starch microspheres with EPCL

International Journal of PharmTech ResearchCODEN (USA) IJPRIF ISSN 0974-4304

Vol1 No4 pp 1394-1402 Oct-Dec 2009

Preparation and Characterization of Rofecoxibmicrospheres using cross-linked starch as novel drug

delivery systemThombre N A1 Chaudhari MR2 Kadam SS 2

1 Department of Pharmaceutics METrsquos Institute of Pharmacy Bhujbal Knowledge CityAdgaon Nashik Maharashtra India ndash 422 003

Telephone +91 253 2303515 Fax +91 253 23032032Bharati Vidyapeethrsquos University Poona College Of Pharmacy Erandwane Pune-411038

Corresponding author nilimathombregmailcom

ABSTRACT The objective of the present investigation was to produce microspheres by cross-linking starch withepichlorhydrin which is a very efficient divalent cross-linking agent for starch An attempt was made to improve thedissolution of poorly soluble drug Rofecoxib Rofecoxib was microencapsulated with developed cross-linked starch usingSolvent Evaporation Technique The prepared microspheres were white free-flowing and almost spherical in shape Theefficiency of the cross-linked starch polymers was evaluated by using different tests like extent of cross-linking of starch byIodine reaction with it IR interpretation Mean particle size Water regain capacity Action of α-amylase on native starch andcross-linked starch Gel filtration chromatography In vitro drug release Extent of cross linked starch was found to be highestMicrospheres ranging 91 to 105 μm with narrow size distribution could be obtained Water regain capacity was found to be609 ww IR studies indicated high stretching of ether linkage of cross-linked starches α-amylase test revealed lesssusceptibility to microbial enzymes Gel filtration chromatography confirmed the higher porosity with entrapment in itsmatrix Release in vitro study of Rofecoxib revealed that the microspheres could gives sustained release of drug The preparedcross-linked polymer system holds good for further drug delivery studies in connection to its super swelling andbiodegradabilityKEYWORDS microspheres solvent evaporation technique crosslinking starch epichlorhydrin

INTRODUCTIONNaturally occurring polymers are high molecular weighthaving hydroxyl carbonyl amino and thiol functionalgroup They are made up from glycosidic peptide esterlinkages Modifications are essential to improve theproperties of these polymers for desired applicationNaturally occurring polymer like starch is very highmolecular weight substances1Starch is homopolysaccharide made from α-D- glucoseand consist of two components amylose andamylopectinThe smaller of the two polysaccharidesamylose is a linear molecules comprising of (1-4) linkedα-D glucopyranosyl units having a molecular weight ofseveral hundred thousandsAmylose is water-soluble butgives an unstable solutionAmylose stains deep blue withiodine (λ max c 660nm)2The larger of the two components amylopectin is highlybranched with molecular weight of several hundred

million This structure contains α-D- glucopyranosylunits linked mainly by (1-4) linkages (as amylose) butwith greater proportion of (1-6) linkages which gives alarge highly branched structureAmylopectin yieldpurple color with iodine (λ max c 540nm) Solution ofamylopectin is relatively stable3Starch is polysaccharide most widely used in foodspharmaceutical and cosmetic industry for their differentapplications The application of starch is based on thepurity and cost Starch is used as an excipient in differentpharmaceutical dosage forms as binder diluentdisintegrant adsorbent lubricant etc It has been used inseveral industries but starch in its native form has manyproblems like stability at high temperature and atdifferent pH47Starch is a biodegradable polymer which degrades veryfast with the help of enzyme amylase present in humansaliva and also by microorganisms Starch degrades very

Thombre N A et al IntJ PharmTech Res20091(4) 1395

fast to generate α-D glucose Starch is a very good mediafor microorganism growth Therefore its fast degradationis hurdle in application of starch in controlled drugdelivery system Hence it has been essential to modifythe starch for the use Modification of the starch is doneto improve biodegradation Chemical crosslinking is oneof the methods used for the modification of starch in thisdirection to improve the stability and reduce thedegradation Various degrees of crosslinking can beintroduced into starch for the purpose of generating largermolecule aggregates with enhanced viscosity profiles orfor the preparation of insoluble products with wide rangeof swelling characteristics Some common cross linkingagents include epichlorhydrin acetaldehyde andformaldehyde Crosslinking of starch develop resistant toaction of enzymes and its degradation is also slowdown4- 5 7

Cross liked starch known as a modified starch havepotential applications in the field of medicine agricultureand food industries controlled release of pesticidemicronutrients in soil to retain flavor in foodpreparations to increase water retention capacity of soilby putting modified starch in soil In analytical fieldmodified starch gels are used as a media for separation bymolecular exclusion chromatography24

Cyclooxygenase-2 (COX-2) inhibitors constitute a newgroup of non steroidal anti-inflammatory drugs(NSAIDs) Rofecoxib is about 100-1000 times moreselective on the COX-2 than on the COX-1 is form withlower incidence of gastric bleeding and other gastro-toxiceffect It is indicated for the treatment of symptoms andsigns of osteoarthritis It is sparingly soluble in acetoneslightly soluble in ethanol and insoluble in water 6The main objective of the present work is to developnewly synthesized cross linked polymer of starch with across-linker epichlorhydrin that could be used as a noveldrug delivery device in future

MATERIALS AND METHODSRofecoxib (Cipla Ltd Mumbai India) Potato starch (Sdfine chemicals Ltd) Epichlorhydrin (Sisco ResearchLab) of commercial purity grade were used All otherchemicals used were of analytical reagent grade FTIRspectrophotometer (Jasco 5300 Jasco Inc Easton MDUSA) and Dissolution test apparatus USP XXIV(Erweka-DT-1 Commerce Dr Easton MD-21601Germany) were used for drug content estimation anddissolution studies respectively

Preparation Of Microspheres Of Cross-LinkedStarch8

Defatted starch has been prepared in alkaline solution andair dried it Cross linked starch have been preparedaccording to Solvent Evaporation Technique usingepichlorhydrin (ECH) as a cross linking agent For atypical batch defatted potato starch (10g) was dispersedin sodium hydroxide (1M 100ml) in presence of sodiumborohydried (250mg) and was kept for 15 hrs Liquidparaffin (250ml) was taken in a one liter 2 necked round

bottom flask equipped with stainless steel mechanicalstirrer and heated to 700C over hot water bath Thedispersed starch was added to liquid paraffin underconstant stirring (1400 rpm) to obtain a uniformemulsion Then epichlorhydrin (40ml) was added to theemulsion drop wise with continuous stirring for 1 hrThen emulsion was neutralized with hydrochloric acid(1M) and liquid phase was decanted The obtainedmicrospheres were washed with toluene Themicrospheres were isolated by centrifugation and washedrepeatedly with saline solution Finally Microsphereswere dehydrated with alcohol and air-dried which kept inclosed containers before use By following the abovementioned procedure six other batches of microsphereswith drug cross linked starch ratio of 11(F1 F2) 12(F3 F4) 13 (F5 F6) were prepared [Figure 1]

Reaction with Iodine38

The extent of cross-linking of starch was determined byIodine reaction The prepared cross linked starch wastreated with Iodine at pH 48 (Acetate buffer 01M)

Fourier Transform Infra Red spectroscopy studiesFT-IR spectra of the cross-linked polymer along withhomopolymers were recorded to check drug polymerinteraction and stability of the drug on a Jasco 5300(Jasco Inc Easton MD USA) spectrophotometer usingKBr pellets in the range 400-4000cm

Particle size analysis9

The particle size of microsphere was determined usingoptical microscopy method approximately 100microspheres were counted for particle size using acalibrated optical microscope (Magnus MLX-DX)

Micromeritic properties9

1 Angle of reposeAngle of repose of different formulations was measuredaccording to fixed funnel standing method [11] ( n = 3)[Table 1]

θ = tan-1 h r

where θ is the angle of repose r is the radius and h is theheight2 Bulk densityBulk and tapped densities were measured by using 10 mlof graduated cylinder The sample poured in cylinder wastapped mechanically for 100 times then tapped volumewas noted down and bulk density and tapped densitywere calculated Each experiment for micromeriticproperties was performed in triplicate manner andreported in [Table 1]3 Carrs indexCompressibility index (Ci) or Carrs index value of microparticles was computed according to the followingequation [Table 1]


4 Hausners ratio Hausners ratio of microparticles was determined bycomparing the tapped density to the bulk density using the equation[Table 1]

Water regain capacityThe solvent absorption in the core of microsphere wasdetermined by water regain capacity Water regaincapacity was evaluated by exposing 100mg ofmicrospheres of cross-linked starch in 5 ml of water for24 hrs Then the microspheres were centrifuged at 500rpm and the water is decanted The water regain capacityof the microspheres was calculated by using the equation

Initial weight of the microspheresWater Regain Capacity = ----------------------------------

Weight of the microspheres after the test

Determination of reducing sugars1011

3 5 dinitro salicylic acid (DNSA)reagent was preparedjust before use by mixing the stock solutions1 ml of testreagent was added to 3 ml of the maltose solution ofdifferent concentration (02 04 06 08 10 12 14mgml) in a test tube Blank was prepared by adding 1 mlof the reagent to the 3 ml of distilled water All the testtubes were covered with a marble amp place in a boilingwater bath for 5 min cooled to room temperatureAbsorbance was recorded against blank on photoelectriccolorimeter at 540nm against the blank

Action of α-amylase 10 11

The action of α-amylase was evaluated by dissolvingeach of 100 mg of starch amp cross linked starch in 10 mlof buffered saline in separate container 1 ml of eachsolution into a series of 7 test tubes for each was dilutedwith 3 ml of saline diluted (about 1 in 100 with water)The tubes were incubated at 370C for upto 1 hr The testtube was removed 05 ml of NaOH was added to it andthe reaction was stopped by adding DNSA reagent Thetest tubes were heated on boiling water bath for 15minutes and cooled to the room temperature Absorbanceof different concentrations was recorded on photoelectriccolorimeter at 540nm

Gel Filtration Chromatography 12 13

This evalution test was carried out at 40CA glass column(D 15 cm L 250 cm) was packed with micro spheres ofcross linked starch and equilibrated with saline (0145MNaCl)The flow rate was adjusted to 120 mlhr with thehelp of a peristaltic pump Void volume and elutionvolume were determined by using Blue Dextran 2000 andGlucose A mixture of BSA (Bovine Serum AlbuminMW-66000) and Cytochrome c (MW 12400) dissolved insaline was applied to column and the separation waschecked on the column The graph of elution profile forcross linked starch beads CS-100 against Absorbance wasobtained

Loading Of drug in the micro spheres of cross linkedstarch 14

The inclusion of the drug Rofecoxib was carried out inthe dark by the evaporation method Saturated solution ofRofecoxib (10 ml) in acetone was poured over 4 gm ofmicro spheres packed in a glass column (D 15 cm L250 CM) and coated with carbon paper to keep it awayfrom light The column was capped for 2 hrs Then it wasuncapped to evaporate acetone completely

In vitro drug release studyIn vitro dissolution studies were carried out on theprepared Rofecoxib microsphere using cross-linkedstarch at 37degC plusmn (05degC) at 100 rpm with USP dissolutionapparatus II 200-mg Rofecoxib microsphere was placedinto the dissolution apparatus The in vitro dissolutionstudies were performed at 74 pH which is simulatedintestinal fluid pH An accurately weighed sample wasresponded in dissolution media consisting 900 ml ofPhosphate buffer (pH 74)The sample (5 ml) waswithdrawn at regular intervals and replaced with the samevolume of test medium and the withdrawn samples werediluted if required and then estimated for rofecoxibconcentration at 219 nm spectrophotometrically(Shimadzu Pharmspec UV-1700 series Japan) Thesample was diluted (05 ml up to 10 ml) and absorbancewas measured at 219 nm Finally the drug content in allfluid was determined from the calibration curve ofrofecoxib to determine the release pattern

RESULT AND DISCUSSIONRofecoxib microspheres with varying proportions ofrofecoxib and cross-linked starch were prepared bysolvent evaporation method

Description of the MicrospheresOcular and stage microscopy shows that the microspheresobtained were spherical and free flowing is shown inFigure The yield obtained in all the batches was goodwhich was above 75 amp none of the variables affectedthe yield It indicated that rofecoxib microspheres have adiscrete spherical structure without aggregation [Figure2]


Reaction with IodineThe treatment of iodine with the Microspheres preparedby using cross linked starch does not show any colorationwith iodine It indicates that there was an extensive cross-linking of starch

FT-IR InterpretationIR Spectrum indicated O-H stretching at 3333cm-1 innative starch which characteristics of polymericassociation and C-H at 1645 858 cm-1 Cross-inkedstarch has shown O-H stretching at 3437 cm-1 C-Hstretching at 2928 amp 1456 cm-1 Also it has been shownweak C-O stretching at 1010 cm-1 which is characteristicof ether functional moiety [Figure 3 and Figure 4]Particle size analysisThe particle size of Microspheres of cross linked starchwas in the range of 91-105μm and most microspheresprepared from the different formulation batches are usedfor the micromeritic studies [Table1] [Figure 2]

Micromeritic properties of cross linked starchmicrospheresAngle of reposeAll the formulations show angle of repose value in therange of 16-20 ie less than 30which shows free-flowing nature of the formed microspheres [Table 1]Bulk density and tapped densityBulk and tapped densities showed good packability of themicrospheres [Table 1]Carrs index (Ci)Carrs index ranges from 14 to 17 F5 had lowest Ciindex indicating excellent compressibility [Table 1]Hausners ratioIt was ranging from 114 to 135 ie all the preparationshowed that they had good flow properties Uponconsidering the micromeritic properties of all theformulations B2 had the best flow property as it hadhigh angle of repose value (20250) the lowest Carrsindex (1404) and Hausners ratio (114) [Table 1]

Water Regain CapacityWater regain capacity is calculated to determine thecapacity of micro spheres for solvent absorption in thecore Water regain capacity of Microspheres of cross-linked starch was found to be 609 ww From thisMicrospheres can retain 609 ww of the solvents

Determination of reducing sugarsStandard curve of the maltose was used them to estimatethe concentration of the native starch amp cross-linkedstarch [Figure5]

Action of α-AmylaseΑ-Amylase catalyses the specific hydrolysis of the α-1-4

glycosidic bonds of starch in a random manner with theformation of series of intermediates determines thepower of polymer to resist microbial attack In presentstudy the action of amylase on native starch andmicrospheres of cross-linked starch was determined byDNSA (dinitro salicylic acid) method The action of α-Amylase on native starch and microspheres of cross-linked is shown in [Figure 6]From the graph it was shown that the native starch ismore susceptible for microbial growth than cross-linkedstarch Native starch is a good nutrient media formicrobial growth therefore microbial contamination wasreadily found in native starch Present study showed thatthe microcapsules of cross-linked starch inhibit microbialcontamination to far extent than native starch

Gel Filtration ChromatographyThe molecular sieve effect and porosity of micro spheresof cross linked starch was determined by Gel FiltrationChromatography The study also determined that themicro spheres binds drug reversibly in its core for itscontrolled delivery in a body system Gel FiltrationChromatography study showed that the microcapsules areporous rigid with high mechanical strength and permitsinclusion of drug in the microcapsules Figure shows thegel filtration profile for a mixture of BSA andCytochrome c[Figure 7]

In vitro drug release studyIn vitro dissolution studies revealed that the release ofplain rofecoxib tablet was found to be 99 in less than50 min while release of rofecoxib from microspheres ofcross linked starch was found to be 40 in the sametimeThe influence of different processing condition wasevaluated on in vitro drug release and percentage drugrelease was found in the range of 7748 to 9644 atperiod of 08 hours A biphasic in-vitro drug releaseprofile was observed with initial burst effect for all theformulation prepared The initial burst release is due tothe presence of drug on the surface preparedmicrospheres The initial burst release can be attributedas desired effect which ensures the quick initial plasmatherapeutic concentration of drug All the formulatedmicrospheres retained their shape and size even afterdissolution which indicated the release of drug diffusionthrough the polymer wall of microspheres Throughdissolution profiles it was observed that the decrease indrug to polymer ratio from 11 to 13 resulted a decreasein release rate It is considered that the higher drug topolymer ratio in the microspheres result in increase incoat thickness surrounding the drug particles therebyincreasing the distance travelled by the drug throughcoat[Figure8]


Table 1 Micromeritic properties of microspheres prepared by using cross-linked starch

FormulationCode

Angle ofrepose(θ)

Bulk Density(gml)

Tapped Density(gml

Carrrsquos Index(Ci) ()

Hausnerrsquos ratio Particlesize (microm)

Mean SD(plusmn) Mean SD(plusmn) Mean SD(plusmn) Mean SD(plusmn) Mean SD(plusmn) Mean SD(plusmn)

F1 1679 0681 0555 0007 0649 0009 1446 1385 116 002 1059 233

F2 2078 0586 0494 0005 0673 0014 1552 083 135 0015 934 295

F3 165 0202 0445 0006 0373 001 1648 061 119 0005 916 223

F4 1701 059 0562 0012 0735 002 1755 1248 128 002 9564 4628

F5 182 0017 0426 0008 0497 0001 1405 171 114 0026 9942 2975

F6 1954 0251 0462 0015 0841 0031 1623 1268 114 0026 10432 178

Table 2 Different parameters of cross linked starch

SrNo Parameters Micro spheres of crosslinked starch

1 Practical Yield ( ww) 70 to 752 Particle size (microm) 91 to 1053 Water regain capacity ( ww) 6094 Flow rate under gravity (mlhr) 120 plusmn055 Void volume (ml) 25006 Total elusion volume (ml) 11000

Figure 1 Reaction of Amylose with Epichlorhydrin

O

CH 2 OH

H

H

OH

OH

H OH

H

H

O

H O

HOH 2 C

HOH

H

H

OH

H

O

H O

HOH 2 C

H OH

H

H

OH

H

OH

A m y l o s e

O

Cl

E p i c h l o r h y d r i n e

O

H O

H 2 C

HOH

H

H

OH

H

O

OO

O

H O

H 2 C

HOH

H

H

OH

H

O

O

F u r t h e r r e a c t i o n

CHOH

OCH 2

O

OH

OH

OOC r o s s l i n k e d s t a r c h


Figure 2 Microspheres of cross linked starch

Figure3 IR Spectra of native starch

Figure4 IR Spectra of Cross-linked starch


Figure 5 Calibration curve for maltose

Figure 6 Comparison between action of Amylase on starch and cross-linked starch

Figure 7 Elution profile for cross-linked starch beads CS-100


Figure 8 In vitro drug release of Rofecoxib conventional tablet with rofecoxib microspheres of cross linked starch formulation F1F2F3F4F5F6

CONCLUSIONThe cross linked starch with epichlorhydrin resulted inmicrospheres with good yield independent of anyvariables The extent of cross linking of native starch andstretching of ether linkage was found to be high withEpichlorhydrinRofecoxib microspheres were prepared successfully bysolvent evaporation method using the cross linked starchas polymers in the ratio of 11(F1 F2) 12 (F3 F4) 13(F5 F6) It was found that the prepared microsphereswere spherical free flowing high percentage entrapmentefficiency and high percentage yielding capacity It canbe concluded from this study that rofecoxib could bemade into controlled-release drug delivery system usingas cross linked starch polymers retardant materials in thedrug to polymer ratios of 11 12 13 stirring speed of1400 rpm and volume of continuous phase of 100 ml asoptimum process parameter The in-vitro controlledrelease of rofecoxib from the prepared microspheresformulations have been reported in this study The extentof cross linking of native starch and stretching of etherlinkage was found to be high with EpichlorhydrinHowever the in-vitro release characteristics of drug fromthe microspheres are subject to confirmation in animaland human studies for coming into conclusion ofenhanced bioavailability and reduced dose frequency toimprove patient complianceThe prepared cross-linked starch was found to have highswelling property biodegradability and also havingcomparatively higher stability Therefore from thesestudies it can be concluded that the prepared polymersystem can be used in drug delivery studies in future

REFERENCES1) Martin Scott Cardinali and Tak Yu (Fiona)Lam

New Advances in Starch-based ParticleTechnologies for Aesthetic ModificationNational Starch Personal CarePCIAManila-2003

2) Fanta GF and Doane in ModifiedStarchesProperties and Uses Edn OB CRCPress Boca RatonFI Wurzburg (1986)149

3) Roberts HJIn starchChemistry andTechnologyvol 1Edn1Whistler andEFPashallAcademic PressNew York1965484

4) Foster JFIn starchChemistry and TechnologyEdn 1 volume 1Whistler andEFPaschallAcdemic PressNew York1965484-490

5) GHamdiGPonchel et al Formulation ofepichlorhydrin cross-linked starch microspheresJournal of Microencapsulation 2001 Vol 18No3 373-383

6) MV Ramana M Himaja Kamal Dua VKSharma A new approach Enhancement ofsolubility of rofecoxib Asian Journal ofPharmaceutics Volume 2 Issue2-2 200896-101

7) Textbook of Pharmaceutical Excipient5228) Chaudhari MRKamath NDBhide SVKale

NRPreparation and Crosslinked starch beads asa medium for GelFiltrationStarchStarkeVol41Issue111989415-416

9) Parul Trivedi AML Verma NGarudPreparation and characterization ofaceclofenac microspheres Asian Journal ofPharmaceutics Volume 2 Issue2-2 2008110-115

10) David T Plumber An Introduction to practicalbiochemistry Edn 3 Tata McGraw-HillPublishing Company Limited NewDelhi2006180-181

11) Godkar PB Godkar DP Textbook of MedicalLaboratory Technology Edn 2BhalaniPublishing HouseMumbai 2003176-217


12) Nandedkar UNBhide SVKale NRSephacryl S-300- an affinity matrix whichdistinguishes concanavallin A from other D-mannoseD-glucose-specific lectins Journal ofChromatography Vol 396Jun 1987 363-8

13) Dubois MKAGilles JKHamilton PASmithFSmithAnalytical Chemistry 28(1956)350

14) Rita Cortesi Gheorghe FundueanuPaoloAscenziEnea Menegatti Preparation and

characterization of StarchCyclodextrinBioadhesive microspheres as platform for nasaladministration of Gabexate Mesylate(Foy(R) ) inallergic rhinitis treatmentBiomaterials Volume25 Issue 12004159-170

15) United State Pharmacopoeia XXI Asian Edition7112673-2681


fast to generate α-D glucose Starch is a very good mediafor microorganism growth Therefore its fast degradationis hurdle in application of starch in controlled drugdelivery system Hence it has been essential to modifythe starch for the use Modification of the starch is doneto improve biodegradation Chemical crosslinking is oneof the methods used for the modification of starch in thisdirection to improve the stability and reduce thedegradation Various degrees of crosslinking can beintroduced into starch for the purpose of generating largermolecule aggregates with enhanced viscosity profiles orfor the preparation of insoluble products with wide rangeof swelling characteristics Some common cross linkingagents include epichlorhydrin acetaldehyde andformaldehyde Crosslinking of starch develop resistant toaction of enzymes and its degradation is also slowdown4- 5 7

Cross liked starch known as a modified starch havepotential applications in the field of medicine agricultureand food industries controlled release of pesticidemicronutrients in soil to retain flavor in foodpreparations to increase water retention capacity of soilby putting modified starch in soil In analytical fieldmodified starch gels are used as a media for separation bymolecular exclusion chromatography24

Cyclooxygenase-2 (COX-2) inhibitors constitute a newgroup of non steroidal anti-inflammatory drugs(NSAIDs) Rofecoxib is about 100-1000 times moreselective on the COX-2 than on the COX-1 is form withlower incidence of gastric bleeding and other gastro-toxiceffect It is indicated for the treatment of symptoms andsigns of osteoarthritis It is sparingly soluble in acetoneslightly soluble in ethanol and insoluble in water 6The main objective of the present work is to developnewly synthesized cross linked polymer of starch with across-linker epichlorhydrin that could be used as a noveldrug delivery device in future

MATERIALS AND METHODSRofecoxib (Cipla Ltd Mumbai India) Potato starch (Sdfine chemicals Ltd) Epichlorhydrin (Sisco ResearchLab) of commercial purity grade were used All otherchemicals used were of analytical reagent grade FTIRspectrophotometer (Jasco 5300 Jasco Inc Easton MDUSA) and Dissolution test apparatus USP XXIV(Erweka-DT-1 Commerce Dr Easton MD-21601Germany) were used for drug content estimation anddissolution studies respectively

Preparation Of Microspheres Of Cross-LinkedStarch8

Defatted starch has been prepared in alkaline solution andair dried it Cross linked starch have been preparedaccording to Solvent Evaporation Technique usingepichlorhydrin (ECH) as a cross linking agent For atypical batch defatted potato starch (10g) was dispersedin sodium hydroxide (1M 100ml) in presence of sodiumborohydried (250mg) and was kept for 15 hrs Liquidparaffin (250ml) was taken in a one liter 2 necked round

bottom flask equipped with stainless steel mechanicalstirrer and heated to 700C over hot water bath Thedispersed starch was added to liquid paraffin underconstant stirring (1400 rpm) to obtain a uniformemulsion Then epichlorhydrin (40ml) was added to theemulsion drop wise with continuous stirring for 1 hrThen emulsion was neutralized with hydrochloric acid(1M) and liquid phase was decanted The obtainedmicrospheres were washed with toluene Themicrospheres were isolated by centrifugation and washedrepeatedly with saline solution Finally Microsphereswere dehydrated with alcohol and air-dried which kept inclosed containers before use By following the abovementioned procedure six other batches of microsphereswith drug cross linked starch ratio of 11(F1 F2) 12(F3 F4) 13 (F5 F6) were prepared [Figure 1]

Reaction with Iodine38

The extent of cross-linking of starch was determined byIodine reaction The prepared cross linked starch wastreated with Iodine at pH 48 (Acetate buffer 01M)

Fourier Transform Infra Red spectroscopy studiesFT-IR spectra of the cross-linked polymer along withhomopolymers were recorded to check drug polymerinteraction and stability of the drug on a Jasco 5300(Jasco Inc Easton MD USA) spectrophotometer usingKBr pellets in the range 400-4000cm

Particle size analysis9

The particle size of microsphere was determined usingoptical microscopy method approximately 100microspheres were counted for particle size using acalibrated optical microscope (Magnus MLX-DX)

Micromeritic properties9

1 Angle of reposeAngle of repose of different formulations was measuredaccording to fixed funnel standing method [11] ( n = 3)[Table 1]

θ = tan-1 h r

where θ is the angle of repose r is the radius and h is theheight2 Bulk densityBulk and tapped densities were measured by using 10 mlof graduated cylinder The sample poured in cylinder wastapped mechanically for 100 times then tapped volumewas noted down and bulk density and tapped densitywere calculated Each experiment for micromeriticproperties was performed in triplicate manner andreported in [Table 1]3 Carrs indexCompressibility index (Ci) or Carrs index value of microparticles was computed according to the followingequation [Table 1]





























FormulationCode

Angle ofrepose(θ)

Bulk Density(gml)

Tapped Density(gml




F1 1679 0681 0555 0007 0649 0009 1446 1385 116 002 1059 233

F2 2078 0586 0494 0005 0673 0014 1552 083 135 0015 934 295

F3 165 0202 0445 0006 0373 001 1648 061 119 0005 916 223

F4 1701 059 0562 0012 0735 002 1755 1248 128 002 9564 4628

F5 182 0017 0426 0008 0497 0001 1405 171 114 0026 9942 2975

F6 1954 0251 0462 0015 0841 0031 1623 1268 114 0026 10432 178





O

CH 2 OH

H

H

OH

OH

H OH

H

H

O

H O

HOH 2 C

HOH

H

H

OH

H

O

H O

HOH 2 C

H OH

H

H

OH

H

OH

A m y l o s e

O

Cl


O

H O

H 2 C

HOH

H

H

OH

H

O

OO

O

H O

H 2 C

HOH

H

H

OH

H

O

O


CHOH

OCH 2

O

OH

OH



























































FormulationCode

Angle ofrepose(θ)

Bulk Density(gml)

Tapped Density(gml




F1 1679 0681 0555 0007 0649 0009 1446 1385 116 002 1059 233

F2 2078 0586 0494 0005 0673 0014 1552 083 135 0015 934 295

F3 165 0202 0445 0006 0373 001 1648 061 119 0005 916 223

F4 1701 059 0562 0012 0735 002 1755 1248 128 002 9564 4628

F5 182 0017 0426 0008 0497 0001 1405 171 114 0026 9942 2975

F6 1954 0251 0462 0015 0841 0031 1623 1268 114 0026 10432 178





O

CH 2 OH

H

H

OH

OH

H OH

H

H

O

H O

HOH 2 C

HOH

H

H

OH

H

O

H O

HOH 2 C

H OH

H

H

OH

H

OH

A m y l o s e

O

Cl


O

H O

H 2 C

HOH

H

H

OH

H

O

OO

O

H O

H 2 C

HOH

H

H

OH

H

O

O


CHOH

OCH 2

O

OH

OH











































FormulationCode

Angle ofrepose(θ)

Bulk Density(gml)

Tapped Density(gml




F1 1679 0681 0555 0007 0649 0009 1446 1385 116 002 1059 233

F2 2078 0586 0494 0005 0673 0014 1552 083 135 0015 934 295

F3 165 0202 0445 0006 0373 001 1648 061 119 0005 916 223

F4 1701 059 0562 0012 0735 002 1755 1248 128 002 9564 4628

F5 182 0017 0426 0008 0497 0001 1405 171 114 0026 9942 2975

F6 1954 0251 0462 0015 0841 0031 1623 1268 114 0026 10432 178





O

CH 2 OH

H

H

OH

OH

H OH

H

H

O

H O

HOH 2 C

HOH

H

H

OH

H

O

H O

HOH 2 C

H OH

H

H

OH

H

OH

A m y l o s e

O

Cl


O

H O

H 2 C

HOH

H

H

OH

H

O

OO

O

H O

H 2 C

HOH

H

H

OH

H

O

O


CHOH

OCH 2

O

OH

OH

































FormulationCode

Angle ofrepose(θ)

Bulk Density(gml)

Tapped Density(gml




F1 1679 0681 0555 0007 0649 0009 1446 1385 116 002 1059 233

F2 2078 0586 0494 0005 0673 0014 1552 083 135 0015 934 295

F3 165 0202 0445 0006 0373 001 1648 061 119 0005 916 223

F4 1701 059 0562 0012 0735 002 1755 1248 128 002 9564 4628

F5 182 0017 0426 0008 0497 0001 1405 171 114 0026 9942 2975

F6 1954 0251 0462 0015 0841 0031 1623 1268 114 0026 10432 178





O

CH 2 OH

H

H

OH

OH

H OH

H

H

O

H O

HOH 2 C

HOH

H

H

OH

H

O

H O

HOH 2 C

H OH

H

H

OH

H

OH

A m y l o s e

O

Cl


O

H O

H 2 C

HOH

H

H

OH

H

O

OO

O

H O

H 2 C

HOH

H

H

OH

H

O

O


CHOH

OCH 2

O

OH

OH
















































































































Documents

starch microspheres with EPCL