Objective To determine the concentration of active metabolite of oxcarbazepine in human plasma and investigate its
pharmacokinetics
in Chinese healthy volunteers. Methods A single 300 mg dose of oxcarbazepine was performed in Chinese healthy male volunteers. Plasma samples were processed by liquid-liquid extraction and
active monohydroxy metabolite (MHD), the active metabolite of oxcarbazepine, in plasma were determined by high performance liquid chromatography. Data were analyzed by a 3P87 program on a Legend computer. Results The method was utilized to determine the plasma concentration of MHD. Plasma concentration curve of MHD in single oral administration of oxcarbazepine conformed to one compartment model of the first order absorption. The major parameters of MHD were: t (max)=(4.10±0.79) h, C (max)=(4.64±0.53) mg·L~(-1), t (1/2 ke)=(15.04±2.32) h, AUC (0-48)=(112.96±14.25) mg·L~(-1)·h. Conclusion The method described in this report was of high sensitivity and selectivity for accurate determination of the plasma concentration of MHD in human. The pharmacokinetic results showed that it exhibited first order kinetic characteristics.