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 mm 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 µg/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 µg/mL. The method was successfully used to study the pharmacokinetics of clopidogrel in healthy volunteers. Copyright © 2006 John Wiley & Sons, Ltd.