WHO Drug Information - - World Health Organization

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WHO Drug Information Vol. 24, No. 4, 2010

WHO PrequalificationProgrammesWHO Prequalification of Medicines

Programme: survey of servicequality provided to manufacturers 293

WHO initiates pilot prequalification ofactive pharmaceutical ingredients 297

New on-line database for WHOprequalified vaccines 298

Safety and Efficacy Issues

H1N1 influenza vaccine: narcolepsy 299Statins: interstitial lung disease 299Tocilizumab: risk of fatal anaphylaxis 300Pioglitazone: potential bladder cancer 301Angiotensin receptor blockers and

cancer: safety review 301GnRH agonists, diabetes and cardio-

vascular disease 301Gadolinium-based contrast agents:

kidney dysfunction 302Lamotrigine: aseptic meningitisTinzaparin sodium: renal Impairment

in elderly 303Tamoxifen: drug interactions involving

CYP2D6 genetic variants 303Zoledronic acid solution: renal

dysfunction 304

Regulatory Action and NewsInfluenza vaccines: 2011 southern

hemisphere 305Rosiglitazone-containing antidiabetes

medicines: suspension of marketingauthorization 305

Modified-release oral opioids: suspensionof marketing authorization 306

Human normal immunoglobulin: sus-pension of marketing authorization 306

Propoxyphene: recommendationagainst use 306

Sitaxentan: worldwide withdrawal 307Sibutramine: suspension of sales 307Sibutramine-containing medicines:

withdrawal 308Testosterone transdermal patch:

withdrawal of extension ofindication application 308

Aliskiren/valsartan: withdrawal ofmarketing authorization application 308

Mometasone furoate/formoterolfumarate: withdrawal of marketingauthorization application 309

EMA and US FDA extend confidentialityarrangements indefinitely 309

Recent Publications,Information and EventsUS Government to share patents with

Medicines Patent Pool 310Clinical trials and global medicines

development 310Evaluation of future nanomedicines 311Reporting on opioid inaccessibility 311

Consultation DocumentsThe International PharmacopoeiaCapreomycin sulfate 312Capreomycin for injection 316Efavirenz tablets 319Efavirenz, emtricitabine and tenofovir

tablets 323Emtricitabine capsules 327Emtricitabine and tenofovir tablets 330Levamisole tablets 334Levofloxacin 337Levofloxacin tablets 342Levonorgestrel tablets 346

Proposed InternationalNonproprietary Names List 104 351

WHO Drug Information

World Health Organization

Contents

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WHO Drug Information Vol. 24, No. 4, 2010World Health Organization

WHO Drug Information

Digital Library,

e-mail table of contents

and subscriptions

available at:

http://www.who.int/druginformation

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WHO PrequalificationProgrammes

The surveyIn administering the Prequalification ofMedicines Programme (PQP), WHOinteracts with a number of stakeholdergroups and organizations whose objec-tives are dependent upon, or related to,WHO prequalification of medicines:manufacturers, government agencies(including national and regional medi-cines regulatory authorities) and donororganizations. In 2009, one such donor

organization recommended that WHOundertake a process optimization reviewwith respect to PQP – an exercise thatwould include feedback from manufactur-ers with experience of WHO prequalifica-tion of medicines.

To provide guidance in developing asurvey of manufacturers, implementingthe survey and analysing the results,PQP retained the services of a marketresearch consulting company, Interclarity

Established in 2001, the Prequalification of Medicines Programme (PQP) is a serviceprovided by the World Health Organization (WHO) to facilitate access to quality medi-cines for treating priority diseases. In order to be prequalified, medicines must meetWHO-specified standards for quality, safety and efficacy. PQP is supported by vari-ous United Nations agencies (e.g., UNAIDS, UNICEF, UNFPA) and the World Bank.

WHO prequalification of medicines is a multi-step process whereby a manufacturersubmits extensive information that is then evaluated by a WHO assessment teamwith respect to product quality, safety and efficacy, site(s) of manufacture and anyclinical studies that may have been carried out during development. Products thatsuccessfully pass PQP evaluation are listed on the WHO List of Prequalified Medici-nal Products (see: http://www.who.int/prequal). This list provides UN agencies with asingle source of reference for quality-assured priority medicines and is also used bya variety of entities, both country-specific and international, that purchase medicinesin bulk quantities.

The Prequalification of Medicines Programme has conducted a comprehensive sur-vey among pharmaceutical manufacturers to assess its level of service. PQP as-sessment and inspection activities reflect those carried out by national regulatoryauthorities before granting marketing authorization (registration) for a medicine. Theassessment review was therefore designed to maximize the diagnostic capability ofthe survey: to measure both the level of service provided by PQP and the levels ofservice expected from regulatory authorities by manufacturers. The survey includeditems relevant to the assessment of product dossiers and on-site inspections of manu-facturing facilities in a way that separated service design (the service process) fromservice delivery (or the “people” aspects of service). The results of this survey pro-vide direction for improvements to the current Programme and have implications forfuture strategic development.

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Research & Consulting, Inc. InterclarityResearch created a survey developmentprocess with both internal and externalcomponents that resulted in a surveywhose contents were relevant to manu-facturers and, when assessed by thosemanufacturers, actionable by PQP. Thesurvey was undertaken with the clearunderstanding that PQP must operate inaccordance with respective WHO andother relevant international technicalstandards. It was also understood that theresults of the survey should neither serveto “lower” PQP’s technical standards norto “relax” the requirements for the sus-tained quality, safety and efficacy of anymedicine that WHO had prequalified.

Survey objectivesPQP identified three main objectives indesigning and conducting a survey ofpharmaceutical manufacturers:

• Implement a comprehensive ap-proach to assessing the level ofservice quality delivered to pharma-ceutical manufacturers by PQP by(i) incorporating aspects of both servicedesign (process) and service delivery

(people) and (ii) including servicesprovided during both the assessment ofproduct dossiers and on-site inspectionsof manufacturing facilities.

• Maximize the diagnostic ability of thesurvey by incorporating questions thatuse manufacturer experience with majorregulatory agencies (US FDA, EMA,etc.) to measure expectations of servicequality and prioritize areas for improve-ment.

• Provide a unified framework formeasurement. While the intent of theinitial survey of pharmaceutical manu-facturers was to include only thosecompanies that have had at least oneproduct prequalified, PQP was alsointerested in developing a survey formatthat could be extended to companiesinvolved for the first time (at some stagein the approval process or awaiting finalapproval) and companies that areconsidering participation.

Survey development processWithout the benefit of previous self-assessment efforts, PQP had little to workwith in terms of survey content in January

Figure 1. Survey development

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2010. The area of service delivery is richin both academic research and practicalapplication [1]; the area of service design,however, is specific to the organization,application, and recipients of the service.Figure 1 on page 294 illustrates theprocess used by PQP to identify andcodify important services related to theprequalification of medicines.

A survey development process wasdesigned to obtain input from within theorganization and from regulatory andquality assurance professionals in phar-maceutical companies. The overall aim ofthis process was to capture and includethe knowledge and experience of PQP sothat, when combined with the “voice ofthe customer”, survey contents would beboth relevant and actionable.

Interclarity Research developed topicguides and facilitated discussions, inter-views and working sessions for bothinternal and external phases of theprocess. Internal working sessions, bothin conference call and in-person formats,were conducted with key PQP membersand groups (e.g. programme manage-ment, PQP assessors and PQP inspec-tors). Following the internal review, in-depth telephone interviews were con-ducted with industry professionals familiarwith PQP. In both phases of the surveydevelopment process, the emphasis wason identifying, from a participant’s point ofview, important stages in the WHOprequalification process — aspects thatwork well and those that fall short ofparticipant expectation. To gain greaterclarity around important issues associ-ated with service delivery, efforts weremade in the “voice of the customer” toidentify detailed descriptions of servicedelivery for both favourable and unfavour-able events, as experienced by PQPmanufacturer participants [2, 3].

A list of candidate survey items related tothe PQP service process was developedfrom the findings of internal and external

qualitative research. Further analysis ofthe qualitative findings suggested thatservice delivery aspects of PQP would bewell-represented by items included in theSERVQUAL scale of service quality [4].SERVQUAL is a widely-applied scale formeasuring the quality of service delivery.Developed in the 1980s, it has beenrefined and applied over the past 25years.

Survey construction and deploymentThe survey was divided into four mainsections:

1. Experience with PQP.

2. PQP Service Design (“process”).

3. PQP Service Delivery (“people”).

4. Other Aspects of PQP.

The first section includes an introductionto the survey and questions that provideindicators and measures of previousexperience with PQP. Section 2 (ServiceDesign) is “custom” to PQP – developedas a result of a process review with PQPstaff and the series of interviews withpharmaceutical manufacturers. Thissection includes two multi-item questionson PQP aspects common to both assess-ment and inspection environments, andtwo separate multi-item questions eachfor regulatory affairs and quality assur-ance professionals respectively. InSection 3 (Service Delivery), measuringthe people component with SERVQUALrequires five separate multi-item ques-tions each for the assessment of productdossiers and on-site inspections respec-tively. The items in Section 4 are alsocustom to PQP and include measuresrelated to the advocacy, training andcompliance aspects of PQP.

Incorporating both common and applica-tion-specific items in a single surveymade deploying the questionnaire on theInternet advantageous. The appropriateprogramming logic was developed to

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display the questions common to allrespondents and the application-specificquestions (i.e. assessment of productdossiers and on-site inspections) only tothose respondents with the relevantbackground and PQP experience. Inaddition, since a relatively large numberof respondents in both the Indian andChinese markets were anticipated, nativelanguage versions of the questionnairefor these two markets were made avail-able, along with the English languageversion. An option was included in thesurvey introduction that allowed respond-ents to select a language option.

MeasurementWHO service performance was measuredusing a 7-point rating scale, where a “1”indicates “low performance” and a “7”indicates “high performance”. The num-bers 2 – 6 are varying degrees in be-tween. To increase the diagnostic value ofthe survey results, two supplementalquestions [4] were included to describemanufacturer expectations around eachservice item:

1. Minimum Service Level. The minimumlevel of service performance that manu-facturers are willing to accept from ANYmajor regulatory agency.

2. Desired Service Level. The level ofservice that a regulatory agency shoulddeliver to manufacturers.

Data CollectionA list of potential survey participants wascompiled by PQP Staff using internalrecords. The list included regulatoryaffairs professionals (assessment ofproduct dossiers) and quality assuranceprofessionals (on-site inspections) whohad participated in WHO prequalificationof medicines during the period 2006 –2010. Individuals on the contact listrepresented manufacturers of bothbranded and generic pharmaceutical

medicines who have had a medicinalproduct or products prequalified by WHO.After cleaning and validation, the initial listof 75 contacts was revised to a final list of62 prospective survey respondents. Allcontacts on the final list received an e-mail invitation from Interclarity Researchon behalf of WHO. Each e-mail includedan embedded link to the survey question-naire on a secure web site. A total of 41completed surveys was collected: 18responses from regulatory affairs profes-sionals and 23 responses from qualityassurance professionals.

Key Findings

• Both PQP assessors and inspectors aremeeting or exceeding manufacturerexpectations for service delivery.

• The structure of PQP generally deliverslevels of service at, or above, thoseexpected by manufacturers. However,the service process is falling short ofmanufacturer expectations with respectto:

- Review/reply time for product dossiers.

- Opportunities for in-person communica-tion during the assessment process.

- Question/problem resolution duringassessment.

- Consistency of membership in the teamof assessors throughout the process.

- Local/national representation in on-siteinspection teams,

• Most manufacturers view PQP GMPrequirements as more stringent thanthose of the US Food and Drug Admin-istration or European Medicines Agency.

• Reducing the time required to prequalifya product requires a joint effort betweenthe manufacturer and the PQP.


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ConclusionsOverall, the findings from this surveyindicate that pharmaceutical manufactur-ers consider PQP to be a well-designed,well-executed programme. PQP asses-sors and inspectors are meeting orexceeding manufacturer expectations forservice delivery in the process. However,pharmaceutical manufacturer applicantsplace a premium on feedback, communi-cations and problem resolution during theprequalification process – with particularemphasis on the assessment of productdossiers – and these are potential im-provement areas in the service design ofPQP.

Based on the survey results, WHO is nowworking on improvements to the Pro-gramme and these will be implemented inthe coming year.


References

1. Parasuraman, A., Valarie A. Zeithaml andLeonard L. Berry. SERVQUAL: A Multiple-Itemscale for measuring customer perceptions ofservice quality. Journal of Retailing,1988;64(1):12–40.

2. Bitner, Mary Jo, Bernard H. Booms andMary Stanfield Tetreault. The service encoun-ter: diagnosing favorable and unfavorableincidents. Journal of Marketing,1990:54:71–84.

3. Hayes, Bob E. Measuring customer satis-faction and loyalty, Third Edition. ed.Milwaukee, WI, American Society for Quality,2008. Quality Press.

4. Zeithaml, Valarie A. and A. Parasuraman.Service Quality, Cambridge, MA, 2004.Marketing Science Institute.

WHO initiates pilotprequalification of activepharmaceutical ingredientsIn October 2010, the WHO Prequalifica-tion of Medicines Programme (PQP)started to pilot prequalification of selectedactive pharmaceutical ingredients (APIs)for products for treating HIV and relateddiseases, malaria and tuberculosis. Itsfirst “Invitation to Manufacturers of ActivePharmaceutical Ingredients to Submit anExpression of Interest (EOI) for Evalua-tion” is available at http://who.int/prequal/

Globalization of pharmaceutical produc-tion has led to diversification of APIsources and made verification of APIquality more difficult. WHO’s decision toprequalify APIs responds to the increas-ing concern expressed by medicinesregulators regarding API quality, includingthe manner in which APIs are manufac-tured.

PQP already assesses API master files(APIMFs) as part of its evaluation offinished pharmaceutical products (FPPs).This can include inspection of the manu-facturing site to assess compliance withWHO good manufacturing practices(GMP), if risk assessment indicates thatan on-site inspection is necessary. An APIsubmitted for evaluation will undergo bothdossier assessment and inspection of themanufacturing site.

Each prequalified API — including detailsof the supplier and manufacturing site(s)— will be added to the WHO List ofPrequalified Active PharmaceuticalIngredients. The List will be of greatinterest to FPP manufacturers seeking toensure the good quality of APIs used inFPP production, and to national medi-cines regulatory authorities who wish toverify the standard of APIs that havebeen used to manufacture nationallyregistered medicines.

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It is expected that the time taken to reachprequalification will be made shorter forFPPs that are manufactured using WHO-prequalified APIs, than for FPPs that aremanufactured using APIs that have notpreviously been evaluated by WHO PQP.

An APIMF that has already been ac-cepted by WHO in relation to the pre-qualification of an FPP may be includedin the WHO List of Prequalified APIswithout reassessment or re-inspection.This is contingent upon the APIMFmeeting certain administrative criteria andthe relevant manufacturing site havingpassed inspection by WHO or a stringentregulatory authority.

Selection of APIs for inclusion in the firstInvitation was based on APIs for whichAPIMFs have already been submitted inconnection with evaluation of an FPP.PQP anticipates that future Invitations willbe expanded to incorporate additionalAPIs. New Invitations will be posted onthe PQP web site and manufacturers aretherefore encouraged to regularly accesshttp://www.who.int/prequal.

New on-line database forWHO prequalified vaccinesA new database for vaccines prequalifiedby WHO by type of vaccine, manufacturerand country of manufacture is nowavailable on WHO’s web site (1). This willenable immunization programme manag-ers, procurement agencies, regulatoryauthorities, and other partners to consultsummary pages for each prequalifiedvaccine and seek information such asdate of prequalification, vaccine presenta-tion, route of administration, shelf life,packaging, and cold chain requirements.

The ultimate goal of WHO’s prequalifica-tion programme for vaccines is to ensurethat all countries have access to vaccinesthat meet international standards of

quality, safety and efficacy and areappropriate for the target population. Therigourous prequalification process in-cludes

• review of comprehensive documentationon production methods, vaccine compo-sition, quality control and clincial experi-ence;

• independent testing for consistency byWHO-accredited laboratories; and

• site audits of the manufacturer to ensurethat vaccine and production methodsconform to international standards.

Complaints about vaccine quality andreports of adverse events followingimmunization are investigated by WHO.Furthermore, United Nations procurementagencies only purchase vaccines thathave been prequalified by WHO.The system is widely credited with con-tributing to the growing number andproportion of quality vaccines beingsupplied by companies in developingcountries, such as Brazil, Cuba, India,Indonesia and Senegal.

The prequalification pages on WHO’sweb site contain sections on overallgoals, principles, process and priority-setting for WHO vaccine prequalification,together with guidance documents forvaccine manufacturers.

References

1. Database on prequalified vaccines at http://www.who.int/immunization_standards/vaccine_quality/PQ_vaccine_list_en/en/index.html

2. Further information on the WHO Prequalifi-cation of Vaccines Programme at http://www.who.int/immunization_standards/vaccine_quality/vq_index/en/index.html


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H1N1 influenza vaccine:narcolepsyEuropean Union — The EuropeanMedicines Agency’s (EMA) Committee forMedicinal Products for Human Use(CHMP) has reviewed all available dataon the suspected link between narcolepsyand Pandemrix® an H1N1 influenzavaccine. The Committee concluded thatthe available evidence was insufficient todetermine whether there is any linkbetween Pandemrix® and reports ofnarcolepsy, and that further studies werenecessary to fully understand this issue.

The Committee agreed that at present thebenefit-risk balance for Pandemrix®continues to be positive and that whilethe review is still ongoing there was noneed for Europe-wide restrictions on use.Narcolepsy is a rare sleep disorder thatcauses a person to fall asleep suddenlyand unexpectedly. Its precise cause isunknown, but it is generally considered tobe triggered by a combination of geneticand environmental factors.

As per 17 September 2010, there were81 reports from healthcare professionalssuggestive of narcolepsy, all collectedthrough spontaneous reporting systems.Of these, 34 reports come from Sweden,30 from Finland, 10 from France, six fromNorway and one from Portugal. In addi-tion, there are a further 13 consumerreports from Sweden and two fromNorway. The age range of patients isbetween four and 52 years.

Reference: EMA Press Release, EMA/CHMP/588294/2010, 23 September 2010 at http://www.ema. europa.eu

Statins: interstitial lungdiseaseCanada — Interstitial lung disease (ILD)is a heterogeneous group of disordersthat can be acute or chronic and maylead to pulmonary fibrosis and pulmonaryinsufficiency (1, 2). Signs and symptomsinclude difficulty breathing, nonproductivecough and diffuse crackles heard onauscultation. ILD has been reported inassociation with several drugs, such asamiodarone, azathioprine, carbamaze-pine, cyclophosphamide, methotrexateand nitrofurantoin (1, 2).

During the past 15 years, 29 cases of ILDsuspected of being associated with HMG-CoA reductase inhibitors (statins) havebeen published (3–14). Of these, 16describe a positive dechallenge with orwithout immunosuppressive treatment(3,4, 6, 8–11,14 ) and three cases de-scribed a positive rechallenge (4, 9). Insome of these reports, ILD was part ofsystemic clinical features consistent withpotential drug-induced diseases such aslupus (7), polymyositis (4, 12), dermato-myositis (5) and Churg-Strauss syndrome(14).

A systematic review of the suspectedassociation between ILD and statins hasrecently been published (15). Althoughthe mechanism of potential statin-inducedILD is unknown, some authors suggestedit could be mediated by the inhibition ofphospholipases; an effect of the statinson mitochondrial metabolism; or immunemediated (15).

As of 31 March 2010, Health Canadareceived 8 adverse reaction reports ofILD, or pathologies associated with ILD,

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suspected of being associated withatorvastatin, pravastatin, rosuvastatin andsimvastatin. Two of the cases received byHealth Canada were published (14).

Extracted from the Canadian AdverseReaction Newsletter, Volume 20, Number4, October 2010

References

1. Kelly HW. Pulmonary fibrosis/interstitialpneumonitis. In: Tisdale JE, Miller DA, editors.Drug-induced diseases: prevention, detection,and management. Bethesda (MD): AmericanSociety of Health-System Pharmacists; 2005.241–7.

2. King TE Jr. Interstitial lung disease. In:Porter RS, Kaplan JL, eds. The Merck manualonline. 18th ed. Whitehouse Station (NJ):Merck Sharp & Dohme Corp.

3. Walker T, McCaffery J, Steinfort C. Poten-tial link between HMG-CoA reductase inhibitor(statin) use and interstitial lung disease. Med JAust 2007;186(2):91–4.

4. Jibbaoui A, Bonniaud P, Jolimoy G, et al.Statin-induced infiltrative lung disease. Aseries of 10 patients. Europ Resp J 2007;30(51):809.

5. Hill C, Zeitz C, Kirkham B. Dermatomyosi-tis with lung involvement in a patient treatedwith simvastatin. Aust N Z J Med 1995;25(6):745–6.

6. De Groot RE, Willems LN, Dijkman JH.Interstitial lung disease with pleural effusioncaused by simvastatin. J Intern Med 1996;239(4):361–3.

7. Sridhar MK, Abdulla A. Fatal lupus-likesyndrome and ARDS induced by fluvastatin.Lancet 1998;352:114.

8. Liebhaber MI, Wright RS, Gelberg HJ, et al.Polymyalgia, hypersensitivity pneumonitis andother reactions in patients receiving HMG-CoAreductase inhibitors: a report of ten cases.Chest 1999;115(3):886–9.

9. Lantuejoul S, Brambilla E, Brambilla C, etal. Statin-induced fibrotic nonspecific intersti-tial pneumonia. Eur Respir J 2002;19(3):577–80.

10. Veyrac G, Cellerin L, Jolliet P. A case ofinterstitial lung disease with atorvastatin(Tahor®) and a review of the literature aboutthese effects observed under statins. Therapie2006;61(1):57–67.

11. Lisco‘t-Loheac N, Andr N, Couturaud F, etal. Hypersensitivity pneumonitis in a patienttaking pravastatin. Rev Mal Respir 2001;18(4pt 1):426–8.

12. Fauchais AL, Iba Ba J, Maurage P, et al.Polymyositis induced or associated with lipid-lowering drugs: five cases. Rev Med Interne2004;25(4):294–8.

13. Naccache JM, Kambouchner M, Girard F,et al. Relapse of respiratory insufficiency oneyear after organising pneumonia. Eur Respir J2004;24(6):1062–5.

14. Rudski L, Rabinovitch MA, Danoff D.Systemic immune reactions to HMG-CoAreductase inhibitors. Report of 4 cases andreview of the literature. Medicine (Baltimore)1998;77(6):378–83.

15. Fernandez AB, Karas RH, Alsheikh-Ali AA,et al. Statins and interstitial lung disease: asystematic review of the literature and of Foodand Drug Administration adverse eventreports. Chest 2008;134(4):824–30.

Tocilizumab: risk of fatalanaphylaxisCanada — The manufacturer oftocilizumab (Actemra®) has informedhealthcare professionals of importantsafety information.

Tocilizumab is a recombinant humanizedanti-human interleukin 6 (IL-6) receptormonoclonal antibody of the immunoglobu-lin (Ig) IgG1 subclass with a H2L2polypeptide structure. It is authorized forintravenous use to reduce the signs andsymptoms of moderately to severelyactive rheumatoid arthritis in adult pa-tients who have inadequate response toone or more disease modifying antirheu-matic drugs (DMARDs) and/or tumournecrosis factor (TNF) antagonists.

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A case of fatal anaphylaxis has beenreported in a patient with rheumatoidarthritis treated with tocilizumab. NoCanadian cases of anaphylactic reactionhave been reported.

As hypersensitivity reactions can occurwith the administration of tocilizumab,patients need to be closely monitoredthroughout the infusion for signs andsymptoms of hypersensitivity.

If a hypersensitivity reaction is suspected,infusion is to be stopped immediately andappropriate treatment should be adminis-tered.

Reference: Communication from Hoffmann-La Roche Limited, dated 13 September 2010at http://www.hc-sc.gc.ca/

Pioglitazone: potentialbladder cancerUnited States of America — The Foodand Drug Administration (FDA) is review-ing data from an ongoing, ten-yearepidemiological study designed to evalu-ate whether pioglitazone (Actos®), isassociated with an increased risk ofbladder cancer. Findings from studies inanimals and humans suggest this is apotential safety risk that needs furtherstudy. Pioglitazone is used in adults withtype 2 diabetes mellitus.

Bladder cancer is estimated to occur in20 per 100 000 persons per year in theUnited States and is thought to be higherin diabetics.

FDA has not concluded that pioglitazoneincreases the risk of bladder cancer. TheAgency is reviewing information related tothe safety concern and will update thepublic when additional information isavailable.

Reference: FDA Drug Safety Communication,17 September 2010 at http://www/fda.gov

Angiotensin receptor blockersand cancer: safety reviewUnited States of America — The Foodand Drug Administration (FDA) is con-ducting a review of the class of medica-tions known as angiotensin receptorblockers (ARBs) after a recently pub-lished study suggested they may beassociated with a small increased risk ofcancer.

ARBs are used in patients with high bloodpressure and other conditions. Brandnames include Atacand®, Avapro®,Benicar®, Cozaar®, Diovan®, Micardis®,and Teveten®. ARBs are also sold incombination with other medications.

The Agency plans to review the availabledata on these medications, and evaluateadditional ways to better assess a possi-ble link between use of ARBs and cancer.FDA will update the public when thisreview is complete.

References

1. Sipahi I, Debanne SM, Rowland DY, SimonDI, Fang JC. Angiotensin-receptor blockadeand risk of cancer: meta-analysis ofrandomised controlled trials. The LancetOncology 2010;11(7), 627-36.

2. FDA Drug Safety Communication, 15 July2010 at http://www/fda.gov

GnRH agonists, diabetes andcardiovascular diseaseUnited States of America — The Foodand Drug Administration (FDA) hasnotified the manufacturers of gonadotro-pin-releasing hormone (GnRH) agonistsof the need to add new safety informationto the Warnings and Precautions sectionof drug labels. This new informationwarns about increased risk of diabetesand certain cardiovascular diseases(heart attack, sudden cardiac death,stroke) in men receiving these medica-

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tions for the treatment of prostate cancer.This action is based on the Agency’sreview of several published studies (1–7),described in the Agency’s ongoing safetyreview of GnRH agonists and possibleincreased risk of diabetes and certaincardiovascular diseases, issued in May2010.

GnRH agonists are approved for palliativetreatment of advanced prostate cancer.The benefits of GnRH agonist use forearlier stages of non-metastatic prostatecancer have not been established.

References

1. Keating NL, O’Malley JO, Smith MR.Diabetes and cardiovascular disease duringandrogen deprivation therapy for prostatecancer. J Clin Oncol. 2006;24:4448–4456.

2. Keating NL, O’Malley JO, Freedland SJ,Smith MR. Diabetes and cardiovasculardisease during androgen deprivation therapy:observational study of Veterans with prostatecancer. J Natl Cancer Inst. 2010;102:39–46.

3. Tsai HK, D’Amico AV, Sadetsky N, Chen M-H, Carroll PR. Androgen deprivation therapyfor localized prostate cancer and the risk ofcardiovascular mortality. J Natl Cancer Inst.2007;99:1516–1524.

4. Saigal CS, Gore JL, Krupski TL, Hanley J,Schonlau M, Litwin MS, and the UrologicDiseases in America project. Androgendeprivation therapy increases cardiovascularmorbidity in men with prostate cancer. Cancer.2007;110:493–500.

5. Van Hemelrijck M, Garmo H, Holmberg L,Ingelsson E, Bratt O, Bill-Axelson A, et al.Absolute and relative risk of cardiovasculardisease in men with prostate cancer: resultsfrom the population-based PCBaSe Sweden.J Clin Oncol. 2010;28:3448–56.

6. Alibhai SMH, Duong-Hua M, Sutradhar R,Fleshner NE, Warde P, Cheung AM, et al.Impact of androgen deprivation therapy oncardiovascular disease and diabetes. J ClinOncol. 2009;27:3452–3458.

7. Efstathiou JA, Bae K, Shipley WU, HanksGE, Pilepich MV, Sandler HM, Smith MR.Cardiovascular mortality after androgendeprivation therapy for locally advancedprostate cancer: RTOG 85-31. J Clin Oncol.2008;27:92–99.

8. FDA Drug Safety Communication, 20October 2010 at http://www/fda.gov

Gadolinium-based contrastagents: kidney dysfunctionUnited States of America — The Foodand Drug Administration (FDA) is requir-ing changes to the drug labelling forgadolinium-based contrast agents(GBCAs) to minimize the risk of nephro-genic systemic fibrosis (NSF), a rare butserious condition associated with the useof GBCAs in certain patients with kidneydysfunction.

These label changes are intended to helpensure these drugs are used appropri-ately, and that patients at risk for NSFwho receive GBCAs are actively moni-tored for the development of NSF. Symp-toms of NSF include scaling, hardeningand tightening of the skin, red or darkpatches on the skin, and stiffness. NSFcan also cause fibrosis of internal organswhich may lead to death. There is noeffective treatment for NSF.

Reference: FDA Drug Safety Communication,9 September 2010 at http://www/fda.gov

Lamotrigine: asepticmeningitisUnited States of America — The Foodand Drug Administration (FDA) hasinformed the public that lamotrigine(Lamictal®), a medication commonlyused for seizures in children two yearsand older and bipolar disorder in adults,can cause aseptic meningitis. FDA isrevising the drug label and the patientmedication guide to include informationabout this risk.

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The decision to revise the Lamictal® labelis based on FDA’s identification of 40cases of aseptic meningitis in patientsfrom December 1994 to November 2009.

Reference: FDA Drug Safety Communication,12 August 2010 at http://www/fda.gov

Tinzaparin sodium: renalImpairment in elderlyCanada — The manufacturer of tinza-parin sodium (Innohep®) has informedhealthcare professionals of importantsafety information related to results froma clinical study that was stopped prema-turely (IRIS – Innohep® in Renal Insuffi-ciency Study) due to the observance ofincreased mortality. This study involvedthe use of therapeutic doses of tinzaparinsodium for the treatment of acute venousthromboembolism (VTE) in elderly pa-tients with renal impairment.

Tinzaparin sodium is a low molecularweight heparin. It is authorized for theprevention of postoperative VTE inpatients undergoing orthopaedic surgeryand in patients undergoing generalsurgery who are at high risk of developingpostoperative VTE; the treatment of deepvein thrombosis (DVT) and/or pulmonaryembolism (PE); and the prevention ofclotting in indwelling intravenous lines forhaemodialysis and extracorporeal circula-tion in patients without high bleeding risk.Based on the observations in IRIS:

• The study was halted by the Data SafetyMonitoring Committee due to an interimfinding of an increase in all-causemortality in patients who receivedtinzaparin sodium compared tounfractionated heparin (UFH).

• Tinzaparin sodium is not recommendedin elderly patients over 70 years of agewith renal impairment.

• Tinzaparin sodium should be used withcaution in patients with moderate to

severe renal impairment and in allcases of impaired renal function pa-tients should be closely monitored.

The IRIS study was an international,multicentre, prospective, open, centrallyrandomized, parallel group study compar-ing treatment doses of tinzaparin sodiumand UFH for the initial treatment of DVTand/or PE in elderly patients with renalimpairment.

Reference: Communication from LEOPharma Inc., dated 14 October 2010 at http://www.hc-sc.gc.ca/

Tamoxifen: drug interactionsinvolving CYP2D6 geneticvariantsUnited Kingdom — CYP2D6 geneticpolymorphisms and concomitant use ofpotent CYP2D6 inhibitors may be associ-ated with variability in clinical response inpatients treated with tamoxifen for breastcancer. Therefore, concomitant use ofmedicines known to be potent CYP2D6inhibitors should be avoided wheneverpossible in patients treated withtamoxifen. Current data for the effect ofgenetic polymorphisms are insufficient tosupport recommending genotyping ofpatients.

Tamoxifen is a selective oestrogen-receptor modulator indicated for palliativeand adjuvant treatment of oestrogen-receptor-positive breast cancer in pre-menopausal and postmenopausalwomen. Tamoxifen is a prodrug, and theformation of the active metabolite,endoxifen, is mediated by the CYP2D6enzyme. Several articles have recentlybeen published regarding the potentialeffect of CYP2D6 genetic variants onclinical response to tamoxifen treatmentin patients with breast cancer.

In patients with inherited non-functionalalleles of the CYP2D6 gene (“poormetabolisers”) or in patients concomi-

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tantly treated with CYP2D6 enzymeinhibitors, concentrations of the tamoxifenmetabolites that most strongly bind to theoestrogen receptor may be reduced.

Reference: Drug Safety Update, Volume 4,Issue 4 November 2010 at http://www.mhra.gov.uk/Safetyinformation/DrugSafetyUpdate/index.htm

Zoledronic acid solution:renal dysfunctionCanada — The manufacturer ofzoledronic acid 5 mg/100 mL solution forintravenous infusion (Aclasta®) hasinformed healthcare professionals ofimportant safety information. As of 30April 2010, 265 spontaneous reports ofrenal impairment have been receivedfollowing administration of Aclasta®,corresponding to a reporting rate ofapproximately 20 cases per 100 000patient-years of exposure.

The following precautions should betaken to minimize the risk of renal ad-verse reactions.

• Zoledronic acid should not be used inpatients with severe renal impairment.

• Zoledronic acid should be used withcaution when concomitantly used withother drugs that could impact renalfunction.

• Creatinine clearance should be calcu-lated before each treatment followed byperiodic monitoring of serum creatininein patients with risk factors. Transientincrease in serum creatinine may begreater in patients with underlyingimpaired renal function.

• Patients should be appropriately hy-drated, especially elderly patients andthose receiving diuretic therapy.

• A single dose of Aclasta® should notexceed 5 mg and the duration of infu-sion should be no less than 15 minutes.

Reference: Communication from NovartisPharmaceuticals Canada Inc. dated 12October 2010 at http://www.hc-sc.gc.ca/


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Regulatory Action and News

Influenza vaccines: 2011southern hemisphereWorld Health Organization — It isexpected that pandemic A(H1N1),A(H3N2) and B viruses will co-circulateand the following viruses are recom-mended for influenza vaccines for the2011 southern hemisphere influenzaseason:

• an A/California/7/2009 (H1N1)-like virus.

• an A/Perth/16/2009 (H3N2)-like virus.(A/Wisconsin/15/2009 and A/Victoria/210/2009 are A/Perth/16/2009-likeviruses.)

• a B/Brisbane/60/2008-like virus.

As in previous years, national or regionalcontrol authorities approve the composi-tion and formulation of vaccines used ineach country. National public healthauthorities are responsible for makingrecommendations regarding the useof the vaccine.

Reference: Recommended viruses forinfluenza vaccines for use in the 2011 south-ern hemisphere influenza season. WeeklyEpidemiological Record, 85:401–402 (2010) athttp://www.who.int/wer

Rosiglitazone-containingantidiabetes medicines:suspension of marketingauthorizationEuropean Union — The EuropeanMedicines Agency has recommendedsuspension of the marketing authoriza-tions for the rosiglitazone-containing anti-diabetes medicines Avandia®, Avanda-met® and Avaglim®.

Patients who are currently taking thesemedicines should make an appointmentwith their doctor to discuss suitablealternative treatments. Patients areadvised not to stop their treatment withoutspeaking to their doctor.

Doctors should stop prescribing rosiglita-zone-containing medicines. Patientstaking rosiglitazone-containing medicinesshould be reviewed in a timely manner toamend their treatment.

The current review of rosiglitazone by theAgency’s Committee for Medicinal Prod-ucts for Human Use (CHMP) was initiatedon 9 July 2010 following the availability ofnew studies questioning the cardiovascu-lar safety of the medicine.

Since its first authorization, rosiglitazonehas been recognized to be associatedwith fluid retention and increased risk ofheart failure and its cardiovascular safetyhas always been kept under close review.Consequently, the use of rosiglitazonewas restricted to second-line treatmentand contraindicated in patients with heartfailure or a history of heart failure when itwas first granted a marketing authoriza-tion as Avandia® in 2000.

Data from clinical trials, observationalstudies and meta analyses of existingstudies that have become available overthe last three years have suggested apossibly increased risk of ischaemic heartdisease associated with the use ofrosiglitazone. Further restrictions on theuse of these medicines in patients withischaemic heart disease were introduced.The availability of recent studies hasadded to the knowledge about rosiglita-zone and overall, the accumulated data

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support an increased cardiovascular riskof rosiglitazone.

In view of the restrictions already in placeon the use of rosiglitazone, the Commit-tee could not identify additional measuresthat would reduce the cardiovascular risk.The Committee therefore concluded thatthe benefits of rosiglitazone no longeroutweigh its risks and recommended thesuspension of the marketing authorizationof the medicines.

Reference: EMA Press Release, EMA/585784/2010, 23 September 2010, at http://www. ema.europa.eu

Modified-release oral opioids:suspension of marketingauthorizationEuropean Union — The EuropeanMedicines Agency has finalized a reviewof modified-release oral opioids of theWHO level III scale for the managementof pain. The Agency’s Committee forMedicinal Products for Human Use(CHMP) concluded that the benefits ofmost of these medicines continue tooutweigh their risks, but that the existingwarnings on the interaction of thesemedicines with alcohol should be madeconsistent across the class. However, formodified-release oral opioids that containa polymethacrylate-triethylcitrate control-led-release system the Committeerecommended suspension of marketingauthorization until they have been refor-mulated to be more stable in alcohol.

Modified-release oral opioids of the WHOlevel III scale for the management of painwere reviewed due to concerns that theymay be unstable in alcohol and that theactive substance may be released tooquickly when patients take them togetherwith alcohol. This could put patients atrisk of serious side effects such asrespiratory depression.

Reference: EMA Press Release, EMA/463702/2010, dated 23 July 2010 at http://www.ema. europa.eu

Human normal immuno-globulin: suspension ofmarketing authorizationEuropean Union — The EuropeanMedicines Agency has recommended thesuspension of the marketing authoriza-tions for human normal immunoglobulin(Octagam®).

Octagam® is an intravenous solutionused to strengthen the body’s immunesystem, including people with primaryimmunodeficiency syndrome, or childrenborn with acquired immune deficiencysyndrome (AIDS). It is also used inpeople with certain immune disorderssuch as idiopathic thrombocytopenicpurpura (ITP) and in patients who havehad a bone marrow transplant.

The CHMP reviewed Octagam® becauseGermany and Sweden had suspendedthe marketing authorization of thesemedicines following an unexpectedincrease in reports of thromboembolicreactions, including stroke, myocardialinfarction and pulmonary embolism inpatients. This increase is thought to berelated to problems with the medicine’smanufacturing process.

The suspension will remain in place untilthe marketing authorization holder hasrectified the problem.

Reference: EMA Press Release, EMA/CHMP/591722/2010, 24 September 2010 at http://www.ema. europa.eu

Propoxyphene:recommendation against useUnited States of America — The Foodand Drug Administration (FDA) is recom-mending against continued prescribing

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and use of the pain reliever propoxy-phene because new data show that thedrug can cause serious toxicity to theheart, even when used at therapeuticdoses. FDA has requested that compa-nies voluntarily withdraw propoxyphenefrom the United States market.

Propoxyphene is an opioid pain relieverused to treat mild to moderate pain. It issold under various names as a single-ingredient product (e.g., Darvon®) and aspart of a combination product with aceta-minophen (e.g., Darvocet®).

The recommendation is based on allavailable data including data from a newstudy that evaluated the effects thatincreasing doses of propoxyphene haveon the heart. FDA has concluded that thesafety risks of propoxyphene outweigh itsbenefits for pain relief at recommendeddoses.

Reference: FDA Drug Safety Communication,19 November 2010 at http://www/fda.gov

Sitaxentan: worldwidewithdrawalAustralia — The Therapeutic GoodsAdministration (TGA) has advised that thesupply of the prescription medicinesitaxentan (Thelin®) will be suspended.The company that supplies the medicinehas announced that it will withdrawThelin® from the market globally.

Sitaxentan is a prescription-only medicineused to treat pulmonary hypertension.Patients currently taking sitaxentanshould contact their physician as soon aspossible to organize the supply of adifferent medicine but should not ceasetheir use of sitaxentan until they havebeen assessed and switched to anothermedication.

This action has been taken in response toa review of safety data in clinical trialsthat showed patients were at risk of acute

liver failure that in some cases was notreversible. The TGA has received 10adverse event reports of abnormal liverfunction in Australian patients receivingsitaxentan.

Reference: TGA Safety Alert, 10 December2010 at http://www.tga.gov.au/alerts/medi-cines/thelin-withdrawal.htm

Sibutramine: suspensionof salesSingapore — The Health SciencesAuthority (HSA) has taken a regulatorydecision to suspend the sales ofsibutramine products following a benefit-risk assessment which took into consid-eration the findings from the SibutramineCardiovascular Outcomes (SCOUT)study, use of the product in the localcontext and developments in otherinternational jurisdictions.

Sibutramine is licensed in Singaporesince 2001 for use as an adjunctivetherapy to diet and exercise for obesepatients with a body mass index (BMI)>30kg/m2, or for overweight patients witha BMI >27kg/m2 with other obesity-relatedrisk factors such as Type 2 diabetesmellitus or dyslipidaemia.

The SCOUT study was a randomized,double-blind, placebo-controlled, multi-centre study conducted in approximately10 000 patients aged ≥55 who wereobese or overweight and had a history ofcardiovascular (CV) disease and/or type2 diabetes with at least one other CV riskfactor treated over a six year period. Thestudy results showed that there was a16% increase in the risk of a primaryoutcome event of nonfatal myocardialinfarction (MI), nonfatal stroke, resusci-tated cardiac arrest and CV death in thesibutramine group as compared with theplacebo group. This was driven primarilyby increase in rates of nonfatal MI andnonfatal stroke seen in the sibutraminegroup. A review of the serious adverse

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events also showed that there weresignificantly more reports of myocardialischaemia and ischaemic stroke insubjects taking sibutramine as comparedto placebo.

The weight loss achieved in the SCOUTstudy was modest. At the end of 12months, the mean weight loss achievedwith sibutramine was up to 2.4 kg morethan placebo. After 12 months of treat-ment, no additional mean weight loss wasachieved and it was not clear if the effecton weight loss could be maintained whensibutramine was stopped.

Based on these findings and the overallassessment, HSA has concluded that thebenefits of sibutramine do not outweightheir risks and has recommended that thesales of sibutramine be suspended. Thissuspension will remain in place until thecompany can provide sufficient data toidentify a group of patients for whomsibutramine’s benefits clearly outweigh itsrisks.

In view of the cessation of marketing ofsibutramine in Singapore with immediateeffect, healthcare professionals areadvised to stop prescribing sibutramine,to review the therapy of existing patientswho have been prescribed sibutramineand to consider suitable alternativeswhere appropriate.

Reference: HSA Safety Alert, 11 October2010 at http://www.hsa.gov.sg

Sibutramine-containingmedicines: withdrawalMexico — The Federal Committee forProtection against Health Risks(COFEPRIS) has requested manufactur-ers of products containing sibutramine tobegin withdrawal of these products fromthe market. Sibutramine is used for thetreatment of obesity and overweight.Evidence now exists of a link to cardio-vascular events.

The Committee has reminded the publicof the risk incurred with self-medication ofproducts claiming weight reduction.

Reference: Communication to Public andHealthcare Professionals, Comision Federalpara la Proteccion contra Riesgos Sanitarios,8 October 2010 at http://www.cofepris.gob.mx

Testosterone transdermalpatch: withdrawal ofextension of indicationapplicationEuropean Union — The EuropeanMedicines Agency (EMA) has beenformally notified by the manufacturer of itsdecision to withdraw its application for anextension of indication for the centrallyauthorized testosterone transdermalpatch (Intrinsa®).

On 10 August 2009, the manufacturersubmitted an application to extend themarketing authorization for Intrinsa® toinclude the treatment of hypoactivesexual desire disorder in menopausalwomen. Intrinsa® is currently authorizedfor the treatment of hypoactive sexualdesire disorder in women who have hadtheir uterus and both ovaries removed. Itis used in patients already taking anoestrogen.

Reference: EMA Press Release, EMA/601877/2010, 29 September 2010 at http://www.ema. europa.eu

Aliskiren/valsartan:withdrawal of marketingauthorization applicationEuropean Union — The EuropeanMedicines Agency has been formallynotified by the manufacturer of its deci-sion to withdraw the application for acentralized marketing authorization foraliskiren/valsartan (Rasival®), 150/160mg and 300/320 mg film-coated tablets.


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This medicine was intended to be usedfor the treatment of essential hyperten-sion as a substitution therapy in adultswhose blood pressure is adequatelycontrolled with aliskiren and valsartan,given as single components concurrently,at the same dose level as in the combina-tion.

The company stated that its decision towithdraw the application was based ontheir inability to address the CHMP’srequests and provide additional datawithin the timeframe allowed in thecentralized procedure.


Mometasone furoate/formoterol fumarate:withdrawal of marketingauthorization applicationEuropean Union — The EuropeanMedicines Agency has been formallynotified by the manufacturer of its deci-sion to withdraw the application for acentralized marketing authorization formometasone furoate/formoterol fumarate(Zenhale®) 50/5, 100/5 or 200/5 mg,pressurised inhalation.

This medicine was intended to be usedfor long-term, twice-daily maintenancetreatment of asthma, including reductionof asthma exacerbations, in adults andchildren aged 12 years or older.

The decision to withdraw the applicationwas based on the manufacturer’s inabilityto address CHMP requests to provide

additional data within the timeframeallowed in the centralized procedure.

Reference: EMA Press Release, EMA/700091/2010, 9 November 2010 at htp://www.ema. europa.eu

EMA and US FDA extendconfidentiality arrangementsindefinitelyEuropean Union/United States ofAmerica — The European MedicinesAgency (EMA) and the United StatesFood and Drug Administration (FDA)have extended their confidentiality ar-rangements related to medicinal productsfor human and veterinary use, followingthe positive experience gained since theinitial arrangements were signed inSeptember 2003. This cooperation willnow continue indefinitely without the needfor further renewal.

The confidentiality arrangements allowboth Agencies to exchange confidentialinformation as part of their regulatory andscientific processes. Their aim is topromote public and animal health and toprotect European and US patients. Thetypes of information covered by thearrangements relate to scientific advice,orphan drug designation, paediatricdevelopment, good manufacturing prac-tice (GMP) and good clinical practice(GCP) inspection planning and reports,marketing authorization procedures andsubsequent changes to the marketingauthorizations together with post-market-ing surveillance.



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Recent Publications,Information and EventsUS Government to sharepatents with MedicinesPatent PoolUnited States of America — A Presiden-tial Policy Directive on Global Develop-ment has been signed that focuses onsustainable development outcomes andplaces a premium on broad-basedeconomic growth, democratic govern-ance, game-changing innovations, andsustainable systems for meeting basichuman needs. The new Policy aims toleverage innovation to solve long-stand-ing development challenges, encouragenew models for innovation and to in-crease developing country utilization ofscience and technology.

The initial contribution by the NationalInstitutes of Health (NIH) and co-patentowner, the University of Illinois at Chi-cago, takes an important step towardmaking affordable and appropriate HIVmedicines available to patients aroundthe world. It builds on the President’sprevious commitment to support humani-tarian licensing policies to ensure thatmedications developed with US taxpayerdollars are available off-patent in develop-ing countries. The patents have previ-ously been licensed for the HIV drugdarunavir. The license to the MedicinesPatent Pool stipulates that the technologywill be available for the benefit of all low-and middle-income countries, as definedby the World Bank, and is royalty-free.

The Medicines Patent Pool is supportedby UNITAID, an innovative global healthfinancing mechanism that was co-founded by Brazil, Chile, France, Norwayand the United Kingdom at the UnitedNations General Assembly in 2006. It is a

voluntary mechanism through whichpharmaceutical patent holders canchoose to license their patents tothe Pool.

Reference: Fact Sheet, 30 September 2010at http://www.WhiteHouse.gov

Clinical trials and globalmedicines developmentEuropean Union — In September 2010,The European Medicines Agency (EMA)held an international workshop with abroad cross section of stakeholders fromaround the world to discuss a way for-ward for a global framework of clinicaltrials that has at its heart the protection ofthe rights, safety and wellbeing of pa-tients participating in clinical trials any-where in the world.

The workshop was part of the consulta-tion process on the Agency’s ‘ReflectionPaper on Ethical and Good ClinicalPractice (GCP) Aspects of Clinical Trialsof Medicinal Products for Human UseConducted in Third Countries and submit-ted in Marketing Authorization Applica-tions to the EMA’.

Some 170 participants from 50 countriesprovided feedback on the ReflectionPaper and discussed international coop-eration. They represented patient organi-sations, health-related nongovernmentalorganizations, clinical trial sponsors,pharmaceutical industry, ethics commit-tees, regulatory authorities from allcontinents and intergovernmental organi-zations.

In marketing authorization applicationssubmitted to the Agency between 2005

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and 2009, only 38.8% of patients enrolledin pivotal clinical trials, received theirtreatments at clinical trial sites within theEU and EEA. These trials involved morethan 44 000 clinical trial sites in 89countries. The data generated was usedto support 347 marketing authorizationapplications as well as some applicationsfor a variation or a line extension of theexisting marketing authorization.

References

1. Draft Reflection Paper on Ethical and GoodClinical Practice (GCP) Aspects of ClinicalTrials of Medicinal Products for Human UseConducted in Third Countries and submitted inMarketing Authorization Applications to theEuropean Medicines Agency, at http://www.ema.europa.eu/docs/en_GB/document_library/Regulatory_and_procedural_guideline/2010/06/WC500091530.pdf

2. EMA Press Release, EMA/559074/2010, 6September 2010 at http:// www.ema.europa.eu

Evaluation of futurenanomedicinesEuropean Union — The EuropeanMedicines Agency (EMA) has hosted thefirst international scientific workshop onnanomedicines in September 2010.Some 200 European and internationalparticipants from 27 countries includingAustralia, Canada, India, Japan and theUnited States discussed benefits andchallenges arising from the application ofnanotechnologies to medicines. Partici-pants included representatives frompatient organizations, health care profes-sional organizations, academia, regula-tory authorities and the pharmaceuticalindustry.

Nanotechnologies have a wide and stillonly partially exploited potential in thedevelopment of medicines. They providescope for engineered nano-systems thatcould lead to a spectrum of useful func-

tions such as refined drug delivery,advanced combined diagnostics/thera-peutic functions, matrices and supportstructures for regenerative medicines.Some eighteen marketing authorizationapplications for nanomedicines havebeen reviewed by the EMA so far.

Emerging therapies give rise to questionson the appropriateness of current regula-tory frameworks, the relevance andadequacy of existing requirements andguidelines, and on the availability ofadequate expertise to regulators. Scien-tific challenges arise from the limitationsof current testing methods and thereliability of novel ones, because of the‘nanosize’ and the unique behaviour ofsuch nano-systems in biological struc-tures.

Reference: European public assessmentreports for nanomedicines and presentationsof the keynote speakers at the workshop(EMA/567306/2010) at: http://www.ema.europa.eu

Reporting on opioidinaccessibilityStrong opioids such as morphine arerarely accessible in low- and middle-income countries, even for patients withthe most severe pain. The three casesrecently reported in the Journal of Painand Palliative Care Pharmacotherapyfrom three diverse countries provideexamples of the terrible and unnecessarysuffering that occurs everyday when thisessential, inexpensive, and safe medica-tion is not adequately accessible bypatients in pain. The reasons for this lackof accessibility are explored, and ways toresolve the problem are proposed.

Reference: Krakauer EL, Wenk R, Buitrago R,Jenkins P, and Scholten W . Opioid inaccessi-bility and its human consequences: ReportsFrom the Field. Journal of Pain and PalliativeCare Pharmacotherapy, 2010;24(3):239–243.

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Consultation Documents

The International Pharmacopoeia

Capreomycini sulfasCapreomycin sulfate

Draft proposal for The International Pharmacopoeia (August 2010).Please address any comments to Quality Assurance and Safety:Medicines, World Health Organization, 1211 Geneva 27, Switzer-land. Fax +41227914730 or e-mail to [email protected]. A subscribermailing list is now available to speed up consultation. For moreinformation please contact [email protected].

Component R1 R2

Capreomycin IA OH -LysylCapreomycin IB H -LysylCapreomycin IIA OH HCapreomycin IIB H H

Capreomycin IA: C25

H48

N14

O16

S2; Capreomycin IB: C

25H

48N

14O

15S

2; Capreomycin IIA:

C19

H35

N12

O15

S2; Capreomycin IIB: C

19H

35N

12O

14S

2

Relative molecular mass. Capreomycin IA: 864.9; Capreomycin IB: 848.9,Capreomycin IIA: 735.7; Capreomycin IIB: 719.7

Chemical name. Capreomycin IA: (3S)-3,6-diamino-N-[[(2S,5S,8Z,11S,15S)-15-amino-11-[(4R)-2-amino-3,4,5,6-tetrahydropyrimidin-4-yl]-8-[(carbamoylamino)

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methylidene]-2-(hydroxymethyl)-3,6,9,12,16-pentaoxo-1,4,7,10,13-pentazacyclo-hexadec-5-yl]methyl]hexanamide; sulfuric acid.

Capreomycin IB: (3S)-3,6-diamino-N-[[(2S,5S,8Z,11S,15S)-15-amino-11-[(4R)-2-amino-3,4,5,6-tetrahydropyrimidin-4-yl]-8-[(carbamoylamino)methylidene]-2-methyl-3,6,9,12,16-pentaoxo-1,4,7,10,13-pentazacyclohexadec-5-yl]methyl]hexanamide;sulfuric acid.

Capreomycin IIA: [(Z)-[(3S,9S,12S,15S)-15-amino-9-(aminomethyl)-3-[(4R)-2-amino-3,4,5,6-tetrahydropyrimidin-4-yl]-12-(hydroxymethyl)-2,5,8,11,14-pentaoxo-1,4,7,10,13-pentazacyclohexadec-6-ylidene]methyl]urea; sulfuric acid.

Capreomycin IIB: [(Z)-[(3S,9S,12S,15S)-15-amino-9-(aminomethyl)-3-[(4R)-2-amino-3,4,5,6-tetrahydropyrimidin-4-yl]-12-methyl-2,5,8,11,14-pentaoxo-1,4,7,10,13-pentazacyclohexadec-6-ylidene]methyl]urea; sulfuric acid.

CAS Reg. No. 1405-37-4 (capreomycin sulfate).

Description. A white or almost white powder.

Solubility. Very soluble in water, practically insoluble in ethanol (~750 g/l) TS and inether.

Category. Antituberculosis drug.

Storage. Capreomycin sulfate should be kept in a tightly closed container or, if sterile,in a hermetically closed container.

Labelling. The label states, where applicable:

(1) that the substance is free from bacterial endotoxins,(2) that the substance is sterile.

REQUIREMENTS

Definition. Capreomycin sulfate is the disulfate salt of capreomycin, a polypeptidemixture produced by the growth of Streptomyces capreolus. It contains not less than93.0% and not more than 102.0% of capreomycin sulfate, calculated with reference tothe dried substance and taking into account the sum of capreomycins sulfate IA, IB,IIA and IIB. The content of capreomycins sulfate IA and IB is not less than 90%.

Identity testsEither tests A and E or tests B, C, D and E may be applied.

A. Carry out the examination as described under 1.7 Spectrophotometry in the infraredregion. The infrared absorption spectrum is concordant with the spectrum obtainedfrom capreomycin sulfate RS or with the reference spectrum of capreomycin sulfate.

B. Carry out the test as described under 1.14.1 Thin-layer chromatography, using silicagel R5

as the coating substance and a mixture of 30 volumes of phenol R, 10 volumes

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of water R and 1 volume of ammonia (~260 g/l) TS as the mobile phase. Apply sepa-rately to the plate 4 µl of each of the following two solutions in water R. For solution(A), use 10 mg of the test substance per ml and for solution (B), use 10 mg ofcapreomycin sulfate RS per ml. After removing the plate from the chromatographicchamber, allow it to dry exhaustively in air. Spray with triketohydrindene/methanol TSand heat the plate for 3 minutes at 120 °C. Examine the chromatogram in daylight.The spots obtained with solution A correspond in position, appearance, and intensitywith those obtained with solution B.

C. The absorption spectrum of a 20 µg/ml solution in hydrochloric acid (0.1 mol/l) VS,when observed between 230 nm and 350 nm, exhibits one maximum at about 268nm; the specific absorbance (A

) is about 300.

D. The absorption spectrum of a 20 µg/ml in sodium hydroxide (0.1 mol/l) VS, whenobserved between 230 nm and 350 nm, exhibits a major maximum at about 287 nm;the specific absorbance (A ) is about 200.

E. A 20 mg/ml solution yields reaction A described under 2.1 General identificationtests as characteristic of sulfates.

pH value (1.3). pH of a 30 mg/ml solution in carbon-dioxide-free water R, 4.5-7.5.

Loss on drying. Dry for 4 hours at 100 °C under reduced pressure (not exceeding0.6 kPa or about 5 mm of mercury); it loses not more than 100 mg/g.

Heavy metals. Use 1.0 g for the preparation of the test solution as described under2.2.3 Limit test for heavy metals, Procedure 3; determine the heavy metals contentaccording to Method A; not more than 30 µg/g.

Sulfated ash (2.3). Not more than 10.0 mg/g.

Bacterial endotoxins. If intended for use in the manufacture of a parenteral dosageform, carry out the test as described under 3.4 Test for bacterial endotoxins; containsnot more than 0.35 IU of endotoxin per mg of capreomycin.

Sterility. If intended for use in the manufacture of either a parenteral or other steriledosage form without a further appropriate sterilization procedure, complies with 3.2.2Sterility testing of antibiotics, applying the membrane filtration test procedure andusing the sampling plan described under 3.2.1 Test for sterility of non-injectablepreparations.

Related substances. Carry out the test as described under 1.14.4 High performanceliquid chromatography, using the conditions given under Assay, Method A.

Prepare the following solutions using water R as diluent. For solution (1) use 2.0 mgof the test substance per ml. For solution (2) dilute a suitable volume of solution (1) toobtain a concentration of 10 µg of capreomycin sulfate per ml.

Operate with a flow rate of 1.0 ml per minute. As a detector use an ultraviolet spectro-photometer set at a wavelength of 268 nm.

1 cm

1%

1 cm

1%


315


Inject 20 µl of solution (1). The test is not valid unless the resolution between the twomajor peaks corresponding to capreomycin IA and capreomycin IB, with a relativeretention of 0.89 and 1, respectively, is at least 2.0. The test is also not valid unlessthe resolution between the peaks corresponding to capreomycin IIA and capreomycinIIB, with a relative retention of 0.53 and 0.63, respectively, is at least 3.5.

Inject separately 20 µl each of solutions (1) and (2).

In the chromatogram obtained with solution (1), the area of any peak, other than thefour major peaks corresponding to capreomycins IA, IB, IIA and IIB, is not greater than4 times the sum of the areas of the four major peaks obtained with solution (2) (2.0%).The area of not more than one such peak is greater than twice the sum of the areas ofthe four major peaks obtained with solution (2) (1.0%). The sum of the areas of allpeaks, other than the four major peaks, is not greater than 14 times the sum of theareas of the four major peaks obtained with solution (2) (7.0%). Disregard any peakwith an area less than 0.1 times the sum of the areas of the four major peaks in thechromatogram obtained with solution (2) (0.05%).

Assay

Either method A or method B may be applied.

A. Carry out the test as described under 1.14.4 High performance liquid chromatogra-phy, using a stainless steel column (25 cm x 4.6 mm) packed with base deactivatedparticles of silica gel the surface of which has been modified with chemically bondedoctadecylsilyl groups (5 µm). ( Hypersil BDS column has been found suitable).

The mobile phases for the gradient elution consist of a mixture of Mobile phase A andMobile phase B, using the following conditions:

Mobile phase A: 5 volumes of acetonitrile R and 95 volumes of phosphate bufferpH 2.3.

Mobile phase B: 15 volumes of acetonitrile R and 85 volumes of phosphate bufferpH 2.3.

Prepare the phosphate buffer pH 2.3 by dissolving 54.4 g of potassium dihydrogenphosphate R in 1500 ml of water R, adjust the pH to 2.3 by adding phosphoric acid(~105 g/l) TS, add 9.4 g of sodium hexanesulfonate R and dilute to 2000 ml with waterR.

Time Mobile phase A Mobile phase B Comments(min) (% v/v) (% v/v)

0–25 55 to 52 45 to 48 Linear gradient25–40 52 48 Isocratic40–60 30 70 Isocratic60–70 55 45 Isocratic re-equilibration

Prepare the following solutions using water R as diluent. For solution (1) use 2.0 mgof the test substance per ml. For solution (2) use 2.0 mg of capreomycin sulfate RSper ml.


316



Inject 20 µl of solution (1). The assay is not valid unless the resolution between the twomajor peaks corresponding to capreomycin IA and capreomycin IB, with a relativeretention of 0.89 and 1, respectively, is at least 2.0. The assay is also not valid unlessthe resolution between the peaks corresponding to capreomycin IIA and capreomycinIIB, with a relative retention of 0.53 and 0.63, respectively, is at least 3.5.


Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2) and calculate the content of capreomycin sulfate (sum of the fourpeaks corresponding to capreomycins IA, IB, IIA and IIB) from the declared content ofcapreomycin sulfate in capreomycin sulfate RS.

B. Dissolve about 40 mg, accurately weighed, in hydrochloric acid (0.1 mol/l) VS toproduce 20 ml. Dilute 1 ml of this solution to 100 ml with the same solvent. Measurethe absorbance of this solution in a 1-cm layer at the maximum at about 268 nm, andcalculate the content of capreomycin sulfate, using the absorptivity value of 30.0(A

= 300).

Capreomycini add injectionemCapreomycin for injection

Draft proposal for The International Pharmacopoeia (August 2010).Please address any comments to Quality Assurance and Safety:Medicines, World Health Organization, 1211 Geneva 27, Switzer-land. Fax +41227914730 or e-mail to [email protected]. A sub-scriber mailing list is now available to speed up consultation. Formore information please contact [email protected].

Description. A white or almost white powder.

Category. Antituberculosis drug.

Storage. Capreomycin for injection should be stored in a well-closed container.

Labelling. The designation on the container of capreomycin for injection should statethat the active ingredient is in the sulfate form, and the quantity should be indicated interms of the equivalent amount of capreomycin.

Additional information. Strength in the current WHO Model List of Essential Medi-cines: 1 g. Strength in the current WHO Model List of Essential Medicines for children:1 g.

The injection is reconstituted by dilution of Capreomycin powder for injections in Waterfor injections.

1 cm

1%


317


REQUIREMENTS

The powder for injection and the reconstituted injection comply with the monograph for“Parenteral preparations”.

Definition. Capreomycin for injection is a sterile powder containing Capreomycinsulfate. It contains not less than 90.0% and not more than 115.0% of the amount ofcapreomycin stated on the label, taking into account the sum of capreomycins IA, IB,IIA and IIB.

Identity tests

Either tests A and E or tests B, C, D and E may be applied.

A. Carry out the examination as described under 1.7 Spectrophotometry in the infra-red region. The infrared absorption spectrum is concordant with the spectrum ob-tained from capreomycin sulfate RS or with the reference spectrum of capreomycinsulfate.

B. Carry out the test as described under 1.14.1 Thin-layer chromatography, usingsilica gel R5

as the coating substance and a mixture of 30 volumes of phenol R, 10

volumes of water R and 1 volume of ammonia (~260 g/l) TS as the mobile phase.Apply separately to the plate 4 µl of each of the following two solutions in water R. Forsolution (A), dissolve a quantity of the powder to obtain a solution containing 10 mg ofthe test substance per ml. For solution (B), use 10 mg of capreomycin sulfate RS perml. After removing the plate from the chromatographic chamber, allow it to dry exhaus-tively in air. Spray with triketohydrindene/methanol TS and heat the plate for 3 minutesat 120 °C. Examine the chromatogram in daylight.

The spots obtained with solution A correspond in position, appearance, and intensitywith those obtained with solution B.

C. Dissolve a quantity of the powder in hydrochloric acid (0.1 mol/l) VS to obtain asolution containing the equivalent of 20 µg of capreomycin per ml. The absorptionspectrum of this solution, when observed between 230 nm and 350 nm, exhibits onemaximum at about 268 nm.

D. Dissolve a quantity of the powder in sodium hydroxide (0.1 mol/l) VS to obtain asolution containing the equivalent of 20 µg of capreomycin per ml. The absorptionspectrum of this solution, when observed between 230 nm and 350 nm, exhibits amajor maximum at about 287 nm.

E. A solution of the powder containing the equivalent of 20 mg of capreomycin per mlyields reaction A described under 2.1 General identification tests as characteristic ofsulfates.

Clarity of solution. A freshly prepared solution of the powder containing the equiva-lent of 1 g of capreomycin in 10 ml of carbon-dioxide-free water R is clear.

pH value (1.3). pH of a solution of the powder containing the equivalent of 0.3 g ofcapreomycin in 10 ml of carbon-dioxide-free water R, 4.5–7.5.


318


Bacterial endotoxins. Carry out the test as described under 3.4 Test for bacterialendotoxins; contains not more than 0.35 IU of endotoxin per mg of capreomycin.

Related substances. Carry out the test as described under 1.14.4 High performanceliquid chromatography, using the conditions given under Assay.

Prepare the following solutions using water R as diluent. For solution (1) dissolve aquantity of the powder to obtain a solution containing the equivalent of 2.0 mg ofcapreomycin per ml. For solution (2) dilute a suitable volume of solution (1) to obtain aconcentration of 10 µg of capreomycin per ml.


Inject 20 µl of solution (1). The test is not valid unless the resolution between the twomajor peaks corresponding to capreomycin IA and capreomycin IB, with a relativeretention of 0.89 and 1, respectively, is at least 2.0. The test is also not valid unless theresolution between the peaks corresponding to capreomycin IIA and capreomycin IIB,with a relative retention of 0.53 and 0.63, respectively, is at least 3.5.


In the chromatogram obtained with solution (1), the area of any peak, other than thefour major peaks corresponding to capreomycins IA, IB, IIA and IIB, is not greater than4 times the sum of the areas of the four major peaks obtained with solution (2) (2.0%).The area of not more than one such peak is greater than twice the sum of the areas ofthe four major peaks obtained with solution (2) (1.0%). The sum of the areas of allpeaks, other than the four major peaks, is not greater than 14 times the sum of theareas of the four major peaks obtained with solution (2) (7.0%). Disregard any peakwith an area less than 0.1 times the sum of the areas of the four major peaks in thechromatogram obtained with solution (2) (0.05%).

Assay

Carry out the test as described under 1.14.4 High performance liquid chromatography,using a stainless steel column (25 cm x 4.6 mm) packed with base deactivated parti-cles of silica gel the surface of which has been modified with chemically bondedoctadecylsilyl groups (5 µm). ( Hypersil BDS column has been found suitable).

The mobile phases for the gradient elution consist of a mixture of Mobile phase A andMobile phase B, using the following conditions:

Mobile phase A: 5 volumes of acetonitrile R and 95 volumes of phosphate bufferpH 2.3.

Mobile phase B: 15 volumes of acetonitrile R and 85 volumes of phosphate bufferpH 2.3.

Prepare the phosphate buffer pH 2.3 by dissolving 54.4 g of potassium dihydrogenphosphate R in 1500 ml of water R, adjust the pH to 2.3 by adding phosphoric acid(~105 g/l) TS, add 9.4 g of sodium hexanesulfonate R and dilute to 2000 ml with waterR.


319



0–25 55 to 52 45 to 48 Linear gradient25–40 52 48 Isocratic40–60 30 70 Isocratic60–70 55 45 Isocratic re-equilibration

Prepare the following solutions using water R as diluent. For solution (1) dissolve aquantity of the powder to obtain a solution containing the equivalent of 2.0 mg ofcapreomycin per ml. For solution (2) use an amount of capreomycin sulfate RSequivalent to 2.0 mg of capreomycin per ml.


Inject 20 l of solution (1). The assay is not valid unless the resolution between the twomajor peaks corresponding to capreomycin IA and capreomycin IB, with a relativeretention of 0.89 and 1, respectively, is at least 2.0. The assay is also not valid unlessthe resolution between the peaks corresponding to capreomycin IIA and capreomycinIIB, with a relative retention of 0.53 and 0.63, respectively, is at least 3.5.


Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2) and calculate the content of capreomycin (sum of the four peakscorresponding to capreomycins IA, IB, IIA and IIB) from the declared content ofcapreomycin in capreomycin sulfate RS.

[Note from Secretariat: it is proposed that the ICRS will have its content expressed onthe label in terms of capreomycin base and capreomycin sulfate]

Efavirenz tablets

Draft proposal for The International Pharmacopoeia (September2010). Please address any comments to Quality Assurance andSafety: Medicines, World Health Organization, 1211 Geneva 27,Switzerland. Fax +41227914730 or e-mail to [email protected]. Asubscriber mailing list is now available to speed up consultation.For more information please contact [email protected].

Category. Antiretroviral (Non-nucleoside Reverse Transcriptase Inhibitor).

Storage. Efavirenz tablets should be kept in a well-closed container, protected fromlight.


320


Additional information. Strengths in the current WHO Model List of Essential Medi-cines: 600 mg. Strengths in the current WHO Model List of Essential Medicines forChildren: 600 mg.

REQUIREMENTS

Comply with the monograph for “Tablets”.

Definition. Efavirenz tablets contain Efavirenz. They contain not less than 90.0% andnot more than 110.0% of the amount of Efavirenz (C

14H

9ClF

3NO

2) stated on the label.

Identity tests

Either test A alone or tests B and D or tests C and D may be applied.

A. To a quantity of the powdered tablets containing 25 mg of Efavirenz, add 10 ml ofmethanol R, shake to dissolve and filter. Evaporate the filtrate to dryness. Carry outthe examination as described under 1.7 Spectrophotometry in the infrared region. Theinfrared absorption spectrum is concordant with the spectrum obtained from efavirenzRS or with the reference spectrum of efavirenz.

If the spectra thus obtained are not concordant, repeat the test using the test residueand the residue obtained by dissolving efavirenz RS in a small amount of methanol Rand evaporating to dryness. The infrared absorption spectrum is concordant with thespectrum obtained from efavirenz RS.

B. Carry out test B.1 or, where UV detection is not available, test B.2.

B.1 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingsilica gel R6 as the coating substance and a mixture of 90 volumes of dichlorometh-ane R, 10 volumes of methanol R and 3 volumes of glacial acetic acid R as the mobilephase. Apply separately to the plate 5 µl of each of the following two solutions inmethanol R. For solution (A) shake a quantity of the powdered tablets containing 5 mgof Efavirenz with 5 ml, filter and use the clear filtrate. For solution (B) use 1 mg ofefavirenz RS per ml. After removing the plate from the chromatographic chamber,allow it to dry exhaustively in air or in a current of cool air. Examine the chromatogramin ultraviolet light (254 nm).

The principal spot obtained with solution A corresponds in position, appearance andintensity with that obtained with solution B.

B.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, using theconditions described under test A.1 but using silica gel R5 as the coating substance.Spray the plate with basic potassium permanganate (~1 g/l) TS. Examine the chroma-togram in daylight.

The principal spot obtained with solution A corresponds in position, appearance andintensity with that obtained with solution B.

C. See the test described under Assay method A. The retention time of the principalpeak in the chromatogram obtained with solution (1) is similar to that in the chromato-gram obtained with solution (2).


321


D. The absorption spectrum of the final solution prepared for Assay method B, whenobserved between 210 nm and 300 nm, exhibits one maximum at about 247 nm.

Related substances. Prepare fresh solutions and perform the test without delay.

Carry out the test as described under 1.14.4 High-performance liquid chromatography,using the conditions given under Assay Method A.

Prepare the following solutions in the dissolution solvent, a mixture of equal volumesof acetonitrile R and water R.

For solution (1) transfer a quantity of the powdered tablets containing about 25 mg ofEfavirenz into about 20 ml of the dissolution solvent, sonicate for 5 minutes, allow tocool to room temperature and dilute to 25.0 ml with the same solvent. Filter a portionof this solution through a 0.45-µm filter, discarding the first few ml of the filtrate. Forsolution (2) dilute 1.0 ml of solution (1) to 50.0 ml with the dissolution solvent anddilute 5.0 ml of the resulting solution to 100.0 ml with the same solvent. For solution(3) dissolve about 5 mg of efavirenz RS in 5 ml of a solution prepared as follows:dissolve 1 mg of efavirenz impurity B RS in the dissolution solvent and dilute to 10 mlwith the same solvent. Dilute 1 ml of the resulting solution to 25 ml with the dissolutionsolvent.

Inject separately 35 µl each of solutions (1), (2) and (3) and of the dissolution solventin the chromatographic system. Examine the blank chromatogram for any extraneouspeaks and disregard the corresponding peaks observed in the chromatogram obtainedwith solution (1).

In the chromatogram obtained with solution (3), the peak due to impurity B is eluted ata relative retention of about 0.9 with reference to Efavirenz (retention time about 20minutes). The test is not valid unless the resolution factor between the peaks due toimpurity B and Efavirenz is at least 3.

In the chromatogram obtained with solution (1) the area of any peak corresponding toimpurity B is not greater than four times the area of the principal peak in the chromato-gram obtained with solution (2) (0.4%), the area of any other peak, apart from theprincipal peak, is not greater than twice the area of the principal peak in the chromato-gram obtained with solution (2) (0.2%) and the area of not more than three such peaksis greater than the area of the principal peak in the chromatogram obtained withsolution (2) (0.1%). The sum of the areas of all peaks, other than the principal peak, isnot greater than eight times the area of the principal peak in the chromatogram ob-tained with solution (2) (0.8%). Disregard any peak with an area less than 0.5 timesthe area of the principal peak in the chromatogram obtained with solution (2) (0.05%).

[Note from Secretariat: retention times and resolution factor to be confirmed.]

Assay


A. Carry out the assay as described under 1.14.4 High-performance liquid chromatog-raphy using a stainless steel column (15 cm x 4.6 mm), packed with cyanopropyl-dimethylsilane monolayer (3.5 µm). (Zorbax® SB-CN has been found suitable.)


322


The mobile phases for gradient elution consist of a mixture of Mobile phase A andMobile phase B, using the following conditions:

Mobile phase A: 90 volumes of a 0.05% solution of trifluoroacetic acid R and10 volumes of methanol R.

Mobile phase B: 10 volumes of a 0.05% solution of trifluoroacetic acid R and90 volumes of methanol R.


0–16 60 to 50 40 to 50 Linear gradient16–23 50 to 35 50 to 65 Linear gradient23–28 35 to 30 65 to 70 Linear gradient28–29 30 to 20 70 to 80 Linear gradient29–31 20 80 Isocratic31–32 20 to 60 80 to 40 Return to initial

composition32–40 60 40 Re-equilibration

Prepare the following solutions in the dissolution solvent, a mixture of equal volumesof acetonitrile R and water R

For solution (1) weigh and powder 20 tablets. Transfer a quantity of the powderedtablets containing about 25 mg of Efavirenz, accurately weighed, into about 20 mlof the dissolution solvent, sonicate for 5 minutes, allow to cool to room temperatureand dilute to 25.0 ml with the same solvent. Filter a portion of this solution through a0.45-µm filter, discarding the first few ml of the filtrate. Dilute 1.0 ml of the resultingsolution to 100.0 ml with the dissolution solvent. For solution (2) dissolve 25 mg ofefavirenz RS in the dissolution solvent and dilute to 25.0 ml with the same solvent.Dilute 1.0 ml of the resulting solution to 100.0 ml with the dissolution solvent. Forsolution (3) dissolve about 5 mg of efavirenz RS in 5 ml of a solution prepared asfollows: dissolve 1 mg of efavirenz impurity B RS in the dissolution solvent and diluteto 10 ml with the same solvent. Dilute 1 ml of the resulting solution to 25 ml with thedissolution solvent.

Operate with a flow rate of 1.5 ml per minute. As a detector use an ultraviolet spectro-photometer set at a wavelength of about 250 nm.

Maintain the column temperature at 40 °C.

Inject separately 35 µl each of solutions (1), (2) and (3). In the chromatogram obtainedwith solution (3), the peak due to impurity B is eluted at a relative retention of about0.9 with reference to efavirenz (retention time about 20 minutes). The assay is notvalid unless the resolution factor between the peaks due to impurity B and efavirenz isat least 3.

Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2), and calculate the content of efavirenz (C

14H

9ClF

3NO

2) in the tablets.


323


[Note from Secretariat: retention times and resolution factor to be confirmed.]

B. Weigh and powder 20 tablets. Transfer a quantity of the powdered tablets contain-ing about 25 mg of Efavirenz, accurately weighed, to a 50-ml volumetric flask. Addabout 25 ml of methanol R, sonicate for about 5 minutes, allow to cool to room tem-perature and make up to volume using the same solvent. Filter a portion of thissolution through a 0.45-µm filter, discarding the first few ml of the filtrate. Dilute 1.0 mlof this solution to 50.0 ml with methanol R. Measure the absorbance (1.6) of a 1-cmlayer of this solution at the maximum at about 247 nm. Calculate the content ofefavirenz (C14H9ClF3NO2) in the tablets using an absorptivity value of 55.0(A

= 550).

Impurities. The impurities limited by the requirements of this monograph includethose listed in the monograph for Efavirenz.

Efavirenz, emtricitabine and tenofovir tablets

Draft proposal for The International Pharmacopoeia (September2010). Please address any comments to Quality Assurance andSafety: Medicines, World Health Organization, 1211 Geneva 27,Switzerland. Fax +41227914730 or e-mail to [email protected] subscriber mailing list is now available to speed up consulta-tion. For more information please contact [email protected].

Category. Antiretroviral (Non-nucleoside/Nucleoside/Nucleotide Reverse Tran-scriptase Inhibitors).

Storage. Efavirenz, emtricitabine and tenofovir tablets should be kept in a tightlyclosed container.

Additional information. Strength in the current WHO Model List of Essential Medi-cines: 600 mg Efavirenz, 200 mg Emtricitabine and 300 mg Tenofovir disoproxilfumarate.

REQUIREMENTS


Definition. Efavirenz, emtricitabine and tenofovir tablets contain Efavirenz, Emtricitab-ine and Tenofovir disoproxil fumarate. They contain not less than 90.0% and not morethan 110.0% of the amount of efavirenz (C

14H

9ClF

3NO

2), emtricitabine (C

8H

10FN

3O

3S)

and tenofovir disoproxil fumarate (C19

H30

N5O

10P,C

4H

4O

4)

stated on the label.

Manufacture. The manufacturing process and the product packaging are designedand controlled so as to minimize the moisture content of the tablets. They ensure that,if tested, the tablets would comply with a water content limit of not more than 60 mg/gwhen determined as described under 2.8 Determination of water by the Karl Fischermethod, Method A, using about 0.5 g of the powdered tablets.

1 cm

1%


324


Identity tests

Either tests A and B or test C may be applied.

A. Carry out test A.1 or, where UV detection is not available, test A.2.

A.1 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingsilica gel R6

as the coating substance and a mixture of 90 volumes of dichloromethane

R, 10 volumes of methanol R and 3 volumes of glacial acetic acid R as the mobilephase. Apply separately to the plate 5 l of each of the following four solutions inmethanol R. For solution (A) disperse a quantity of the powdered tablets to obtain aconcentration of 5 mg of Emtricitabine per ml, filter and use the filtrate. For solution (B)use 5 mg of emtricitabine RS per ml. For solution (C) use 7.5 mg of tenofovir diso-proxil fumarate RS per ml. For solution (D) use 15 mg of efavirenz RS per ml. Afterremoving the plate from the chromatographic chamber, allow it to dry exhaustively inair or in a current of air. Examine the chromatogram in ultraviolet light (254 nm).The three principal spots obtained with solution A correspond in position, appearanceand intensity with those obtained with solutions B, C and D.

A.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingthe conditions described above under test A.1 but using silica gel R5 as the coatingsubstance. Stain the plate with iodine vapour and examine the chromatogram indaylight.

The three principal spots obtained with solution A correspond in position, appearanceand intensity with those obtained with solutions B, C and D.

B. Carry out test B.1. or, where UV detection is not available, test B.2.

B.1 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingsilica gel R6

as the coating substance and a mixture of 50 volumes of heptane R, 30

volumes of glacial acetic acid R and 20 volumes of dichloromethane R as the mobilephase. Apply separately to the plate 5 l of each of the following two solutions in etha-nol R. For solution (A) disperse a quantity of the powdered tablets to obtain a concen-tration of 10 mg of Tenofovir disoproxil fumarate per ml, filter and use the filtrate. Forsolution (B) use 2 mg of fumaric acid R per ml. Develop the plate in an unsaturatedtank over a path of 10 cm. After removing the plate from the chromatographic cham-ber, allow it to dry exhaustively in air or in a current of air. Examine the chromatogramin ultraviolet light (254 nm).

One of the spots obtained with solution A corresponds in position, appearance andintensity with that obtained with solution B.

B.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingthe conditions described above under test B.1 but using silica gel R5 as the coatingsubstance. Spray lightly with a 16 g/l solution of potassium permanganate R andexamine the chromatogram in daylight.



325


C. See the test described under Assay. The retention times of the principal peaks dueto efavirenz, emtricitabine, tenofovir disoproxil and fumarate in the chromatogramobtained with the test solution are similar to those in the chromatogram obtained withthe reference solution.

Dissolution. Carry out the test as described under 5.5 Dissolution test for solid oraldosage forms, using as the dissolution medium, 1000 ml of a 2% solution of sodiumdodecyl sulfate R, and rotating the paddle at 100 revolutions per minute. At 45 minuteswithdraw a sample of 10 ml of the medium through an in-line filter. Allow the filteredsample to cool to room temperature and dilute if necessary [solution (1)]. Preparesolution (2) using 0.60 mg of efavirenz RS, 0.20 mg of emtricitabine RS and 0.30 mgof tenofovir disoproxil fumarate RS per ml of dissolution medium. Determine thecontent of efavirenz (C14H9ClF3NO2), emtricitabine (C8H10FN3O3S) and tenofovir diso-proxil fumarate (C

19H

30N

5O

10P,C

4H

4O

4) as described under Assay using solution (1)

and solution (2).

For each of the six tablets tested, calculate the total amount of efavirenz(C

14H

9ClF

3NO

2), emtricitabine (C

8H

10FN

3O

3S) and tenofovir disoproxil fumarate

(C19H30N5O10P,C4H4O4) in the medium from the results obtained. The amount in solu-tion for each tablet is not less than 80% of the amount stated on the label. If theamount obtained for one of the six tablets is less than 80%, repeat the test using afurther six tablets; the average amount for all 12 tablets tested is not less than 75%and no tablet contains less than 60%.

Tenofovir monoester. Carry out the test as described under 1.14.4 High-performanceliquid chromatography, using the conditions given under Assay.

After preparation, keep the solutions at about 6 °C, or use an injector with cooling.Prepare the following solutions using a mixture of 20 volumes of acetonitrile R and 80volumes of water R as a diluent. For solution (1) weigh and powder 20 tablets. Dis-perse a quantity of the powder containing about 100 mg of Tenofovir disoproxil fuma-rate, accurately weighed in 100 ml of the diluent and filter. For solution (2) dilute asuitable volume of solution (1) to obtain a concentration of 5 µg of Tenofovir disoproxilfumarate per ml. For solution (3) heat carefully 1 mg of tenofovir disoproxil fumarateRS per ml of water R in a boiling water-bath for 20 minutes.



Inject 20 µl of solution (3). The peak due to tenofovir monoester elutes at a relativeretention of about 0.9 with reference to tenofovir disoproxil (retention time about 18minutes). The test is not valid unless the resolution between these peaks is at least 5.Inject separately 20 µl each of solutions (1) and (2).

In the chromatogram obtained with solution (1), the area of any peak due to tenofovirmonoester, is not greater than 7 times the area of the principal peak obtained withsolution (2) (3.5%).


326


Assay

Carry out the test as described under 1.14.4 High-performance liquid chromatography,using a stainless steel column (25 cm x 4.6 mm) packed with base-deactivated parti-cles of silica gel the surface of which has been modified with chemically bondedoctadecylsilyl groups (5 m).


Mobile phase A: 5 volumes of potassium dihydrogen phosphate (27.2 g/l) TSand 95 volumes of water R.

Mobile phase B: 70 volumes of acetonitrile R, 5 volumes of potassium dihydrogenphosphate (27.2 g/l) TS and 25 volumes of water R.


0–9 93 7 Isocratic9–15 93 to 0 7 to 100 Linear gradient15–19 0 100 Isocratic

19–19.1 0 to 93 100 to 7 Return to initial composition

19.1–30 93 7 Re-equilibration

After preparation, keep the solutions at about 6 °C, or use an injector with cooling.Prepare the following solutions using a mixture of 20 volumes of acetonitrile R and 80volumes of water R as a diluent. For solution (1) weigh and powder 20 tablets. Dis-perse a quantity of the powder containing about 10 mg of Tenofovir disoproxil fuma-rate, accurately weighed in 100 ml of the diluent and filter. For solution (2) use 0.2 mgof efavirenz RS, 0.1 mg of tenofovir disoproxil fumarate RS and 66.7 µg of emtricitab-ine RS per ml of diluent. For solution (c) use 0.02 mg of fumaric acid R per ml of waterR.

If necessary adapt the concentration of solution (2) according to the ratio of Efavirenz,Emtricitabine and Tenofovir disoproxil fumarate in the tablets.



Inject separately 20 µl each of solutions (1), (2) and (3).

The test is not valid unless in the chromatograms obtained with solutions (1) and (2),four principal peaks, that elute at the following retention times, are shown: fumarate(about 2.5 minutes), emtricitabine (about 9 minutes), tenofovir disoproxil (about 18minutes) and efavirenz (about 22 minutes).


327


Calculate the content of efavirenz (C14H9ClF3NO2), emtricitabine (C8H10FN3O3S) andtenofovir disoproxil fumarate (C

19H

30N

5O

10P,C

4H

4O

4) in the tablets.

Emtricitabinum capsulaeEmtricitabine capsules


Category. Antiretroviral (Nucleoside Reverse Transcriptase Inhibitor).

Storage. Emtricitabine capsules should be kept in a tightly closed container.

Additional information. Strength in the current WHO Model List of Essential Medi-cines: 200 mg Emtricitabine.

REQUIREMENTS

Comply with the monograph for “Capsules”.

Definition. Emtricitabine capsules contain Emtricitabine. They contain not less than90.0% and not more than 110.0% of the amount of emtricitabine (C

8H

10FN

3O

3S)

stated

on the label.

Identity tests


A. Carry out test A.1 or, when UV detection is not available, test A.2.



R, 10 volumes of methanol R and 3 volumes of glacial acetic acid R as the mobilephase. Apply separately to the plate 5 µl of each of the following two solutions inmethanol R. For solution (A) disperse a quantity of the contents of the capsules toobtain a concentration of 5 mg of Emtricitabine per ml, filter and use the filtrate. Forsolution (B) use 5 mg of emtricitabine RS per ml. After removing the plate from thechromatographic chamber, allow it to dry exhaustively in air or in a current of air.Examine the chromatogram in ultraviolet light (254 nm).

The principal spot obtained with solution A corresponds in position, appearance, andintensity with that obtained with solution B.

A.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, using theconditions described above under test A.1 but using silica gel R5 as the coatingsubstance. Stain the plate with iodine vapour and examine in daylight.


328


The principal spot obtained with solution A corresponds in position, appearance, andintensity to that obtained with solution B.

B. Disperse the quantity of contents of the capsules containing about 50 mg of Em-tricitabine with 40 ml of methanol R, dilute to 50 ml and filter. Dilute 1 ml of the filtrateto 50 ml with methanol R. The absorption spectrum (1.6) of the resulting solution,when observed between 220 and 350 nm, exhibits two maxima at about 242 nm and284 nm.

C. See the test described under Assay, Method A. The retention time of the principalpeak in the chromatogram obtained with the test solution is similar to that in thechromatogram obtained with the reference solution.

Dissolution. Carry out the test as described under 5.5 Dissolution test for solid oraldosage forms, using as the dissolution medium, 900 ml of hydrochloric acid (~4 g/l) TSand rotating the paddle at 50 revolutions per minute. At 45 minutes withdraw a sampleof 10 ml of the medium through an in-line filter. Allow the filtered sample to cool toroom temperature. Measure the absorbance (1.6) of a 1-cm layer of the resultingsolution, suitably diluted if necessary, at the maximum at about 280 nm. Determine thecontent of emtricitabine (C

8H

10FN

3O

3S) in the medium from the absorbance obtained

from a solution of known concentration of emtricitabine RS.

For each of the six capsules tested, calculate the total amount of emtricitabine(C8H10FN3O3S) in the medium from the results obtained and from the declared contentof C

8H

10FN

3O

3S in emtricitabine RS. The amount in solution for each capsule is not

less than 80% of the amount declared on the label. If the amount of emtricitabineobtained for one of the six capsules is less than 80%, repeat the test using a furthersix capsules; the average amount of emtricitabine for all 12 capsules tested is not lessthan 75% and no capsule contains less than 60%.

Related substancesCarry out the test as described under 1.14.4 High-performance liquid chromatography,using the conditions given under Assay, Method A.

Prepare the following solutions using a mixture of 20 volumes of acetonitrile R and 80volumes of water R as a diluent. For solution (1) weigh and mix the contents of 20capsules and disperse a quantity containing about 50 mg of Emtricitabine in 80 ml ofthe diluent, dilute to 100 ml with the diluent, filter and use the filtrate. For solution (2)dilute a suitable volume of solution (1) with the diluent to obtain a concentration of0.50 µg of Emtricitabine per ml.

For the system suitability test: prepare solution (3) using 5 ml of solution (1) and 2 mlof phosphoric acid (~105 g/l) TS, heat carefully in a boiling water-bath for 15 minutes.Operate with a flow rate of 1.0 ml per minute. As a detector use an ultraviolet spectro-photometer set at a wavelength of 280 nm.


Inject 20 µl of solution (3). The test is not valid unless the resolution between the peakdue to emtricitabine (retention time about 9 minutes) and the peak with a relativeretention of about 1.3 is not less than 6.


329



In the chromatogram obtained with solution (1) the area of any peak eluting before theprincipal peak is not greater than 5 times the area of the principal peak in the chroma-togram obtained with solution (2) (0.5%); the area of not more than two such peaks isgreater than the area of the principal peak in the chromatogram obtained with solution(2) (0.1%); the area of any peak eluting after the principal peak is not greater than 7times the area of the principal peak in the chromatogram obtained with solution (2)(0.7%); the area of not more than two such peaks is greater than the area of theprincipal peak in the chromatogram obtained with solution (2) (0.1%). The sum of theareas of all peaks, other than the principal peak is not greater than 10 times the areaof the principal peak in the chromatogram obtained with solution (2) (1%). Disregardany peak with an area less than 0.5 times the area of the principal peak in the chroma-togram obtained with solution (2) (0.05%).

Assay

Either test A or test B may be applied.

A. Carry out the test as described under 1.14.4 High-performance liquid chromatogra-phy, using a stainless steel column (25 cm x 4.6 mm) packed with base-deactivatedparticles of silica gel the surface of which has been modified with chemically bondedoctadecylsilyl groups (5 µm). (Hypersil BDS C18 has been found suitable.).The mobile phases for gradient elution consist of a mixture of Mobile phase A andMobile phase B, using the following conditions:










330


Prepare the following solutions using a mixture of 20 volumes of acetonitrile R and 80volumes of water R as a diluent. For solution (1): weigh and mix the contents of 20capsules and disperse a quantity containing about 50 mg of Emtricitabine in 80 ml ofthe diluent, dilute to 100 ml with the diluent, filter and use the filtrate.

For solution (2) use 0.5 mg of emtricitabine RS per ml of the diluent.

For the system suitability test: prepare solution (3) using 5 ml of solution (1) and 2 mlof phosphoric acid (~105 g/l) TS, heat carefully in a boiling water-bath for 15 minutes.Inject 20 l of solution (3). The test is not valid unless the resolution between the peakdue to emtricitabine (retention time about 9 minutes) and the peak with a relativeretention of about 1.3 is not less than 6.


Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2), and calculate the content of emtricitabine (C

8H

10FN

3O

3S).

B. Weigh and mix the contents of 20 capsules and disperse a quantity containingabout 50 mg of Emtricitabine in 40 ml of methanol R, dilute to 50 ml with methanol Rand filter. Dilute 1 ml of the filtrate to 50 ml with methanol R.

Measure the absorbance (1.6) of the resulting solution in a 1-cm layer at the maximumat about 284 nm.

Calculate the content of emtricitabine (C8H

10FN

3O

3S)

, using the absorptivity value of

33.2 (A1cm

1% = 332).

* * *

New reagent to be added to The International Pharmacopoeia:

Hydrochloric acid (~4 g/l) TS.

Dilute 10 ml of hydrochloric acid (~420 g/l) TS with sufficient water to produce 1000 ml(approximately 0.1 mol/l).

Emtricitabini et tenofoviri compressiEmtricitabine and tenofovir tablets


Category. Antiretroviral (Nucleoside/Nucleotide Reverse Transcriptase Inhibitor).


331


Storage. Emtricitabine and tenofovir tablets should be kept in a tightly closed con-tainer.

Additional information. Strength in the current WHO Model list of essential medi-cines: 200 mg Emtricitabine and 300 mg Tenofovir disoproxil fumarate.

REQUIREMENTS


Definition. Emtricitabine and tenofovir tablets contain Emtricitabine and Tenofovirdisoproxil fumarate. They contain not less than 90.0% and not more than 110.0% ofthe amounts of emtricitabine (C8H10FN3O3S) and tenofovir disoproxil fumarate(C

19H

30N

5O

10P,C

4H

4O

4)

stated on the label.

Manufacture. The manufacturing process and the product packaging are designedand controlled so as to minimize the moisture content of the tablets. They ensure that,if tested, the tablets would comply with a water content limit of not more than 60 mg/gwhen determined as described under 2.8 Determination of water by the Karl Fischermethod, Method A, using about 0.5 g of the powdered tablets.

Identity tests


A. Carry out test A.1 or, where UV detection is not available, test A.2.



R, 10 volumes of methanol R and 3 volumes of glacial acetic acid R as the mobilephase. Apply separately to the plate 5 µl of each of the following three solutions inmethanol R. For solution (A) disperse a quantity of powdered tablets to obtain aconcentration of 5 mg of Emtricitabine per ml, filter and use the filtrate. For solution (B)use 5 mg of emtricitabine RS. For solution (C) use 7.5 mg of tenofovir disoproxilfumarate RS per ml. After removing the plate from the chromatographic chamber,allow it to dry exhaustively in air or in a current of air. Examine the chromatogram inultraviolet light (254 nm).

One of the two principal spots obtained with solution A corresponds in position, ap-pearance and intensity with that obtained with solution B and the other one corre-sponds with that obtained with solution C.

A.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, using theconditions described above under test A.1 but using silica gel R5 as the coatingsubstance. Stain the plate with iodine vapour and examine the chromatogram indaylight.

One of the two principal spots obtained with solution A corresponds in position, ap-pearance and intensity with that obtained with solution B and the other one corre-sponds with that obtained with solution C.


332


B. Carry out test B.1. or, where UV detection is not available, test B.2.

B.1 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingsilica gel R6 as the coating substance and a mixture of 50 volumes of heptane R, 30volumes of glacial acetic acid R and 20 volumes of dichloromethane R as the mobilephase. Apply separately to the plate 5 µl of each of the following two solutions inethanol R. For solution (A) disperse a quantity of powdered tablets to obtain a concen-tration of 10 mg of Tenofovir disoproxil fumarate per ml, filter and use the filtrate. Forsolution (B) use 2 mg of fumaric acid R per ml. Develop the plate in an unsaturatedtank over a path of 10 cm. After removing the plate from the chromatographic cham-ber, allow it to dry exhaustively in air or in a current of air. Examine the chromatogramin ultraviolet light (254 nm).


B.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, using theconditions described above under test B.1 but using silica gel R5 as the coatingsubstance. Spray lightly with a 16 g/l solution of potassium permanganate R andexamine the chromatogram in daylight.


C. See the test described under Assay. The retention times of the principal peaks inthe chromatogram obtained with the test solution are similar to those due to emtricit-abine, tenofovir disoproxil and to fumarate in the chromatogram obtained with thereference solution.

DissolutionCarry out the test as described under 5.5 Dissolution test for solid oral dosage forms,using as the dissolution medium, 900 ml of hydrochloric acid (~0.4 g/l) TS, and rotat-ing the paddle at 50 revolutions per minute. At 45 minutes withdraw a sample of 10 mlof the medium and filter. Allow the filtered sample to cool to room temperature anddilute if necessary [solution (1)]. Prepare solution (2) using 0.22 mg of emtricitabineRS and 0.33 mg of tenofovir disoproxil fumarate RS per ml of dissolution medium.Determine the content of emtricitabine (C

8H

10FN

3O

3S) and tenofovir disoproxil fuma-

rate (C19

H30

N5O

10P,C

4H

4O

4) as described under Assay using solution (1) and solution

(2).

For each of the six tablets tested, calculate the total amount of emtricitabine(C

8H

10FN

3O

3S) and tenofovir disoproxil fumarate (C

19H

30N

5O

10P,C

4H

4O

4) in the medium

from the results obtained. For both substances, the amount in solution for each tabletis not less than 80% of the amount stated on the label. If the amount obtained for oneof the six tablets is less than 80%, repeat the test using a further six tablets; theaverage amount for all 12 tablets tested is not less than 75% and no tablet containsless than 60%.

Tenofovir monoester. Carry out the test as described under 1.14.4 High-performanceliquid chromatography, using the conditions given under Assay.


333


After preparation, keep the solutions at about 6 °C, or use an injector with cooling.

Prepare the following solutions using a mixture of 20 volumes of acetonitrile R and 80volumes of water R as a diluent. For solution (1) weigh and powder 20 tablets. Dis-perse a quantity of the powder containing about 100 mg of Tenofovir disoproxil fuma-rate, accurately weighed, in 100 ml of the diluent and filter. For solution (2) dilute asuitable volume of solution (1) to obtain a concentration of 5 µg of Tenofovir disoproxilfumarate per ml. For solution (3) heat carefully 1 mg of tenofovir disoproxil fumarateRS per ml of water R in a boiling water-bath for 20 minutes.



Inject 20 µl of solution (3). The peak due to tenofovir monoester elutes at a relativeretention of about 0.9 with reference to tenofovir disoproxil (retention time about 18minutes).

Inject separately 20 µl each of solutions (1) and (2). The test is not valid unless in thechromatogram obtained with solution (1), three principal peaks are shown.

In the chromatogram obtained with solution (1), the area of any peak due to tenofovirmonoester, is not greater than seven times the area of the principal peak obtained withsolution (2) (3.5%).

AssayCarry out the test as described under 1.14.4 High-performance liquid chromatography,using a stainless steel column (25 cm x 4.6 mm) packed with base-deactivated parti-cles of silica gel the surface of which has been modified with chemically bondedoctadecylsilyl groups (5 µm). (Hypersil BDS column.)









334


After preparation, keep the solutions at about 6 °C, or use an injector with cooling.

Prepare the following solutions using a mixture of 20 volumes of acetonitrile R and 80volumes of water R as a diluent. For solution (1) weigh and powder 20 tablets. Dis-perse a quantity of the powder containing about 10 mg of Tenofovir disoproxil fuma-rate, accurately weighed in 100 ml of the diluent and filter. For solution (2) use 0.1 mgof tenofovir disoproxil fumarate RS and 66.7 µg of emtricitabine RS per ml of diluent. Ifnecessary, adapt the concentration of solution (2) according to the ratio of Emtricitab-ine and Tenofovir disoproxil fumarate in the tablets. For solution (3) use 0.02 mg offumaric acid R per ml of water R.



Inject separately 20 µl each of solutions (1), (2) and (3).

The test is not valid unless in the chromatograms obtained with solutions (1) and (2),three principal peaks are shown and the resolution factor between those peaks is atleast 5.

Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2), and calculate the content of emtricitabine (C8H10FN3O3S) and tenofo-vir disoproxil fumarate (C

19H

30N

5O

10P,C

4H

4O

4) in the tablets.

[Note from Secretariat: a test for related substances is not available, due to the over-lapping of the impurities from both APIs and the non-availability of reference sub-stances for the impurities that would be required to allow the identification of thepeaks.]


Hydrochloric acid (~0.4 g/l) TS.

Levamisole tablets


Category. Anthelminthic.

Storage. Levamisole tablets should be kept in a tightly closed container.


335


Labelling. The designation on the container of Levamisole tablets should state thatthe active ingredient is in the hydrochloride form and the quantity should be indicatedin terms of equivalent amount of levamisole.

Additional information. Strengths in the current WHO Model List of Essential Medi-cines: 50 mg, 150 mg. Strengths in the current WHO Model List of Essential Medi-cines for Children: 50 mg, 150 mg

REQUIREMENTS


Definition. Levamisole tablets contain Levamisole hydrochloride. They contain notless than 90.0% and not more than 110.0% of the amount of levamisole (C11H12N2S)stated on the label.

Identity tests

Either tests A, B and D or tests A, C and D may be applied.

A. Shake a quantity of the powdered tablets containing the equivalent of about 450 mgof levamisole with 30 ml of water R, filter. Wash the filter with 20 ml of water R and addthe washings to the filtrate. To the combined filtrate add ammonia (~100 g/l) TS tomake it alkaline and extract with two quantities, each of 25 ml and 15 ml, of dichlo-romethane R. Combine the dichloromethane extracts and evaporate to dryness. Add0.5 ml of hydrochloride acid (~420 g/l) TS, heat on a water-bath to dryness. Dissolvethe residue in 10 ml of hydrochloric acid (0.1 mol/l) VS. The optical rotation of theresulting solution is not less than -5°

B. See the test described below under Related substances using ultraviolet light (254nm) to examine the chromatogram. The principal spot obtained with solution B corre-sponds in position, appearance, and intensity with that obtained with solution D.

C. See the test described below under Assay, Method A. The retention time of theprincipal peak in the chromatogram obtained with solution (1) is similar to that in thechromatogram obtained with solution (2).

D. Shake a quantity of the powdered tablets containing the equivalent of about 100 mgof levamisole with 40 ml of water R and filter. The filtrate yields reaction B describedunder 2.1 General identification tests as characteristic of chlorides.

Related substancesCarry out the test as described under 1.14.1 Thin-layer chromatography, using silicagel R6 as coating substance and a mixture of 60 volumes of toluene R, 40 volumes ofacetone R, and 1 volume of ammonia (~260 g/l) TS as the mobile phase. Applyseparately to the plate 10 µl of each of the following four solutions in methanol R. Forsolution (A) shake a quantity of the powdered tablets containing the equivalent ofabout 85 mg of levamisole with 5 ml, filter, and use the filtrate. For solution (B) dilute 1ml of solution A to 10 ml. For solution (C) dilute 1 ml of solution B to 20 ml. For solution(D) use 2.0 mg of levamisole hydrochloride RS per ml. After removing the plate fromthe chromatographic chamber, dry it at 105 °C for 15 minutes, and examine thechromatogram in ultraviolet light (254 nm).


336


Any spot obtained with solution A, other than the principal spot, is not more intensethan that obtained with solution C (0.5%).

Expose the plate to iodine vapour in a tightly closed chamber for 15 minutes andexamine the chromatogram in daylight.

Any spot obtained with solution A, other than the principal spot, is not more intensethan that obtained with solution C (0.5%).

Assay


A. Carry out the test as described under 1.14.4 High-performance liquid chromatogra-phy, using a stainless steel column (10 cm x 4.6 mm) packed with particles of silicagel, the surface of which has been modified with chemically bonded octadecylsilylgroups (3 µm). (Phenomenex Gemini C18 has been found suitable.)


Mobile phase A: acetonitrile R

Mobile phase B: a 0.75% solution of monobasic ammonium phosphate Rin water R adjusted to pH 7 with diisopropylamine R


0–5 20 to 80 80 to 20 Linear gradient5–7 80 20 Isocratic7–8 80 to 20 20 to 80 Return to initial

composition8–12 20 80 Re-equilibration

Prepare the following solutions. For solution (1) weigh and powder 20 tablets. Shake aquantity of the powdered tablets containing the equivalent of about 170 mg oflevamisole, accurately weighed, with 100 ml of water R, and filter. Dilute a suitablevolume of the filtrate with methanol R to obtain a concentration equivalent to 0.17 mgof levamisole per ml. For solution (2) use 0.2 mg of levamisole hydrochloride RS perml in methanol R. For solution (3) dissolve the equivalent of 17 mg of levamisole in 5ml of a 0.1 mol/l solution of sodium hydroxide R in a test tube, and heat in a waterbath at 100 °C for 5 hours. Allow to cool and dilute 1 ml of the resulting solution to 25ml with methanol R.

Operate with a flow rate of 2 ml per minute. As a detector use an ultraviolet spectro-photometer set at a wavelength of about 215 nm.


337


Inject 10 µl of solution (3). In the chromatogram obtained with solution (3), the peakdue to the major degradation product elutes at the following relative retention withreference to levamisole (retention time about 3 minutes): about 1.3. The test is notvalid unless the resolution between the peak due to levamisole and the peak due tothe major degradation product with a relative retention of about 1.3 is at least 6.0.

Inject separately 10 µl, each of solutions (1) and (2).

Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2), and calculate the content of levamisole (C11H12N2S) in the tablets.

B. Weigh and powder 20 tablets. To a quantity of the powdered tablets containing theequivalent of about 170 mg of levamisole, accurately weighed, add 30 ml of water Rand shake for 10 minutes. Filter, wash the filter with 20 ml of water R and add thewashings to the filtrate. To the combined filtrate add ammonia (~100 g/l) TS to make italkaline and extract with three quantities, each of 25 ml, 15 ml and 15 ml, of dichlo-romethane R. Filter each quantity through cotton wool covered with a layer of anhy-drous sodium sulfate R and wash the filter with 15 ml of dichloromethane R. Combinethe dichloromethane extracts and evaporate to dryness. Dissolve the residue in 50 mlof anhydrous glacial acetic acid R. Titrate with perchloric acid (0.1 mol/l) VS, asdescribed under 2.6 Non-aqueous titration, Method A, using crystal violet/acetic acidTS solution as indicator.

Each ml of perchloric acid (0.1 mol/l) VS is equivalent to 20.43 mg of C11

H12

N2S.

Levofloxacin


C18

H20

FN3O

4,1/ 2 H2

O


338


Relative Molecular Mass. 370.4

Chemical name. (S)-9-Fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid hemihydrate; CAS Reg. No.138199-71-0.

Description. Yellowish white to bright yellow, crystals or crystalline powder.

Solubility. Slightly soluble in water, soluble in glacial acetic acid, slightly soluble orsoluble in dichloromethane, slightly soluble in methanol.

Category. Antibacterial.

Storage. Levofloxacin should be kept in a tightly closed container, protected from light.

REQUIREMENTS

Definition. Levofloxacin contains not less than 99.0% and not more than 101.0% oflevofloxacin (C18H20FN3O4) calculated with reference to the anhydrous substance.

Manufacture. The production method is validated to ensure that the substance is the(S-enantiomer).

Identity test

Either tests A and D or tests B, C and D may be applied.

A. Carry out the examination as described under 1.7 Spectrophotometry in the infraredregion. The infrared absorption spectrum is concordant with the spectrum obtainedfrom levofloxacin RS or with the reference spectrum of levofloxacin.

B. Carry out the test as described under 1.14.1. Thin layer chromatography, usingsilica gel R6 as the coating substance and a mixture of 10 volumes of dichlorometh-ane R, 5 volumes of methanol R and 1 volume of ammonia solution 1% as the mobilephase. Apply separately to the plate 5 µl of each of the following two solutions in amixture of 1 volume of methanol R and 4 volumes of dichloromethane R. For solution(A) use 5 mg of Levofloxacin per ml. For solution (B) use 5 mg of levofloxacin RS perml. After removing the plate from the chromatographic chamber, allow it to dry exhaus-tively in air or in a current of cool air. Examine the chromatogram in ultraviolet light(254 nm).


C. Transfer 25 mg of Levofloxacin to a 50-ml volumetric flask. Add about 20 ml ofhydrochloric acid (~4 g/l) TS, sonicate for about 5 minutes, allow to cool to roomtemperature and make up to the volume using the same solvent. Filter a portion of thissolution through a 0.45-µm filter, discarding the first few ml of the filtrate. Dilute 1.0 mlof this solution to 100.0 ml using water R. The absorption spectrum (1.6) of the result-ing solution, when observed between 210 and 350 nm, exhibits two maxima at about


339


294 nm and at about 327 nm. The specific absorbance (A ) at 294 nm is between876 and 948.

D. Determine the specific optical rotation (1.4) using a 30 mg/ml solution dissolved in amixture of 10 volumes of methanol R and 40 volumes of dichloromethane R andcalculate with reference to the anhydrous substance; [α] α] α] α] α] 20 °C = -12° to -11°.

[Note from Secretariat: suitability of carrying out the Optical rotation test in methanolunder investigation and corresponding limits to be confirmed.]

Heavy metals

[Note from Secretariat: suitable test for heavy metals under investigation.]

Sulfated ash (2.3). Not more than 1.0 mg/g.

Water. Determine as described under 2.8 Determination of water by Karl FischerMethod, Method A. Use 1.0 g of the test substance. The water content is not less than21 mg/g and not more than 27 mg/g.

Impurity ACarry out the test as described under 1.14.1. Thin layer chromatography, using silicagel R6 as the coating substance and a mixture of 10 volumes of glacial acetic acid R,10 volumes of water R and 20 volumes of ethyl acetate R. Apply separately to theplate 10 l of each of the two following solutions in the dissolution solvent prepared bymixing 10 volumes of methanol R and 40 volumes of dichloromethane R. For solution(A) use 50 mg of Levofloxacin per ml. For solution (B) use 0.1 mg of levofloxacinimpurity A RS per ml. After removing the plate from the chromatographic chamber,allow to dry in air. Examine the chromatogram in ultraviolet light (254 nm).

Any spot obtained with solution A corresponding impurity A is not more intense thanthe principal spot obtained with solution B.

Other related substancesPrepare fresh solutions, protected from light and perform the tests without delay.Carry out the test as described under 1.14.4 High-performance liquid chromatography,using a stainless steel column (15 cm x 4.6 mm), packed with particles of silica gel thesurface of which has been modified with chemically bonded octadecylsilyl groups(5 µm). (Symmetry 150 x 46 mm (5 µm) is suitable.)


Prepare the mobile phase as follows: dissolve 4.0 g of ammonium acetate R and 7.0 gof sodium perchlorate R in water R and dilute to 1300 ml; adjust to pH 2.2 with phos-phoric acid R and add 240 ml of acetonitrile R.

Prepare the following solutions in the dissolution solvent prepared in mixing 10 vol-umes of acetonitrile R and 60 volumes of water R.

For solution (1) dissolve 10 mg of Levofloxacin in the dissolution solvent and dilute to50.0 ml with the same solvent. For solution (2) dilute 1.0 ml of solution (1) to 50.0 ml


1 cm 1%

340


with the same solvent. Dilute 1.0 ml of this solution to 10.0 ml with the same solvent.For solution (3) dissolve 10 mg of levofloxacin impurity E RS in the dissolution solventand dilute to 100.0 ml with the same solvent. Mix 10 ml with 5 ml of solution (1) anddilute to 50.0 ml with the same solvent. Dilute 1.0 ml of this solution to 50.0 ml with thesame solvent.


Inject 20 µl of solution (3). The test is not valid unless the resolution factor betweenthe peaks due to impurity E and Levofloxacin is at least 2.

Inject separately 20 µl each of solutions (1), (2) and of the dissolution solvent in thechromatographic system.

In the chromatogram obtained with solution (1), the following impurity peaks, ifpresent, are eluted at the following relative retention with reference to Levofloxacin(retention time about 17 minutes): impurity B about 0.36; impurity C about 0.57;impurity D about 0.75; impurity E about 0.91; impurity F about 1.50.

In the chromatogram obtained with solution (1):

• the area of any peak corresponding to impurity B, when multiplied by a correctionfactor of 2.6, is not greater than the area of the principal peak obtained with solution(2) (0.2%);

• the area of any peak corresponding to impurity D, when multiplied by a correctionfactor of 4.2, is not greater than the area of the principal peak obtained with solution(2) (0.2%);

• the area of any peak corresponding to impurity C, E or F is not greater than the areaof the principal peak obtained with solution (2) (0.2%);

• the area of any other impurity peak is not greater than 0.5 times the area of theprincipal peak obtained with solution (2) (0.1%);

• the sum of the areas (corrected, where necessary) of all the peaks, other than theprincipal peak, is not greater than 2.5 times the area of the principal peak obtainedwith solution (2) (0.5%). Disregard any peak with an area less than 0.25 times thearea of the principal peak obtained with solution (2) (0.05%).

[Note from Secretariat: following information to be confirmed:- correction factors for impurities B and D,- limit for individual unspecified impurities,- limit for total of impurities]

Assay

Dissolve about 0.300 g, accurately weighed, in 100 ml of glacial acetic acid and titratewith perchloric acid (0.1 mol/l) VS as described under 2.6. Non aqueous titrations,


341


Method A determining the end point potentiometrically. Each ml of perchloric acid(0.1 mol/l) VS is equivalent to 36.14 mg of C

18H

20FN

3O

4.

Impurities

The following list of known and potential impurities that have been shown to be con-trolled by the tests in this monograph is given for information:

A. (3S)-9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid,

B. (3S)-9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazin-7-one,

C. (3S)-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid,

D. (3S)-10-fluoro-3-methyl-9-(4-methylpiperazin-1-yl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid,


342


E. (3S)-9-fluoro-3-methyl-7-oxo-10-(piperazin-1-yl)-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid,

F. 4-[(3S)-6-carboxy-9-fluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazin-10-yl]-1-methylpiperazine 1-oxide.




Levofloxacin tablets

Draft proposal for The International Pharmacopoeia (September2010). Please address any comments to Quality Assurance andSafety: Medicines, World Health Organization, 1211 Geneva 27,Switzerland. Fax +41227914730 or e-mail to [email protected] subscriber mailing list is now available to speed up consulta-tion. For more information please contact [email protected].

Category. Antibacterial.

Storage. Levofloxacin tablets should be kept in a well closed container, protectedfrom light.

Labelling. The designation of the container of Levofloxacin tablets should statethat the active ingredient is the hemihydrate form and the quantity should be indicatedin terms of the equivalent amount of Levofloxacin.

Additional information. Strengths in the current WHO Model List of Essential Medi-cines: 200 mg, 400 mg. Strengths in the current WHO Model List of Essential Medi-cines for Children: 200 mg, 400 mg.


343


REQUIREMENTS


Definition. Levofloxacin tablets contain Levofloxacin. They contain not less than90.0% and not more than 110.0% of the amount of Levofloxacin (C

18H

20FN

3O

4) stated

on the label.

Identity test

Either test A alone or any two of tests B, C and D may be applied

A. To a quantity of the powdered tablets containing 100 mg of Levofloxacin, add 10 mlof acetonitrile R, shake, filter and evaporate to dryness. Carry out the examination asdescribed under 1.7 Spectrophotometry in the infrared region. The infrared absorptionspectrum is concordant with the spectrum obtained from levofloxacin RS or with thereference spectrum of levofloxacin.

B. Carry out the test as described under 1.14.1. Thin-layer chromatography, usingsilica gel R6 as the coating substance and a mixture of 10 volumes of dichlorometh-ane R, 5 volumes of methanol R and 1 volume of ammonia solution 1% as the mobilephase. Apply separately to the plate 5 µl of each of the two following solutions in amixture of 1 volume of methanol R and 4 volumes of dichloromethane R. For solution(A) shake a quantity of the powdered tablets containing 25 mg of Levofloxacin with 5ml, filter and use the clear filtrate. For solution (B) use 5 mg of levofloxacin RS per ml.After removing the plate from the chromatographic chamber, allow it to dry exhaus-tively in air or in a current of cool air. Examine the chromatogram in ultraviolet light(254 nm).


C. See the test described under Assay method A. The retention time of the principalpeak in the chromatogram obtained with solution (1) is similar to that in the chromato-gram obtained with solution (2).

D. The absorption spectrum of the final solution prepared for Assay method B, whenobserved between 210 and 350 nm, exhibits two maxima at about 294 nm and atabout 327 nm.

[Note from Secretariat: a specific optical rotation test to differentiate levofloxacin fromofloxacin is under investigation, with the possibility to include such test under a Manu-facture section.]

Dissolution test

Carry out the test as described under 5.5 Dissolution test for solid oral dosage forms,using as the dissolution medium, 900 ml of hydrochloric acid (~ 4 g/l) TS, and rotatingthe paddle at 100 revolutions per minute. At 30 minutes withdraw a sample of about 5ml of the medium through an in-line filter. Measure the absorbance (1.6) of a 1-cmlayer of the filtered sample at the maximum at about 294 nm. At the same time,


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measure the absorbance at the maximum at about 294 nm of a suitable solution oflevofloxacin RS in hydrochloric acid (~4 g/l) TS using hydrochloric acid (~4 g/l) TS as ablank.

For each of the six tablets, calculate the total amount of Levofloxacin (C18

H20

FN3O

4), in

the medium. The amount in solution for each tablet is not less than 75% of the amountdeclared on the label. If the amount obtained for one of the six tablets is less than75%, repeat the test using a further six tablets; the average amount for all 12 tabletstested is not less than 70% and the amount obtained for no tablet is less than 55%.

[Note from Secretariat: dissolution conditions and limits to be confirmed.]

Related substancesPrepare fresh solutions and perform the tests without delay. Carry out the test asdescribed under 1.14.4 High-performance liquid chromatography, using the conditionsgiven under Assay, method A.

For solution (1) transfer a quantity of the powdered tablets containing about 10 mg ofLevofloxacin into about 20 ml of the dissolution solvent, sonicate for 5 minutes, allowto cool to room temperature and dilute to 50.0 ml with the same solvent. Filter aportion of this solution through a 0.45-µm filter, discarding the first few ml of the filtrate.For solution (2) dilute 1.0 ml of solution (1) to 50.0 ml with the same solvent. Dilute 1.0ml of this solution to 10.0 ml with the same solvent. For solution (3) dissolve 10 mg oflevofloxacin impurity E RS in the dissolution solvent and dilute to 100.0 ml with thesame solvent. Mix 10 ml with 5 ml of solution (1) and dilute to 50.0 ml with the samesolvent. Dilute 1.0 ml of this solution to 50.0 ml with the same solvent.

Inject 20 µl of solution (3). The test is not valid unless the resolution factor betweenthe peaks due to impurity E and Levofloxacin is greater than 2.

Inject separately 20 µl each of solutions (1) and (2) and of the dissolution solvent inthe chromatographic system. Examine the dissolution solvent chromatogram for anyextraneous peaks and disregard the corresponding peaks observed in the chromato-gram obtained with solution (1).

In the chromatogram obtained with solution (1), the following impurity peaks, ifpresent, are eluted at the following relative retention with reference to Levofloxacin(retention time about 17 minutes): impurity B about 0.36; impurity C about 0.57;impurity D about 0.75; impurity E about 0.91; impurity F about 1.50.

In the chromatogram obtained with solution (1):

• the area of any peak corresponding to impurity B, when multiplied by a correctionfactor of 2.6, is not greater than the area of the principal peak obtained with solution(2) (0.2%);

• the area of any peak corresponding to impurity D, when multiplied by a correctionfactor of 4.2, is not greater than the area of the principal peak obtained with solution(2) (0.2%);


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• the area of any peak corresponding to impurity C, E or F is not greater than the areaof the principal peak obtained with solution (2) (0.2%);

• the area of any other impurity peak is not greater than 0.5 times the area of theprincipal peak obtained with solution (2) (0.1%);

• the sum of the areas (corrected, where necessary) of all the peaks, other than theprincipal peak, is not greater than 2.5 times the area of the principal peak obtainedwith solution (2) (0.5%). Disregard any peak with an area less than 0.25 times thearea of the principal peak obtained with solution (2) (0.05%).

[Note from Secretariat: as for the API monograph, following information to be con-firmed:

- correction factors for impurities B and D,- limit for individual unspecified impurities- limit for total of impurities.]

Assay


A. Prepare fresh solutions and perform the tests without delay. Carry out the test asdescribed under 1.14.4 High-performance liquid chromatography, using a stainlesssteel column (15 cm x 4.6 mm), packed with particles of silica gel the surface of whichhas been modified with chemically bonded octadecylsilyl groups (5 µm). (Symmetry150 x 46 mm (5 µm) is suitable).


Prepare the mobile phase as follows: dissolve 4.0 g of ammonium acetateR and 7.0 gof sodium perchlorate R in water R and dilute to 1300 ml; adjust to pH 2.2 with phos-phoric acid R and add 240 ml of acetonitrile R.

Prepare the following solutions in the dissolution solvent prepared by mixing 10volumes of acetonitrile R and 60 volumes of water R.

For solution (1) weigh and powder 20 tablets. Transfer a quantity of the powderedtablets containing about 20 mg of Levofloxacin, accurately weighed, into about 20 mlof the dissolution solvent, sonicate for 5 minutes, allow to cool to room temperatureand dilute to 50.0 ml with the same solvent. Filter a portion of this solution through a0.45-µm filter, discarding the first few ml of the filtrate. Dilute 5 ml of this solution to25 ml with the dissolution solvent.

For solution (2) dissolve 2.0 mg of ofloxacin RS in the dissolution solvent and dilute to25.0 ml with the same solvent.

For solution (3) dissolve 10 mg of levofloxacin impurity E RS in the dissolution solventand dilute to 100.0 ml with the same solvent. Mix 10 ml with 5 ml of solution (1) anddilute to 50.0 ml with the same solvent. Dilute 1.0 ml of this solution to 50.0 ml with thesame solvent.


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Inject 20 µl of solution (3). The test is not valid unless the resolution factor betweenthe peaks due to impurity E and Levofloxacin is at least 2.

Inject separately 20 µl each of solutions (1) and (2) and of the dissolution solvent inthe chromatographic system.

In the chromatogram obtained with solution (1), the following peaks are eluted at thefollowing relative retention with reference to Levofloxacin (retention time about 17minutes): impurity B about 0.36; impurity C about 0.57; impurity D about 0.75; impu-rity E about 0.91; impurity F about 1.50.

Measure the areas of the peak responses in the chromatograms obtained with solu-tions (1) and (2). Calculate the content of Levofloxacin (C

18H

20FN

3O

4).

B. Weigh and powder 20 tablets. Transfer a quantity of the powdered tablets contain-ing about 25 mg of Levofloxacin, accurately weighed, to a 50-ml volumetric flask. Addabout 20 ml of hydrochloric acid (~4 g/l) TS, sonicate for about 5 minutes, allow to coolto room temperature and make up to the volume using the same solvent. Filter aportion of this solution through a 0.45-µm filter, discarding the first few ml of the filtrate.Dilute 1.0 ml of this solution to 100.0 ml using water R. Measure the absorbance (1.6)of a 1-cm layer of this solution at the maximum at about 294 nm. Calculate the contentof Levofloxacin in the tablets using an absorptivity value of 91.2 ( A = 912).

Impurities. The impurities limited by the requirements of this monograph includeimpurities B to F listed in the monograph for Levofloxacin.

* * *New reagent to be added to The International Pharmacopoeia:



Levonorgestrel tablets


Category. Contraceptive.

Storage. Levonorgestrel tablets should be kept in a well-closed container, protectedfrom light.


1 cm 1%

347


Additional information. Strength in the current WHO Model List of Essential Medi-cines: 30 µg, 750 µg, 1.5 mg.

REQUIREMENTS


Definition. Levonorgestrel tablets contain Levonorgestrel. They contain not less than90.0% and not more than 110.0% of the amount of levonorgestrel (C21H28O2) stated onthe label.

Identity tests

Either tests A and B or tests A and C may be applied.

A. To a quantity of the powdered tablets containing 37.5 mg of Levonorgestrel, add 5quantities of dichloromethane R, each of 40 ml. After each addition, stir thoroughlyand filter through a sintered-glass filter (G4). Wash the residue and the filter withdichloromethane R, combine the filtrates, evaporate to dryness on a water-bath withthe aid of a stream of air and allow to cool. Dissolve the residue in 5 ml of dichlo-romethane R and measure the optical rotation. The optical rotation of the resultingsolution is not less than -0.18°.

B. Carry out test B.1 or, where UV detection is not available, test B.2.

B.1 Carry out the test as described under 1.14.1 Thin-layer chromatography, usingsilica gel R6 as the coating substance and a mixture of 7 volumes of cyclohexane Rand 3 volumes of acetone R as the mobile phase. Apply separately to the plate 10 l ofeach of the following two solutions in acetonitrile R. For solution (A) shake a quantityof the powdered tablets containing 1.5 mg of Levonorgestrel with 5 ml, filter, and usethe clear filtrate. For solution (B) use 0.30 mg of levonorgestrel RS per ml. Afterremoving the plate from the chromatographic chamber, allow it to dry exhaustively inair or in a current of cool air. Examine the chromatogram in ultraviolet light at 254 nm.The principal spot obtained with solution A corresponds in position, appearance andintensity to that obtained with solution B.

B.2 Carry out the test as described under 1.14.1 Thin-layer chromatography, using theconditions described under test B.1 but using silica gel R5 as the coating substance.Spray with a mixture of equal volumes of sulfuric acid TS and ethanol (~750 g/l) TS.Heat the plate for a few minutes at 105 °C. Examine the chromatogram in daylight.

The principal spot obtained with solution A corresponds in position, appearance andintensity to that obtained with solution B.

C. See the method described below under the test for Dextronorgestrel. The retentiontime of the principal peak in the chromatogram obtained with solution (2) is similar tothat in the chromatogram obtained with the solution (3).

Dissolution testCarry out the test as described under 5.5 Dissolution test for solid oral dosage forms,using as the dissolution medium, 500 ml of 0.1% solution of sodium dodecyl sulfate R


348


in hydrochloride solution (0.1 mol/l) VS, and rotating the paddle at 75 revolutions perminute. At 30 minutes withdraw a sample of 10 ml of the medium through an in-linefilter and use the filtrate. Prepare standard solution as follows: add a suitable volumeof ethanol (~750 g/l) TS to dissolve a suitable amount of levonorgestrel RS, then adda suitable volume of the dissolution medium to obtain a concentration of 6 µg per ml.

Carry out the test as described under 1.14.4 High-performance liquid chromatography,using the chromatographic conditions as described under Assay.

For each of the six tablets, calculate the total amount of levonorgestrel (C21H28O2), inthe medium. The amount of levonorgestrel in solution for each tablet is not less than80% of the amount declared on the label. If the amount obtained for one of the sixtablets is less than 80%, repeat the test using a further six tablets; the averageamount for all 12 tablets tested is not less than 75% and no tablet contains less than60%.

[Note from Secretariat: possible alternative dissolution method for the 30 µg tablets,which will not use sodium dodecyl sulfate is under investigation.]

DextronorgestrelCarry out the test as described under 1.14.4 High-performance liquid chromatography,using a stainless steel column (15 cm x 4.6 mm) packed with particles of silica gel,the surface of which has been modified with chemically bonded octadecylsilyl groups(5 µm). (Hypersil ODS is suitable.) As the mobile phase, use a solution prepared asfollows: dissolve 5.0 g of gamma-cyclodextrin R in 500 ml of water R and dilute to1000.0 ml with methanol R.

Prepare the following solutions in a dissolution solvent prepared by mixing 80 volumesof methanol R and 20 volumes of water R. For solution (1) transfer a quantity ofpowdered tablets containing about 3.0 mg of Levonorgestrel to a 25-ml volumetricflask. Add about 15 ml of the dissolution solvent Cheat in a water-bath at 60 °C for 10minutes, shaking occasionally. Allow to equilibrate to room temperature, dilute tovolume with the dissolution solvent and mix. Filter through a 0.45-µm filter. For solu-tion (2), dilute a suitable volume of solution (1) to obtain a concentration of 6 µg ofLevonorgestrel per ml. For solution (3) use 6 µg of levonorgestrel RS per ml. Forsolution (4), use 12 µg of norgestrel RS per ml. For solution (5), use 0.12 µg of Lev-onorgestrel RS per ml.

Operate with a flow rate of 1.5 ml per minute. As a detector, use an ultraviolet spectro-photometer set at a wavelength of 242 nm.

Inject 20 µl of solution (3). In the chromatogram obtained with solution (3), the test isnot valid unless the resolution factor between the peaks due to levonorgestrel anddextronorgestrel is at least 1.5.

Inject separately 20 µl, each of solutions (1), (2), (3), (4) and (5).

In the chromatogram obtained with solution (1) the area of the peak due todextronorgestrel , is not greater than the area of the principal peak in the chromato-gram obtained with solution (5) (0.1%).


349


Related substances

Carry out the test as described under 1.14.4 High-performance liquid chromatography,using a stainless steel column (25 cm x 4.6 mm) packed with particles of silica gel,the surface of which has been modified with chemically bonded octadecylsilyl groups(5 µm). (Spherisorb ODS 2 is suitable). As the mobile phase, use a solution preparedas follows: mix 15 volumes of methanol R, 35 volumes of acetonitrile R and 50 vol-umes of water R.

Prepare the following solutions in a dissolution solvent prepared by mixing equalvolumes of methanol R and water R. For solution (1), transfer a quantity of powderedtablets containing about 0.18 mg of Levonorgestrel, accurately weighed, in 5 ml.Sonicate for 30 minutes, stir vigorously for 15 minutes, centrifuge and use thesupernatant liquid. For solution (2), dilute a suitable volume of solution (1) to obtain aconcentration of 0.36 g of Levonorgestrel per ml. For solution (3) use 4 µg of ethi-nylestradiol RS and 4 µg of levonorgestrel RS per ml.



Inject 100 µl of solution (3). Record the chromatogram for twice the retention time oflevonorgestrel (retention time about 26 minutes ). The test is not valid unless, in thechromatogram obtained with solution (3), the resolution factor between the peaks dueto ethinylestradiol and levonorgestrel is at least 12.

Inject separately 100 µl of each of solutions (1) and (2). Record the chromatogram fortwice the retention time of levonorgestrel.

In the chromatogram obtained with solution (1) the area of any peak, other than theprincipal peak, is not greater than the area of the principal peak in the chromatogramobtained with solution (2) (1.0%). The sum of the areas of all peaks, other than theprincipal peak, is not greater than twice the area of the principal peak in the chromato-gram obtained with solution (2) (2.0%).

Assay

Use the average of the 10 individual results obtained in the test for Uniformity ofcontent.

Uniformity of content

The tablets comply with the test for 5.1 Uniformity of content for single-dose prepara-tions, using the following method of analysis.

Carry out the test as described under 1.14.4 High-performance liquid chromatography,using a stainless steel column (15 cm x 4.6 mm) packed with particles of silica gel,the surface of which has been modified with chemically bonded octadecylsilyl groups(5 µm). (Spherisorb ODS 2 is suitable.)


350


As the mobile phase, use a solution prepared by mixing equal volumes of acetonitrileR and water R.

Prepare the following solutions. For solution (1), transfer one powdered tablet to astoppered test-tubes, add 5.0 ml of the mobile phase, sonicate for 45 minutes, shakefor 15 minutes, and centrifuge. Dilute a suitable volume to produce a solution contain-ing 6 µg of Levonorgestrel per ml. For solution (2), accurately weigh 12 mg of lev-onorgestrel RS, dissolve in sufficient mobile phase to produce 100.0 ml, and mix.Dilute 5.0 ml of this solution to 100.0 ml with the same solvent.

Operate with a flow rate of 1.3 ml per minute. As a detector, use an ultraviolet spectro-photometer set at a wavelength of 220 nm.

Inject 25 µl, each solution (1) and (2). The retention time of levonorgestrel is about 7.9minutes. The test is not valid unless the column efficiency, determined for the peakdue to levonorgestrel using solution (2) is at least 5000. The symmetry factor of thepeak due to levonorgestrel is not more than 1.6.

Measure the areas of the peak responses obtained in the chromatograms from solu-tions (1) and (2), and calculate the content of levonorgestrel (C

21H

28O

2) in each tablet.
