Pharmacokinetics of N-desmethyldiazepam in healthy volunteers after single daily doses of dipotassium chlorazepate

Dipotassium chlorazepate was administered to 12 healthy volunteers (8 males and 4 females), aged 22–38 years, as a single daily dose of 20 mg for 14 days. Plasma concentrations of N-desmethyldiazepam were monitored with a gas-chromatographic method during the medication period and for 5 days after withdrawal of the drug. The plasma half-life (t_1/2), the elimination coefficient (K_β), the concentration (\(\bar C_{{\text{ss}}} \)), and the apparent volume of distribution (V_β) were calculated at steady state, and the mean values±SEM were 53±6 h, 0.0147±0.0013 h^-1, 884±73 ng/ml, and 1.13±0.08 l/kg, respectively. A moderate interindividual variability was observed regarding these parametes. There was no tendency toward a biexponential elimination. A significant difference in the apparent volume of distribution was found when males and females were compared.