Plasma quantification of quazepam and its 2-oxo and N-desmethyl metabolites by capillary gas chromatography.
The authors have developed a gas chromatographic method for the simultaneous quantification of quazepam in plasma and its two main metabolites, 2-oxoquazepam and N-desmethylquazepam. This method involves an extraction from plasma using butyl acetate, and an analysis by electron-capture detection on a CP-Sil 5 WSCOT capillary column. Intra- and inter-day precision and accuracy were better than 10% for each of these three compounds, even near their detection limit estimated at 0.2 ng/ml. Linearity proved satisfactory between 0.2 and 60-70 ng/ml. For endogenous plasma components, adequate specificity was achieved. Despite some inconveniences, a long analysis time, a progressive saturation of the column owing to a low oven temperature, and a relatively short life-span of the CP-Sil 5 columns, this method was the only one available in the literature for the quantification of quazepam and its metabolites from the same plasma sample. It was successfully applied to phase I studies in healthy volunteers.
D014151:Anti-Anxiety Agents; D001569:Benzodiazepines / Q000097:blood*; D001570:Benzodiazepinones / Q000097:blood*; D002849:Chromatography, Gas; D003640:Dealkylation; D006207:Half-Life; D006801:Humans; D007700:Kinetics
D014151:Anti-Anxiety Agents; D001570:Benzodiazepinones; D001569:Benzodiazepines; C049741:N-desmethylquazepam; C039103:2-oxoquazepam; C025130:quazepam