Pharmacokinetics of chlorazepate after intravenous and intramuscular administration.

Dichlorazepate (DPC) was given to eight healthy volunteers aged 22-38 years (five males and three females). The dose was 20 mg (48.9 mumol) given either as an IV or an IM injection. The interval between the injections was at least 1 week. Plasma samples were analysed for desmethyldiazepam (DMD) by HPLC before and after acid hydrolysis. The kinetics after both IV and IM administration could be explained by a one or two compartment open model. By comparing values before and after hydrolysis an estimate of di- and/or monopotassiumchlorazepate (MPC) could be made. The bioavailability was almost 100% after IM administration. The plasma half lives of DPC and DMD were independent of the form of administration (2.42 and 46.0 h respectively after IV and 2.29 and 45.1 h respectively after IM injection).