Pharmacokinetics and bioequivalence of lorazepam tablets in Chinese healthy volunteers

Objective To study the pharmacokinetics and bioequivalence of lorazepam tablets in Chinese healthy volunteers. Methods Twenty Chinese healthy male volunteers were involved in the study. Each subject received a single dose of 3 mg lorazepam test or reference formulation with a randomised crossover study. Blood sampling was conducted consequently within 48 hours. The plasma lorazepam concentration were determined by HPLC. The pharmacokinetics parameters were calculated and the bioavailability and bioequivalence of two formulations were evaluated by 3P97 program.Results After a single dose of 3 mg tested or reference formulation, the pharmacokinetic parameters of lorazepam were as follows: C_ max were (35.77 ± 6.84) and (36.95 ± 4.60) μg·L~ -1 ; t_ max were (2.38 ± 0.56) and( 2.23 ± 0.47) h; t_ 1/2 were (13.72 ± 2.07) and (13.83±2.49) h; AUC_ (0-48) were (542.19 ± 84.33) and (527.53 ± 63.52) ng·h·mL~ -1 ; AUC_ (0-inf) were ( 605.22 ± 93.52 ) and( 599.37±71.56) ng·h·mL~ -1 for test and reference formulation respectively. The relative bioavailability of tested formulation to reference formulation was F= (103.5±15.9)%. Conclusion The two formulations were bioequivalence.