## STP FOR CLOPIDOGREL TABLETS

1.0) Description: Visual

2.0) Average Weight: Check weight of 20 tablets at randomly and calculate the average weight by formula :  wt of 20 tablets (gm) x 1000 / 20. found avg. wt in mg

3.0)   Uniformity of weight:

Weigh 20 tablets selected at random and calculate the average weight. Not more than two of the individual weights deviate from the average weight by more than the percentage shown in table.

Weigh the tablets individually and calculate the percentage of deviation for each tablet. By using formula = (experimental weight – theoretical weight)    x 100%

Theoretical weight

 Average weight of tablets Percentage deviation More than 80mg but Less than 250mg 7.5% 250mg or More 5%

4.0) Identification Test:

In the assay, the principal peak in the chromatogram obtained with the test solution corresponds to the peak in the chromatogram obtained with the reference solution (a).

5.0)      Hardness:

The standard method used for tablet hardness testing is compression testing. The tablet is placed between two jaws that crush the tablet. The machine measures the force applied to the tablet and detects when it fractures. Although compressive force is applied to the tablet, along the diameter of the tablet at right angles to the applied force.

6.0)      Disintegration Time

Unless otherwise stated in the individual monograph, introduce one tablet into each tube and add a disc to each tube. The assembly is suspended in the liquid medium in a suitable vessel, preferably a 1-litre beaker. The volume of liquid is such that the wire mesh at its highest point is at least 15mm below the surface of the liquid, and at its lower point is at least 25mm above the bottom of the beaker. At no time should the top of the basket-rack assembly become submerged. There is a thermostatic arrangement for heating the liquid and maintaining the temperature at 37±2°.

If 1 or 2 tablets fail to disintegrate, repeat the test on 12 additional tablets; not less than 16 of the total of 18 tablets tested disintegrate.

If the tablets adhere to the disc and the preparation under examination fails to comply, repeat the test omitting the disc. The preparation complies with the test if all the tablets in the repeat test disintegrate.

7.0)      Dimension of Tablet:

Length, breadth and thickness are determined by vernier in mm

8.0)      Dissolution:

Medium: 900ml of 0.1 M HCl

Speed: 50rpm

Time: 30 minutes

Limit: NLT 85% of the stated amount of Clopidogrel.

Withdraw a suitable volume of the medium and filter. Measure the absorbance of the filtrate, suitably diluted with the dissolution medium if necessary, at the maximum at about 240nm. Calculate the content of Clopidogrel in the medium from the absorbance obtained from a solution of known concentration of Clopidogrel prepared b dissolving a suitable quantity of Clopidogrel bisulphate reference standard in 20ml of methanol and further diluting with medium.

9.0)      Leak test:

The apparatus is used to test for the integrity of packed strips, blisters and Alu-Alu Blister pack containing tablets. Ensure apparatus bath is filled with purified water up to mark indicated and add 0.5% crystal violet solution in water. Samples are placed into the desiccators and the lid is placed in position. The pump starts to produce a vacuum 15inHg inside the desiccators and the vacuum is held for 1 minute. The sample remains at the required vacuum level for given time interval buzzer will sound after time is over and will cut off the vacuum pump. As the package is immersed in a colored dye solution the venting of the desiccators will allow any holes to be penetrated by the dye and the contents of the flexible packaging will also be stained with the same coloring material.

Examine all the strips for any leakage by opening the pockets manually. If anyone pocket shows evidence of leakage, reject the sample, stop the Blister / Strip machine and immediately take corrective action.

10.0)    Related substances: Determine by liquid chromatography.

Test solution: Weigh and powder 20 tablets. Weigh accurately a quantity of the powder containing 75mg of clopidogrel, add 5ml of methanol and dilute to 200ml with mobile phase. Allow to stand for 10 minutes and mix filter.

Reference solution (a): A solution containing  clopidogrel bisulphate reference standard equivalent to 40µg per ml of clopidogrel, 250µg per ml of [(+)-(s)-(o-chlorophenyl)-6,7-dihydrothieno(3,2-c]pyridine-5(4H)-acetic acid] reference standard (clopidogrel impurity A reference standard) and 300µg per ml of[methyl(-)-(R)-o-chlorophenyl)-6,7 dihydrothiebo(3,2-c)pyridine-5(4H)-acetate, hydrogen sulphate] reference standard (clopidogrel impurity C reference standard) in methanol. Dilute 5.0ml of the solution to 200ml with the mobile phase.

Reference solution (b): A solution containing clopidogrel bisulphate reference standard equivalent to 100µg per ml of clopidogrel, and 200µg per ml of [methyl(±)-(o)-chlorophenyl)-4,5 dihydrothieno(2,3-c)pyridine-6(7H)-acetate, hydrogen sulphate] reference standard (clopidogrel impurity B reference standard) in methanol. Dilute 5.0ml of the solution to 200ml with the mobile phase.

Chromatographic system:

• A stainless steel column 15cm X4.6mm, packed with chiral recognition protein, ovomucoid, chemically bonded to porous silica (5µm),
• Mobile phase: a mixture of 75 volumes of a buffer solution prepared by dissolving 1.36 g of potassium phosphate in 1000ml of water and 25 volumes of acetonitrile,
• Flow rate: 1ml per minute.
• Spectrophotometer set at 220nm,

The relative retention times with respect to clopidogrel for enantiomers of clopidogrel impurity B are about 0.8 and 1.2, for clopidogrel impurity A is about 0.5 and for clopidogrel impurity C is about 2.0.

Inject reference solution (b). The resolution between clopidogrel and the first enantiomer of clopidogrel impurity B is not less than 2.5. Inject reference solution (a). The relative standard deviation for replicate injections is not more than15.0 per cent for each peak.

In the chromatogram obtained with the test solution the area of the peak due to clopidogrel impurity A is not more than 0.7 times the area of the corresponding peak in the chromatogram obtained with reference solution (a) (1.2 per cent), and the area of the peak due to clopidogrel impurity C is not more than 0.75 times the area of the corresponding peak in the chromatogram obtained with reference solution (a) (1.5 per cent). The area of any peak due to other impurities is not more than 0.75 times the area of the peak due to clopidogrel bisulphate reference standard in the chromatogram obtained with reference solution (a) (0.2 per cent, excluding impurity B). The sum of all the impurities is not more than 2.5 per cent, excluding impurity B.

11.0)    Assay: Determined by liquid chromatography.

Test solution: Weigh and powder 20 tablets. Weigh accurately a quantity of the powder containing about 75mg Clopidogrel, disperse in 100.0ml of the methanol. Dilute 5ml of the solution to 50ml with methanol and filter.

Reference solution (a):  A 0.01 per cent w/v solution of clopidogrel bisulphate reference standard in methanol.

Reference solution (b): a solution containing clopidogrel bisulphate reference standard equivalent to 100µg per ml of clopidogrel, and 200µg per ml of [methyl(±)-(o)-chlorophenyl)-4,5 dihydrothieno(2,3-c)pyridine-6(7H)-acetate, hydrogen sulphate] reference standard (clopidogrel impurity B reference standard) in methanol. Dilute 5.0ml of the solution to 200ml with the mobile phase.

Chromatographic system:

• A stainless steel column 15cm X4.6mm, packed with chiral recognition protein, ovomucoid, chemically bonded to porous silica (5µm),
• Mobile phase: a mixture of 75 volumes of a buffer solution prepared by dissolving 1.36 g of potassium phosphate in 1000ml of water and 25 volumes of acetonitrile,
• Flow rate: 1ml per minute.
• Spectrophotometer set at 220nm,

The relative retention times with respect to clopidogrel, for enantiomers of clopidogrel impurity B are about 0.8 and 1.2.

Inject reference solution (b). The test is not valid unless the resolution between clopidogrel and the first enantiomer of clopidogrel impurity B is not less than 2.5.

Inject reference solution (a). The test is not valid unless the relative standard deviation for replicate injections is not more than 2.0 per cent.

Inject reference solution (a) and the test solution.

Calculate the content of Clopidogrel in the temperature.

Alternative Method: By UV Spectrophotometer

Test Solution: Weigh and powder 20 tablets. Weight sample equivalent to 25mg of Clopidogrel 100ml volumetric flask add 20ml 0.1 M HCl into it and sonicate to dissolve the test sample. Make up to mark with 0.1 M HCl. Filter and dilute 10ml of this solution to 25ml in 0.1 M HCl.

Reference Solution: Weigh 25mg of reference standard of Clopidogrel bisulphate in 100ml of volumetric flask. Add 20ml 0.1 M HCl into it and sonicate to dissolve. Make up to mark with 0.1 M HCl. Dilute 10ml of this solution to 25ml with 0.1 M HCl.

Check Absorbance of test as well as reference standard at about 277nm in UV Spectrophotometer.

Calculate the content of Clopidogrel in the tablets.

Formula:

Abs. of Test      STD Wt.(mg)  10            100             25       Potency

—————–X————–X——-X—————X——–X———–X Average wt.

Abs. of STD        100               25     Test Wt.(mg)     10           100

Acceptance criteria: 90.0%-110.0%

13.0)    MICROBIOLOGICAL PURITY

Perform the test according to requirements of IP,

Total aerobic Microbial count (TAMC): NMT 103 CFU/g

Total combined yeasts/Moulds count (TYMC): NMT 102 CFU/g

Pathogens: in 1gm drug.

Escherichia Coli – Should be absent

Pseudomonas aeroginosa – Should be absent

Salmonella – Should be absent

Staphylococcus aureus– Should be absent

Abbreviations:

Wt.: Weight

mg: Miligram

ml: Milileter

STD: Standard

inHg: Inch of Mercury

rpm: Rounds per minute

CFU: Colony forming unit

HCl: Hydrochloric acid

Abs. Absorbance