Preparation of
phosphate buffer solution : Dissolve 2.72gms of monobasic potassium phosphate in about
500ml of water and dilute to 1000ml with same solvent. Adjust pH to 6.0 ± 0.1
with KOH.
Mobile Phase : Prepare a filtered and degassed mixture of
Phosphate Buffer and acetonitrile (35:65) .Make adjustment if necessary.
Standard Preparation : Dissolve 50mg 0f Clopidogrel
Bisulphate Working Standard in methanol, sonicate and make volume to 50ml with
methanol.Dilute 5ml of solution to 50ml with mobile phase (conc.0.1mg/ml).
Filter the solution with 0.22µm before injection.
Assay Preparation : Crush finely 20 tablets into powder
and weigh an amount of powder containg 100mg of Clopidogrel Bisulphate in a
100ml volumetric flask . Dissolve the content with methanol, sonicate and
dilute with methanol to volume and mix, filter. Pipette 5ml of this solution to
a 50ml volumetric flask, dilute with mobile phase to volume and mix.
Chromatographic System
:
Column
: 4.6mm x 25cm column that contains packing L1
Flow rate :
1.5ml /min
Wavelength :
265nm
Temperature :
Ambient
Injection volume :
20µL
The relative standard deviation (RSD) for replicate
injections determined from Clopidogrel Bisulphate is not more than 1.0% .
Procedure :
Seperately inject equal volumes (about 10µL) of the standard
preparation and the assay preparation into the chromatograph ,record the
chromatograms, and measure the areas for all peaks . Calculate the quantity in
mg of C16H16ClN02S.H2S04
in
The portion of the tablet taken by the formula :
Peak
area of sample Wt.of sample
% of Clopidogrel Bisulphate :------------------------X --------------------X Potency of WS
Peak of standard Wt.of
standard
Where : WS is the
Working Standard .
