Bioavailability and pharmacokinetics of lorazepam tablets in healthy volunteers

OBJECTIVE To study pharmacokinetics and bioequivalence of lorazepam tablets by dual crossing test of test sam- ple and reference sample.METHODS Twenty health volunteers were randomly divided into 2 groups,randomized,self cross o- ver study was used.The plasma lorazepam concentration was determined by HPLC.The data were processed by DAS program to obtaine the pharmacokinetic parameters.RESULTS The main pharmacokinetic parameters:t_(1/2)of lorazepam tablets were (19.7±2.0)h in test group and(18.9±1.7)h in reference group,t_(max)were(2.58±0.18)h and(2.60±0.21)h,C_(max)were(24.8±4.0)μg·L~(-1)and(24.6±3.6)μg·L~(-1),AUC_(0-6)were(628.2±90.7)μg·L~(-1)·h and(636.2±62.6)μg·L~(-1)·h,AUC_(0-∞)were (718.1±84.6)μg·L~(-1)·h and(722.9±57.9)μg·L~(-1)·h relative bioavailability F of lorazepam tablet test sample was(98.7±8.8)%.There was no significant difference in AUC_(0-∞),AUC_(0-60),t_(max),t_(1/2),C_(max)between the two groups by variance analysis and two-way-one-side test(P0.05).CONCLUSION The method established is suitable for determining the plasma loraze- pam concentration,The two preparations are bioequivalent.