Validated HPLC method for determination of carboxylic acid metabolite of clopidogrel in human plasma and its application to a pharmacokinetic study.

A new, simple, and reproducible method for determination of carboxylic acid metabolite of clopidogrel in human plasma has been developed. After liquid-liquid extraction in acidic medium with chloroform, samples were quantified on a Nova-pak C(8), 5 microm column using a mixture of 30 mM K(2)HPO(4)-THF-acetonitrile (pH = 3, 79:2:19, v/v/v) as mobile phase with UV detection at 220 nm. The flow rate was set at 0.9 mL/min. Ticlopidine was used as internal standard and the total run time of analysis was about 12 min. The method was linear over the range of 0.2-10 microg/mL of clopidogrel metabolite in plasma (r(2) > 0.999). The within-day and between-day precision values were in the range 1.0-4.8%. The limit of quantification of the method was 0.2 microg/mL. The method was successfully used to study the pharmacokinetics of clopidogrel in healthy volunteers.