Pharmacokinetics of dipotassium chlorazepate in patients after repeated 50 mg oral doses

Dipotassium chlorazepate (DPC) was administered to ten patients (five males and five females), ages 18-37 years (mean 27.4), as a once daily dose of 50 mg until a steady state was reached. Plasma concentrations of the main metabolite N-desmethyldiazepam (DMD) were monitored by a high pressure liquid chromatographic (HPLC) method during the medication period and for 5 days after withdrawal of the drug. The plasma half life (t1/2), the elimination coefficient (K beta), the steady state concentration (Css), and the apparent volume of distribution (V beta), were calculated at steady state and the mean values +/- SEM were 44 +/- 5 h. 0.0184 +/- 0.0026 h(-1), 1590 +/- 163 ng/ml and 1.41 +/- 0.17 l/kg, respectively. A moderate inter-individual variability was observed. There was no tendency towards dose dependent elimination.