[Determination of clopidogrel sulfate in pharmaceutical formulation and biological fluids by extraction...

A simple and sensitive spectrofluorimetric method has been developed for the determination of clopidogrel sulfate in pharmaceutical formulation and human urine/serum. It is based on the formation of ion-pair complex between clopidogrel sulfate and alizarin red in 0.3 mol x L(-1) hydrochloric acid solution. The ion pair complex was extracted in dichloromethane and the fluorescence intensity was measured at 550 nm after excitation at 428 nm. The various factors influencing ion-pair complex formation and fluorescence determination were discussed. Under the optimized conditions, the fluorescence value showed a good linear relationship with the clopidogrel sulfate concentration ranging from 1.0 to 11.0 μg x mL(-1). The equation of calibration curve was F = 53.32 + 35.01c (μg x mL(-1)), r = 0.994, and the detection limit was found to be 0.11 μg x mL(-1). No interference was observed from common co-existing substances or pharmaceutical excipient. The determination recoveries of clopidogrel sulfate in pharmaceutical formulation and human urine/serum samples were 90.6%-99.3%, 104.6%-109.3%, 96.3%-105.0%, respectively. The method was successfully applied to detect clopidogrel sulfate in clopidogrel sulfate tablet and human urine/ serum. The obtained results of clopidogrel sulfate tablet were in good agreement with the results of HPLC. Therefore, it is concluded that the proposed method is simple, sensitive and rapid for the determination of clopidogrel sulfate in real samples.