High performance liquid chromatographic method for the determination of cinepazide maleate and its application to a pharmacokinetic study in rats.

A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated to quantify cinepazide maleate, a calcium blocker, in rat plasma. Cinepazide maleate and Tinidazole (internal standard) have been extracted by a simple liquid-liquid extraction before injection into chromatographic system. Chromatographic separation was achieved on a reversed phase C18 column with a mobile phase consisted of a water mixture of 10mM potassium dihydrogen phosphate (pH=4.5):methanol (40:60, v/v), pumped at flow rate of 1.0mL/min, and detected at 303nm. The method exhibited a linear range of 0.12-120μg/mL in blank rat plasma, with the lower detection limit of 0.06μg/mL. The method was statistically validated for linearity, accuracy, precision, selectivity and stability following FDA guidelines. The intra- and inter-assay coefficients of variation did not exceed ±15% from the nominal concentration. The accuracy of cinepazide maleate was within ±15% of the theoretical value. The assay has been applied successfully in a pharmacokinetic study of cinepazide maleate after a single intravenous at three doses in rat. And cinepazide maleate injection can improve the bioavailability of cinepazide maleate greatly, and has a dose-dependence profile in rats.