International Journal of PharmTech ResearchCODEN (USA): IJPRIF ISSN : 0974-4304Vol. 3, No.2, pp 968-979, April-June 2011

Formulation Development and Invitro Evaluationof Tamsulosin Hcl Extended Release Pellets

M. Anand Kumar1*, Dr. P. K. Lakshmi1, Dr. J. Balasubramanium2

1G.Pulla Reddy College of Pharmacy,Mehdipatnam,Hyderabad,India.2RA Chem Pharma Pvt.Ltd,Nacharam, Hyderabad,India.

*Corres.author: anand.mvrs@gmail.com

Abstract: The purpose of this study was to develop and optimize oral extended release formulation for tamsulosinhydrochloride using a combination of ethyl cellulose N-50 and Eudragit L-100 as a coating material. Initially trials weredone to optimize the drug loading on to sugar pellets for its uniformity of size and Assay, varying the concentration ofHPMC E-5 as binder, Aerosil as lubricant and sodium starch glycollate as disintegrant.The drug release percentages at 2,3, 5, and 8 hours were the target responses and were restricted to 13-34%,47-68%, NLT 70%, NLT 80% respectively.The optimal coating formulation was achieved with Eudragit L-100 9% of the weight of the drug loaded pellets andethyl cellulose N-50 with 25% of the Eudragit L-100 content.The drug release from the optimized pellets was compared with the Innovator product FLOMAX ® capsule. It showedthe similarity factor (F2) of 76.43Keywords: Tamsulosin HCl, Eudragit L-100, Ethyl cellulose N-50, pellets.

1. Introduction:In the last two decades, pellets have established theirposition for many reasons 1, 2. Pellets offer a greatflexibility in pharmaceutical solid dosage form designand development. Pellets can be prepared by manymethods, the compaction and drug-layering techniquesbeing the most widely used today. They flow freelyand pack easily without significant difficulties,resulting in uniform and reproducible fill weight ofcapsules and tablets 3, 4, 5. Successful film coating canbe applied onto pellets due to their ideal sphericalshape and a low surface area-to-volume ratio6. Evenpellets with different release rates of the same drug canbe supplied in a single dosage form7.The pelletizedproducts can improve the safety and efficacy of theactive agent. The pelletized product can freely dispersein the gastrointestinal tract as a subunit, thusmaximizing drug absorption and reducing peak plasmafluctuation. Consequently, potential side effects can be

minimized without impairing drug bioavailability.Local irritation derived from high local concentrationsof a drug from a single-unit dose, can be avoided. Themost important reason for the wide acceptance ofmultiple-unit products is the rapid increase inpopularity of oral controlled-release dosage forms.Controlled-release oral solid dosage forms are usuallyintended either for delivery of the drug at a specificsite within the gastrointestinal tract or to sustain theaction of drugs over an extended period of time. Withpellets, the above mentioned goals can be obtainedthrough the application of coating materials (mainlydifferent polymers), providing the desired function 8, 9,

10, 11, 12, 13, 14 or through the formulation of matrix pelletsto provide the desired effect 15, 16.

Tamsulosin hydrochloride is a highly selective alpha1A-adrenoreceptor antagonist that has been used fortreatment of lower urinary tract symptoms suggestive

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 969

of benign prostatic hyperplasia (LUTS/BPH) 17.Moreover, following oral administration of 0.4mgtamsulosin hydrochloride, the drugs absorbed from theintestine and is almost completely bioavailable18.However, many LUTS/BPH patients are elderlysubjects with impaired cardiovascular regulation. Theyare particularly at risk for cardiovascular adverseevents, which are not only unpleasant, but can alsolead to serious morbidity, such as falls and fractures,potentially resulting in hospitalization, nursing homeplacement and/or death19. Therefore, the preferredformulation of tamsulosin hydrochloride provides acontrolled-release that can modulate both the releaserate of the drug and the absorption of the drug in theintestinal tract20. Prior to thesePolymeric film coatings are frequently used to controldrug release from solid pharmaceutical dosage forms.To obtain a particular, desired release profile which isadapted to the pharmacokinetic /pharmacodynamiccharacteristics of the drug and type ofpharmacotreatment, different formulation andprocessing parameters can be varied, such as thecoating level, type of polymer and type and amount ofadded plasticizer. However, the variation of theseparameters is generally restricted and it is sometimesdifficult to adjust optimized release kinetics. Forinstance, too low and too high coating levels must beavoided to prevent accidental film rupturing (andsubsequent dose dumping) and too long processingtimes. The type of polymer used should be known tobe non-toxic; otherwise time-and cost intensivetoxicity studies are required. Too high amounts ofadded plasticizers lead to intense sticking of the coateddosage forms, whereas too low amounts result in toobrittle films. Here we are using blend of polymer tocontrol the release as per specifications and A blend ofEudragit L-100 and ethyl cellulose N-50 are used tocontrol the drug release. The objective of this study isto develop a novel controlled release tamsulosinhydrochloride using Eudragit L-100 and ethylcellulose N-50.where as earlier studies have been doneon tamsulosin hydrochloride using different coatingagents 21, 22, 23, 24, 25.

2. Materials and Method:Tamsulosin hydrochloride is obtained from RA chem.Pharma Pvt Ltd. Hydroxymethylpropylcellulose(HPMC were obtained from SHIN-ETSU, Japan).Methacrylic acid copolymer-A (Eudragit L100 fromEvonik Degussa India Pvt Ltd).Ethylcellulose N-50USP grade from Feicheng chemicals Ltd,China,Aerosil,PEG-6000, Talc and Isopropyl alcohol (IPAfrom Ranchem laboratories), Flomax

®(Tamsulosin

HCl) Capsules 0.4 mg for comparison All organicsolvents were of high performance liquid

chromatography (HPLC) grade. All other chemicalswere of reagent grade.

3. Compatibility StudiesCompatibility studies were performed using IRspectrophotometer. The IR spectrum of pure drug andphysical mixture of drug and polymer were studied.The compatibility studies were carried out at250C/60% RH and 400C/75% RH for 0, 2 and 4 weeks.With respect to physical and chemical aspects, theywere tested for incompatibilities between TamsulosinHydrochloride and the excipients; sugar pellets (basiccore pellets),HPMC-E5 (Binder), ethyl cellulose ,Eudragit L 100, poly ethylene glycol (plasticizer),Aerosil, sodium starch glycollate, and talc.

4. Preparation of Drug Loaded Pellets.A slurry of Tamsulosin hydrochloride is prepared in asolution of HPMC in isopropyl alcohol along with itAerosil and sodium starch glycollate was added intothe slurry. The sugar spheres (#20-#22) are preheatedto about 35o C with gentle movement. In a fluid bedcoater, and then sprayed with the coating solutionprepared above while more drying air is introducedand fluidization intensified. Spray rate, inlet airtemperature are adjusted in such a way that the corebed reaches a temperature of about 35o C. Over wettingof the cores is to be avoided as it may causeagglomeration. After complete quantity of the coatingsolution is consumed, the fluidization is reduced for abrief post-drying period. The pellets are then dried in atray drier at about 45o C to moisture content of <2%.The dried pellets are sized on a sifter to removeagglomerates, broken pellets and fine powder. Thepellets are now ready for coating.

5. Coating of Drug Loaded Pellets: A solution of ethyl cellulose, methacrylic acidcopolymers A and poly ethylene glycol is prepared inadequate quantity of isopropyl alcohol and water. Talcis suspended in this solution. The drug pellets arepreheated to about 35o C with gentle movement in afluid bed coater, and then sprayed with the coatingsolution prepared above while more drying air isintroduced and fluidization intensified. Spray rate,inlet air temperature are adjusted in such away that thecore bed reaches a temperature of about 35o C. Overwetting of the cores is to be avoided as it may causeagglomeration. The pellets are then dried in a tray drierat about 45o C to a moisture content of <2%. The driedpellets are sized on a sifter to remove agglomerates,broken pellets and fine powder. After checking theweight of the pellets and noting down the yield theyare packed.

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 970

Fig.1: Tamsulosin Hydrochloride API

Fig.2: Tamsulosin Hydrochloride-Physical Mixture

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 971

Fig .3: Tamsulosin Hydrochloride –Pellets

Table no.1:

25°C / 60% RH& 40°C / 75% RH (Closed)S.

No. Excipients Initial PhysicalDescription

1st Week 2nd Week 4th Week1 Tamsulosin White crystalline powder * * *2 Tamsulosin + Sugar spheres Off-white powder * * *

3 Tamsulosin + Hydroxy propylmethyl cellulose Off-white powder * * *

4 Tamsulosin + Colloidal silicondioxide Off-white powder * * *

5 Tamsulosin + Ethyl cellulose Off-white powder * * *

6 Tamsulosin + Methacrylic acidcopolymer Type A Off-white powder * * *

7 Tamsulosin + Starch White powder * * *

8 Tamsulosin +Poly ethylene glycol Off-white powder * * *

9

Tamsulosin + Sugar spheres +HPMC + Ethyl cellulose +Starch+ methacrylic acidcopolymerType A, + sodiumstarch glycolate+talc+Sugar + Colloidal silicon dioxide+ Poly ethylenglycol.

Off-white powder * * *

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 972

Table No.2: Coating equipment parameters

Parameter StageFluidized air Volume 80-100m3/hrProduct bed temperature 37-420cSpray rate 30-40g/minAtomizing air temperature 1.5barrInlet air temperature 45-550c

Table no. 3: Optimization of Drug loading onto pellets

Ingredients Tam1 Tam2 Tam3 Tam4 Tam5 Tam6 Tam7 Tam8 Tam9 Tam10TamsulosinHCl

0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2

SugarPellets(#20-#22)

99.79 99.75 99.70 99.60 99.59 99.58 99.4 99.19 98.99 98.9

HPMC E-5 0.01 0.05 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2Colloidalsilicondioxide

- - - - 0.001 0.002 0.002 0.002 0.002 0.002

SodiumStarchGlycolate

- - - - - - 0.2 0.4 0.6 0.8

IPA(mL) 100 100 100 100 100 100 100 100 100 100

Table No.4: Optimized Drug loaded Pellet

Ingredients OPTIMIZED FORMULATamsulosin HCL 0.2Sugar pellets(#20-#22) 98.7HPMC E-5 0.2Colloidal silicon dioxide 0.002Sodium Starch glycolate 0.8Isopropyl alcohol(ml) 100

Optimization of Coating SolutionTable no.5: Effect of Coating Levels of Methacrylic Acid Copolymer on Drug-Release in 0.1 N HydrochloricAcid(pH 1.2)

INGREDIENTS TAM 11 TAM 12 TAM 13 TAM 14Tamsulosin HCL 0.2 0.2 0.2 0.2Sugar pellets(#20-#22) 98.7 98.7 98.7 98.7HPMC E-5 0.2 0.2 0.2 0.2Colloidal silicon dioxide 0.002 0.002 0.002 0.002Sodium Starch glycolate 0.8 0.8 0.8 0.8Isopropyl alcohol(ml) 100 100 100 100Eudragit L-100 as percentage weightof the drug loaded pellets

3 6 9 12

PEG – 6000 8.33 8.33 8.33 8.33Talc 10 10 10 10Purified Water (ml) 10 10 10 10Isopropyl alcohol (ml) 350 350 350 350

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 973

6. Formulation Trials:Initial formulation trials were done on optimization ofDrug loaded pellets (TAM1-TAM10) and then trialsare done on the Coating solution composition forextending the drug release and the compilation of thetrials are given in the table: 2, 4, 5

7. Dissolution:The release of tamsulosin hydrochloride from coatedpellets was performed according to the USP XXVpaddle method using a dissolution apparatus(Electrolab).The coated pellets containing 0.2 mg of drug werefilled into hard gelatin capsules. The capsules wereadded into 500 mL of simulated gastric fluid withoutpepsin (adjusted to pH 1.2 with HCl) containingpolysorbate 80 (0.003%, w/w) at 37 ± 0.1°C and with apaddle speed of 100 rev/min. A sinker was used toavoid capsule flotation. Each sample (5mL) waswithdrawn at defined time intervals, and the samevolume of simulated gastric fluid was compensated.After 2 h, 500 mL of simulated intestinal fluidswithout pancreatin (pH 7.2, phosphate bufferaccording to the USP without enzyme) wasreplaced to adjust pH of dissolution medium from pH1.2 to 7.2. The samples were analyzed using HPLC(LC-20AD). Dissolution tests were repeated six timesfor all formulations and then the % drug released fromthe controlled release pellets was calculated.

Chromatographic conditionsColumn : Intersil ODS 3V, 250mm x4.6mm x 5µm or its equivalentFlow Rate : 1.0 ml/min

Wavelength : 220nmColumn Temperature : 250CInjection volume : 10µLRun Time : 10 mins

8. Loading of the Optimized Pellets intoCapsules.The pellets which are optimized after the trials werechecked for the bulk density and were loaded intocapsules No.2 with automatic capsule filling machine(Rimek formulations).

9. Evaluation of Loaded Capsules:Weight variation testTen capsules were individually weighed and thecontents were contents removed. The emptied capsuleswere individually weighed and the net weight of thecontents was calculated by subtraction and the percentweight variation was calculated by using the followingformula.

Weight variation (Wt of capsule-Average Wt)= -------------------------------------- ×100 Average Wt of capsules Weight variation should not be more than 7.5 %.

Lock lengthTen individual capsules were taken from formulationtrial batch and lock length was measured manually byusing vernier calipers and average of ten capsules wasnoted.

Table no.6: Effect of Coating Levels of Ethyl cellulose-N50 on Drug-Release in 0.1N HCl & pH 7.2Phosphate bufferINGREDIENTS TAM 15 TAM 16 TAM 17 TAM 18 TAM 19 TAM 20Tamsulosin HCL 0.2 0.2 0.2 0.2 0.2 0.2Sugar pellets(#20-#22) 98.7 98.7 98.7 98.7 98.7 98.7HPMC E-5 0.2 0.2 0.2 0.2 0.2 0.2Colloidal silicon dioxide 0.002 0.002 0.002 0.002 0.002 0.002Sodium Starch glycollate 0.8 0.8 0.8 0.8 0.8 0.8Isopropyl alcohol(ml) 100 100 100 100 100 100Eudragit L-100 as percentageweight of the drug loaded pellets

9 9 9 9 9 9

Ratio of Ethyl cellulose toEudragit L-100 as % of theEudragit L-100 content

15 30 45 60 27.7 25

PEG – 6000 10 10 10 10 10 10Talc 8.33 8.33 8.3 8.33 8.33 8.33Purified Water (ml) 10 10 10 10 10 10Isopropyl alcohol (ml) 350 350 350 350 350 350

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 974

Comparision drug re lease profi le of TAM 15with Flomax

020406080

100120

0 5 10

Time (Hrs)

% D

rug

Rel

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Flomax

TAM 15

DisintegrationThe capsules are placed in the basket rack assembly,which is repeatedly immersed 30 times per minute intoa thermostatically controlled fluid at 37ºC andobserved over the time described in the individualmonograph. To fully satisfy the test the capsulesdisintegrate completely into a soft mass having nopalpably firm core, and only some fragments of thegelatin shell.

AssayPreparation of Standard solution:Accurately weigh and transfer 25mg of TamsulosinHCl into a 50 mL of volumetric flask, add 30mL ofmethanol and sonicate dissolve dilute to volume withmethanol. Transfer 2mL of the solution to a 100mLvolumetric flask; dilute the volume with mobile phase.Filter the solution through 0.45µ nylon filter paper.

Preparation of Sample solution:Accurately weigh and transfer the twenty capsulescontaining pellets of Tamsulosin HCl pellets crushedin to powder and transfer equivalent to about 2.0 mg ofTamsulosin HCl into a 200mL volumetric flask, add60mL of methanol, shake for 2 minutes and add 60mLof mobile phase and sonicate for 15 minutes and diluteto volume with mobile phase. Filter the solutionthrough 0.45µ nylon membrane filter.

Content uniformityThe amount of active ingredient determined by assayis with in the range of 85% to 115% of the label claimfor 9 of 10 dosage units assayed with no unit outsidethe range of 70% to 125% of label claim.

Invitro Dissolution and Data Analysis:There are many methods for the comparison ofdissolution profiles. Here we Studied the similarityfactor.

Similarity factor is the Logarithmic transformation ofthe sum-squared error of differences between the testand reference product over all time points (Moore&Flanner, 1996). Where Log denotes logarithm basedon 10.The scale up and post approval changes forimmediate and modified release dosage formsguidance suggest that an f2 value between 50 and 100be required to conclude similarity of two dissolutionprofiles. Only one time point after reaching 85% ofdissolution was used to calculate f2 to avoid bias.

SEM Studies: Photographs of optimized pellets weretaken in order to determine external morphology ofpellets.

Stability Studies:The optimized pellets were evaluated for its stability atdifferent temperature conditions and compared withthat of the commercial product. This includes storageat both normal and exaggerated temperatureconditions, with the necessary extrapolations to ensurethe product will, over its designed shelf life, providemedication for absorption at the same rate as whenoriginally formulated.Storage conditionsStability samples are stored atAccelerated : 40±2°C/75±5% RHIntermediate: 30±2°C/65±5% RHLong term : 25±2°C/60±5% RHTesting Intervals forAccelerated: Initial, 1, 2, 3 & 6 monthsLong term: Initial, 3, 6, 9, 12, 18, 24 & 36 months.Intermediate: Initial, 3, 6, 9 & 12 months.

Comparative Dissolution Profiles.

Comparative dissolution profile of TAM 16with Flomax

0

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40

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80

100

0 5 10

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% D

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Rel

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TAM 16

Fig. 4: TAM 15 Vs Flomax Fig. 5: TAM 16 Vs Flomax

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 975

Comparative dissolution profile of TAM17with Flomax

020406080

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TAM 17

Comparative dissolution profile of TAM19with Flomax

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TAM 19

Comparative dissolution profile of TAM 18with Flomax

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TAM 18

Fig. 6: TAM 17 Vs Flomax Fig. 7: TAM 18 Vs Flomax

Comparative dissolution profile of TAM 20with Flomax

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0 2 4 6 8 10Time(Hrs)

% D

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Rel

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TAM 20

Fig.8 : TAM 19 Vs Flomax Fig. 9: TAM 20 Vs Flomax

Table no.7: Invitro Release Studies of Trial Batch TAM 15 –TAM20

Table no.8: Characteristics of Optimized Pellet Formulation

S.NO TIME (Hrs) SECOTEX TAM 15 TAM 16 TAM 17 TAM 18 TAM 19 TAM 201 0 0 0 0 0 0 0 02 2 (13-34%) 18.82 16.8 15.4 17.1 16.35 17.10 16.823 3 (47-68%) 63.26 74.2 55.3 46.81 43.75 58.66 53.104 5 (NLT-70%) 74.83 88.5 68.40 63.21 54.98 70.42 74.045 8 (NLT-80%) 96.08 99.7 94.34 80.56 78.62 93.21 95.42

Yield (Limit-NLT 96%) 99%Sieve analysis for 100 gm#16 passed 98 g#20 retained 98 g# 16 passed and 20 retained 98 gBulk density 0.829 g/mlTapped density 0.842 g/mlCompressibility index 1.54Angle of repose 25.760

Hausner’s ratio 1.01

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 976

Table no.9: Evaluation of loaded capsules:

Table No.10: Evaluation parameter values at different temperature condition

Table No.11: In-vitro dissolution profile of optimized batch TAM 20 at 250 C/60% RH,300 C/65 % RH and 400 C/75 % RH

Fig . 10: Comparative dissolution profile offormulations TAM 15-TAM 20

Comparative Dissolution Profiles

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FlomaxTAM 15TAM 16TAM 17TAM 18TAM 19TAM 20

Comparative Dissolution Profile of StabilityStudies:

Fig.11: Comparative dissolution profile offormulation TAM 20 and Flomax at 250 C/60% RH

Comparative Dissolution profile of TAM 20with Flomax at 25°C±2ºC/60% ± 5% RH

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TAM 20

S.NO Parameters Observed Value Limits1 Assay 97.9%-102.01% 95%-105%2 Avg Weight Variation 201.7 186.6-216.83 Disintegration time 3.2 minutes NMT 30 minutes

Stability conditions atS.No Parameter 25°C 30°C 40°C1 Assay 101.13% 99.35% 100.10%2 Moisture content 1.74 % 1.78% 1.75 %

3 Disintegration time inminutes 3.30 3.25 3.20

Percentage of Drug release25°C±2ºC/60% ± 5% RH 30°C±2ºC/65% ± 5% RH 40°C±2ºC/ 75% ± 5% RH

Time(Hrs)

Flomax TAM 20 Flomax TAM 20 Flomax TAM 200 0 0 0 0 0 02 15.03 16.25 15.81 17.03 15.43 16.333 63.68 58.53 62.36 59.48 62.12 60.465 74.93 73.69 73.46 72.39 73.08 74.018 95.80 95.54 94.92 94.56 94.16 93.82

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 977

Fig.12: Comparative dissolution profile offormulation TAM 20 and Flomax at 300 C/65 % RH

Comparative Dissolution profile of TAM 20with Flomax at 30°C±2ºC/65% ± 5% RH

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Fig.13: Comparative dissolution profile offormulation TAM 20 and Flomax at 400 C/75 % RH

Comparative Dissolution profile of TAM 20 withFlomax at 40°C±2ºC/75% ± 5% RH

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Fig.14: SEM photographs of optimized pellets

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 978

Results and Discussion:Various batches of pellet formulation TAM 1- TAM14 for the drug Tamsulosin HCl were developed usingHPMC as binder , Colloidal silicon dioxide aslubricant , Sodium starch glycolate as disintegrant andTAM15-TAM20 were developed using ethyl celluloseN50 and Eudragit L100 as coating solutions in variousratios. All the pellets were developed by drug solutionlayering onto sugar pellets. As indicated in table:3formulations TAM 1 – TAM4 were formulated usingHPMC E-5 as binder and the concentration of binderwas varied from 5 to 100% of the drug concentration.It was noted that the binder concentration in the rangeof 25% (TAM2) of the drug was optimum with smoothfinish, uniform in size and without agglomeration butwith slight breakage of pellets and the binderconcentration in the range of 100 % of the drug wasalso very smooth finish but with some agglomeration,so we tried to include lubricant to avoidagglomeration.

In the next formulation in order to optimize thelubricant concentration we took the formulation ofTAM 4 and varied the colloidal silicon dioxide aslubricant (TAM5-TAM6) and it was observed thatpellets with 0.002% of lubricant to that of drugconcentration produced smooth pellets withoutagglomeration, but they was slight decrease in the drugrelease than the other pellets. In next trial formulationin order to increase the release rate as that of otherpellets processed to study the effect of superdisintegrant sodium starch glycolate. Varying thepercentage of super disintegrant from 100 to 400 % ofthat drug in concentration (TAM7-TAM10). It wasfound that super disintegrant in the range of 400% ofthe drug was optimum and produced the pellets withsmooth finish and prompt release (TAM 10). From theformulation TAM1 to TAM10 we optimized theexcipients for the drug loading onto sugar pellets, afteroptimizing the drug loaded pellets formulation westudied the effect of coating levels. In the formulationof trial batch TAM11-TAM14 we studied the effect ofEudragit L100 concentration and the drug release inpH 1.2,shown in table:5.The % of the Eudragit L100were varied from 3% to 12% (TAM11-TAM14) of theweight of drug loaded pellets. It was found that TAM

13 with 9% was optimized as it controlled the releaserate in acid buffer. As the release of drug in the acidmedia is controlled with Eudragit L100 the next trialwas to control the release rate of drug in the in 7.2phosphate buffer. For this we had a formulation of thetrial batches TAM 14-TAM18 by varying theconcentration of ethyl cellulose N50 in the range of 15to 60 % of that of Eudragit L100 in the formulation.The drug release from all the above formulations(TAM14-18) were studied in the both acid media for0-2hours and 3-8 hours in the 7.2 phosphate buffermedium. It was found that TAM 15 was almost givingthe release rate as specified but it failed in the 5th hourin phosphate buffer. So in order to increase the releaserate in 5th hour we reduced the concentration of ethylcellulose to 27.7% (TAM19) here in this formulationthe drug release was near to specification, and in thenext formulation (TAM20) we still reduced the %ethyl cellulose to 25% which gave the releasespecifications. After optimizing the pellets formulationwe had gone to characterize the pellets for its particlesize, assay, moisture content, bulk density, tappeddensity, angle of repose.

Based on the observed bulk density we had selectedcapsule no.2 for loading of pellets, later evaluated thefilled capsules and the results was shown in table no:9, the lock length was found to be 17.7, and thecapsules were passing the weight variation and contentuniformity test.

SEM photographs of optimized pellets were shown infig. 14 and it was observed that coating was even onthe pellets and it was also observed that pelletsappeared smooth.

The optimized pellets were compared with theInnovator product for their in-vitro drug release andthe similarity factor (f2) was found to be 73.45.Finally the pellets were studied for its stability atdifferent temperatures and evaluated for theparameters as shown in the table no:10 and it wasfound to be stable at all temperature where drugrelease comparing with the commercial product wasshown in table no:11 .

M. Anand Kumar et al /Int.J. PharmTech Res.2011,3(2) 979

References:1. Ghebre-Sellassie, I.Pellets: A general overview. In

Ghebre-Sellassie,I(ed.), PharmaceuticalPelletization Technology. Marcel Dekker, Inc.,New York, USA,1989, Vol. 37, pp. 1-13.

2. Hellén, L., Yliruusi, J., Muttonen, E. andKristoffersson, E. Process variables of the radialscreen extruder. Part II: Size and size distributionof pellets. Pharm Techn. Int.1992b, 5 (2),

3. Conine, J. W. and Hadley, H. R. Small solidpharmaceutical spheres. Drug Cosmet. Ind.19707, 90, 38-41

4. Lyne, C.W. and Johnston, H.G. The selection ofpelletisers. Powder Technol. 1981,29, 211-216.

5. Ghebre-Sellassie, I., Gordon, R., Fawzi, M.B. andNesbitt, R.U. Evaluation of a high-speedpelletization process and equipment. Drug Dev.Ind. Pharm .1985. 11. 1523-1541.

6. Vertommen, J. and Kinget, R . The influence of fiveselected processing and formulation variables onthe particle size, particle size distribution, andfriability of pellets produced in a rotary processor.Drug Dev. Ind. Pharm.1997, 23 (1), 39-46.

7. Wan, L. S. C. and Lai, W. F. Factors affecting drugrelease from drug-coated granules prepared byfluidized-bed coating. Int. J. Pharm.1991, 72, 163-174

8. Mehta, A. M., Valazza, M. J. and Abele, S. E.Evaluation of fluid-bed processes for entericcoating systems. Pharm. Technol.1986, 10, 46-56.

9. IIey, W. J. Effect of particle size and porosity onparticle film coatings. Powder Tech.1991, 65, 441-445

10. Ragnarsson, G., Sandberg, A., Johansson, M. O.,Lindstedt, B. and Sjögren, J. In vitro releasecharacteristics of a membrane-coated pelletformulation - influence of drug solubility andparticle size. Int. J. Pharm.1992, 79, 223-232

11. Ragnarsson, G. and Johansson, M. O. Coated drugcores in multiple-unit preparations. Influence ofparticle size. Drug Dev. Ind. Pharm. 1988, 14,2285-2297

12. Bianchini, R. and Vecchio, C. Oral controlledrelease optimization of pellets prepared byextrusion-spheronization processing. IIFarmaco.1989, 44, 645-654.

13. Marvola, M., Nykänen, P., Rautio, S., Isonen, N.and Autere, A. M. Enteric polymers as bindersand coating materials in multiple-unit site-specificdrug delivery systems. Eur. J. Pharm. Sci.1999, 7,259-267

14. Holm, P., Holm, J. and Lång, P- O. A comparisonof two fluid bed systems Acta Pharm. Nord.1991,3, 235-241

15. Zhang, G., Schwartz., J. B. and Schnaare, R. L.Bead coating: Change in release kinetics (andmechanism) due to coating levels. Pharm.Res.1991a, 8, 331-335.

16. Peh, K.-K. and Yuen K-H. Development and invitro evaluation of a novel multiparticulate matrixcontrolled release formulation of theophylline.Drug Dev. Ind. Pharm. 1995,21 (13), 1545-1555

17. O’Leary, M.P., 2001. Tamsulosin: current clinicalexperience. Urology 58,42-48.

18. Van Hoogdalem, E.J., Kamimura, H., Higuchi, S.Pharmacokinetics of the α_1A-adrenoreceptorantagonist tamsulosin in man, and interspeciesscaling versus preclinical data. Euro. J. Pharm.Sci.1996, 4, S60.

19. Chapple, C., Andersson, K.E., 2002. Tamsulosin:an overview. World J. Urol.2002,19, 397–404.

20.Wilde, M.I., McTavish, D. Tamsulosin. A review ofits pharmacological properties and therapeuticpotential in the management of symptomaticbenign prostatic hyperplasia. Drugs.1996, 52, 883–898.

21. Kim, M.-S., Jun, S.W., Lee, S., Lee, T.-W., Park,J.-S., Hwang, S.-J., .The influence of Sureleaseand sodium alginate on the in-vitro release oftamsulosin hydrochloride in pellet dosage form. J.Pharm. Pharmacol.2005a, 57,735–742.

22. Kim, M.-S., Park, G.-D., Jun, S.W., Lee, S., Park,J.-S., Hwang, S.-J. Controlled release tamsulosinhydrochloride from alginate beads with waxymaterials. J. Pharm. Pharmacol.2005b, 57, 1521–1528.

23. Kim, M.-S., Kim, J.-S., Lee, S., Jun, S.W., Park, J.-S.,Woo, J.-S., Hwang, S.-J. Optimization oftamsulosin hydrochloride controlled release pelletscoated with Surelease and neutralized HPMCP. J.Pharm. Pharmacol.2006, 58,1611–1616.

24. Kim, M.-S., Kim, J.-S., Kang, S.-H., Yoo, Y.-H.,Lee, S., Park, J.-S., Woo, J.-S., Hwang, S.-J.Influence of water soluble additives and HPMCPon drugrelease from Surelease-coated pelletscontaining tamsulosin hydrochloride. , Arch.Pharm.Res., 2005, 28, 619—625.

25. Kim, M.-S., Kim, J.-S., Kang, S.-H., Yoo, Y.-H.,Lee, S., Park, J.-S., Woo, J.-S., Hwang.Development and optimization of a novel oralcontrolled delivery system for tamsulosinhydrochloride using response surface methodologyInternational Journal of Pharmaceutics 341 (2007)97–104

26. Moore, J.W., Flanner, H.H. Mathematicalcomparison of dissolution profiles. Pharm.Tech.1996, 20, 64–74

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