Abstract: An HPLC assay for moricizine determination in plasma or serum, which is relatively simple, sensitive, selective and rapid. has been developed. Plasma samples were prepared by addition of internal standard (estazolam) followed by dichloromethane extraction. The mobile phase consisted of methanol-water-0.065 mol·L^-1 ammonium acetate-glacial acetic acid (75:24:1:0.015, v/v/v/v). The calibration curve was linear in the range from 50 ng·mL^-1 to 5000 ng·mL^-1 with r = 0.9997. The detection limit of this method was 4 ng·mL^-1. The method showed good precision and the recovery of moricizine from plasma was 96-102%. The relative standard deviations for within-day and between-day were 0.7-3.2% and 2.3-4.0% respectively. The plasma drug concentration-time course in rabbits after intravenous bolus administration conformed to the two-compartment open model. Mean t1/2β value was 6.35±2.23h.

Key words: Moricizine, Moricizine, HPLC, HPLC, Pharmacokinetics, Pharmacokinetics