A high performance liquid chromatographic method was developed for the determination of ligustrazine in human plasma. The chromatographic separation was performed on a Luna C-18 column (150 mm x4. 6 mm i. d. , 5 mu m) at column temperature of 40 degrees C. The mobile phase, a mixture of methanol-acetonitrile-acetate buffer of pH 5. 0 (50 : 8 : 42, v/v), was delivered at a flow rate of 1. 0 mL/min. The detection wavelength was 280 nm. Plasma samples were prepared with a C-8 solid-phase extraction column. Linearity was confirmed in the mass concentration range of 25 - 5 000 mu g/L with the correlation coefficient of 0. 999 9. The extraction recovery of ligustrazine ranged from 96. 72% to 100. 90%. The relative standard deviations (RSDs) of intra- and inter-day assay at the mass concentrations of 50, 500 and 3 000 mu g/L were less than 8. 64% and the accuracies were between 99. 59% - 103. 26%. The limit of detection (LOD) was 10 mu g/L. The results of this method validation satisfactorily meet the acceptance criteria of bioanalysis and the method is applicable to the pharmacokinetic studies of ligustrazine in human beings.
