Determination of atorvastatin and gemfibrozil in human plasma by reversed-phase liquid chromatography

A simple, sensitive and reproducible RP-HPLC method was developed and validated for the simultaneous determination of atorvastatin and gemfibrozil in human plasma. After a single step liquidliquid extraction of both the drugs with acetonitrile, the separation was accomplished on a Merck C 18 column (250 x 4.6, 5 µm). Diode array detection at a wavelength of 240 nm was carried out with a mobile phase comprising of a mixture of 0.1M ammonium acetate buffer (pH 5.0) and acetonitrile in the ratio of (45:55, v/v). The method was linear in the concentration range of 0.1-20 µg/ml for atorvastatin and 6-1200 µg/ml for gemfibrozil with correlation coefficient between 0.9997 and 0.9976. The limit of detection was 0.03 µg/ml for atorvastatin and 1.8 µg/ml for gemfibrozil. The limit of quantitation was 0.1 µg/ml for atorvastatin and 6 µg/ml for gemfibrozil. The average recovery of both the analytes was greater than 75 %. The method was validated in terms of linearity, recovery, precision, specificity, LOD/LOQ values and stability of solutions and it was applied successfully for the determination of atorvastatin and gemfibrozil in spiked human plasma. Colegio de Farmacéuticos de la Provincia de Buenos Aires