Material and Methods

Vaginal mucoadhesive tablets of clotrimazole for vaginal candidiasis were prepared. Tablets mainly contain cysteamine thiomer which was thiol derivative of natural polysaccharide Xyloglucan. Along with thiomer HPMC and lactose were used. Tablets were optimized for HPMC and thiomer concentration. In vitro antifungal activity of drug was carried out on formulation and marketed formulation.

Results and Conclusion.

It was seen formulation has similar release and better mucoadhesion than marketed tablet. Permeation study shows that xyloglucan thiomer enhances permeation of formulation by forming covalent bonding. Formulation containing thiomer has better antifungal activity.

Abstract

Vaginal candidiasis is a common infection affecting most women in reproductive age. The topical treatment is preferred as infection resides in mucosal layer and it ensures patient compliance. An important factor in topical delivery is retention of dosage form in vagina, mucoadhesive drug delivery can overcome this limitation. The purpose of this research was to develop vaginal drug delivery system of clotrimazole which, after vaginal administration should have the ability to prolong residence time with desired in vitro release profile. Mucoadhesive clotrimazole tablets were prepared using thiomeric derivative xyloglucan derived from tamarind seeds. A Simplex Centroid design was employed to optimize the quantities of thiomer, HPMC K100M and lactose, in order to get high mucoadhesion and desired drug release. In vitro antifungal activity of formulation based on zone of inhibition showed better performance of thiomer tablet over marketed mucoadhesive formulation.

Keywords: Clotrimazole; Vaginal Tablet; Thiomer; Simplex Centroid Design

Abbreviations

CLO: Clotrimazole; XG: xyloglucan; TKP : Tamrind seed kernel; SDA : sabouraud Dextrose Agar; DMF: Di Methyl Formamide; MIC: Minimum Inhibitory Concentration

Introduction

Infectious vaginitis accounts for 90% of all cases in women of reproductive age [1,2] commonly called candida vaginitis. Candidiasis is a fungal infection developed in mucosa that usually causes a watery, white, cottage cheese-like vaginal discharge [3].

The discharge is irritating to the vagina and the surrounding skin. Conventional treatment includes both combined treatment of oral and vaginal administration. Vaginal administration has following advantages like bypassing first pass metabolism, local drug delivery, low toxicity [4] For many years imidazole derivatives are used as drug of choice for treating infection. Clotrimazole is BCS class II drug which has prominent antifungal action Clotrimazole works to kill individual Candida or fungal cells by altering the permeability of the fungal cell wall. It binds to phospholipids in the cell membrane and inhibits the biosynthesis of ergosterol and other sterols required for cell membrane production. This leads to the cell’s death via loss of intracellular elements [5]. Clotrimazole for local treatment is available in various formulations like tablets, creams, gels. However, a major problem with these formulation is less residence time [6]. There is little literature regarding formulation attempt to improve effectiveness of vaginal formulations by use of cyclodextrins, mucoadhesive polymers etc. [6]. Xyloglucan is polysaccharide made from tamarind seed kernel (TKP) [7,8,9,10] modification of xyloglucan using various thiol residues is reported [11,12,13] thiolation enhances mucoadhesion by means of covalent bonding with mucin and enhances transmucosal penetration by causing reversible and efficient opening of the tight junctions of the mucosal epithelium Thiomers possess CYP 34 enzyme inhibition properties have been reported to exert an inhibitory effect on efflux pumps [14]. In addition, it possesses antibacterial and antifungal activity and due to its good mucoadhesive properties resulted from the cationic behavior [12].

The aim of this work was to design mucoadhesive vaginal tablets of clotrimazole by using xyloglucan cysteamine thiomers a matrix in order to improve drug residence time compared to commercially available mucoadhesive tablet. The prepared tablets were optimized by using mixture design to possess desired values of mucoadhesion, release and t50. In vitro antifungal activity was performed to assess effectiveness of formulation.

Material

Clotrimazole was gift from Medly pharma. Xyloglucan was kind gift from Encore Natural Polymers Pvt. Ltd, Ahmadabad and HPMC K 100M was purchased from Sigma Aldrich. Sabauraud dextrose broth and agar were procured from oxide. Solvents used were of analytical grade. All other chemicals were procured from local sources and were of analytical grade.

Methods

Preparation of Xyloglucan Thiomer

Being reported as detailed paper separately by method reported in literature. Briefly TKP was dispersed in cold water and xyloglucan was precipitated using ethanol as per method described in literature to remove proteins and fibres [15].

Synthesis of Xyloglucan-Cysteamine Conjugates (Thiomer)

Part A: Oxidation of Xyloglucan[16]

The XG was oxidized by using Sodium periodate. The reaction was continued for 6 h in the dark at 250C. and was quenched by the addition of ethylene glycol.The Oxidized Xyloglucan was purified by dialysis (Hi Media molecular cut off 11500 Da) against distilled water for 12 h and the product formed was precipitated in ethanol and vacuum dried at room temperature.

Part B: Thiolation of Thiomer

Cysteamine derivative (Thiomer) [16]

The preparation of thiolated xyloglucan was a 2 step reaction. Firstly, to 1g of aldehydic xyloglucan, 40 ml of distilled water was added, followed by addition of 0.5g cysteamine. The pH was adjusted to 5 with 5M HCl. The mixture was adjusted to 50 ml with distilled water followed by incubation for 3 hours under stirring at room temperature. After this, 4g of sodium cyanoborohydride was added to the solution and stirred for 72 hours at room temperature. For the isolation of polymer and elimination of un reacted product, the reaction mixture was dialyzed 6 times in tubing (molecular weight cut-off 12 KDa: Dialysis membrane 150; Hi Media, Mumbai, India) at 10⁰C in dark. The reaction mixture was dialyzed 1 time against distilled water; 1 time against 0.2mM HCl and then 2 times against the same medium but holding 1% NaCl to quench ionic interactions between sulfhydryl compound and cationic polymer. It was then dialyzed 2 times against 0.2mM HCl followed by lyophilization (-78⁰C, 0.002 mbar, Labcono Freezone 2.5 Lyophilizer, USA) and stored at 4⁰C for further use.

Analytical Method [17]

Solutions of clotrimazole ranging from 10-50 μg/ml in methanol were prepared. The absorbance of these solutions was measured at 260nm against a reagent blank (methanol) using UV/Visible Double Beam Spectrophotometer (Lab India 3000+) standard curve was constructed by plotting absorbance versus concentration in μg/ml

Drug Excipient Compatibility

Drug excipient interaction study was carried out by FTIR spectroscopy (Shimadzu, 8400-S) using KBr press palate technique. Clotrimazole was combined with cysteamine thiomer, and HPMC K100M (1:1 ratio) and stored at 40ºC for two weeks. IR spectra of clotrimazole and mixtures were recorded and studied

Preparations of Vaginal Tablets [18]

Tablets were prepared by using wet granulation technique. All the contents like HPMC, lactose, magnesium stearate, talc, thiomer were accurately weighed and granulated using 10% PVP in ethanol as binder solution. dough is formed. Wet mass was passed through sieve no 18 granules were oven dried at 40ºC for 30 min. These granules were compressed on 12-station rotary tablet compression machine (Rimek, Karnavati, India) using an 8-mm standard concave die punch set.

Optimization

Optimization was carried out using Simplex Mixture experimental design. Design-Expert (Version 10.4.0; Stat-Ease Inc., Minneapolis, Minnesota, USA) was used for mathematical modeling and assessment of the responses.

Then the optimum level of these variables was determined by Simplex Mixture design including center point which is the most accepted response surface methodology (RSM). The simplex centroid design for a 3-component system (A, B, and C) is represented by an equilateral triangle in a 2-dimentional space Fig. 3. The amount of cysteamine thiomer (A) HPMC K100M (B, and lactose C were selected as independent variables as shown in Table 2. clotrimazole was mixed with required quantity of polymer HPMC K100M (A), cysteamine Thiomer (B), and lactose (C) and mixed for 5 min, quantity of talc and magnesium stearate was kept invariant in all batches showed in Table 1.

The percent release values of drug after 24 h; T50 and Mucoadhesive force were selected as dependent variables. The levels of the three factors were selected on the basis of the preliminary studies carried out before implanting the experimental design. According to the Table 3 runs were examined.

Table 1: Trial runs of simplex centroid design for optimization of mucoadhesive clotrimazole tablet

Methods

Sample Collection

Table 2: Following brands of Paracetamol tablets were collected from the market.

Names of the brands

Strength/ Nature of the Formulation

Company Name

Panadol(Paracetamol)

500mg/ Film-Coated Tablet

GlaxoSmithkline

Adol(Paracetamol)

500mg/Caplets

Julphar

Tylenol Forte(Paracetamol)

500mg/Tablet

Janssen

Omol(Paracetamol)

500mg/Uncoated Tablet

NPI Pharma

Table 3: Following brands of Atorvastatin tablets were collected from the market.

Names of the brands

Strength/Nature of the Formulation

Company Name

Tovast(Atorvastatin Calcium Trihydrate)

20mg/ Film-Coated Tablet

Spimaco

Torvast( Atorvastatin Calcium)

20mg/ Film-Coated Tablet

NPI Pharma

Storvas(Atorvastatin Calcium Trihydrate)

20mg/ Film-Coated Tablet

Ranbaxy

Lipitor(Atorvastatin Calcium)

20mg/ Film-Coated Tablet

Pfizer

Evaluation of tablets

Following tests were carried out

Weight Variation

Ten tablets of each sample were weighed using analytical balance. The average weight and standard deviation were calculated for weight variation test. According to the USP, the requirements for weight variation should be:

Table 4:

Average weight of tablets(mg)

    Maximum percentage difference allowed

130mg or less

10

130mg-324mg

7.5

More than 324mg

5

Not more than 2 tablets should deviate from the average weight by more than the percentage listed in the table.

Friability Test

Ten tablets for each sample were weighed on the analytical balance and then placed in the friability tester which was rotated at 100 rpm. Finally, the tablets were dedusted and reweighed again. The difference in weight was taken and percent loss in weight was calculated.

Hardness Test

Ten tablets of each sample were subjected for hardness testing and the crushing strength of the tablet was measured. Average hardness of the tablets was calculated and standard deviation was determined. A force of 4-6 kg is the minimum requirement for a satisfactory tablet.

Disintegration Test

Six tablets of each sample were placed in the disintegration apparatus, where the volume of disintegration medium was 600 ml of water maintained at 37±1°C. The time taken to break each tablet into small particles and pass through the mesh was recorded and average time was calculated.

Dissolution Test

Atorvastatin

The release rate of Atorvastatin was determined by using Tablet Dissolution test apparatus (USP apparatus II Paddle). At first, phosphate buffer of pH6.8 was prepared with disodium hydrogen phosphate and potassium dihydrogen phosphate.28.8g of disodium hydrogen phosphate was measured and made up to 1000ml with distilled water in a volumetric flask.11.45 g of potassium dihydrogen phosphate was measured and made up to 100ml with distilled water in a volumetric flask. Then 920 ml of disodium hydrogen phosphate and 80ml of potassium dihydrogen phosphate were mixed and made to 1000 ml with phosphate buffer. pH was adjusted to 6.8 with 0.1N HCL as needed. 900ml of this was used as dissolution medium for each study. The in vitro release of Atorvastatin 20mg tablet (single) was studied by running batches in dissolution test apparatus-USP type2. The tablets were weighed using analytical balance. Then tablets were placed in the dissolution apparatus beaker containing 900ml of phosphate buffer pH6.8, using paddles rotating at a speed of 75rpm. The temperature was maintained at 37°C during the duration of release studies. The temperature was measured using thermometer. 10ml samples from each vessel were withdrawn during the duration of release studies and kept in marked test tubes. Fresh dissolution medium (10ml) was added to the vessels after each sample was taken to replace for the sample withdrawn. All the samples were filtered using funnel and filter paper. Absorbance of the samples was measured using UV spectrophotometer at wavelength of 242nm. Phosphate buffer pH 6.8 was used as a blank.

Preparation of Calibration Curves for Atorvastatin in Phosphate Buffer

Stock solution was prepared by dissolving 100mg of accurately weighed Atorvastatin in 100 ml of methanol to get 1mg/ml solution. Further 10 ml of this solution was pipetted into 100ml volumetric flask and made up to 100ml with phosphate buffer pH 6.8 to get 100mcg/ml solution. From this 5, 10,15,20,25,30,35,40,45,50,55 and 60 ml solutions were pipetted into series of 100ml volumetric flask and were made up to 100ml with phosphate buffer pH6.8 to get 5-60mcg/ml solutions of Atorvastatin respectively. The absorbance of resulting solutions was measured at ƛ max against the blank. A graph was plotted by taking concentration on X-axis and absorbance on Y-axis.

Results and Discussion

Results and Discussion for Paracetamol

Weight Variation Test Results for Paracetamol Tablets

Table 4.1: Weights of Tylenol Forte tablets (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

6.673

0.653

0.664

0.676

0.672

0.662

0.671

0.671

0.668

0.665

0.671

Weight(g)

6673

653

664

676

672

662

671

671

668

665

671

Weight(mg)

0

-14.3

-3.3

8.7

4.7

-5.3

3.7

3.7

0.7

-2.3

3.7

Deviation

388.1

204.49

10.89

75.69

22.09

28.09

13.69

13.69

0.49

5.29

13.69

d2

Mean=6673mg÷10=667.3mg
Variation allowed: ±5% (to pass the weight variation test)
±5% = (667.3×5) ÷100= ±33.365 (633.935mg- 700.665mg-permissible range)
Table 4.1.2: Weights of Adol tablets (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

6.462

0.640

0.655

0.639

0.644

0.641

0.646

0.646

0.653

0.646

0.652

Weight(g)

6462

640

655

639

644

641

646

646

653

646

652

Weight(mg)

0

-6.2

8.8

-7.2

-2.2

-5.2

-0.2

-0.2

6.8

-0.2

5.8

Deviation

279.6

38.44

77.44

51.84

4.84

27.04

0.04

0.04

46.24

0.04

33.64

d2

Mean=6462mg ÷10=646.2mg
Variation allowed: ±5% (to pass the weight variation test) ±5% = (646.2×5) ÷100= ±32.31 (613.89mg-678.51mg-permissible range)
Table 4.1.3: Weights of Panadol tablets (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

6.748

0.674

0.675

0.675

0.671

0.677

0.678

0.676

0.678

0.668

0.676

Weight(g)

6748

674

675

675

671

677

678

676

678

668

676

Weight(mg)

0

-0.8

0.2

0.2

-3.8

2.2

3.2

1.2

3.2

-6.8

1.2

Deviation

89.6

0.64

0.04

0.04

14.44

4.84

10.24

1.44

10.24

46.24

1.44

d2

Mean=6748mg÷10=674.8mg
Variation allowed: ±5% (to pass the weight variation test)
±5% = (674.8×5) ÷100= ±33.74 (641.06mg-708.54mg-permissible range)
Table 4.1.4: Weights of Omol tablets (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

5.481

0.554

0.541

0.542

0.537

0.559

0.548

0.556

0.542

0.555

0.547

Weight(g)

5481

554

541

542

537

559

548

556

542

555

547

Weight(mg)

0

5.9

-7.1

-6.1

-11.1

10.9

-0.1

7.9

-6.1

6.9

-1.1

Deviation

512.9

34.81

50.41

37.21

123.21

118.81

0.01

62.41

37.21

47.61

1.21

d2

Mean= 5481mg÷10=548.1mg
Variation allowed: ±5% (to pass the weight variation test) ±5% = (548.1×5) ÷100= ±27.405 (520.695mg-575.05mg-permissible range)

Friability test results for different brands of Paracetamol tablets

The results of tests done on the tablets are listed in Tables

Table 4.2.1: Friability test results for various brands of Paracetamol tablets

Name of the brand (n=10)

Initial weight of 10 tablets(g)

End weight of 10 tablets(g)

Weight lost(g)

%weight lost

Tylenol Forte tablets

6.6806

6.6240

0.0566

0.8472

Adol tablets

6.4742

6.4661

0.0081

0.1251

Panadol tablets

6.7717

6.7706

0.0011

0.0162

Omol tablets

5.4909

5.4769

0.014

0.255

Mean=6673mg÷10=667.3mg
Variation allowed: ±5% (to pass the weight variation test)
±5% = (667.3×5) ÷100= ±33.365 (633.935mg- 700.665mg-permissible range)

Hardness test for Paracetamol tablets

Table 4.3.1: Hardness test on Tylenol Forte tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

6.5

6

6.5

5.5

6

6

7

5.5

7.5

7.5

Deviation

0.1

-0.4

0.1

-0.9

-0.4

-0.4

0.6

-0.9

1.1

1.1

D2

0.001

0.16

0.001

0.81

0.16

0.16

0.36

0.81

1.21

1.21

Mean = 64/10= 6.4Kg/cm2
Table 4.3.2: Hardness test on Adol tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

6.5

6.5

6.5

5.5

6.5

6.5

6.5

5.5

6

5.5

Deviation

0.35

0.35

0.35

-0.65

0.35

0.35

0.35

-0.65

-0.15

-0.65

D2

0.1225

0.1225

0.1225

0.4225

0.1225

0.1225

0.1225

0.4225

0.0225

0.4225

Mean = 61.5/10= 6.15Kg/cm
Table 4.3.3: Hardness test on Panadol tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

6.5

6.5

6

6.5

6.5

6.5

6.5

6

7

6.5

Deviation

0.05

0.05

-0.45

0.05

0.05

0.05

0.05

-0.45

0.55

0.05

D2

0.0025

0.0025

0.2025

0.0025

0.0025

0.0025

0.0025

0.2025

0.3025

0.0025

Mean = 64.5/10= 6.45Kg/cm2
Table 4.3.4: Hardness test on Omol tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

7

6

6

5.5

6

5.5

5

6.5

6

7

Deviation

0.95

-0.05

-0.05

-0.55

-0.05

-0.55

-1.05

0.45

-0.05

0.95

D2

0.9025

0.0025

0.0025

0.3025

0.0025

0.3025

1.1025

0.2025

0.0025

0.9025

Mean= 60.5/10= 6.05Kg/cm2

Disintegration test results for Paracetamol tablets

Table 4.4.1: Disintegration test on Tylenol Fort tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

2.10min

-0.865

0.748225

2

2.41min

-0.555

0.308025

3

3.4min

0.435

0.189225

4

3.11min

0.145

0.021025

5

3.32min

0.355

0.126025

6

3.45min

0.485

0.235225

17.79min

0

1.62775

Mean=17.79/6=2.965min
Table 4.4.2: Disintegration test on Adol tablets :( n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

3.27min

-1.12

1.254

2

4.2min

-0.19

0.0361

3

4.7min

0.31

0.0961

4

4.45min

0.06

0.0036

5

4.53min

0.14

0.0196

6

5.2min

0.81

0.6561

26.35min

-0.07

2.0655

Mean=26.35min/6=4.39min
Table 4.4.3: Disintegration test on Panadol tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

0.58sec

-0.69

0.4761

2

1.8min

0.53

0.2809

3

1.20min

-0.07

0.0049

4

1.24min

-0.03

0.0009

5

1.30min

0.03

0.0009

6

1.50min

0.23

0.0529

7.62min

0

0. 8166

Mean=7.62/6=1.27min
Table 4.4.4: Disintegration test on Omol tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

1.41min

-0.83

0.6889

2

2.2min

-0.04

0.0016

3

2.6min

0.36

0.1296

4

2.8min

0.56

0.3136

5

2.14min

-0.1

0.01

6

2.29min

0.05

0.0025

13.44min

0

1.1462

Mean=13.44/6=2.24min

Discussion

The quality of different brands of Paracetamol tablets was assessed by weight variation, hardness, friability, disintegration and dissolution.

p align="justify">Weight Variation

As per USP, the permissible weight variation limit for the tablets which are having the weight equal to or more than 324 mg is 5 % and the given results have shown that all four brands of Paracetamol are having weight variation less than 5 % which proves that the four brands (Tylenol forte, Adol, Panadol and Omol) of paracetamol tablets passed the official weight variation test.The difference in weight between these four brands (Tylenol forte, Adol, Panadol and Omol) of Paracetamol tablets may be due to pressure difference during compression process and non-uniform amount of in-active ingredients.

Friability

Tables 2.1 to 2.4 show the % weight loss for Tylenol forte, Adol, Panadol and Omol. Tylenol forte showed the highest weight loss and Panadol exhibited the lowest percentage weight loss. All of them exhibited weight loss less than 1%, so they passed the test.

Hardness

The tablets require some strength or hardness to withstand the mechanical shocks of handling and transport and at the same time are still sufficiently flexible to be able to disintegrate properly after swallowing. Since there is also a relationship between the hardness and the disintegration rate of the tablets, it is essential that the hardness of the tablets is within the acceptable range. Tablets with increased hardness values tend to have an increasing disintegration time. However, a minimum hardness of 4kg is essential. All four brands of Paracetamol have hardness in the acceptable range and therefore comply with specification of USP.

Disintegration

Panadol showed the lowest disintegration time. Adol exhibited the highest disintegration time. The disintegration time for all the four brands met the USP requirement which states that the tablets disintegrated within 30 minutes.

Results and Discussion for Atorvastatin

Weight variation test results for Atorvastatin Tablets

Table 4.4.5: Weights of Tovast tablets: (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

3.07

0.307

0.303

0.309

0.308

0.307

0.308

0.304

0.307

0.308

0.309

Weight(g)

3070

307

303

309

308

307

308

304

307

308

309

Weight(mg)

0

0

-4

2

1

0

1

-3

0

1

2

Deviation

36

0

16

4

1

0

1

9

0

1

4

d2

Mean=3070mg÷10=307mg
Variation allowed: ±7.5% (to pass the test)
±7.5%= (307 ×7.5) ÷100= ±23.025 (283.975mg-330.025mg-permissible limit)
Table 4.4.6: Weights of Torvast tablets: (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

2.974

0.297

0.298

0.295

0.296

0.298

0.296

0.297

0.298

0.297

0.302

Weight(g)

2974

297

298

295

296

298

296

297

298

297

302

Weight(mg)

0

0.4-

0.6

2.4-

1.4-

0.6

1.4-

0.4-

0.6

0.4-

4.6

Deviation

32.4

0.16

0.36

5.76

1.96

0.36

1.96

0.16

0.36

0.16

21.16

d2

Mean=2974/10=297.4 mg
Variation allowed: ±7.5% (to pass the test)
±7.5%= (297.4×7.5)/100= ±22.305 (275.095mg- 319.705mg-permissible limit)
Table 4.4.7: Weights of Storvas and Lipitor tablets: (n=10)

10

9

8

7

6

5

4

3

2

1

Sample

3.149

0.316

0.314

0.319

0.308

0.317

0.318

0.313

0.314

0.315

0.315

Weight(g)

3149

316

314

319

308

317

318

313

314

315

315

Weight(mg)

1.6

1.1

0.9-

4.1

6.9-

2.1

3.1

1.9-

0.9-

0.9

0.9

Deviation

86.5

1.21

0.81

16.81

47.61

4.41

9.61

3.61

0.81

0.81

0.81

d2

Mean=3158/10=315.8mg
Variation allowed: ±7.5% (to pass the test)
±7.5%= (315.8×7.5) ÷100= ±23.685 (292.115mg-339.485mg-permissible limit)
Table 4.4.8: Weights of Storvas and Lipitor tablets: (n=10)

 

10

9

8

7

6

5

4

3

2

1

Sample

3.158

0.320

0.322

0.314

0.321

0.310

0.312

0.313

0.309

0.318

0.319

 

Weight(g)

3158

320

322

314

321

310

312

313

309

318

319

Weight(mg

0

4.5

6.2

1.8-

5.2

5.8-

3.8-

2.8-

6.8-

2.2

3.2

Deviation

206.21

20.25

38.44

3.24

27.04

33.64

14.44

7.84

46.24

4.84

10.24

d2

Mean=3149/10=314.9mg
Variation allowed: ±7.5% (to pass the test)
±7.5%= (314.9×7.5)/100=±23.6175 (291.2828mg-338.5175mg-permissible limit)

Friability Test for Different Brands of Atorvastatin Tablets

Table 4.5.1: Friability Test Results For Various Brands of Atorvastatin Tablets

Name of the brand (n=10)

Initial weight of 10 tablets(g)

End weight of 10 tablets(g)

Weight lost(g)

%weight lost

Tovast tablets

3.0697

3.0690

0.0007

0.8472

Torvast tablets

2.9858

2.9849

0.0009

0.030

Storvas tablets

3.1711

3.1707

0.0004

0.012

Lipitor tablets

3.1548

3.1537

0.0011

0.034

Hardness Test for Atorvastatin Tablets

Table 4.5.2: Hardness Test on Tovast Tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

5

5

5.5

5.5

5.5

5.5

5

5.5

6

5.5

Deviation

-0.4

-0.4

0.1

0.1

0.1

0.1

-0.4

0.1

0.6

0.1

D2

0.16

0.16

0.01

0.01

0.01

0.01

0.16

0.01

0.36

0.01

Mean= 54/10= 5.4Kg/cm2
Table 4.5.3: Hardness test on Torvast tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

6

5.5

5.5

5.5

6

6.5

6

7

6.5

7

Deviation

-0.15

-0.65

-0.65

-0.65

-0.15

0.35

-0.15

0.85

0.35

0.85

D2

0.0225

0.4225

0.4225

0.4225

0.0225

0.1225

0.0225

0.7225

0.1225

0.7225

Mean= 54/10= 5.4Kg/cm2
Table 4.5.4: Hardness Test on Tovast Tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

6

6.5

6

6.5

6.5

6

6.5

6

5

6.5

Deviation

-0.15

0.35

-0.15

0.35

0.35

-0.15

0.35

-0.15

-1.15

0.35

D2

0.0225

0.1225

0.0225

0.1225

0.1225

0.0225

0.1225

0.0225

1.3225

0.1225

Mean= 61.5/10= 6.15Kg/cm2
Table 4.5.5: Hardness Test on Lipitor Tablets. (n=10)

Sample No.

1

2

3

4

5

6

7

8

9

10

Force required (Kg/cm2)

6.5

7

6.5

8

7.5

7

6.5

7

7

7.5

Deviation

-0.55

-0.05

-0.55

0.95

0.45

-0.05

-0.55

-0.05

-0.05

0.45

D2

0.3025

0.0025

0.3025

0.9025

0.2025

0.0025

0.3025

0.0025

0.0025

0.2025

Mean= 70.5/10= 7.05Kg/cm2

Disintegration test for Atorvastatin tablets:

Table 4.5.5: Disintegration test on Tovast tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

1.52min

-0.448

0.1936

2

1.57min

-0.398

0.158404

3

2.02min

0.052

0.002704

4

2.21min

0.242

0.058564

5

2.22min

0.252

0.063504

6

2.27min

0.302

0.091204

11.81min

0.002

0.56798

Mean=11.81min/6=1.968min
Table 4.5.6: Disintegration test on Torvast tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

0.50sec

-0.335

0.112225

2

0.53sec

-0.305

0.093025

3

0.59sec

-0.245

0.060025

4

0.59sec

-0.245

0.060025

5

1.3min

0.465

0.21625

6

1.5min

0.665

0.442225

5.01min

0

0.983775

Mean=5.01min/6=0.835min
Table 4.5.7: Disintegration test on Storvas tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

0.59sec

-0.608

0.369664

2

1.8min

0.602

0.362404

3

1.13min

-0.068

0.004624

4

1.18min

-0.018

0.000324

5

1.20min

0.002

0.000004

6

1.29min

0.092

0.008464

7.19min

0.002

0.745484

Mean=5.01min/6=0.835min
Table 4.5.8: Disintegration test on Lipitor tablets: (n=6)

Sample

Disintegration time

deviation(d)

(d2)

1

1.38min

-0.085

0.007225

2

1.40min

-0.065

0.004225

3

1.43min

-0.035

0.001225

4

1.48min

0.015

0.000225

5

1.54min

0.075

0.005625

6

1.56min

0.095

0.009025

8.79min

0

0.02755

Mean=8.79min/6=1.465min
Table 4.5.5: Disintegration test on Tovast tablets: (n=6)
Mean=11.81min/6=1.968min

Calibration Curve of Atorvastatin in Phosphate Buffer (pH 6.8)

The dilution of Atorvastatin in the concentration range from 5-60 mcg/ ml were prepared in phosphate buffer (pH 6.8). Absorbance was obtained using UV spectroscopy. The absorbance is presented in the Figure 3

Table 5.1: Disintegration test on Tovast tablets: (n=6)

Absorbance

Concentration(mcg/ml)

0.154

5

0.228

10

0.292

15

0.372

20

0.443

25

0.543

30

0.643

35

0.735

40

0.807

45

0.878

50

0.945

55

0.984

60

Figure 1: below shows the comparative dissolution profiles of various brands of Atorvastatin.
Table 6.1: Dissolution test results on Tovast tablets :( n=3)

% of Drug Released

Total Amount Dissolved in 900ml (mg)

Absorbance

Time (minutes)

13.87%

2.77±0.9

0.1155

0

32.93%

6.58±0.7

0.1831

15

32.65%

6.53±0.9

0.1821

30

37.41%

7.48±0.5

0.1990

45

52.38%

10.47±0.3

0.2521

60

33.29%

6.65±0.1

0.1844

90

37.10%

7.42±0.8

0.1979

120

32.17%

6.43±0.2

0.1804

150

71.08%

14.21±0.5

0.3184

180

Table 6.2: Dissolution test results on Torvast tablets: (n=3)

% of Drug Released

Total Amount Dissolved in 900ml (mg)

Absorbance

Time (minutes)

0

0±0.1

0

0

12.74%

2.54±0.4

0.0889

15

20.24%

4.04±0.6

0.1022

30

34.34%

6.86±0.8

0.1272

45

63.04%

12.60±1

0.1781

60

34.45%

6.89±0.3

0.1274

90

25.48%

5.09±0.7

0.1115

120

26.95%

5.39±0.6

0.1141

150

16.91%

3.38±0.3

0.0963

180

Table 6.3: Dissolution test results on Storvas tablets: (n=3)
Table 6.4: Dissolution test results on Lipitor tablets: (n=3)

% of Drug Released

Total Amount Dissolved in 900ml (mg)

Absorbance

Time (minutes)

0

0±0.1

0

0

31.55%

6.31±0.6

0.1782

15

33.18%

6.63±0.5

0.184

30

27.71%

5.54±0.4

0.1646

45

24.64%

4.92±0.5

0.1537

60

31.29%

6.25±0.7

0.1773

90

29.35%

5.87±0.9

0.1704

120

25.68%

5.13±1

0.1574

150

47.00%

9.40±0.2

0.2330

180

Discussion

The quality of different brands of Atorvastatin tablets was assessed by weight variation, hardness, friability, disintegration and dissolution.

Weight Variation

As per USP, the weight variation limit for the tablets which are having weight between 130mg-324mg is 7.5 % and the given results have shown that all four brands of Atorvastatin are having weight variation less than 7.5% which proves that the four brands (Torvast, Storvas, Lipitor and Tovast) of Atorvastatin tablets passed the official weight variation test. The difference in weight between these four brands (Torvast, Storvas, Lipitor and Tovast) of Atorvastatin tablets may be due to pressure difference during compression process and non-uniform amount of in-active ingredient.

Friability

Table 4.2.5 to 4.2.8 showed the % weight loss for Torvast, Storvas, Lipitor and Tovast tablets. Lipitor tablet showed the highest weight loss and Storvas exhibited the lowest percentage weight loss. All of them exhibited loss less than 1%, so they passed the test.

Hardness

Hardness of Atorvastatin tablets was found to be in the range of 5.4 to 7.05 kg/cm2 indicating all brands have good mechanical strength.

Disintegration

Torvast showed the lowest disintegration time. Tovast exhibited the highest disintegration time. The disintegration time for all the four brands met the USP requirement which states that the tablets disintegrated within 30 minutes.

Dissolution

A dissolution study gives an idea of the amount of drug available for absorption after oral administration. Drugs with poor dissolution profiles will not be available in the body system or target organ /tissues to elicit therapeutic effect. The in vitro dissolution profiles were found to be varying between Atorvastatin film- coated tablets. Maximum release of Tovast tablet was seen at 30 minutes (100.54%) and then it started decreasing until it became constant. On the other hand, Torvast showed the maximum release at 180 minutes (71.08%). Storvas showed the maximum release at 60 minutes (63.04%) and then started decreasing, while Lipitor showed the maximum release at 180 minutes (47.00%).

The area under curve was found from the values obtained from drug released at various time intervals. Trapezoidal method equation gave the values of Area under curve obtained for various brands of Atorvastatin.. Comparative values of various brands are shown as below.

Table : )

Brands Names of Atorvastatin Tablets

Nature of the Formulation

AUC (mg.min/ml)

Tovast

Film-Coated Tablet

1471.35

Torvast

Film-Coated Tablet

1393.35

Storvas

Film-Coated Tablet

1056.9

Lipitor

Film-Coated Tablet

1046.4

The comparative table clearly shows that Tovast showed highest AUC concluding that the extent of drug availability is expected maximum from Tovast tablets.

Conclusion

The main objective of this study was to carry out quality control tests for different brands of Paracetamol and Atorvastatin tablets and to find the Cmax, Tmax and AUC for different brands of Atorvastatin tablets available in the local market. The study found that all four brands of Atorvastatin film-coated tablets (Tovast, Torvast, Storvas and Lipitor) met the pharmacopoeia specifications and complied with the criteria laid in the official monographs. The study also, found that the four brands of Atorvastatin differed slightly in term of various parameters of quality control tests like weight variation, hardness, friability, disintegration and dissolution tests. The pharmacokinetics parameters ( Cmax, Tmax and AUC) obtained from this study were 20.10 mg, 30 minutes and 1471.35mg. min/ml for Torvast, 14.21mg, 180 minutes and 1393.35mg.min/ml for Torvast, 12.60mg, 60 minutes and 1056.9mg.min/ml for Storvas, 9.40mg, 180 minutes and 1046.4mg.min/ml for Lipitor respectively.

This study also showed that all four brands (Panadol, Adol, Tylenol Forte and Omol) of Paracetamol tablets met the pharmacopoeia specifications with respect to different parameters. As a result of this study we have concluded that all the four brands of Paracetamol tablets met the criteria laid in the official monographs and they differed slightly in terms of various parameters like weight variation, hardness, friability, and disintegration tests.

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