Abstract

A sensitive and rapid high-performance liquid chromatographic method with ultraviolet detection was developed and validated for the determination of atorvastatin in human plasma. After separation of drug from plasma samples and following protein precipitation, the chromatographic separation was accomplished using C₁₈ analytical column. The mobile phase consisted of methanol, acetonitrile, and sodium phosphate buffer (0.01 M, pH 4.5) in the ratio of 40:30:30 (v:v:v). The ultraviolet detection was done at 247 nm. The average recovery of drug was 98.7%, with a limit of detection of 7.82 ng/ml and limit of quantification of 22.86 ng/ml. The calibration curve was found to be linear in concentration range of 5 to 160 ng/ml of atorvastatin, both in mobile phase as well as in plasma. After studying the performance parameters, the method was applied in a randomized, cross-over bioequivalence study of two different tablet preparations of atorvastatin (Lipitor, the brand leader and Lipirex, the generic product) in twelve healthy male volunteers. The values for C_max, T_max, and AUC_0-t for Lipitor and Lipirex were found to be 50.5 ng/ml, 3 h and 882.5 h.ng/ml and 49.5 ng/ml, 3.2 h, and 845.5 h.ng/ml, respectively. The pharmacokinetic parameters of both preparations were found to be comparable; hence, can be regarded as bioequivalent.

Key words: Atorvastatin, bioequivalence, high-performance liquid chromatographic-ultraviolet (HPLC-UV).