1. Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt
2. Department of Chemistry, Faculty of Science, Banha University, Banha, Egypt

(Received: April 19, 2007; Accepted: July 12, 2007)

   Two different techniques are developed for the determination of clopidogrel in pharmaceutical preparations.  HPLC method has been developed where chromatographic analysis is performed on Nova-Pak® C18 column (3.9 mm × 150 mm, 5 µm) with an ammonium formate buffer adjusted with formic acid to pH 4.0, acetonitrile (40:60, v/v) as mobile phase, and detection at 225 nm. Good linearity (0.9993, r), accuracy (≥ 99.20 %), and precision (≤ 0.6 RSD) were obtained.  Potentiometric measurments are based on tetrakis (p-chlorophenyl) borate-clopidogrel ion-pair as an electroactive material incorporating a plasticized PVC membrane with o-nitrophenyl octyl ether or dioctyl phthalate.  The sensor is conditioned for at least two days in 0.1 M drug solution before use.  It exhibits fast and stable Nernstian response for clopidogrel over the concentration range of 1.0 × 10-5 ~ 1.0 × 10-2 M and pH range of 1.5 - 4.0.  Results with an average recovery of 100.6% and a mean standard deviation of 0.86% of the nominal were obtained.  The sensor shows reasonable selectivity towards clopidogrel hydrogen sulphate in presence of many cations.  No significant interferences are caused by drug excipients and diluents.

Key words: HPLC, potentiometry, pharmaceutical analysis, clopidogrel determination