Spectrophotometric Methods for Determination of Clopidogrel in Bulk and in Pharmaceutical Formulations

The present article reports three simple, sensitive, and accurate spectrophotometric methods which have been progressed for monitoring of clopidogrel bisulphate (CG) in bulk and in pharmaceutical formulations. The three methods are depended on the production of yellow ion-pair complexes between the investigated drug and bromophenol blue (BPB), bromthymol blue (BTB), and bromocresol purple (BCP) as dyes in a universal buffer of pH range (2.0- 4.0). The chloroform was used for formed complexes extraction and measured at 421 nm, 414 nm, and 409 nm, respectively for the three systems. The best conditions of the reactions were tested and optimized. Beer’s law was obeyed in the concentration ranges 2.0 – 18.0 µg mL-1 with molar absorptivity of 4.4 × 104 , 6.4 × 104 and 6.9 × 104 L mol-1cm-1, for the BPB, BTB and BCP methods, respectively. Sandell’s sensitivity, correlation coefficient, quantification and detection limits are also studied. The investigated methods have been achieved successfully for the determination of the drug in pure form and in pharmaceutical formulations. Interference between common pharmaceutical excipients and additives was disappeared. Statistical comparison of the results with those observed by the HPLC method exhibits excellent agreement and shows no significant difference in terms of accuracy and precision.