[Determination of simvastatin in human plasma by high performance liquid chromatography]

Simvastatin is widely used in the treatment of hypercholestero-lemia. Recently, it was reported that it is also effective in reducing lethality in coronary heart disease. A simple and sensitive reversed-phase liquid chromatographic method has been developed and validated for the analysis of simvastatin in human plasma. Simvastatin and internal standard lovastatin in plasma were extracted with cyclohexane-dichloromethane (3.5:1, V/V), and then measured by HPLC using a Lichrospher C18 column as stationary phase and an acetonitrile-water (70:30, V/V) mixture as mobile phase. The flow rate was 1.2 mL/min. Simvastatin was quantified by UV at 237 nm. The calibration curve showed a good linearity in the mass concentration range of 0.25-50.0 micrograms/L. The regression equation is: Y = 0.0364 rho + 0.00583, r = 0.9998. Intra-day and inter-day coefficients of variation of assay for simvastatin in plasma < 7.94% and < 8.58%, respectively. The recoveries of simvastatin were > 93.3%. The method has been used to determine simvastatin in plasma from 12 healthy male volunteers.