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 ® C 18 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.
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