herbs with the view of reducing the contents 307

of toxic ingredients or altering the chemical composition in order to modify their therapeutic 308

activity. Examples of herbs so processed include Aconitum, nux-vomica and Panax species. 309

310 The herbal preparations described above may serve as crude materials for use as herbal 311

medicines. In many cases, they will undergo further treatment procedures before being used 312



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to manufacture the finished herbal products. The active ingredients are usually not purified 313

but rather are obtained along with other components of the medicinal plant part. Sometimes 314

the active ingredients are further concentrated by the removal of inactive and/or undesirable 315

substances. The herbal preparations thus obtained include extracts, decoctions, tinctures, 316

essential oils, and others. The processes involved include extraction, distillation, 317

fractionation, purification, concentration, fermentation, or other chemical/biological methods. 318

319

1.2.3 Processing of herbal materials or herbal preparations into herbal dosage forms 320

321 Depending on the intended use, herbal materials could be regarded as starting materials and 322

herbal preparations could be regarded as intermediates in the process of producing finished 323

products or as final dosage forms for therapeutic applications. In the latter case, it is not 324

uncommon that simple dosage forms are prepared from either herbal materials (such as 325

unprocessed seeds or plant exudates) or herbal preparations (such as ground powders and 326

dried extracts) ready for administration to the patients. These herbal dosage forms, produced 327

under GMP conditions, include liquid extracts, decoction, tea bags, granules, syrups, 328

ointments/creams, inhalations, patches, among others. 329

330

1.3 Objectives of guidelines 331

332 These new guidelines will provide technical guidance on good herbal processing practices 333

(GHPP) for the production of herbal materials, herbal preparations and finished herbal dosage 334

forms. Under the overall context of quality assurance and control of herbal medicines, the 335

main objectives of these guidelines are to: 336

337

provide general and specific technical guidance on GHPP for herbal medicines; 338

provide technical information on general as well as specific good herbal processing 339

techniques and procedures applied for the preparation of herbal materials from 340

herbs/medicinal plant; 341

provide technical information on good herbal processing techniques and procedures 342

applied for the production of herbal preparations from herbal materials; 343

provide technical information on good herbal processing techniques and procedures 344

applied for the production of dosage forms of herbal medicines; 345

provide a model for the formulation of national and/or regional good herbal processing 346

practice guidelines and monographs for herbal materials, as well as for herbal preparations, 347

and related standard operating procedures (SOP); and 348

contribute to the quality assurance and control of herbal materials, herbal preparations and 349

herbal dosage forms, and to promote safety, efficacy and sustainability of herbal 350

medicines. 351

352

Use of these guidelines 353

These guidelines should be considered in conjunction with the existing WHO technical 354

documents and publications relating to the quality assurance of herbal medicines and 355

medicinal plants (for details, see References), for example: 356

357

WHO guidelines on good agricultural and collection practices (GACP) for medicinal 358



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plants [WHO, 2003a]; 359

WHO guidelines on good manufacturing practices (GMP) for herbal medicines [WHO, 360

2007a]; 361

Good Manufacturing Practices for pharmaceutical products: main principles [WHO, 362

2014]; 363

Quality control methods for herbal materials [WHO, 2011]; 364

WHO guidelines on assessing quality of herbal medicines with reference to contaminants 365

and residues [WHO, 2007b]; 366

Safety issues in the preparation of homeopathic medicines [WHO, 2010]; 367

WHO guidelines for selection of substances of herbal origin for quality control of herbal 368

medicines [in press, WHO, 2017]; 369

WHO monographs on selected medicinal plants, Vol. 1-4 [WHOM-1999, WHOM-2002, 370

WHOM-2007, WHOM-2009]; 371

WHO monographs on selected medicinal plants commonly used in the Newly Independent 372

States (NIS) [WHOM-2010]; and 373

General guidelines for methodologies on research and evaluation of traditional medicine 374

[WHO, 2000]. 375

376

The WHO guidelines on good herbal processing practices (GHPP) for herbal medicines is 377

one of a series of guidance documents concerned with control measures necessary to produce 378

quality herbal medicines for safe and efficacious use as directed by the appropriate authority 379

body. The present document concerns the assurance of the quality of the herbal materials 380

being prepared through various methods and steps of processing of the medicinal plant and its 381

medicinal plant part obtained under GACP; and of the herbal preparations being prepared 382

through various methods and steps of processing of the herbal materials. Herbal materials can 383

be used directly as herbal medicines or to serve as source materials for the GMP production of 384

finished products. These guidelines are applicable to the processing operations from post-385

harvest to finished herbal products. The processing of medicinal plants or plant parts should 386

meet all applicable national and/or regional quality standards. The guidelines therefore may 387

need to be adjusted according to local legislation and practice in each Member State. Each 388

Member State should develop its own national guidelines on good herbal processing practices 389

for herbal medicines that are appropriate to the country’s actual situation. 390

391

1.4 Definitions of terms 392

393 The terms used in these guidelines are defined below. The terms and their definitions have 394

been selected and adapted from other WHO documents and guidelines that are widely used by 395

WHO Member States, as well as from other reference sources (reference source is indicated 396

with [ ]). These definitions may differ from those included in national regulations, and are 397

therefore, for reference only. 398

399

1.4.1 Terms related to herbal medicines 400 401

Herbal medicines include herbs and/or herbal materials and/or herbal preparations and/or 402

finished herbal products in a form suitable for administration for patients. [WHO, 2017, in 403

press] 404



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Note: In some countries herbal medicines may contain, by tradition, natural organic or 405

inorganic active ingredients that are not of plant origin (e.g. animal and mineral 406

materials). [WHO, 2017, in press] 407

408

Herbs [WHO, 2017, in press] 409

Herbs are crude plant material which may be entire, fragmented or powdered. Herbs 410

include, e.g. the entire aerial part, leaves, flowers, fruits, seeds, roots, barks (stems) of 411

trees, tubers, rhizomes or other plant parts. 412

413

Herbal materials [WHO, 2017, in press] 414

Herbal materials include, in addition to herbs, other crude plant materials. Examples 415

of these other plant materials include gums, resins, balsams, exudates. 416

417

Herbal preparations [WHO, 2017, in press] 418

Herbal preparations are produced from herbal materials by physical or biological 419

processes. 420

These processes may be extraction (with water, alcohol, supercritical carbon dioxide 421

(CO2)), fractionation, purification, concentration, fermentation, and other processes. 422

They also include processing herbal materials with a natural vehicle or steeping or 423

heating them in alcoholic beverages and/or honey, or in other materials. 424

The resulting herbal preparations include, among others, simply comminuted 425

(fragmented) or powdered herbal materials as well as extracts, tinctures, fatty (fixed) 426

or essential oils, expressed plant juices, decoctions, cold and hot infusions. 427

428

Finished herbal products [WHO, 2017, in press] 429

Finished herbal products consist of one or more herbal preparations made from one or 430

more herbs (i.e. from different herbal preparations made of the same plant as well as 431

herbal preparations from different plants. Products containing different plant materials 432

are called “mixture herbal products”). 433

434

Finished herbal products and mixture herbal products may contain excipients in 435

addition to the active ingredients. However, finished products or mixture herbal 436

products to which chemically defined active substances have been added, including 437

synthetic compounds and/or isolated constituents from herbal materials, are not 438

considered to be “herbal”. 439

440

Herbal dosage forms 441 Herbal dosage forms are herbal products in the forms in which they are marketed for use or 442

taken by the patient. They are produced either from herbal materials (such as dried roots or 443

leaves) or herbal preparations (such as freeze-dried extracts). The herbal dosage forms may 444

contain substances originated from a single herb or a combination of herbs. 445

446

Medicinal plants are plants (wild or cultivated) used for medicinal purposes [WHO, 2003a]; 447

[WHO, 2007a]. 448

449

Medicinal plant materials: see Herbal materials 450



13

451

1.4.2 Terms related to herbal processing practices 452 453

Processing 454 The processing of herbal materials refers to a series of post-harvest treatments applied to the 455

crude medicinal plant materials. For the purpose of the present guidelines, “processing” 456

includes primary processing, such as sorting, removal of untargeted plant materials, cleaning, 457

and drying as described in the WHO guidelines on GACP for medicinal plants [WHO, 2003a]; 458

it also includes secondary and special processing as defined in the present guidelines. 459

460

Primary processing 461 Primary processing refers to a series of simple preparatory procedures that may be performed 462

at the harvest/collection site, including sorting, removal of untargeted plant materials, 463

cleaning, drying, and where appropriate, cooling and freezing. 464

465

Secondary processing 466 Secondary processing refers to the preparative steps applied to herbs in addition to the 467

primary processing before they can be used as materials for therapeutic treatment or as 468

intermediate materials for manufacturing of finished herbal products. They are considered 469

important pharmaceutical techniques in the herbal industry, through which purity of raw herbs 470

is assured (such as removal of foreign matter, prevention of microbial and insect 471

infection/infestation), and the therapeutic properties of raw herbs are altered (such as 472

enhancement of effectiveness or reduction of toxicity). The secondary processing procedures 473

may vary from one herbal material to another, depending on the characteristics of the active 474

ingredients as well as the therapeutic purposes. These processes, along with below described 475

“Special Processing”, have been grouped under the term “specific processing” in the WHO 476

guidelines on GACP for medicinal plants [WHO, 2003a]. 477

478

Special processing 479 Special processing is an extension of the secondary processing by further treatments using a 480

series of well-defined special procedures after the general secondary processing, for the 481

purpose of further detoxification of some toxic herbs (e.g. aconite) or further enhancement of 482

the therapeutic properties (e.g. ginseng). It is often practiced by the herbal industry according 483

to traditional medicine knowledge and customs. 484

485

Adjuvants 486 Adjuvants are adjunctive substances used during the herbal processing procedures alongside 487

the herbal materials, included for the purpose of altering the pharmacological/therapeutic 488

properties of the herbal preparations or neutralizing/reducing toxicity. Common adjuvants 489

include wine, vinegar, honey, milk, and clarified butter, among other materials. 490

491

1.4.3 Terms relating to quality control 492

493 For a comprehensive list of terms on quality control of herbal medicines, please refer to the 494

WHO guidelines on GMP for herbal medicines [WHO, 2007a], Good Manufacturing 495

Practices for pharmaceutical products: main principles [WHO, 2014]; Quality control 496



14

methods for herbal materials [WHO, 2011], and WHO guidelines for selection of substances 497

of herbal origin for quality control of herbal medicines [WHO, 2017]. The following terms 498

are more directly or indirectly applicable to the present guidelines than others. 499

500

Batch (or lot) [WHO, 2007a – WHO, 2003b]; [WHO, 2014] 501

A defined quantity of starting material, packaging material or product processed in a single 502

process or series of processes so that it is expected to be homogeneous. It may sometimes be 503

necessary to divide a batch into a number of sub-batches which are later brought together to 504

form a final homogeneous batch. In the case of terminal sterilization the batch size is 505

determined by the capacity of the autoclave. In continuous manufacture the batch must 506

correspond to a defined fraction of the production, characterized by its intended homogeneity. 507

The batch size can be defined either as a fixed quantity or as the amount produced in a fixed 508

time interval. 509

510

Batch number (or lot number) [WHO, 2007a – WHO, 2003b]; [WHO, 2014] 511

A distinctive combination of numbers and/or letters which uniquely identifies a batch on the 512

labels, its batch records and corresponding certificates of analysis, etc. 513

514

Contamination [WHO, 2007a – WHO, 2003b]; [WHO, 2014] 515

The undesired introduction of impurities of a chemical or microbiological nature, or of 516

foreign matter, into or on to a starting material or intermediate during production, sampling, 517

packaging or repackaging, storage or transport. 518

519

Cross-contamination [WHO, 2007a- WHO, 2003b]; [WHO, 2014] 520

Contamination of a starting material, intermediate product or finished product with another 521

starting material or product during production. 522

523

Good manufacturing practice (GMP) [WHO, 2014] 524

GMP is that part of quality management which ensures that products are consistently 525

produced and controlled according to the quality standards appropriate to their intended use 526

and as required by the marketing authorization, clinical trial authorization or product 527

specification. GMP is concerned with both production and quality control. GMP is aimed 528

primarily at managing and minimizing the risks inherent in pharmaceutical manufacture to 529

ensure the quality, safety and efficacy of products. 530

531

In-process control [WHO, 2007a – WHO, 2003b]; [WHO, 2014] 532

Checks performed during production in order to monitor and, if necessary, to adjust the 533

process to ensure that the product conforms to its specifications. The control of the 534

environment or equipment may also be regarded as a part of in-process control. 535

536

Master formula [WHO, 2007a – WHO, 2003b];[WHO, 2014] 537

A document or set of documents specifying the starting materials with their quantities and the 538

packaging materials, together with a description of the procedures and precautions required to 539

produce a specified quantity of a finished product as well as the processing instructions, 540

including the in-process controls. 541

542



15

Chemical reference substance (or standard) [WHO, 2007c] 543

An authenticated, uniform material that is intended for use in specified chemical and physical 544

tests, in which its properties are compared with those of the product under examination, and 545

which possesses a degree of purity adequate for its intended use. 546

547

Specification [WHO, 2007a – WHO, 2003b]; [WHO, 2014] 548

A list of defined requirements with which the products or materials used or obtained during 549

manufacture have to conform. They serve as a basis for quality evaluation. 550

551

Standard operating procedure (SOP) [WHO, 2007a – WHO, 2003b]; [WHO, 2014] 552

An authorized written procedure giving instructions for performing operations not necessarily 553

specific to a given product or material (e.g. equipment operation, maintenance and cleaning; 554

validation; cleaning of premises and environmental control; sampling and inspection). 555

Certain SOPs may be used to supplement product-specific master and batch production 556

documentation. 557

558

2. GOOD HERBAL PROCESSING PRACTICES FOR THE PRODUCTION OF 559

HERBAL MATERIALS 560

561

2.1 General information 562

563 Processing for the preparation of herbal materials from medicinal plants is often specific to 564

the medicinal plant and to the part and may involve unique procedures. The particular 565

processing methods may have a history as old as the use of medicinal plants, and they are 566

sometimes proprietary procedures. Many of the traditional processing procedures are subject 567

to standardization in modern settings. 568

569

When the medicinal plant and its parts are obtained through wild collection or cultivation 570

under GACP for medicinal plants [WHO, 2003a], they must be subjected to a series of good 571

practice of post-harvest processing procedures. The exact processing procedures may vary 572

from one herbal material to another. Some consist of only a few simple steps such as sorting, 573

cleaning and drying, and they are generally referred to as the “primary processing”. Others 574

may require some more complicated steps such as cutting, sectioning, comminuting, 575

aging/sweating, baking/roasting, boiling/steaming, and stir-frying, for the purpose of 576

improving the purity, preventing damage from mould and other microorganisms, detoxifying 577

intrinsic toxic ingredients, or enhancing therapeutic efficacy. Such processing procedures are 578

referred to as the “secondary processing” in these guidelines. They may have a significant 579

impact on the quality of the resulting herbal preparations. 580

581

Special processing is an extension of the secondary processing by further treatments using a 582

series of well-defined special treatment procedures applied to the herbs for specific purposes 583

such as reduction of toxicity or alteration/modification of therapeutic properties. Examples of 584

herbs (medicinal plants) using special processing include Aconitum, nux-vomica and Panax 585

species. 586

587 The safety and efficacy of herbal medicines are closely dependent on the quality of the 588



16

starting and processed source materials. To assure their quality, the good practices for 589

processing herbal materials may be considered. In general, good practices for processing 590

herbal materials mirror the good manufacturing practices for herbal medicine as delineated in 591

the WHO guidelines on GMP for herbal medicines [WHO, 2007a], with the first step being 592

the post-harvest handling and preparation of the starting medicinal plant materials under 593

sanitary conditions. All critical equipment for processing must be qualified; all processing 594

methods and procedures are standardized (SOP); master formulae, master and batch records 595

documented; and quality control parameters established and adhered to. GHPP 596

monograph/SOP protocol on specific herbal material should be developed and implemented. 597

598

2.2 Purposes and functions of processing 599

600 Through experiences gained over the centuries, knowledge has been acquired for the 601

development of processing procedures for maximizing the quality and therapeutic value of 602

herbal materials. The final form of a herbal medicine depends upon the nature of the herb and 603

its intended use. In general, the traditional processing of herbal materials serves several 604

purposes, such as concentrating the components, removing undesirable substances, modifying 605

the therapeutic properties, facilitating dispensing and compounding, and facilitating storage. 606

Thus, the major objectives for the processing of herbal materials are summarized as below. 607

608

Neutralization of toxicity and diminishing side effects 609

Herbal materials that possess significant levels of toxicity, highly potent pharmacological 610

activity or being known to cause severe side effects must be pre-treated in certain specific 611

manners in order to neutralize the toxicity or to reduce the side effects prior to use. Such a 612

detoxifying process is particularly important for those medicinal plants that are known to 613

contain toxic or undesirable chemical components; they must be properly processed to 614

remove those unwanted substances. Through the pre-treatment processes such as “steaming” 615

and “frying”, the heat-sensitive toxic components will be degraded. In other cases, processes 616

such as “sweating” and “aging” would result in enzymatic degradation of the toxic 617

ingredients. For example, raw aconite (Aconitum species) root, containing significant 618

amounts of toxic alkaloids such as aconitine, must be boiled or steamed for hours to hydrolyse 619

aconitine into less toxic derivatives. In the case of cascara (Frangula purshiana, synonym 620

Rhamnus purshiana) bark, they have to be aged for at least one year before use, to allow 621

oxidation to occur, by which the strongly laxative hydroxyanthracene glycosides are 622

converted to oxidized compounds of lower laxative potencies. 623

624

Modification of therapeutic properties 625

Some herbal materials require specific processing to alter their therapeutic properties. For 626

example, rhubarb (Rheum palmatum) in its raw form possesses purgative action and is useful 627

as a cathartic. After being steamed with wine, however, the purgative action is attenuated and 628

the processed rhubarb can be used for other purposes such as reducing inflammation. 629

630

The specific action of some herbal materials may be changed through processing. For 631

example, the unprocessed raw rehmannia (Rehmannia glutinosa) root is used to treat fever, 632

hypertension and skin eruptions; whereas after being cooked in wine, the processed 633



17

rehmannia is often used for tonic and anti-aging purposes in some traditional medicine 634

context. 635

636

In the case of ginseng (Panax ginseng) roots, different post-harvest processing procedures 637

give rise to several processed products, such as "white ginseng" and "red ginseng". "White 638

ginseng" is the material dried by the sun or heat, whereas “red ginseng” is prepared through a 639

series of steaming and cooking steps. These two types of ginseng products have found 640

different uses in some traditional medicine context, the former can nourish the Yin function 641

while the latter supports Yang. 642

643

Enhancing efficacy and reinforcing therapeutic effects 644

The therapeutic efficacy of certain herbal materials can be augmented through specific 645

methods of preparation. For instance, the pain-relieving property of corydalis (Corydalis 646

yanhusuo) rhizomes is believed to increase when they are stir-fried with rice vinegar. 647

Similarly the honey-treated ephedra (Ephedra species) is regarded to possess stronger 648

antitussive and anti-asthma properties than the unprocessed ephedra, which is mostly used as 649

a diaphoretic. 650

651

2.3 Processing techniques and procedures 652

653 Appropriate measures of general processing are dependent on the individual materials. These 654

processes should be carried out in conformity with state/provincial, national and/or regional 655

quality standards, regulations and norms. These protocols should also comply with the 656

regulatory requirements that apply in the producer and the purchaser countries. The SOP of 657

processing should describe in detail the various operations to be performed on the medicinal 658

plant material, such as sorting, washing, drying, crushing, milling, pulverization and sifting. 659

They should also include the length of time and temperature, among others. As much as 660

possible, the SOP should be followed. If modifications are made, they should be justified by 661

adequate test data demonstrating that the quality of the herbal materials is enhanced and/or 662

not compromised. 663

664

2.3.1 Preparation of harvested/collected medicinal plant part for processing 665

666 Harvested or collected raw medicinal plant materials should be promptly unpacked upon 667

arrival at the processing facility. Prior to processing, they should be protected from rain, 668

excessive sunlight, moisture and any other conditions that might cause microbial growth, 669

mould, aflatoxin formation, fermentation and thermal degradation. The unprocessed raw 670

medicinal plant materials should be stored in appropriate containers under adequate and 671

ventilated environmental conditions (special conditions of humidity and temperature may be 672

required and monitored); as well as protected from insects, rodents, birds, livestock, domestic 673

animals, and other pests. 674

675

Consistent quality for the finished herbal products can only be assured if the starting raw 676

medicinal plant materials are defined in a rigorous and detailed manner. For this reason, the 677

crude/raw medicinal plant materials must be adequately documented prior to the secondary 678

processing procedures to include, as far as possible, the following information; 679



18

680

Botanical name (Binomial), synonyms, and applicable variety, local name; plant part(s) of 681

the medicinal plant; 682

Source (cultivation/wild growing region); 683

Accession number/information; 684

Name and affiliation of collector or supplier; 685

Batch (or lot) number and size; 686

Collection (harvest) conditions (e.g. season/month and date; plant part; wet/dry 687

environment); 688

State of the plant material (e.g. fresh or dried); 689

Botanical authentication of the source medicinal plant materials; 690

Physical appearance such as colour, odour, form, shape, size and texture; 691

Suitable identification tests such as thin-layer chromatography (TLC) or other 692

chromatographic fingerprints; 693

Assay results, where appropriate, of active ingredient(s) or chemical reference standard(s); 694

Limit tests such as ash value, water content, and extractives; and 695

Determination of possible contaminants such as pesticides and heavy metals, mycotoxins, 696

microbiological load, and where appropriate, fumigation sulphur residue, and radioactivity. 697

698

2.3.2 Primary processing procedures 699

700 Harvested/collected medicinal plants and/or their parts undergo a series of post-harvest (and 701

post-collection) good practice of processing procedures, which in the broadest sense include 702

all steps from the immediate on-site primary clean-up of the desired medicinal plant part to its 703

being processed into a form (herbal materials) ready for therapeutic use or as a starting source 704

material for the production of a finished herbal products. While the exact processing methods 705

may differ from one herbal material to another, the procedures shall be adopted from those 706

good practice protocols specified in the national pharmacopoeia or recommended by other 707

authoritative documents of the end-user’s country. In the event that no acceptable good 708

processing procedures are available, or that modification of existing or reference cited 709

protocols are required, they should be justified by adequate quality control test data that the 710

quality of the herbal material is not diminished. In the absence of national/regional 711

procedures or protocols, international guidelines, such as WHO guidelines on GACP for 712

medicinal plants [WHO, 2003a], and the present guidelines, may be consulted. 713

714

2.3.2.1 Sorting (Garbling) 715

The sorting process serves as the first step to ensure the purity and cleanness of the medicinal 716

plant materials. After the bulk amount of the desired plant part is harvested or collected, all 717

extraneous and unwanted matters including dirt (e.g. soil, dust, mud, stones), impurities (e.g. 718

insects, rotten tissues, untargeted medicinal plants and/or plant parts), and residual non-719

medicinal parts must be separated from the medicinal part(s). The process may involve, 720

depending on the plant material, procedures such as removing dirt and foreign substances, 721

discarding damaged parts, peeling (to separate unwanted plant parts from the medicinal plant 722

parts such as removing unwanted root bark from the roots or collecting stem bark from the 723

stem), sieving, trimming, singeing (to remove hairs or rootlets), removal of residuals of 724

unwanted plant parts (e.g. removing unwanted seeds from fruits and stripping leaves from 725



19

stems). Although sorting may be done by mechanical means in some cases, it is usually 726

performed by hand operation. Only suitably trained and equipped (e.g. gloves, dust mask, etc. 727

as appropriate) staff should carry out this work. 728

729

2.3.2.2 Washing 730

Raw medicinal plant materials, especially roots, rhizomes and tubers, are usually washed with 731

clean water, dried soon after harvest/collection. During the washing process, scraping and 732

brushing may be necessary. It is generally recommended not to soak the medicinal plant 733

materials in water for an unnecessarily long period of time. Change water frequently as 734

required. 735

736

2.3.2.3 Parboiling (Blanching) 737

After washing, certain raw medicinal plant materials may undergo a parboiling or blanching 738

process in which they are put into boiling water for a brief period of time without being fully 739

cooked. Such a heating procedure may serve several purposes, such as improving storage life 740

of the processed materials by gelatinizing the starch and preventing mould/insect 741

contamination, and facilitating further processing such as removal of the seed coat of 742

almonds. 743

744

2.3.2.4 Leaching 745

Some impurities can be removed by the action of running water over the raw medicinal plant 746

materials. The length of leaching has to be controlled in order to prevent excessive loss of 747

other ingredients. 748

749

2.3.2.5 Drying 750

Unless used in the fresh state, the raw medicinal plant materials are to be dried after being 751

sorted and washed. In general, they must be dried as soon as possible in order to reduce 752

damage from mould and other microbial infestation. Drying will also avoid tissue 753

deterioration and phytochemical alteration caused by the actions of enzymes and microbial 754

organisms; and will also facilitate grinding and milling, and convert the herbal materials into a 755

convenient form for further processing. 756

757

The final moisture content for dried herbal materials varies depending on the tissue structure, 758

but should generally be below 10-12%. Information on the appropriate moisture content for 759

particular herbal material may be available from pharmacopoeias or other authoritative 760

monographs. 761

762

Proper drying involves three major aspects: control of temperature, humidity and air flow. 763

The drying conditions are determined by the nature of the raw medicinal plant material to be 764

dried (tissue structure and chemical composition) and by the desired appearance of the final 765

form. The drying method used may have considerable impact on the quality of the resulting 766

herbal materials. Hence, the choice of proper operational procedure is crucial. Information 767

on the appropriate drying methods and procedures for particular herbal materials may be 768

available from pharmacopoeias or other authoritative monographs. In general, raw medicinal 769

plant materials are most often dried by sun-drying, shade-drying, or by artificial heat. 770

771



20

The drying conditions chosen should be appropriate to the type of the medicinal plant 772

material. They are dependent on the characteristic (e.g. volatility, stability) of the ingredients 773

and the texture of the plant part collected (e.g. root, leaf or flower). In general, the following 774

drying processes can be adapted. 775

776

Sun-drying 777

Some medicinal plant materials can be dried in the open air under direct sunlight, provided 778

the climate is suitable for such a practice. The duration of the drying process depends largely 779

on the physical state of the medicinal plant material and the weather conditions. 780

781

In the case of natural drying in the open air, medicinal plant materials should be spread out in 782

thin layers on drying frames and kept away from possible contaminations such as vehicle 783

exhaust, heavy dusts, and rain, as well as protected from insects, rodents, birds and other 784

pests, livestock and domestic animals. The material should be turned periodically to achieve 785

uniform drying. The drying frames should be located at least 15 cm above the ground. 786

Efforts should be made to achieve uniform drying within the shortest period of time to avoid 787

mould formation. 788

789

Shade-drying 790

Some medicinal plant materials can be dried in the shade with or without artificial air flow to 791

avoid direct exposure to strong sunlight. The drying process is slow, but it is preferred to 792

maintain (or minimize loss of) colour of leaves and flowers. Low temperatures (relative to 793

heat-drying) will also preserve most of the volatile and aromatic components by reducing 794

evaporation. 795

796

Drying by artificial heat 797

Drying by artificial heat can be more rapid than open-air drying and is often necessary on 798

rainy days or in regions where the humidity is high. Medicinal plant materials may be dried 799

by means of ovens, stoves, rack dryer, tunnel dryer, belt driers, other heating devices or with 800

open fires. The use of open fire should be avoided as much as possible, as residues of 801

combustion may introduced contamination. When open fire is used, the area must be well 802

ventilated. 803

804

For artificial-heat drying, the temperature, humidity and other conditions should be governed 805

by the physical nature of the drug and the physical/chemical properties of its active 806

ingredients. Over-heating may lead to an excessive loss of the volatile components and/or 807

decomposition of chemical ingredients. In general, the temperature should be kept below 808

65°C for barks and root and below 40°C for leaves, herbs and flowers. 809

810

2.3.3 Secondary processing procedures 811

812 In addition to the primary processing, the WHO guidelines on GACP for medicinal plants 813

[WHO, 2003a] also addressed, albeit very briefly, the fact that some herbal materials require 814

“specific” processing to improve their purity and quality. In the current guidelines, this term 815

is delineated into “secondary” and “special” processing. This section highlights the principles 816

and practice of the commonly used secondary processing techniques. In all cases, good in-817



21

process control measures must be employed to assure the quality of the end product. National 818

and/or regional botanical and chemical quality standards for each processed herbal material 819

must be met. In absence of national standards, regional or international pharmacopoeial 820

standards may be adopted. Guidance for compliance measures can be found in the annex to 821

the Quality control methods for herbal materials [WHO, 2011], WHO guidelines for selection 822

of substances of herbal origin for quality control of herbal medicines [WHO, 2017], WHO 823

guidelines on GMP for herbal medicines [WHO, 2007a], and the present guidelines. An 824

example of a model format of good herbal processing practices monograph/SOP protocol on 825

secondary processing is given as Annex 1. 826

827

The applicable procedures of the secondary processing nature are as follows: 828

829

2.3.3.1 Cutting, sectioning, and comminution (see also section 3.2.1.2 for Comminution 830

(fragmentation)/grinding/milling) 831

832

When thoroughly dried, the herbal materials are processed by cutting and sectioning into 833

convenient or specific sizes and shapes or forms for storage or direct use as decoction 834

slices/pieces, and/or further processing for the manufacture of herbal preparations or finished 835

herbal products. Decoction slices or pieces are available in many Member States for direct 836

use as herbal medicines. Where applicable, the entire, sectioned or cut herbal materials are 837

comminuted/pulverized into powder form according to common practice found in herbal 838

medicines for use as a finished herbal products. 839

840

White and/or red ginseng products presented as root pieces, slices, or in powder form 841

prepared from naturally dried roots of Panax ginseng, marketed as herbal medicines, are good 842

examples of herbal materials derived from simple processing procedures. 843

844

2.3.3.2 Aging/Sweating 845

The aging (or wilting) process refers to storing the herbal materials for a period of time after 846

being harvested or collected from the field prior to use. It is generally done under the sun or 847

in the shade for up to a year, depending on the specific herbal material. During the process of 848

aging, excessive water is evaporated and enzymatic reactions (such as hydrolysis of the 849

glycone portion from glycosides) may occur to alter the chemical composition of the herbal 850

material. For example, cascara (Frangula purshiana, synonym Rhamnus purshiana) bark 851

should be aged for at least one year (or artificially heated to speed up the process) prior to use 852

in medicinal preparations, for the purpose of curtailing the strong irritating effects that may 853

cause vomiting and upset stomach. 854

855

A similar process known as sweating involves keeping the herbal materials at a temperature 856

of 45-65 °C with high humidity for an extended period of time, from one week to a couple of 857

months, depending on the plant species. The herbal materials are usually densely stacked 858

between woollen blankets or other kinds of cloth. The sweating process is considered a 859

hydrolytic and oxidative process in which some of the chemical ingredients within the herbal 860

materials are hydrolysed and/or oxidized. 861

862

For example, vanilla beans (Vanilla planifolia) are well known to undergo repeated sweating 863



22

between woollen blankets in the sun during the day and packing in wool-covered boxes at 864

night for about two months, during which the vanilla pods lose up to 80% of weight and take 865

on the characteristic colour and odour of the commercial drug. 866

867

2.3.3.3 Baking/Roasting 868

The baking/roasting process is a dry-heating using indirect, diffused heat, where the herbal 869

materials are put in a heating device, often embedded in bran or magnesium silicate (talc) 870

powder to ensure even heating on the entire surface at an elevated temperature for a specified 871

period of time. Some herbal materials are wrapped in moistened papers during the roasting 872

process. The exact temperature used and duration of baking/roasting vary from one herbal 873

material to another. Some are baked or roasted until the surface colour turns yellowish 874

brown; some may be further heated until charred. 875

876

For example, the processing procedure of nutmeg (Myristica fragrans) and kudzu (Pueraria 877

montana var. lobata) root requires being roasted with bran. 878

879

2.3.3.4 Boiling/Steaming 880

The boiling process involves cooking the raw medicinal plant materials in water or another 881

liquid solvent such as vinegar, wine, milk or other vehicles. 882

883

In the steaming process, raw medicinal plant materials and/or herbal materials are kept 884

separate from the boiling water but have direct contact with the steam, resulting in a moist 885

texture to the herbal materials. Such treatment is often done by placing the herbal materials in 886

a steamer or in a special utensil equipped with a flat frame hanging over boiling water. In 887

some cases, the herbal materials are pre-mixed with excipient substances such as wine, brine, 888

or vinegar before being steamed. The boiling/steaming process serves to soften plant tissues, 889

to denature enzymes present in the herbal materials, and/or to thermally degrade selected 890

chemical constituents. At the same time, the excipient, if used, is absorbed into the plant 891

tissues to become an integral part of the processed herbal materials. 892

893

For example, Reynoutria multiflora (synonym Polygonum multiflorum) root is often steamed 894

in the presence of a black-bean decoction in order to enhance its tonic effects. Boiling the 895

raw medicinal plan materials such as Croton tiglium, Abrus precatorius, Nerium oleander 896

(synonym N. indicum), and Gloriosa superba, in cow’s milk is practiced in some traditional 897

medicine context to reduce the levels of their toxic ingredients and thus diminish the toxicity 898

of the herbal materials. 899

900

2.3.3.5 Stir-frying 901

Stir-frying is a process in which the herbal materials are put in a pot or frying pan, 902

continuously stirred or tossed for a period of time under heating, until the external colour 903

changes, charred, or even carbonized. Depending on the medicinal plant species, the stir-904

drying process may require the addition of adjuvants such as wine, vinegar, honey, saline, and 905

ginger juice, which would be infused into the herbal matrix to become an integral part of the 906

processed herbal material. 907

908

To ensure even heating on the surface of the herbal materials, sand, rice, bran, talc or clay can 909



23

be admixed with the herbal material during stir-frying. 910

911

For example, liquorice (Glycyrrhiza glabra) root and rhizome and Astragalus mongholicus 912

(synonym A. membranaceus) roots are often stir-fried with honey for the preparation of 913

decoction slices, whereas the Salvia miltiorrhiza root is stir-fried with wine. In the case of 914

ginger, fresh ginger is often stir-fried together with sand until the surface colour turns brown. 915

In other instances, ginger can be further stir-fried over intense fire to a carbonized state for 916

use as decoction pieces. 917

918

2.3.3.6 Fumigation 919

Fumigation by sulphur dioxide has been employed in post-harvest handling of some 920

medicinal herbs for the purpose of preserving colour, improving fresh-looking appearance, 921

bleaching, preventing the growth of insect and overcoming decays caused by moulds. Thus 922

the process has been frequently applied to herbal materials of light and bright colours to avoid 923

“browning”. Due to concerns about the undesirable residues, this process should be avoided 924

as much as possible. When a real need is identified, treatment should be carried out at the 925

earliest possible stage and exclusively by adequately trained and qualified personnel, 926

according to the specific recommendations for use. All relevant regulations (e.g. limits on 927

sulphur residue) should be complied with. 928

929

2.3.3.7 Irradiation 930

In some cases, infrared or ultraviolet lights can be used to eliminate or reduce microbial load 931

of the medicinal plant materials. The use of these procedures has to comply with the national 932

and/or regional regulations. 933

934

2.3.3.8 Selection of processing method 935

Herbal materials derived from the same species but processed by different methods may show 936

significant differences in quality and therapeutic properties, owing to the influence of the 937

treatment process on the chemical composition. 938

939

It is not uncommon to find different processing methods for the same medicinal plant/plant 940

part, depending on intended use. For example, raw (unprocessed) liquorice is used as an 941

antitussive and expectorant; but after being stir-fried with honey or ghee, the processed 942

liquorice becomes a tonic drug to be used for replenishing body strength. 943

944

Prior to processing, consult the national or regional regulatory standards and other literature 945

sources to decide on the most appropriate method to use. Once a method is adopted, adhere to 946

the SOP to ensure batch-to-batch consistency. For industrial production, method validation 947

should be adopted as part of the SOP. 948

949

Only suitably trained staff should carry out the work, which should be conducted in 950

accordance with the SOP and national and/or regional regulations in both the 951

grower/collector, manufacturer and the end-user countries. 952

953

2.3.3.9 Temperature 954



24

With in-processing procedures that involve heating, the temperature used is critical. Ensure 955

that the required temperature is achieved during the process. In some cases, pre-heating the 956

equipment (e.g. oven, frying pan and steamer) and/or the additives (such as sand, bran and 957

rice) is required before putting in the herbal materials. When heating equipment (e.g. electric 958

oven) is used, the heating device should be regularly calibrated. 959

960

2.3.3.10 Duration of procedure/treatment 961

It is also critical to control the duration of the procedure/treatment of the herbal materials. 962

Both over- and under- treatment will affect the quality of the resulting materials. Duration of 963

procedure/treatment should be monitored through adequate in-process controls performed on 964

the basis of organoleptic alterations (such as changes in colour, odour, and texture) or changes 965

in the contents of constituents with appropriate instruments or testing. 966

967

2.3.3.11 Use of adjuvants 968

Any adjuvant (e.g. wine, vinegar, salt, ginger juice and honey) used in the processing 969

procedures should be of the required/appropriate quality. The quality of adjuvants must be 970

clearly defined and controlled (according to pharmacopoeial requirements and/or relevant 971

regulatory requirements). The exact amounts and quality of these adjuvants used (the ratio of 972

herbal material and the adjuvant) should also be consistent from batch to batch. 973

974

2.3.4 Special processing procedures 975

976 For herbal materials derived from toxic medicinal plants, general primary and/or secondary 977

processing might be insufficient to reduce or attenuate their adverse effects. Such herbal 978

materials require further special processing procedures before they can be used for therapeutic 979

purpose. These special processing procedures serve as a means to detoxify or neutralize the 980

toxicity, or to reduce the side effects. Such processes are particularly important for those 981

medicinal plant parts that are known to contain toxic or undesirable chemical components; 982

they must undergo proper processes in order to have the unwanted substances degraded. On 983

the other hand, a number of herbal materials require special methods of processing in order to 984

enhance their therapeutic efficacy or to modify their therapeutic properties for the treatment of 985

other disease conditions. The following are examples of special herbal material processing 986

used in some traditional medicine context. 987

988

2.3.4.1 Detoxification 989

Aconite (Aconitum species) root is a highly toxic substance and should not be taken in the 990

crude form. Only after proper processing procedures can the toxicity of aconite root be 991

reduced so that it becomes suitable for use in herbal medicine by trained practitioners. The 992

specific process generally involves boiling in water or steaming, or both, to significantly 993

reduce the content of aconitine and related alkaloids. 994

Nux-vomica (Strychnos nux-vomica) seeds are specifically processed by frying in 995

ghee/clarified butter or boiling in water or other media such as cow’s milk to reduce the 996

content of their toxic ingredients, strychnine and brucine. 997

Pinellia ternata tuber: To reduce the gastrointestinal irritant property, the raw herb is 998

soaked in a solution containing glycyrrhiza and calcium oxide at a pH ≥ 12. Another way 999

of reducing the irritant property is soaking in water together with potassium aluminum 1000



25

sulphate, or boiled in water together with ginger and potassium aluminum sulphate. 1001

Arisaema erubescens rhizome: The raw medicinal plant material is first soaked in water 1002

together with potassium aluminum sulphate for several days, followed by cooking with 1003

ginger and potassium aluminum sulphate to reduce the strong irritant effect on the 1004

respiratory and gastrointestinal tracts. An alternate method for processing Arisaema 1005

rhizome is by steaming with animal bile. 1006

Euphorbia kansui and E. pekinensis herb: Processing by frying with vinegar is needed to 1007

degrade the toxic components that cause severe vomiting and diarrhoea, and central 1008

nervous system poisoning. 1009

Seeds of Xanthium strumarium (synonym X. sibiricum), Ricinus communis and Croton 1010

tiglium are often processed by stir-frying for the purpose of degrading their contained toxic 1011

proteins. 1012

Cascara sagrada (Frangula purshiana, synonym Rhamnus purshiana) bark: Following 1013

primary post-harvest processing, the bark is aged (stored) for at least one year prior to use 1014

as a laxative. During the aging period, natural enzymatic action reduces the drastic 1015

cathartic potency of its active glycoside constituents to a non-toxic level. 1016

1017

2.3.4.2 Modification of therapeutic properties 1018

Ginseng (Panax ginseng and Panax quinquefolius): Fresh ginseng is converted to red 1019

ginseng through a series of repeated steaming procedures to afford a product with altered 1020

medicinal properties. 1021

Corydalis yanhusuo rhizomes are stir-fried or cooked with rice vinegar to enhance their 1022

analgesic property. 1023

Rehmannia glutinosa root: The unprocessed herbal material is used to treat fever, 1024

hypertension and skin eruptions; whereas after being cooked in wine, the processed 1025

rehmannia is used as a tonic and anti-aging drug in some traditional medicine context. 1026

1027

2.3.4.3 Use of adjuvants 1028

Common adjuvants used during the special processing procedures include wine (e.g. rice 1029

wine, wheat wine, and sorghum wine), vinegar, honey, ginger juice, liquorice extract, cow 1030

milk, ghee and brine, etc. Under special circumstances, other auxiliaries such as, other animal 1031

derived materials including their tissues and secretions (e.g. goat milk, animal bile, goat fat, 1032

cow’s urine), butter, black bean extract, coconut water, tamarind juice, turmeric, lemon juice 1033

and mineral materials (e.g. borax) have been used. The quality of adjuvants must be clearly 1034

defined and controlled (according to pharmacopoeial requirements and/or relevant regulatory 1035

requirements). 1036

1037

In addition, the use of any materials derived from animal/animal products in any processing 1038

procedures should be evaluated for safety and contamination, especially of pathogens, prior to 1039

use. General guidance could be found e.g. in Safety issues in the preparation of homeopathic 1040

medicines [WHO, 2010]. 1041

1042

2.3.5 Documentation 1043

1044 All processing procedures that could affect quality and safety of herbal materials should be 1045

documented. Guidance for good documentation can be found in the Good Manufacturing 1046



26

Practices for Pharmaceutical Products: main principle [WHO, 2007a -WHO, 2003b]; 1047

[WHO, 2014], as well as WHO guidelines on good agricultural and collection practices for 1048

medicinal plants [WHO, 2003a]. Thus it is important to establish a record keeping system so 1049

that all records are up-to-date, maintained and traceable for the entire processing procedures 1050

for each batch of herbal materials. 1051

1052 Written processing records should include, but not be limited to, the following information; 1053

1054

Botanical (scientific) and the local/common names of the source medicinal plant material; 1055

and plant part(s) being processed; 1056

Site and time of harvesting/collection; 1057

Batch number and any other identification code; 1058

State of the plant (e.g. fresh or dried); 1059

Dates of receipt of the material, processing of the material, and completion of the process; 1060

Name of person in charge of the processing; 1061

General processes that the plant material has already undergone (drying, washing, cutting, 1062

for example., including drying time and temperatures, and size of herbal material); 1063

Gross weight of the plant material before and after processing; 1064

Method used for special processing; 1065

Details of the procedures (master formula), including descriptions of the utensil and 1066

equipment used, steps of operation, amount and quality grade of the auxiliary (e.g. wine, 1067

vinegar) and/or other substances (e.g. sand, bran) used, temperature control, length of 1068

processing time, after-process steps (e.g. cooling, drying, cutting), and other relevant 1069

information; 1070

Batch production detail deviations/modifications of the master formula; 1071

In-process control, e.g. organoleptic changes of the plant material after processing (such as 1072

change in colour, shape, texture, odour and taste); 1073

Quality control parameters, specifications, and assay results, where appropriate, of active 1074

ingredient(s) or Chemical reference standard(s); and 1075

Shelf-life/retest period. 1076

1077


HERBAL PREPARATION 1079

1080


1082 The herbal materials described in Section 2 of these guideline may be ready to serve as the 1083

starting materials for use as herbal medicines. In some cases, they are cut into sections or 1084

ground into powder and used directly as the final dosage form. But in many other cases, the 1085

herbal materials will undergo further treatment processes before being used to manufacture 1086

the finished herbal products. The ingredients are usually not purified and the extracts are 1087

further concentrated by the removal of inactive and/or undesirable substances. 1088

1089 Herbal preparations are thus obtained by subjecting the herbal materials to treatments such as 1090

extraction, distillation, fractionation, purification, concentration, fermentation, or other 1091

chemical/biological methods. These include extracts, decoctions, tinctures, essential oils, and 1092



27

others. 1093

1094

3.1.1 Preparation of herbal materials for processing 1095 1096

Authentication of herbal materials should be performed prior to extraction. Purity (devoid 1097

of contaminants) should also be ensured. 1098

Proper documentation on the herbal material should be available as recommended in 1099

Section 2.3.5. 1100

The herbal material should be cleaned, dried (unless fresh material is required), and 1101

comminuted into an optimal size for extraction. 1102

The herbal materials should be processed as soon as possible after arrival at the processing 1103

facility. Otherwise they must be properly stored to avoid contamination, damage, and 1104

deterioration. 1105

All operational steps should be reproducible and performed hygienically, forming parts of 1106

the processing SOP. 1107

1108


1110 In general, for processes such as extraction, fractionation, purification and fermentation, the 1111

rationale for the guidelines should be established on a case-by-case basis. An example of a 1112

model format of good herbal processing practice monograph/SOP protocol to produce a 1113

herbal preparation is given as Annex 2. The general guidance is provided below. 1114

1115

3.2.1 Extraction 1116 1117

Extraction is a process in which soluble plant chemical constituents (including those which 1118

have therapeutic activity) are separated from insoluble plant metabolites and cellular matrix, 1119

by the use of selective solvent (which is sometimes called the menstruum). The purpose of 1120

extraction of medicinal plant matrix is to eliminate unwanted materials and to concentrate 1121

other constituents in a soluble form. Herbal extracts include decoctions, liquid extracts, soft 1122

extract, fluidextracts, tinctures, oleoresins, dry extracts, and others. The herbal preparations 1123

so obtained may be ready for use as a medicinal agent, or it may be further processed into 1124

finished herbal products such as tablets and capsules. 1125

1126

Various techniques are used for extraction, including maceration, infusion, digestion, 1127

percolation, and decoction. Modern separation techniques can also be applied, e.g. counter-1128

current extraction, microwave-assisted extraction, ultrasonic extraction (sonication), and 1129

supercritical fluid extraction. 1130

1131

3.2.1.1 Common methods of extraction 1132

In order to produce herbal preparations of defined quality, the use of appropriate extraction 1133

technology, extraction solvents, and type of equipment are crucial. Some common methods 1134

of extraction are illustrated below. 1135

1136

Maceration 1137



28

Maceration involves the procedures of mixing the properly comminuted herbal materials with 1138

the solvent and allowing the mixture to stand at a certain temperature (in most cases at room 1139

temperature) for a defined period of time with frequent agitation. During the maceration 1140

process, chemical constituents are separated from the plant tissues through a dissolution 1141

process into the liquid solvent. A common practice is to put the herbal material in a container 1142

and add solvent until the herbal powder is thoroughly moistened. An additional amount of 1143

solvent is then introduced. The mixture is agitated at regular intervals for a defined period of 1144

time, strained, and the marc (the solid materials) is pressed. All liquids are collected, 1145

combined, and separated by decantation, centrifugation, straining or filtration. The 1146

maceration process may be repeated if desirable. In the process of maceration, the herbal 1147

materials are macerated in definite quantities of a solvent (at an optimal ratio of the amounts 1148

of herbal material and solvent), and a definite duration should be specified. Exhaustive bulk 1149

extractions can be quite time-consuming and require large volumes of solvent. 1150

1151

In a special case, a modified maceration procedure involves pre-soaking the herbal material in 1152

water for a period of time to induce fermentation. In other cases, maceration can be 1153

performed by gentle heating in order to enhance the extraction efficiency in a process known 1154

as “digestion”. 1155

1156

“Sonication-assisted extraction” and “microwave-assisted extraction” are modified methods 1157

of maceration, in which ultrasound or microwave is utilized to enhance the extraction 1158

efficiency, to reduce the amount of solvent used, and to shorten the extraction time. For 1159

sonication, the herbal material is placed in a container together with a solvent, which is in turn 1160

put in an ultrasonic bath. The ultrasound provides sufficient power to breakdown the cell 1161

walls of the herbal material and facilitates the solubilization of metabolites into the solvent. 1162

The frequency of ultrasound, length of treatment, and temperature of sonication are important 1163

factors affecting the extraction yield. For microwave-assisted extraction, the herbal material 1164

is placed in a container together with water and subjected to microwave treatment. Heat 1165

generated by the microwave energy facilitates the dissolution of compounds from the herbal 1166

matrix into the solvent. Sonication-assisted and microwave-assisted extraction are rarely 1167

applied to large-scaled extraction; they are used mostly for the initial extraction of a small 1168

amount of material. 1169

1170

Infusion 1171

Infusion refers to an extraction procedure in which the herbal material is immersed in hot 1172

liquid for a brief period of time to produce a dilute liquid preparation. Typically, the herbal 1173

material is steeped in hot water and allowed to stand for some time (15-20 minutes). 1174

Sometimes another part of hot water is added and allowed to stand for additional time. The 1175

extracted plant material is removed by straining and the infusion is ready for use. Infusion is 1176

commonly employed to make herbal teas. 1177

1178

Percolation 1179

Percolation is the procedure in which the solvent is allowed to continuously flow through the 1180

herbal material in a percolator (a vessel with an outflow at the bottom ends). Typically, the 1181

properly comminuted herbal material is moistened with an appropriate amount of solvent and 1182

allowed to stand (macerate) for a few hours before being packed into the percolator. 1183



29

Additional solvent is added to totally wet the plant powder for a day or two. The bottom end 1184

(valve) of the percolator is then opened (adjusted), with fresh solvent being replenished from 1185

the top of the percolator to maintain a steady flow of solvent through the bed of herbal 1186

materials. The flow rate of the liquid is controlled by adjusting the valve of the outlet. The 1187

extraction liquid is collected from the bottom outlet of the percolator. When the process is 1188

completed, the marc is pressed and all liquids are pooled to obtain the percolate. In addition 1189

to the solvent used for the extraction, the flow rate and the temperature would influence the 1190

extraction yields and they have to be carefully controlled. Percolation is often used for an 1191

exhaustive extraction of the herbs and is applicable to both initial and large-scale extraction. 1192

In some cases, the process of percolation can be modified by applying vacuum to increase the 1193

flow of solvent. 1194

1195

Decoction 1196

Decoction is the most common method to make herbal preparations in various traditional 1197

medicine context. It involves boiling the herbal material in water, during which time the 1198

chemical ingredients are dissolved into the hot liquid. This procedure is suitable for 1199

extracting water-soluble and heat-stable ingredients of the medicinal plant and/or herbal 1200

materials. 1201

1202

A special technique of decoction is the “hot continuous (Soxhlet) extraction” using the 1203

Soxhlet apparatus. Typically, the Soxhlet instrument includes an extraction chamber with 1204

reflux condenser and a collection flask. The chamber is placed between the collection flaks 1205

and the condenser. The herbal powder or pieces are kept inside the extraction chamber. A 1206

suitable solvent is added to the flask and heated under refluxing. The solvent will first be 1207

evaporated up into the condenser, then liquefied and drops into the chamber and covers up the 1208

herbal powder. When the condensed solvent in the chamber reaches a certain height, it is 1209

siphoned back into the flask, and the next cycle of extraction starts. Usually, 50-60 times of 1210

recycling are necessary for an extraction to complete. Due to continuous extraction, this 1211

method is more efficient than simple decoction with less consumption of solvent. However, 1212

due to continuous heating at the boiling point of the solvent used, thermolabile compounds 1213

may be damaged and/or artefacts may be formed. Besides the laboratory scale setup for 1214

continuous extraction, industrial scale stainless steel extractors and high pressure extraction 1215

are commonly used in many manufacturing facilities. 1216

1217

Supercritical fluid extraction 1218

Supercritical fluid extraction is a modern technique making use of the solvating property of a 1219

supercritical fluid (carbon dioxide is the most common supercritical solvent) to dissolve the 1220

chemical constituents in herbal materials. The density of the supercritical fluid (thus its 1221

solvating property) can be adjusted by altering the temperature and pressure, or by the 1222

addition of modifiers (e.g. ethanol) to change the polarity of the supercritical fluid. 1223

1224

3.2.1.2 Steps involved in the extraction of herbs and herbal materials 1225

The following steps are generally involved in the extraction procedures. 1226

1227

Comminution (fragmentation)/grinding/milling (see also section 2.3.3.1) 1228



30

Prior to extraction, the medicinal plant part is generally dried and reduced to a size of 30-40 1229

mesh (the actual size can be adjusted as the need arises). If fresh material is used for 1230

extraction, it is necessary to perform extraction as soon as possible after the material is 1231

collected to avoid deterioration (microbial fermentation). The purpose of powdering the plant 1232

material is to rupture its tissues and cell structures so that the chemical ingredients are more 1233

readily exposed to the extraction solvent. Moreover, size reduction increases the surface area, 1234

which in turn enhances the mass transfer of chemical ingredients from plant tissue to the 1235

solvent. However, excessive grinding can degrade the herbal material through mechanical 1236

heating and oxidation from exposure to the air, and an excessively fine powder will block the 1237

pores of the extraction filter, slowing or preventing the passage of the filtrate. 1238

1239

Extraction 1240

The extraction process is carried out in the selected solvent at a desirable temperature for an 1241

optimal period of time. Depending on the polarity of the desirable chemical components, 1242

water or other solvents can be used, either at room temperature (“cold” extraction) or at an 1243

elevated temperature (“hot” extraction). 1244

1245

Filtration 1246

After the completion of extraction, the liquid so obtained is separated from the marc by 1247

filtration through a filter cloth or filter paper to remove any particulate insoluble residues. 1248

Other filtering devices/methods, including decantation, centrifugation, or straining, may be 1249

used depending on the method of extraction and matrix. 1250

1251

Concentration 1252

The extract is often concentrated by the removal of excessive solvent to a thick concentrated 1253

extract or to a solid mass. The concentration procedures may involve evaporation under 1254

reduced pressure, freeze-drying or spray-drying. 1255

1256

3.2.1.3 Common herbal preparations prepared by extraction 1257

Decoction 1258

A water-based herbal preparation made by boiling herbal materials with water, and is most 1259

common utilized in various traditional medicine context. Generally, it is recommended that 1260

only freshly prepared decoctions should be used. However, decoctions may be prepared by a 1261

programmable decocting machine that processes the herbal material at a specific temperature 1262

for a specific duration and then dispenses the decoction in hermetically sealed plastic pouches 1263

of a specified single-dosage volume that can be refrigerated for subsequent reheating and 1264

consumption. The amounts of herbal materials and water used, as well as the length of the 1265

decocting process, should be specified. 1266

1267

Infusion 1268

A dilute solution prepared by steeping the herbal materials in hot (sub-boiling) water over a 1269

short period of time. Infusions prepared in edible oil or vinegar are also available. 1270

1271

Extract 1272

A preparation of liquid, semi-solid or solid consistency obtained from herbal materials by an 1273

extraction process using suitable solvents. “Liquid (fluid) Extract” is a liquid preparation of 1274



31

herbal materials obtained using water, alcohol or other extraction solvents. When the 1275

evaporation of the solvent leads to a semi-solid extract composed of a resin in solution of an 1276

essential and/or fatty oil, it is called “Oleoresin”. In some cases, the solvent is partially 1277

evaporated to afford a semi-solid preparation called “Soft Extract”. When the solvent is 1278

completely removed, “Dry Extract” is obtained as a solid preparation. Dry extract can also be 1279

prepared by spray-drying with or without the use of an adsorbent (such as methyl cellulose), 1280

or by drying and milling to produce a powder. This may be further processed by compression 1281

or with use of a binding agent or granulation liquid to produce multi-particulate granules. 1282

1283

Fluidextract 1284

An aqueous alcoholic preparation typically made in a ratio of one part (e.g. one millilitre) of 1285

liquid to one part (one gram) of the extract of the original herbal materials. 1286

1287

Tincture 1288

An ethanol extract of herbal materials, typically made up of 1 part of herbal material and 5-10 1289

parts of solvent. Tinctures can be prepared by extracting herbal materials with ethanol of a 1290

suitable concentration or a spirit (an alcoholic beverage). The ratio of water to alcohol should 1291

be recorded. 1292

1293

Macerate 1294

A liquid preparation extemporaneously prepared by soaking the herbal material(s), reduced to 1295

a suitable size, in water at room temperature for a defined period of time, usually for 30 1296

minutes, when not otherwise specified. 1297

1298

3.2.1.4 Factors influencing extraction of herbal materials 1299

There are a number of factors that would influence the efficiency and reproducibility of the 1300

extraction process. A few issues to consider include the solvent used to make an extract, 1301

particle size of the herbal material, the herb-to-solvent ratio, kind of extraction process (e.g. 1302

percolation or maceration), extraction time, temperature and other relevant conditions. All 1303

these factors should be optimized and incorporated into the SOP, and be strictly adhered to. 1304

1305

3.2.1.5 Selection of extraction methods 1306

The choice of extraction method is governed by the nature (stability, solubility, etc.) and 1307

amount of material to be extracted. For large amounts, the feasibility of extracting in bulk 1308

scale should be considered. 1309

The extraction method should be as exhaustive as possible, i.e. removing as much of the 1310

desired ingredients as possible from the plant matrix. 1311

It should be fast, simple, economical, environment-friendly, and reproducible. 1312

1313

3.2.1.6 Extraction conditions and procedures 1314

Solvent 1315

Depending on the nature of the target compounds or undesirable compounds, an 1316

appropriate solvent (or solvent mixture) should be selected for use. While water has been, 1317

and is, most commonly used as a solvent, organic solvents of varying polarities are 1318

generally selected in modern methods of extraction to exploit the various solubilities of 1319

plant constituents. For example, an aqueous solution of alcohol (e.g. 60-80% aqueous 1320



32

ethanol) can extract the majority of organic secondary metabolites from herbal materials. 1321

Other solvents may apply for the extraction of specific types of ingredients (such as 1322

proteins and polysaccharides). 1323

When selecting a solvent or solvent mixture, the following factors should be considered: 1324

solubility of the target compounds, stability and reactivity of the solvent, safety (low 1325

toxicity, low flammability, non-corrosiveness), cost, ease of subsequent solvent removal 1326

and solvent recovery (low boiling point), and environmental friendliness. 1327

Before using a solvent, the material safety data sheet (MSDS) should be reviewed and 1328

appropriate protective measures should be used. Precautions must be taken to minimize 1329

the risk of fire and explosion. Care should be taken to reduce environmental 1330

contamination and to protect the workers and other people in the vicinity from exposure to 1331

chemical hazards. 1332

Toxic solvents and those detrimental to the environment, e.g. benzene, toluene, and carbon 1333

tetrachloride, must not be used. Diethyl ether should be avoided as it is highly flammable 1334

and can lead to the formation of explosive peroxides. The use of chlorinated solvents is 1335

discouraged; if used, dichloromethane is preferred to chloroform, the latter being more 1336

toxic. Ethanol is preferred over methanol; the latter has higher toxicity. 1337

Solvents are classified by ICH (CPMP/ICH 238/95), according to their potential risk, into: 1338

o class 1 (solvents to be avoided such as benzene); 1339

o class 2 (limited toxic potential such as methanol or hexane); and 1340

o class 3 (low toxic potential such as ethanol) [WHO, 2007b]. 1341

Solvents of general-purpose grade available in plastic containers are often contaminated by 1342

plasticizers, and minimizing contamination is especially important when bulk extraction is 1343

carried out requiring large volumes of solvent. It is advisable to distil solvents prior to use. 1344

The amounts of solvent used must be optimized to ensure batch-to-batch conformity. 1345

The quality and specification of solvent used should be specified and controlled. 1346

Solvents should be properly stored in non-plastic containers in a well ventilated, fire and 1347

explosion containable area; and away from direct exposure to sun light. 1348

When solvents are recycled, strength and purity must be confirmed prior to re-use. 1349

Recycled solvent should be used in the same extraction process only. 1350

Waste solvents must be disposed safely and properly. Guidelines from national, local, or 1351

institutional regulations of waste solvent disposal must be strictly observed and followed. 1352

Limits for solvent residue may be important to observe especially when the solvent is not 1353

considered safe for general consumption. 1354

1355

Temperature 1356

To avoid thermal degradation of the chemical constituents, extractions are preferably 1357

performed under 40 °C, unless evidence is available for the use of higher temperatures. 1358

For heat stable constituents, Soxhlet extraction or decocting in boiling water can be used. 1359

In any case, higher than required temperatures should be avoided. 1360

Temperature during the entire extraction process should be controlled and recorded. 1361

1362

Length of treatment 1363

The length of extraction time depends on the purpose for which the extraction is performed 1364

and the nature of the active constituents. Insufficient time will result in incomplete 1365



33

extraction, but prolonged extraction will lead to excessive extraction of the unwanted 1366

constituents and/or degradation of active chemical ingredients. 1367

The number of repeated extraction cycles required for the complete removal of the 1368

desirable constituents is as important as the length of time per each extraction. 1369

The length of extraction time and the number of cycles should be controlled and recorded. 1370

1371

3.2.2 Distillation 1372 1373

For the extraction of volatile components of the herbal materials, such as essential (volatile) 1374

oils, the odorous and volatile principles of plants, techniques such as distillation, expression 1375

and enfleurage may be employed. 1376

1377

Water or steam distillation is a method of choice for extracting volatile ingredients from 1378

medicinal plants. In brief, the herbal material is packed in a still, a sufficient amount of water 1379

is added and brought to a boil (water distillation). Alternatively a stream of steam is 1380

introduced to the herbal material pre-soaked in water (water-steam distillation), or a stream of 1381

steam is introduced to medicinal plant materials without water being added (direct steam 1382

distillation). The method of distillation depends on the condition of the herbal materials. 1383

Water distillation can be applied to fresh plant materials to avoid steam to penetrate into the 1384

materials such as rose flowers, while direct steam distillation is often used for fresh or dried 1385

medicinal plant materials. Freed from the plant tissue, the essential oil is carried away with 1386

the steam. Upon condensation, both water and oil are collected in the liquid form, and the 1387

latter separates from the former into two immiscible layers. 1388

1389

The yield and quality of essential oil obtained by distillation is affected by the process 1390

parameters. It is advisable to design the most optimal conditions in order to obtain the best 1391

results. Among the contributing factors are: mode of distillation, condition of raw medicinal 1392

plant materials, loading of raw medicinal plant materials, steam pressure and temperature, and 1393

length of time for distillation. 1394

1395

For volatile oils that may be decomposed during distillation, they can be obtained by 1396

expression (mechanical pressing), solvent extraction, supercritical carbon dioxide extraction, 1397

or by the enfleurage process for delicate flowers of which volatile chemicals may decompose 1398

during distillation. 1399

1400

3.2.2.1 Distillation procedures 1401

The distillation apparatus must be set up properly and safely according to the 1402

manufacturer’s instructions. 1403

Distillation should be carried out in a well ventilated room. 1404

Optimum distillation conditions, e.g. heating rate and distilling rate, have to be specified 1405

and controlled. 1406

The equipment employed should be in conformance with the official safety standards and 1407

all procedures must conform to the operational instructions and safety requirements. 1408

The water used for distillation should at least comply with local requirements for drinking 1409

water. 1410

1411



34

3.2.3 Fractionation and Purification 1412

1413 Fractionation is a separation process in which a mixture is divided into a number of smaller 1414

quantities (fractions) with higher content of target substances (compounds). The crude 1415

extracts of herbal materials contain complex mixtures of secondary metabolites with 1416

diversified chemical and physical characteristics. It is often desirable to divide the chemical 1417

constituents into different groups based on their similarities in chemical and physical 1418

properties, such as a flavonoid-rich preparation, total glycosides, or an alkaloid fraction. 1419

Fractional separation of an herbal extract can be achieved by subjecting the extract to a 1420

variety of fractionation techniques such as liquid-liquid partition and various forms of 1421

chromatography. The method can be applied to produce semi-purified preparations in order 1422

to enrich active constituents, to remove inactive and/or toxic constituents. 1423

1424

3.2.3.1 Liquid-liquid partition 1425

The liquid-liquid partition (or solvent partition) method involves the use of a series of liquid 1426

solvents. The herbal extract is usually dissolved or suspended in water and partitioned with 1427

organic solvents successively in a sequence of increasing polarities, e.g. n-hexane, 1428

dichloromethane, ethyl acetate, and water-saturated n-butanol. As a result, chemical 1429

compounds possessing different polarities are transferred from the water portion to different 1430

solvent fractions according to the principle of “like dissolves like”. For example, the initial 1431

step of partition using non-polar solvents (such as n-hexane or petroleum ethers) removes 1432

lipophilic substances (such as alkanes, fatty acids, sterols) from the herbal mixture, and such a 1433

process is sometimes referred to as “defatting”. The compounds with intermediate polarity 1434

(such as flavonoids and quinones) will dissolve in the medium-polarity solvents (such as 1435

dichloromethane and ethyl acetate), whereas more polar compounds (such as glycosides, 1436

polyphenols) will be concentrated in the more polar solvents (such as butanol) or retained in 1437

the water phase. 1438

1439

The counter-current extraction technique can be applied for fractionation and purification 1440

purposes, where applicable. 1441

1442

3.2.3.2 Chromatography 1443

Further purification of the extract fractions can be achieved by various chromatographic 1444

techniques, of which column chromatography is commonly employed, particularly in the 1445

preparative scale. Column chromatography can be carried out using materials based on 1446

different mechanisms. Common modes are adsorption, partition, size exclusion, affinity and 1447

ion-exchange. The most frequently used stationary phases (sorbents) are silica gel and 1448

alumina in adsorption chromatography; in size exclusion and ion-exchange chromatography, 1449

polymeric gels and ion-exchange resins, respectively, are used. A proper column packed with 1450

the appropriate stationary phase and eluted by a mobile phase with suitable elution power is 1451

crucial to obtain optimized separation of constituents in the herbal extract. 1452

1453

3.2.3.3 Fractionation and purification procedures 1454

Liquid-liquid partition 1455

The storage, use, and disposal of solvents must be handled with care and in conformance 1456

with the national/local/institutional regulations. 1457



35

The experimental procedures should be carried out in certified facilities with sufficient 1458

ventilation and safety measures. They are preferably performed inside fume hoods. 1459

1460

Column chromatography 1461

The choice of stationary phase depends on the polarity, molecular size, or the charge of the 1462

desired ingredients. It should be supported by a good rationale. 1463

The choice of mobile phase (solvent system) must be optimized. 1464

Column operation and development procedures (e.g. column length and inner diameter, 1465

amount of stationary phase used, column packing, particle or bead size or macropore size, 1466

porosity and surface area, phase, and support, sample application, elution gradient 1467

formation, flow rate, temperature, fraction collection, and detection method), should be 1468

specified and standardized. 1469

1470

3.2.4 Concentration and drying 1471

The herbal extracts or semi-purified extracts are often concentrated to produce a concentrated 1472

liquid preparation by the removal of excessive solvent. This can be achieved through 1473

evaporation or vaporization. Solvent (single) can be recovered and may be reused provided 1474

that appropriate quality control is ensured. Mixed or mixture of solvents are not reusable. 1475

The degree of concentration depends on the desired end product. 1476

1477

Equipment for concentration may include descending film, thin layer or plate concentrators. 1478

Any method used to concentrate the extracts must avoid excessive heat because the active 1479

compounds may be subject to degradation. The liquid preparation so obtained may be used as 1480

is or further processed into a dry extract. 1481

1482

When complete drying is required, the drying process can make use of vacuum freeze dryers, 1483

cabinet vacuum dryers, continuously operating drum or belt dryers, microwave ovens, or 1484

atomizers. The technique for drying depends on the stability of the product and the amount of 1485

moisture that must be removed. The total removal of solvent results in a dry extract, which is 1486

less subject to microbial contamination than are liquid extracts. Powdered extracts are often 1487

produced by drying the extract onto an inert carrier, such as methyl cellulose, to facilitate 1488

processing into the final finished product. 1489

1490

3.2.4.1 Concentration and drying procedures 1491

• The minimization of loss and/or damage to the chemical constituents of interest is critical 1492

to ensuring the effectiveness of the preparation. Therefore, the preservation of the active 1493

ingredients is of paramount importance during the concentration stage when heat is often 1494

applied to evaporate the solvent. Any concentration process should ensure minimal 1495

thermal decomposition and chemical reactions (such as oxidation) to occur. For organic 1496

solvents, evaporation under reduced pressure at a temperature below 40 °C is preferred. 1497

• Solvent removal should be done as soon as possible after extraction. Prolonged exposure 1498

to sunlight should also be avoided. 1499

• While evaporation is the most common and the most applied technique for concentration, 1500

other approaches such as membrane technology and freeze concentration are available. 1501

1502

3.2.5 Fermentation 1503



36

1504

In some cases, herbal preparation is obtained after undergoing through a fermentation process 1505

of the plant powder or decoction. Fermentation can be either natural (“self-fermentation”) 1506

involving microbial cultures already present on the herb, enzymes naturally occurring in the 1507

herb (which may be activated by bruising the herb), or both, or by introducing an appropriate 1508

microbial organism (e.g. Lactobacillus bacteria). 1509

1510

For natural fermentation, the dry plant powder, a decoction, or an extract of herbal material is 1511

often mixed with the juice of sugarcane, brown sugar or honey, and the mixture is kept in an 1512

airtight utensil for several weeks for anaerobic fermentation to occur. 1513

1514

In some cases, herbal materials are mixed with a small amount of water and shaped into 1515

bricks, followed by microbial cultivation in an incubation room for a week or so, letting the 1516

mould grow on the surface of the herbal materials. 1517

1518

3.2.5.1 Fermentation procedures 1519

• When fermentation is required to produce a herbal preparation, all utensils should be 1520

completely cleaned. A non-corrosive fermentor is required. 1521

• The water to be used should comply with local requirement for potable water, not be 1522

alkaline and should be free of inorganic matters (deionized water). 1523

• The temperature and length of fermentation should be optimized and controlled. 1524

• When fermentation is complete, the solution is filtered and stored in suitable containers. 1525

1526

3.2.6 Powdering 1527 1528

Content needs to be developed. 1529

We kindly request reviewers to provide us with suggested input, as well as, any relevant 1530

technical information for formulating description on this sub-section. 1531

Thank you very much. 1532 1533

3.2.6.1 Powdering procedures 1534




Thank you very much. 1538 1539

3.3 Documentation 1540 1541

The general principles for documentation are set out in the GMP for pharmaceutical 1542

products: main principles [WHO, 2007a – WHO, 2003b]; [WHO, 2014]. 1543

1544

In addition to the data called for in the above guidelines, the documentation for herbal 1545

preparations should as far as possible include, as a minimum, the following information: 1546

1547

Botanical (scientific) name and the taxonomic authority (abbreviation if used should be 1548

according to internationally-accepted rules), the plant family name, any synonyms for the 1549



37

scientific name that are well established in the literature or in commerce, and the 1550

local/common name and well-established synonyms of the source medicinal plant material; 1551

and plant part(s) being processed; 1552

Site and time of harvest/collection of the plant; 1553

State of the plant (e.g. fresh or dried); 1554

Batch number, batch size, and any other identification code; 1555

Supplier; 1556

Dates of receipt of the herbal material, retained sample identifier, processing of the 1557

material, and completion of the process; 1558

Name of person in charge of the processing; 1559

Previous processes that the herbal material has already undergone; 1560

Characteristics of the herbal preparation (such as type of the preparation, ratio of the herbal 1561

material to the herbal preparation, organoleptic characters); 1562

Methods used for processing to produce herbal preparation; 1563

Details of the procedures (master formula), including quantity of herbal materials, 1564

extraction solvent, additive, descriptions of the steps of operation, operational conditions 1565

used during the process, and other relevant information; 1566

Batch production detail deviations/modifications of the master formula; and 1567

Quality control parameters (such as identification tests, tests on water content, impurities, 1568

residual solvents, microbial limits, shelf-life) and assay results, where appropriate, of 1569

active ingredient(s) or Chemical reference standard(s). 1570

1571

The SOP including all processing steps should be adopted and documented in the Master 1572

Record. Batch records should be kept and any deviations from the SOP should be fully 1573

recorded and investigated. Name(s) of all operators, and the dates and time on which each 1574

step/stage are carried out should be documented. 1575

1576


HERBAL DOSAGE FORMS 1578

1579


1581 In contrast to synthetic pharmaceutical drugs, many herbal materials and herbal preparations 1582

may undergo simpler good practice processes to become suitable dosage forms and final 1583

products for administration. However, these dosage forms should be produced under 1584

applicable Good Manufacturing Practices (WHO, 2007a). Starting materials for the 1585

preparation/production of various herbal dosage/final dosage forms should consist of good 1586

practice processed herbal materials or herbal preparations as described previously (Sections 2 1587

and 3). 1588

1589

Examples of a number of herbal dosage forms are presented in the Japanese Pharmacopoeia 1590

(16th Edition) (see Annex 3). 1591

1592

The following describes some common dosage forms of herbal medicines. 1593

1594




38

1596

4.2.1 Liquid herbal dosage forms 1597 1598

Liquid herbal dosage forms as described herein pertains to oral preparations, including, but 1599

not limited to the following product types/categories: 1600

1601 4.2.1.1 Fluidextracts 1602

For description, see section 3.2.3. 1603

1604 4.2.1.2 Infusions 1605


1607 4.2.1.3 Decoctions 1608


1610

4.2.1.4 Liquid (fluid) extracts 1611

For description, see section 3.2.3 1612

1613 4.2.1.5 Tinctures 1614

For description, see section 3.2.3 1615

1616 4.2.1.6 Syrups 1617

Syrups are viscous liquid containing sugars or other sweetening agents. They are prepared by 1618

dissolving, mixing, suspending or emulsifying herbal extracts or decoctions in a solution of 1619

honey, sucrose or other sweetening agents. When necessary, the mixture is boiled and 1620

filtered. 1621

1622 4.2.1.7 Oral emulsions 1623

Oral emulsions are liquid oil-in-water preparations that are rendered homogeneous by the 1624

addition of emulsifying agent. For example, an oil obtained from herbs (e.g. castor oil) is 1625

dispersed in water and emulsified with an emulsifying agent such as gum acacia. 1626

1627

4.2.2 Solid herbal dosage forms 1628 1629

4.2.2.1 Herbal tea bags 1630

Herbal tea bags are prepared by placing finely ground herbal materials (such as dried roots, 1631

leaves or flowers) into paper or cloth bags. When used, boiling water is poured into the vessel 1632

containing the bag to make an infusion. 1633

1634 4.2.2.2 Plant powders 1635

Powders are prepared by grinding/pulverizing herbal materials to a suitable particle size. 1636

1637 4.2.2.3 Powdered extracts 1638

Powdered extracts are prepared by spray-drying with or without the use of an adsorbent (such 1639

as methyl cellulose), or by drying and milling to produce a powder. 1640

1641



39

4.2.2.4 Granules 1642

Granules are dried liquid (fluid) extracts in the form of spherical particles. They are prepared 1643

by adding diluents, binders or other suitable excipients to extract powders, mixed to 1644

homogeneity and granulated by a suitable method. Typically, granules are dissolved in hot 1645

water to make a “herbal tea” for administration. 1646

1647 4.2.2.5 Pills 1648

Pills are dried extracts or decoctions in the form of small, spherical solids, similar to granules. 1649

They may be prepared by adding suitable excipients to extract powders, mixed to homogenize 1650

and granulated by a suitable method. Typically, pills are swallowed with warm water. 1651

1652 4.2.2.6 Capsules 1653

Capsules are prepared by enclosing herbal powder or dry/powder extract in capsule shells or 1654

in a suitable capsule base such as gelatine in a particular shape and size. 1655

1656 4.2.2.7 Tablets 1657

Tablets are solid preparations having a defined shape and size. They are usually prepared by 1658

mixing the homogenous dry/powder extract with excipients such as diluents and binders, 1659

followed by compression into a defined shape and size. 1660

1661 4.2.2.8 Lozenges 1662

Lozenges are solid dosage forms that are designed to dissolve slowly in the mouth to provide 1663

local action in the oral cavity or the throat, such as cough drops or pastilles. In addition to 1664

herbal ingredient, lozenges often contain flavouring agents and sweetened bases. 1665

1666

4.2.3 Other herbal dosage forms 1667 1668

4.2.3.1 Ointments/creams 1669

Ointments/creams are topical preparations for application to the skin. They are usually semi-1670

solid emulsions dissolved or dispersed in a suitable base. Alongside with the herbal 1671

ingredients, they may contain emulsifiers or thickening agents. 1672

1673 4.2.3.2 Inhalations 1674

Inhalations are preparations intended for administration as aerosols to the bronchial tubes or 1675

lungs. They are usually either dry powder inhalers or inhalation liquid preparations. For 1676

administration of inhalations, suitable devices or apparatus are required. 1677

1678 Dry powder inhalers are prepared by pulverizing dried extracts into fine particles. When 1679

necessary, lactose or other suitable excipients are added to make a homogenous mixture. 1680

Inhalation liquid preparations are usually prepared by mixing dried herbal extracts with a 1681

vehicle and suitable pH adjusting agents to make a solution or suspension. Suitable 1682

preservatives may be added to prevent the growth of microorganisms. 1683

1684 4.2.3.3 Plasters and patches 1685

Plasters and patches contain herbal preparations such as dry or soft extracts on pieces of fabric 1686

or plastic sheets. When applied topically to the skin, they deliver the herbal ingredients 1687



40

through the skin to underlying tissues, usually for the relief of pain, backache, or sore 1688

muscles. 1689

1690 4.2.3.4 Aromatic waters 1691

Aromatic waters are water preparations containing saturated essential oils or other volatile 1692

substances. Usually, an essential oil (1 part) is shaken in water (999 parts) and set aside for 1693

12 hours or longer after mixing with 10 parts of talcum powder. The solution is filtered and 1694

made up to a certain volume with water. Aromatic waters have a characteristic odour of the 1695

essential oil or volatile substances used. 1696

1697

4.2.3.5 Gel capsules 1698




Thank you very much. 1702

1703

5. TECHNICAL ISSUES SUPPORTING GOOD HERBAL PROCESSING 1704

PRACTICES 1705

1706 In the formulation of a good practice protocol for processing herbal materials, a number of 1707

supporting technical issues must be considered and adopted. Since the primary objective is to 1708

produce quality processed herbal materials and preparations, many of the same technical 1709

issues associated with the GACP, GMP and quality control (QC) methods are applicable to 1710

GHPP. 1711

1712

Therefore, these guidelines have been consulted for applicable good practice items for 1713

adoption. Moreover, the same technical issues on the post-harvest processing of cultivated 1714

and collected medicinal plant materials were addressed in section 4 of the WHO guidelines on 1715

GACP for medicinal plants [WHO, 2003a]. Thus, the applicable good practice guidelines 1716

have been adopted in whole or modified as appropriate for the present guidelines. 1717

1718

5.1 Processing facilities 1719

1720 The ideal design and construction of a herbal material processing facility incorporating the 1721

most appropriate location, buildings, medicinal plant material handling and processing areas, 1722

water supply, effluent and waste disposal, changing facilities and toilets, hand-washing 1723

facilities in processing areas, disinfection facilities, lighting, ventilation, dust and storage of 1724

waste and unusable materials, have already been fully described in Sections 4.1.5 (pages 19-1725

23) of the WHO guidelines on GACP for medicinal plants [WHO, 2003a]. Therefore, they 1726

are adopted for the present guidelines and the descriptions are excerpted and presented in 1727

Annex 4 for easy reference. 1728

1729

5.2 Packaging and labelling 1730

1731 Processed herbal materials or herbal preparations should be packaged as quickly as possible to 1732

preserve their quality by preventing deterioration of the herbal medicines and to protect 1733



41

against unnecessary exposure to pest infestations and other sources of contamination. 1734

1735

Continuous in-process quality control measures should be implemented to eliminate sub-1736

standard materials, contaminants and foreign matter prior to and during the final stages of 1737

packaging. Processed medicinal plant materials should be packaged in clean, dry boxes, 1738

sacks, breathable bags or other containers in accordance with standard operating procedures 1739

and meeting national and/or regional regulations of the producer and the end-user countries. 1740

Materials used for packaging should be non-polluting, clean, dry and in undamaged condition 1741

and should conform to the quality requirements for the processed herbal materials or herbal 1742

preparations concerned. Fragile medicinal plant materials should be packaged in rigid 1743

containers. Wherever possible, the packaging used should be agreed upon between the 1744

supplier and buyer. 1745

1746

A label affixed to the packaging should clearly indicate the scientific name, usual common 1747

name, brand name, the processed plant part with date, the processing techniques used, the 1748

name and address of the processor, finished product manufacturer, importer or distributor, i.e. 1749

the entity who should be responsible for receiving consumer complaints and conducting a 1750

recall should the need arise, as well as information on the potency or strength of the medicinal 1751

ingredient if applicable (e.g., for an extract the drug extract ratio (DER) of herbal material to 1752

extract, or the concentration of active or marker substance(s) used for standardization), net 1753

amount in the immediate container in terms of weight, measure or number, and in the case of 1754

a prepared dosage form the quantity of each medicinal ingredient per dosage unit, list of 1755

excipients, recommended storage conditions, and expiry date. Retail labelling should also 1756

provide the recommended use or purpose, the recommended dose and frequency per day, 1757

recommended duration of use, and cautionary information (e.g., known side effects, warnings 1758

regarding interactions, contraindications). The label should also contain information 1759

indicating quality approval and compliance with other national and/or regional labelling 1760

requirements. The label should bear a number that clearly identifies the production batch. 1761

Additional information about the production and quality parameters of the medicinal plant 1762

materials may be added in a separate certificate, which is clearly linked to the package 1763

carrying the same batch number. 1764

1765

Records should be kept of batch packaging, and should include the product name, place of 1766

origin, batch number, weight, assignment number and date. The records should be retained 1767

for a period of three years or as required by national and/or regional authorities. 1768

1769

5.3 Storage and transportation 1770

1771 All processed herbal materials or herbal preparations should be properly stored and preserved 1772

before use. They must be protected from microbial and insect contaminations, and rodents 1773

and other pests. Every effort should be tried to use the type of packaging that provides ample 1774

protection against physical damages to the materials and to keep away, as much as possible, 1775

from exposure to moisture, light, heat, and insect attack. 1776

1777

Substandard herbal medicines should be kept in a separate designated area, clearly labelled 1778

and with specified handling period. Toxic or specific herbal medicines should be checked, 1779



42

labelled and stored according to the government’s regulations. 1780

1781

Storage areas should be of sufficient capacity to allow orderly storage of the various types of 1782

processed herbal materials and herbal preparations with proper separation and segregation. In 1783

particular, they should be clean, dry, sufficiently lit and maintained within acceptable 1784

temperature and humidity limits, and controlled, monitored and recorded where appropriate to 1785

ensure good storage conditions. 1786

1787

Conveyances used for transporting processed herbal materials and herbal preparations from 1788

the place of processing to storage should be clean and, where appropriate, well ventilated to 1789

keep an appropriate level of air flow and to prevent condensation. 1790

1791

Fumigation against pest infestation in conveyances and in storage areas should be carried out 1792

only when necessary, and should be carried out by licensed or trained personnel. Only 1793

registered chemical agents authorized by the regulatory authorities of the source country and 1794

the countries of intended end-use should be used. All fumigation, fumigation agents, and 1795

dates of application should be documented. When freezing or saturated steam is used for pest 1796

control, the humidity of the materials should be checked after treatment. 1797

1798

5.4 Equipment 1799

1800 All equipment, including tools and utensils used in the processing of herbal materials and 1801

herbal preparations should be made of materials that do not transmit toxic substances, odour 1802

or taste; are non-absorbent; are resistant to corrosion and are capable of withstanding repeated 1803

cleaning and disinfection. The use of wood and other materials that cannot be adequately 1804

cleaned and disinfected should be avoided, except when their use would clearly not be a 1805

source of contamination. The use of metals known to cause corrosion should be avoided. 1806

1807

All equipment and utensils should be designed and constructed so as to prevent hygienic 1808

hazards and permit easy and thorough cleaning and disinfection. Where practicable, they 1809

should be accessible for visual inspection. Stationary equipment should be installed in such a 1810

manner as to permit easy access and thorough cleaning. 1811

1812

Containers for unusable materials or waste should be leak-proof, constructed of metal or other 1813

suitable impervious materials, should be easy to clean or be disposable, and should close 1814

securely. 1815

1816

All refrigerated spaces should be equipped with temperature measurement or recording 1817

devices. 1818

1819

5.5 Quality assurance and quality control 1820

1821 Quality assurance system is essential to ensure that herbal processing practice is consistently 1822

executed and controlled. Compliance with quality assurance measures should be verified 1823

through regular internal oversight personnel (QA manager) and external auditing visits to 1824

processing facilities by expert representatives of buyers and other stake holders and through 1825



43

inspection by national and/or local regulatory authorities. No processed herbal material or 1826

processed herbal preparation shall be released until its quality complies or conforms with 1827

standard specifications. 1828

1829

5.6 Documentation 1830

1831 The SOP should be adopted and documented. All methods and procedures involved in the 1832

processing of herbal materials and herbal preparations and the dates on which they are carried 1833

out should be documented. 1834

1835

The types of information that should be collected include the items described in Sections 2.3.5 1836

and 3.3 above. Additionally, documentation on post-processing transportation and storage of 1837

processed products should be prepared. 1838

1839

Where applicable, the results of inspection should be documented in an inspection report 1840

which contains copies of all documents, (QC) analysis reports, and local, national and/or 1841

regional regulations, and which are stored according to their requirements. 1842

1843

5.7 Personnel 1844

1845

5.7.1 General 1846

1847 All personnel should receive proper post-harvest handling and herbal processing training. All 1848

personnel required to handle chemical solvents and adjuvants should receive adequate training 1849

and possess sufficient knowledge and appropriate techniques employed for their safe handling 1850

and proper use. Training records should be signed by the trainer and trainee and documented. 1851

1852

Local, national and/or regional regulations governing labour should be respected in the 1853

employment of staff for all phases of herbal processing. 1854

1855

5.7.2 Health, hygiene and sanitation 1856

1857 All personnel involved in the pre-processing and during processing handling of herbal 1858

materials should be trained and perform tasks in compliance with local, national and/or 1859

regional regulations on safety, materials handling, sanitation and hygiene. 1860

1861

All personnel should be protected from contact with toxic or potentially allergenic herbs by 1862

means of adequate protective clothing, including gloves and masks. 1863

1864

Health status 1865

All personnel known, or suspected to be suffering from or to be a carrier of a disease or illness 1866

likely to be transmitted, should not be allowed to enter any processing area, and should 1867

immediately be reported to the management, and suspended from work as deemed medically 1868

appropriate. 1869

1870

Health conditions that should be reported to the management for consideration regarding 1871



44

medical examination and/or possible exclusion from handling of medicinal plant and 1872

processing/processed herbal materials and associated equipment including but not limited to: 1873

such as jaundice, diarrhoea, vomiting, fever, sore throat with fever, visibly infected lesions 1874

(boils, cuts, among other conditions) and discharges from the ear, nose or eye. Any personnel 1875

who have cuts or wounds and are permitted to continue working should cover their injuries 1876

with suitable waterproof dressings. 1877

1878

Personal hygiene and behaviours 1879

Personnel who handle processing/processed herbal materials should be trained to maintain a 1880

high degree of personal cleanliness, and, where appropriate, wear suitable protective clothing 1881

and gloves, including head/hair covering and footwear. 1882

1883

Personnel should always wash their hands at the start of handling activities, after using the 1884

toilet, and after handling medicinal plant materials or any contaminated material. 1885

1886

Smoking, drinking, and eating should not be permitted in medicinal plant processing areas. 1887

1888

Visitors 1889

Visitors to processing and handling areas should wear appropriate protective clothing and 1890

adhere to all of the personal hygiene provisions mentioned above [WHO, 2003a]. 1891

1892

6. OTHER RELEVANT ISSUES 1893

1894

6.1 Ethical and legal considerations 1895 1896

All herbal processing must be carried out in accordance with applicable legal and 1897

environmental requirements and with the ethical codes or norms of the community and 1898

country in which the activities take place. 1899

1900

6.2 Research, research training and information sharing 1901

1902 Research to understand and gain knowledge on the mechanism and scientific basis of 1903

processing procedures as traditional or historical methods is needed; Research to find 1904

alternate processing procedures to achieve the same therapeutic effect as traditional or 1905

historical methods is also needed. Additionally, research to determine the chemical 1906

conversion process and mechanism involved in the qualitative and quantitative alteration of 1907

the biologically active chemical constituents following processing is also needed and 1908

encouraged. 1909

1910

Technical information resulting from processing method research is useful for promoting 1911

technical advancement, and should be shared through publication, conferences or otherwise 1912

conveyed to interested stakeholders. 1913

1914

As in all technical endeavours, education and research training are essential to preserve 1915

technical expertise and to promote innovation in development of new and better techniques 1916

and procedures in herbal processing. 1917



45

1918

Research to develop good herbal processing practices for individual medicinal plant part and 1919

document each in a monograph. 1920

1921

6.3 Adoption of good herbal processing practices 1922 1923

Member States or nations that have not adopted good herbal processing practices for herbal 1924

medicines are encouraged to establish or adopt such practices as part of quality assurance and 1925

control measures, as well as a part of their regulatory requirements for herbal medicines. 1926

1927

6.4 Intellectual property rights and benefits-sharing 1928 1929

Agreements on intellectual property rights and the return of benefits and compensation for the 1930

use of source herbal materials or herbal preparations concluded in writing by the sourcing 1931

contractor, shall be acknowledged and followed by the processor as appropriate. 1932

1933

6.5 Threatened and endangered species 1934 1935

When obtaining medicinal plants that are protected by national and international laws, such as 1936

those listed in national “red” lists, for processing, the processor shall ascertain and obtain 1937

appropriate documentation from the sourcing contractor that said materials were acquired 1938

only by relevant permission according to national and/or international laws, and that the 1939

provisions of the Convention on International Trade in Endangered Species of Wild Fauna 1940

and Flora (CITES) have been complied with. 1941

1942

7. REFERENCES 1943 1944 WHO, 2000:General guidelines for methodologies on research and evaluation of traditional medicine 1945 WHO/EDM/TRM/2000.1, Geneva, World Health Organization, 2000. 1946 1947 WHO, 2003a:WHO guidelines on good agricultural and collection practices (GACP) for medicinal plants. 1948 Geneva, World Health Organization, 2003. 1949 1950 WHO, 2003b: Good Manufacturing Practices for pharmaceutical products: main principles In: WHO 1951 Expert Committee on Specifications for Pharmaceutical Preparations. Thirty-seventh report. Geneva, 1952 World Health Organization, 2003 (WHO Technical Report Series, N0. 908), Annex 4. 1953 1954 WHO, 2007a: WHO guidelines on good manufacturing practices (GMP) for herbal medicines. Geneva, 1955 World Health Organization, 2007. 1956 1957 WHO, 2007b:WHO guidelines on assessing quality of herbal medicines with reference to contaminants 1958 and residues, Geneva, World Health Organization, 2007. 1959 1960 WHO, 2007c:General guidelines for the establishment, maintenance and distribution of chemical reference 1961 substances. In: WHO Expert Committee on Specifications for Pharmaceutical Preparations. Forty-first 1962 report. Geneva, World Health Organization, 2007 (WHO Technical Report Series, No. 943), Annex 3. 1963 1964 WHO, 2010: Safety issues in the preparation of homeopathic medicines, Geneva, World Health 1965 Organization, 2010. 1966



46

WHO, 2011:Quality control methods for herbal materials. Geneva, World Health Organization, 2011. 1967 1968 WHO, 2014:Good Manufacturing Practices for pharmaceutical products: main principles In: WHO Expert 1969 Committee on Specifications for Pharmaceutical Preparations. Forty-eighth report. Geneva, World Health 1970 Organization, 2014 (WHO Technical Report Series, N0. 986), Annex 2. 1971 1972 WHO, 2017:WHO guideline for selecting marker substances of herbal origin for quality control of herbal 1973 medicines. Geneva, World Health Organization, 2017 (in press). 1974 1975 WHOM-1999:WHO monographs on selected medicinal plants, Volume 1, Geneva, World Health 1976 Organization, 1999. 1977 1978 WHOM-2002:WHO monographs on selected medicinal plants, Volume 2, Geneva, World Health 1979 Organization, 2002. 1980 1981 WHOM-2007:WHO monographs on selected medicinal plants, Volume 3, Geneva, World Health 1982 Organization, 2007. 1983 1984 WHOM-2009:WHO monographs on selected medicinal plants, Volume 4, Geneva, World Health 1985 Organization, 2009. 1986 1987 WHOM-2010:WHO monographs on selected medicinal plants commonly used in the Newly Independent 1988 States (NIS), Geneva, World Health Organization, 2010. 1989

1990



47

Annex 1: Example of a model format of good herbal processing practices 1991

monograph/SOP protocol to produce a herbal material 1992 1993

TITLE of the monograph/protocol: 1994 1995 Processing of [name of the plant] (Scientific name of the medicinal plant; medicinal plant part) 1996 1997 1. Objective of the SOP Protocol 1998 1999 2. Scope 2000 2001 3. Procedures 2002 2003 3.1 Sampling 2004 2005 Sampling of herbal materials should follow applicable national or regional specifications. In absence 2006 of appropriate specifications, the following method may be considered: When a batch consists of five 2007 containers or packaging units, take a sample from each one. From a batch of 6-50 units, take a sample 2008 from five. In the case of batches of over 50 units, sample 10%, rounding up the number of units to the 2009 nearest multiple of ten (WHO, 2011). 2010 2011 Quality testing of the raw material 2012 Perform morphological identification/validation by macroscopic and microscopic examinations and 2013 physicochemical tests by following the procedures set out in the national pharmacopoeia or other 2014 authoritative documents. 2015 2016 The following requirements must be fulfilled. 2017 Morphology: Conform with the national pharmacopoeial standards 2018 Identification (including macroscopic, microscopic examination, and/or chromatographic tests): 2019

Conform with the pharmacopoeial standards 2020 Water content: ≤ xxx % 2021 Total ash: ≤ xxx % 2022 Acid-insoluble ash: ≤ xxx % 2023 Extractive: ≥ xxx % 2024 2025 3.2 Quality control assay 2026 2027 3.2.1 Marker compound 2028 Compound “Z” is used as the marker compound for plant X..y.. for quality control purpose. Obtain 2029 analytical grade Compound Z (≥ 98% purity) from a reliable source to serve as Chemical reference 2030 substance. 2031 2032 3.2.2 High-performance liquid chromatographic (HPLC) analysis 2033 Set up the HPLC system. Perform system suitability test to ensure suitability of the instrument and 2034 method. 2035 Under the recommended HPLC conditions, establish calibration curves by injecting an appropriate 2036 amount of the chemical reference (marker) standard solution in a series of concentrations. 2037 Obtain HPLC chromatogram of the herbal material. Identify the analyte signal in the chromatogram 2038 by comparing the retention time with that of the peak of the chemical reference substance obtained 2039 under same HPLC conditions. 2040 Calculate the percentage content of the analyte in the sample using the calibration curve. 2041



48

Determine the percentage content of the marker compound again after final drying of the processed 2042 herbal material (section 3.10 below). 2043 2044 The following requirement must be fulfilled. 2045 Content of Compound Z before processing: ≥ xxx % calculated with reference to the dry weight of 2046

the starting material 2047 Content of Compound Z after processing: ≥ xxx % calculated with reference to the dry weight of 2048

the processed material 2049 2050 3.3 Testing of the excipient* 2051

(*This step is not required if excipient(s) are not employed in the processing protocol) 2052 2053 Perform tests by following the procedures set out in the SOP document. The following requirements 2054 must be fulfilled. 2055 Appearance: Conform with internal standards 2056 Total excipient content: ≥ xxx % 2057 2058 3.4 Initial sorting of the plant material for processing 2059 2060 The source herbal materials are manually sorted by trained personnel according to the requirements 2061 specified in the SOP. Impurities (e.g. dirt and non-medicinal plant parts) should be removed, and any 2062 materials of non-uniformed sizes should be excluded. 2063 2064 The following requirements must be fulfilled. 2065 Impurity: ≤ xxx % 2066 Size uniformity: ≥ xxx % 2067 Total recovery: ≥ xxx % (Recovery = Weight after sorting / Weight before sorting X 100%) 2068 2069 3.5 Washing 2070 2071 Washing should be performed by following the procedures set out in the SOP document. Pay attention 2072 to the quality of water used, the length of washing time, and any precautions applicable to the specific 2073 herb. 2074 2075 The following requirements must be fulfilled. 2076 Appearance after washing: in conformance with the SOP standard 2077 Recovery: xxx-xxx % (Recovery = Weight after washing/Weight before washing X 100%) 2078 2079 3.6 Steaming (or other treatment) 2080 2081 The procedures set out in the SOP document should be strictly followed. All equipment should be 2082 properly maintained, clean, and performing at optimal and safe conditions. 2083 2084 The following requirements must be fulfilled. 2085 Appearance after steaming/treatment: in conformance with the SOP standard 2086 Recovery: ≥ xxx % (Recovery = Weight after steaming/Weight before steaming X 100%) 2087 2088 3.7 Semi-drying 2089 2090 If required, dry the samples according to SOP guideline, either by sunlight or by artificial heating. 2091 2092



49

The following requirements must be fulfilled. 2093 Appearance after semi-drying : in conformance with the SOP standard 2094 Recovery: xxx-xxx% (Recovery = Weight after drying/Weight before drying X 100%) 2095 2096 3.8 Cutting/sectioning/comminuting 2097 2098 The processed material should be comminuted into the required size and shape in conformance with 2099 the SOP standard. 2100 2101 The following requirements must be fulfilled. 2102 Non-conformed pieces: ≤ xxx % 2103 Powder fineness: 2104 Recovery: ≥ xxx % (Recovery = Weight after cutting/Weight before cutting X 100%) 2105 2106 3.9 Final drying of processed herbal material 2107 2108 The cut materials should be thoroughly dried according to the SOP requirement. 2109 2110 The following requirements must be fulfilled. 2111 Water content of the final product: xxx-xxx % 2112 Recovery: ≥ xxx % (Recovery = Weight after drying/Weight before drying X 100%) 2113 2114 3.10 Final sorting 2115 2116 The dried material should be carefully inspected by trained personnel, with impurities removed, and 2117 sorted into specific grades in accordance with the pharmacopoeial or trading standard. 2118 2119 The following requirements must be fulfilled. 2120 Impurity: ≤ xxx % 2121 Grade-1 pieces: ≥ xxx% 2122 Grade-2 pieces: xxx –xxx% 2123 Recovery: ≥ xxx % (Recovery = Weight after sorting/Weight before sorting X 100%) 2124 2125 3.11 Packaging, labelling, and storage 2126 2127 3.11.1 Packaging 2128 Processed materials should be packaged quickly and appropriately in appropriate, non-corrosive 2129 containers, and protected from light to preserve quality, prevent deterioration and to protect against 2130 contamination. 2131 2132 3.11.2 Labelling 2133 Labels affixed to each package should clearly indicate the scientific name of the medicinal plant, the 2134 plant part, the processing method, the date of processing, the batch number, quality specification and 2135 compliance, quantitative and other relevant information. 2136 2137 3.11.3 Storage 2138 The packaged products must be stored in a clean, dry and well-ventilated area, at a constant 2139 temperature appropriate for the proper maintenance of the final product, and protected against 2140 microbial and other sources of contaminations and free from insects and animal pest attacks. 2141



50

Annex 2: Example of a model format of good herbal processing practices 2142

monograph/SOP protocol to produce a herbal preparation 2143 2144

TITLE of the monograph/protocol 2145 2146

Processing of [name of the plant] (Scientific name of the medicinal plant; medicinal plant part) 2147 2148 1. Objective of the SOP Protocol 2149 The objective of this protocol is to establish a procedure for preparation of the finished product. 2150 2151 2. Scope 2152 This procedure applies to processes required in the preparation of the fluidextract of the herb of X…y... 2153 2154 3. Procedures 2155 This protocol should be carried out in accordance with the standard operating procedures (SOP) for 2156 the processing of material X…y... as described in this document, the SOP for equipment operation and 2157 maintenance, as well as those for facility management and cleaning. Any other relevant requirements 2158 may also apply. 2159 2160 The protocol should be adhered to in conjunction with relevant internal standards of the processing 2161 facility. 2162 2163 After the completion of each processing step, the products should be inspected by qualified personnel. 2164 All inspection records should be properly filed and retained for a period of three years or as required 2165 by national and/or regional authorities. 2166 2167 4. Plant substance 2168 The identity of the raw plant material should be confirmed using morphological 2169 identification/validation by macroscopic and microscopic examinations and physicochemical tests by 2170 following the procedures set out in the pharmacopoeia or other authoritative documents. 2171 2172 Specifications such as those below should be in place. 2173 2174 Origins of the plant material (natural state/cultivation): Describe appropriate origins of the 2175

plant material 2176 Plant part: Describe the desired plant part/parts (i.e. flowers) 2177

Growing conditions: 2178 o Climatic conditions: length of day, rainfall, field temperature (coldness/warmth) 2179 o Soil conditions: soil type, drainage/moisture retention, fertility 2180 o Shade level 2181 o Fertilizers: Specify allowable fertilizers in compliance with applicable regulations 2182 o Pest controls: Specify allowable pesticides and/or biological pest controls, in compliance 2183

with applicable regulations 2184 o Fungicides: Specify allowable fungicides (if any) in compliance with applicable regulations 2185 o Fumigants: Specify allowable fumigants (if any) in compliance with applicable regulations 2186

Harvest time: Describe the appropriate months for harvest (i.e. during flowering (June-July) 2187 Harvesting: Describe the process for harvesting (i.e. mechanical process) 2188 Drying conditions: Describe the process for drying, if applicable 2189 Purification: Describe the process for inspection and removal of impurities 2190



51

Storage conditions: Specify the storage conditions. In general, the plant material should be 2191 stored in a clean, dry and well-ventilated area, at a constant, appropriate temperature, protected 2192 against microbial and other sources of contaminations, free from attack by insects and animal 2193 pests. 2194

Transportation conditions: Commercial vehicles should be clean, dry, deprived of any foreign 2195 matter. Conditions should ensure protection against moisture and contamination. Baskets, chests 2196 and jute bags can be used as containers. Each container should be labelled with the name of the 2197 material, date of harvest, harvesting site, net and gross weight and the name of the supplier. 2198

2199 5. Processing 2200 Descriptions of the processing facility requirements should be maintained, i.e. certification of the site 2201 as a good practice facility. Details are given here for the raw components to be used in the production 2202 of the final herbal preparation. 2203 2204 As an example, raw X...y... material to be processed into X...y... juice are detailed in the table below. 2205 In this example, the plant material is extracted using ethanol 95% (V/V) and water as needed. The 2206 drug extract ratio (DER) is 1:1. 2207 2208

Raw Material Components in the Production of X...y...juice 2209 Raw Materials Function Amount per 100 kg Standard

Fresh X...y... herb Plant material 100.0 kg Standard specification

Ethanol 95% Extraction solvent Xx litres Pharmacopoeia .XYZ

Extraction water Extraction solvent quantum satis Pharmacopoeia .XYZ

2210 Raw materials accepted for processing must meet specifications for identity and quality. 2211 Specifications include appearance/description of the plant material(s), water content, total ash, as well 2212 as appropriate chemical assays. These criteria may follow criteria detailed in pharmacopoeial 2213 monograph(s). 2214 2215 The steps below describe the preparation of the juice of the herb of X..y.. 2216 Step 1. The fresh fragmented plant material is stabilized with the vapours of boiling 95% ethanol 2217

in an autoclave. The duration, temperature and vapour pressure are specified in the SOP. When 2218 the process is completed, the fluid separates from the plant material. 2219

Step 2. The stabilized plant material is placed in a macerator with post-stabilization fluid and 2220 water. The maceration process lasts for a period of time (n days) specified. At the end of the 2221 extraction process, the extract is separated from the plant matter in a manner specified by the SOP. 2222 The ethanol content of the extract and density of the extract are specified. 2223

Step 3. The resulting extract is stored in a stainless steel container for a minimum time 2224 (days/weeks) specified. The process ensures sedimentation of inorganic residual waste. 2225

Step 4. The extract is filtered using a pressurized process. The filter size and input pressure are 2226 selected as specified by the manufacturer or manufacturer’s catalogue of the filtering unit. 2227 2228

6. Process controls 2229 Controls for tests conducted during the process should be described. A description of the tests, their 2230 methods and the acceptance criteria should be given. These include appearance (i.e. colour), particle 2231 size (amount expected to pass through a specified sieve size), water or alcohol content, and/or relative 2232 density. 2233 2234 7. Release specifications of final product 2235



52

Identify criteria that must be met for release of the final product. These criteria generally include 2236 appearance, relative density, and specified quantities for chemical constituent(s), as well as limits for 2237 heavy metals, microbial content and residual matter. 2238 2239 Chemical profile: i.e. TLC/HPLC fingerprint of chemical constituents 2240 Pharmacopoeial/standard quantitation of chemical markers, where applicable 2241 Heavy metals: limits defined 2242 Microbial: limits defined 2243 Residuals: limits for pesticides, fertilizers, foreign matter, solvent residue, mycotoxins, etc. 2244 2245 8. Certificate of analysis 2246 A certificate of analysis should be generated following completion of quality control testing. This 2247 document should include the assay methods as well as the results obtained using those methods. 2248 2249 9. Packaging 2250 The appropriate packaging of the containers should be described. Processed materials should be 2251 packaged quickly and appropriately in air-tight, non-corrosive containers, and protected from light to 2252 preserve quality, prevent deterioration and to protect against contamination. 2253 2254 10. Labelling 2255 Labels affixed to each package should clearly indicate the scientific name of the medicinal plant, the 2256 plant part, the processing method, the date of processing, the batch number, quality specification and 2257 compliance, quantitative and other relevant information. 2258 2259 11. Storage conditions 2260 The packaged products must be stored in a clean, dry and well-ventilated area, at a constant 2261 temperature appropriate for the proper maintenance of the final product, and protected against 2262 microbial and other sources of contaminations and free from insects and animal pest attacks. 2263 2264 12. Stability 2265 Stability testing should be conducted to determine an appropriate shelf-life. 2266 2267 13. Retained samples 2268 Sufficient materials (raw material and finished goods) must be retained in proper storage conditions to 2269 allow for future verification of identity and quality. 2270



53

Annex 3: Example of general rules for preparations/monographs of herbal 2271

preparations and herbal dosage forms 2272 2273 [Reference Source: Japanese Pharmacopoeia 16th edition, Ministry of Health, Labour and Welfare, Mach 2011] 2274

2275

Japanese Pharmacopoeia, 16th Edition (2011): 2276

General Rules for Preparations/Monographs for Preparations Related to Crude Drugs 2277

2278 Monographs for Preparations Related to Crude Drugs 2279

2280 Preparations Related to Crude Drugs 2281 2282 (1) Preparations related to crude drugs are preparations mainly derived from crude drugs. Extracts, 2283 Pills, Spirits, Infusions and Decoctions, Teabags, Tinctures, Aromatic Waters, and Fluidextracts are 2284 included in this category. 2285 2286 Definitions, methods of preparations, test methods, containers and packaging, and storage of these 2287 preparations are described in this chapter. 2288 2289 (2) The descriptions of the test methods and the containers and packaging in this chapter are 2290 fundamental requirements, and the preparation methods represent commonly used methods. 2291 2292 1. Extracts 2293 (1) Extracts are preparations, prepared by concentrating extractives of crude drugs. There are 2294 following two kinds of extracts. 2295

(i) Viscous extracts 2296 (ii) Dry extracts 2297

2298 (2) Unless otherwise specified, Extracts are usually prepared as follows. 2299

(i) Crude drugs, pulverized to suitable sizes, are extracted for a certain period of time with 2300 suitable solvents by means of cold extraction or warm extraction, or by percolation as directed in (ii) 2301 of (2) under 6. Tinctures. The extractive is filtered, and the filtrate is concentrated or dried by a 2302 suitable method to make a millet jelly-like consistency for the viscous extracts, or to make crushable 2303 solid masses, granules or powder for the dry extracts. Extracts, which are specified the content of 2304 active substance(s), are prepared by assaying active substance(s) in a portion of sample and adjusting, 2305 if necessary, to specified strength with suitable diluents. 2306

(ii) Weigh crude drugs, pulverized to suitable sizes, according to the prescription and heat for a 2307 certain period of time after adding 10 ñ 20 times amount of water. After separating the solid and liquid 2308 by centrifugation, the extractive is concentrated or dried by a suitable method to make a millet jelly-2309 like consistency for the viscous extracts, or to make crushable solid masses, granules or powder for the 2310 dry extracts. 2311

2312 (3) Extracts have odour and taste derived from the crude drugs used. 2313 2314 (4) Unless otherwise specified, Extracts meet the requirements of Heavy Metals Limit Test <1.07>

1 2315 (for detail of test methods, procedure, and regents and solutions, see end note of this annex), when 2316 the test solution and the control solution are prepared as follows. 2317 2318 Test solution: Ignite 0.30 g of Extracts to ash, add 3mL of dilute hydrochloric acid, warm, and filter. 2319 Wash the residue with two 5-mL portions of water. Neutralize the combined filtrate and washings 2320



54

(indicator: a drop of phenolphthalein TS) by adding ammonia TS until the color of the solution 2321 changes to pale red, filter where necessary, and add 2mL of dilute acetic acid and water to make 2322 50mL. 2323 2324 Control solution: Proceed with 3mL of dilute hydrochloric acid in the same manner as directed in the 2325 preparation of the test solution, and add 3.0mL of Standard Lead Solution and water to make 50mL. 2326 2327 (5) Tight containers are used for these preparations. 2328 2329 2. Pills 2330 (1) Pills are spherical preparations, intended for oral administration. 2331 2332 (2) Pills are usually prepared by mixing drug substance(s) uniformly with diluents, binders, 2333 disintegrators or other suitable excipient(s) and rolling into spherical form by a suitable method. They 2334 may be coated with a coating agent by a suitable method. 2335 2336 (3) Unless otherwise specified, Pills comply with Disintegration Test. 2337 2338 (4) Well-closed or tight containers are usually used for these preparations. 2339 2340 3. Spirits 2341 (1) Spirits are fluid preparations, usually prepared by dissolving volatile drug substance(s) in ethanol 2342 or in a mixture of ethanol and water. 2343 2344 (2) Spirits should be stored remote from fire. 2345 2346 (3) Tight containers are used for these preparations. 2347 2348 4. Infusions and Decoctions 2349 (1) Infusions and Decoctions are fluid preparations, usually obtained by macerating crude drugs in 2350 water. 2351 2352 (2) Infusions and Decoctions are usually prepared by the following method. 2353

Cut crude drugs into a size as directed below, and transfer suitable amounts to an infusion or 2354 decoction apparatus. 2355

Leaves, flowers and whole plants: Coarse cutting 2356 Woods, stems, barks, roots and rhizomes: Medium cutting 2357 Seeds and fruits: Fine cutting 2358

2359 (i) Infusions: Usually, damp 50 g of crude drugs with 50mL of water for about 15 minutes, pour 2360

900 mL of hot water to them, and heat for 5 minutes with several stirrings. Filter through a cloth after 2361 cooling. 2362

(ii) Decoctions: Usually, heat one-day dose of crude drugs with 400 ñ 600mL of water until to 2363 lose about a half amount of added water spending more than 30 minutes, and filter through a cloth 2364 while warm. Prepare Infusions or Decoctions when used. 2365 2366 (3) These preparations have odour and taste derived from the crude drugs used. 2367 2368 (4) Tight containers are usually used for these preparations. 2369 2370



55

5. Tea bags 2371 (1) Tea bags are preparations, usually packed one day dose or one dose of crude drugs cut into a size 2372 between coarse powder and coarse cutting in paper or cloth bags. 2373 2374 (2) Teabags are usually used according to the preparation method as directed under 4. Infusions and 2375 Decoctions. 2376 2377 (3) Well-closed or tight containers are usually used for these preparations. 2378 2379 6. Tinctures 2380 (1) Tinctures are liquid preparations, usually prepared by extracting crude drugs with ethanol or with a 2381 mixture of ethanol and purified water. 2382 2383 (2) Unless otherwise specified, Tinctures are usually prepared from coarse powder or fine cuttings of 2384 crude drugs by means of either maceration or percolation as described below. 2385 2386

(i) Maceration: Place crude drugs in a suitable container, and add an amount of a solvent, 2387 equivalent to the same volume or about three-fourths of the volume of the crude drugs. Stopper 2388 container, and allow the container to stand for about 5 days or until the soluble constituents have 2389 satisfactorily dissolved at room temperature with occasional stirring. Separate the solid and liquid by 2390 centrifugation or other suitable methods. In the case where about three-fourths volume of the solvent is 2391 added, wash the residue with a suitable amount of the solvent, and squeeze the residue, if necessary. 2392 Combine the extract and washings, and add sufficient solvent to make up the volume. In the case 2393 where the total volume of the solvent is added, sufficient amounts of the solvent maybe added to make 2394 up for reduced amount, if necessary. Allow the mixture to stand for about 2 days, and obtain a clear 2395 liquid by decantation or filtration. 2396 2397

(ii) Percolation: Pour solvent in small portions to crude drugs placed in a container, and mix well 2398 to moisten the crude drugs. Stopper container, and allow it to stand for about 2 hours at room 2399 temperature. Pack the contents as tightly as possible in an appropriate percolator, open the lower 2400 opening, and slowly pour sufficient solvent to cover the crude drugs. When the percolate begins to 2401 drip, close the opening, and allow the mixture to stand for 2 to 3 days at room temperature. Then, open 2402 the opening, and allow the percolate to drip at a rate of 1 to 3mL per minute. Add an appropriate 2403 quantity of the solvent to the percolator, and continue to percolate until the desired volume has passed. 2404 Mix thoroughly, allow standing for 2 days, and obtain a clear liquid by decantation or filtration. The 2405 time of standing and the flow rate may be varied depending on the kind and amount of crude drugs to 2406 be percolated. 2407 2408 Tinctures, prepared by either of the above methods and specified the content of marker constituent or 2409 ethanol, are prepared by assaying the content using a portion of the sample and adjusting the content 2410 with a sufficient amount of the percolate or solvent as required on the basis of the result of the assay. 2411 2412 (3) Tinctures should be stored remote from fire. 2413 2414 (4) Tight containers are used for these preparations. 2415 2416 7. Aromatic Waters 2417 (1) Aromatic Waters are clear liquid preparations, saturated essential oils or other volatile substances 2418 in water. 2419 2420 (2) Unless otherwise specified, Aromatic Waters are usually prepared by the following process. Shake 2421



56

thoroughly for 15 minutes 2mL of an essential oil or 2 g of a volatile substance with 1000 mL of 2422 lukewarm purified water, set the mixture aside for 12 hours or longer, filter through moistened filter 2423 paper, and add purified water to make 1000 mL. Alternatively, incorporate thoroughly 2 mL of an 2424 essential oil or 2 g of a volatile substance with sufficient talc, refined siliceous earth or pulped filter-2425 paper, add 1000 mL of purified water, agitate thoroughly for 10 minutes, and then filter the mixture. 2426 To obtain a clear filtrate repeat the filtration if necessary, and add sufficient purified water passed 2427 through the filter paper to make 1000mL. 2428 2429 (3) Aromatic Waters have odour and taste derived from the essential oils or volatile substances used. 2430 2431 (4) Tight containers are used for these preparations. 2432 2433 8. Fluidextracts 2434 (1) Fluidextracts are liquid percolates of crude drugs, usually prepared so that each mL contains 2435 soluble constituents from 1 g of the crude drugs. Where the content is specified, it takes precedence. 2436 2437 (2) Unless otherwise specified, Fluidextracts are usually prepared from coarse powder or fine cutting 2438 of crude drugs by either of following maceration or percolation. 2439 2440

(i) Maceration: Place a certain amounts of crude drugs in a suitable vessel, add a solvent to cover 2441 the crude drugs, close the vessel, and allow the vessel to stand at room temperature with occasional 2442 stirring for about 5 days or until the soluble constituents have satisfactorily dissolved. Separate the 2443 solid and liquid by centrifugation or other suitable method. Usually, reserve a volume of the liquid 2444 equivalent to about three-fourths of the total volume, and use it as the first liquid. Wash the residue 2445 with appropriate amount of the solvent, combine the washings and the remaining of the first liquid, 2446 concentrate if necessary, mix with the first liquid, and use it as solution (A). To the solution (A) add 2447 the solvent, if necessary, to make equal amount of the mass of the crude drugs. Allow the mixture to 2448 stand for about 2 days, and collect a clear liquid by decantation or filtration. 2449 2450

(ii) Percolation: Mix well 1000 g of the crude drugs with the first solvent to moisten them, close 2451 the container, and allow it to stand for about 2 hours at room temperature. Transfer the content to a 2452 suitable percolator, stuff it as tightly as possible, open the lower opening of the percolator, and slowly 2453 pour the second solvent to cover the crude drugs. Close the lower opening when the solvent begins to 2454 drop, and allow the mixture to stand for 2 to 3 days at room temperature. Open the lower opening, and 2455 allow the percolate to run out at the rate of 0.5 to 1.0mL per minute. Set aside the first 850 mL of the 2456 percolate as the first percolate. Add the second solvent to the percolator, then drip the percolate, and 2457 use it as the second percolate. 2458 2459 The period of standing and the flow rate during percolation may be varied depending on the kind and 2460 the amount of crude drugs used. The flow rate is usually regulated as follows, depending on the using 2461 amount of crude drugs. 2462 2463

Mass of crude drug

Volume of solution running per

minute

Not more than 1000 g

Not more than 3000 g

Not more than 10000g

0.5 - 1.0mL

1.0 - 2.0mL

2.0 - 4.0mL

2464 Concentrate the second percolate, taking care not to lose the volatile substances of the crude drug, mix 2465 with the first percolate, and use it as solution (A). To the solution (A) add the second solvent to make 2466



57

1000 mL, and allow the mixture to stand for about 2 days. Decant the supernatant liquid or filter the 2467 liquid to obtain a clear solution. 2468 2469 Fluidextracts for which the content of marker constituent or ethanol is specified are obtained by 2470 adjusting the content with a sufficient amount of the second solvent as required on the basis of the 2471 result of the assay made with a portion of the solution (A). 2472 2473 (3) Fluidextracts have odour and taste derived from the crude drugs used. 2474 2475 (4) Unless otherwise specified, Fluidextracts meet the requirements of Heavy Metals Limit Test 2476 <1.07>

1 when the test solution and the control solution are prepared as follows. 2477

2478 Test solution: Ignite 1.0 g of Fluidextracts to ash, add 3 mL of dilute hydrochloric acid, warm, and 2479 filter. Wash the residue with two 5-mL portions of water. Neutralize the combined filtrate and 2480 washings (indicator: a drop of phenolphthalein TS) by adding ammonia TS until the colour of the 2481 solution changes to pale red, filter if necessary, and add 2 mL of the dilute acetic acid and water to 2482 make 50 mL. 2483 2484 Control solution: Proceed with 3 mL of dilute hydrochloric acid in the same manner as directed in the 2485 preparation of the test solution, and add 3.0 mL of Standard Lead Solution and water to make 50 mL. 2486 2487 (5) Tight containers are used for these preparations. 2488 2489 1Test <1.07> 1.07 Heavy Metal Limit test (JP 16, pp21-23) 2490

Heavy Metals Limit Test is a limit test of the quantity of heavy metals contained as impurities in drugs. The heavy metals 2491 are the metallic inclusions that are darkened with sodium sulfide TS in acidic media, as their quantity is expressed in terms of 2492 the quantity of lead (Pb). In each monograph, the permissible limit for heavy metals (as Pb) is described in terms of ppm in 2493 parentheses. 2494 2495 Procedure: 2496 Add 1 drop of sodium sulfide TS to each of the test solution and the control solution, mix thoroughly, and allow to stand for 5 2497 minutes. Then compare the colors of both solutions by viewing the tubes downward or transversely against a white 2498 background. The test solution has no more color than the control solution. 2499 2500 Solutions and Reagents: 2501 Standard Lead Solution 2502 Measure exactly 10 mL of Standard Lead Stock Solution, and add water to make exactly 100 mL. Each mL of this solution 2503 contains 0.01 mg of lead (Pb). Prepare before use. 2504 2505 Standard Lead Stock Solution 2506 Weigh exactly 159.8 mg of lead (II) nitrate, dissolve in 10 mL of dilute nitric acid, and add water to make exactly 1000 mL. 2507 Prepare and store this solution using glass containers, free from soluble lead salts. 2508 2509 Ammonia solution (28) 2510 NH4OH [K 8085, Ammonia Water, Special class, Density: 0.90 g/mL, Content: 28- 30%] 2511 2512 Ammonia TS 2513 To 400 mL of ammonia solution (28) add water to make 1000 mL (10%). 2514 2515 Acetic acid, dilute 2516 Dilute 6 g of acetic acid (100) with water to make 100 mL (1 mol/L). 2517 2518 Acetic acid (100) 2519 CH3COOH [K 8355, Acetic Acid, Special class] 2520 2521 Dilute acetic acid 2522 See acetic acid, dilute. 2523



58

2524 Dilute hydrochloric acid 2525 See hydrochloric acid, dilute. 2526 2527 Hydrochloric acid, dilute 2528 Dilute 23.6 mL of hydrochloric acid with water to make 100mL (10%). 2529 2530 Hydrochloric acid 2531 HCl [K 8180, Special class] 2532 2533 Phenolphthalein TS 2534 Dissolve 1 g of phenolphthalein in 100 mL of ethanol (95). 2535 2536 Phenolphthalein 2537 C20H14O4 [K 8799, Special class] 2538 2539 Ethanol (95) 2540 C2H5OH [K 8102, Special class] 2541 2542 Sodium sulfide enneahydrate 2543 Na2S.9H2O [K 8949,Special class] 2544 2545 Sodium sulfide TS 2546 Dissolve 5 g of sodium sulfide enneahydrate in a mixture of 10 mL of water and 30 mL of glycerin. Or dissolve 5 g of 2547 sodium hydroxide in a mixture of 30 mL of water and 90 mL of glycerin, saturate a half volume of this solution with 2548 hydrogen sulfide, while cooling, and mix with the remaining half. Preserve in well-filled, light-resistant bottles. Use within 3 2549 months. 2550 2551 Sodium hydroxide 2552 NaOH [K 8576, Special class] 2553 2554 Glycerin 2555 C3H8O3 [K 8295, Glycerol, Special class. Same as the monograph Concentrated Glycerin] 2556 2557 Hydrogen sulfide 2558 H2S Colorless, poisonous gas, heavier than air. It dissolves in water. Prepare by treating iron (II) sulfide heptahydrate with 2559 dilute sulfuric acid or dilute hydro chloric acid. Other sulfides yielding hydrogen sulfide with 2560 dilute acids may be used. 2561 2562 Sulfuric acid 2563 H2SO4 [K 8951, Special class] 2564 2565 Sulfuric acid, dilute 2566 Cautiously add 5.7 mL of sulphuric acid to 10 mL of water, cool, and dilute with water to make 100 mL (10%). 2567 2568 Iron (II) sulfate heptahydrate 2569 FeSO4.7H2O [K 8978, Special class] 2570



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Annex 4: Processing facilities 2571

2572 The following is extracted from Section 4.1.5 of the WHO guidelines on good agricultural and collection 2573 practices (GACP) for medicinal plants (WHO, 2003) (pages 19-23). 2574 2575 4.1 Processing facilities 2576 2577 In constructing or designing a processing facility, the following elements should be considered that 2578 will allow the establishment of a quality assurance system adaptable to the different types and steps of 2579 processing to yield the desired end products. 2580 2581 Location 2582 Facilities should preferably be located in areas that are free from objectionable odours, smoke, dust or 2583 other contaminants, and are not subject to flooding or other natural adverse conditions. 2584 2585 Buildings 2586 Buildings should be of sound construction and maintained in good repair. Filthy areas must be isolated 2587 from clean processing areas. All construction materials should be such that they do not transmit any 2588 undesirable substance including toxic vapours to medicinal plant materials. Electrical supply, lighting, 2589 and ventilation should be appropriately installed. 2590 2591 Buildings should be designed to: 2592 provide adequate working space and storage room to allow for satisfactory performance of all 2593

operations; 2594 to ensure the logical flow of materials and personnel; 2595 facilitate efficient and hygienic operations by allowing a regulated flow in processing from the 2596

arrival of the raw medicinal plant materials at the premises to the dispatch of the processed 2597 medicinal plant materials; 2598

permit appropriate control of temperature and humidity; 2599 permit control of access to different sections, where appropriate; 2600 permit easy and adequate cleaning and facilitate proper supervision of hygiene; 2601 prevent the entry of environmental contaminants such as smoke, dust, the entrance and harbouring 2602

of pests, livestock and domesticated animals. 2603 2604 Medicinal plant material handling and processing areas 2605 The layout and design of the work area should be such as to minimize the risk of errors and permit 2606 effective cleaning and maintenance in order to avoid cross contamination, and otherwise avoid any 2607 adverse effect on the quality of the processed product. 2608 2609 Windows and other openings should be constructed so as to avoid accumulation of dirt, and where 2610

appropriate, those that open should be fitted with insect-proof screens. Screens should be easily 2611 removable for cleaning and kept in good repair. Internal window sills, if present, should be sloped 2612 to prevent use as shelves. 2613

Doors should have smooth, non-absorbent surfaces and, where appropriate, be self-closing and 2614 close-fitting. 2615

Overhead structures and fittings should be installed in such a manner as to avoid contamination of 2616 medicinal plant materials (both raw and processed) by condensation and drippings, and should be 2617 protected to prevent contamination in case of breakage. They should be insulated, where 2618 appropriate, and be designed and finished so as to prevent the accumulation of dirt and to 2619 minimize condensation, mould development and flaking. They should be easy to clean. 2620



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Food preparation and eating areas, changing facilities, toilets should be completely separated from 2621 and not open directly onto medicinal plant material processing areas. 2622

2623 Water supply 2624 An ample supply of potable water, under adequate pressure and at suitable temperature, used for 2625

processing medicinal plant materials, should be available with appropriate facilities for its storage, 2626 where necessary, and distribution, and with proper protection against contamination. 2627

Ice should be made from potable water; it should be manufactured, handled and stored so as to 2628 protect it against contamination. 2629

Unless there is a post water filtration or treatment system, non-potable water used for steam 2630 production, refrigeration, fire control and other similar purposes not connected with processing 2631 should be carried in completely separate pipes, identifiable preferably by colour, and with no 2632 cross-connection with or back siphonage into the system carrying potable water. 2633

2634 Effluent and waste disposal 2635 Facilities should have an effective effluent and waste disposal system, which should at all times be 2636 maintained in good order and repair; and should be constructed so as to avoid contamination of 2637 potable water supplies. 2638 2639 Changing facilities and toilets 2640 Adequate, suitable and conveniently located changing facilities and toilets should be provided. Hand-2641 washing facilities with warm or hot and cold water, a suitable hand-cleaning preparation and hygienic 2642 means of drying should be provided adjacent to toilets and located so that employees have to pass 2643 them when returning to the processing area. Notices should be posted directing personnel to wash 2644 their hands after using the toilet. 2645 2646 Hand-washing facilities in processing areas 2647 Adequate and conveniently located facilities for hand-washing and a hygienic means of drying should 2648 be provided whenever the process demands. Where appropriate, facilities for hand disinfection should 2649 also be provided. 2650 2651 Disinfection facilities 2652 Where appropriate, adequate facilities for cleaning and disinfection of working implements and 2653 equipment should be provided. These facilities should be constructed of corrosion-resistant materials, 2654 should be easy to clean, and should be fitted with hot and cold water supplies. 2655 2656 Lighting 2657 Adequate natural or artificial lighting should be fitted throughout the facility. Where appropriate, the 2658 lighting should not alter colours of the medicinal plants undergoing processing. 2659 2660 Ventilation 2661 Adequate ventilation should be provided to prevent excessive heat, steam condensation and dust and 2662 to remove contaminated air from both the processing and storage areas/facilities. 2663 2664 Storage of waste and unusable materials 2665 Facilities should be provided for the storage of waste and unusable materials prior to removal from the 2666 premises. 2667

Documents

Revised Draft: WHO guidelines on good herbal … Do not distribute without permission from WHO R-Draft WHO guidelines for comments, March 2017 - - WHO guidelines on good herbal processing