Objective:To establish a HPLC method for the determination of
flunarizine hydrochloride in human plasma and investigate its
pharmacokinetic characteristics dichloromethane in healthy volunteers after a single oral dose.Methods:The drug and internal standard(Diazepam,DZP)were extracted from plasma with n -pentane—iso-propyl alcohol,1 mol·L -1 hydrochloric acid,and then detected by UV detector at 254 nm with the C 18 column and methanol-water (containing 0 02 mol·L -1 tetrabutyl ammonium bromide)(74∶26) as mobile phase at a flow rate of 0 8 mL·min -1 .The data obtained were fitted with 3p87 program on computer.Result:The calibration curve was linear in the range of 2 34 and 150 ng·mL -1 with a correlation coefficient of 0 998 5.The limit of detection of
flunarizine hydrochloride in plasma was 2 ng·mL -1 .The mean recovery of flunarizine hydrochloride was 99 94% in plasma.This assay procedure has been applied to pharmacokinetic study of flunarizine hydrochloride.The results showed that the drug concentration-time profile conformed to the one-compartment model.The pharmacokinetic parameters were estimated as follows: t 1/2( K a) =1 61 h, t 1/2( K e) =4 09 h, t p=2 82 h, C max=59 54 ng·mL -1 .Conclusion:The method was sensitive,precise and reliable. It is suitable for the monitoring of
blood drug concentration and its pharmacokinetic studies.