Liquid chromatographic assay and pharmacokinetics of quazepam and its metabolites following sublingual administration of quazepam.
A reverse-phase liquid chromatographic method is described for simultaneous quantification of quazepam, and two of its metabolites, 2-oxoquazepam and N-desaklyl-2-oxoquazepam. The method uses a solid-phase extraction procedure to prepare plasma samples. After extraction, the methanolic extract is evaporated; the residue is then reconstituted in a small volume of mobile phase and chromatographed. The total chromatography time for a single sample is about 20 min. A sensitivity of 1 ng/ml for quazepam and its metabolites is attained when 1 ml of plasma is extracted. Analytical recovery of quazepam and its metabolites added to plasma ranged from 87 to 96%. The maximum within-day and day-to-day coefficients of variation for each compound at concentrations of 20 and 60 ng/ml were 7.6 and 11.2%, respectively. The method was applied to sublingual pharmacokinetic studies of quazepam in healthy volunteers.
Gupta
S K
SK
Department of Psychiatry, Duke University Medical Center, Durham, North Carolina 27710.
Ellinwood
E H
EH
D000286:Administration, Sublingual; D000328:Adult; D014151:Anti-Anxiety Agents; D001569:Benzodiazepines / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*; D001570:Benzodiazepinones / Q000097:blood; D001682:Biological Availability; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D005479:Flurazepam / Q000031:analogs & derivatives / Q000097:blood; D006801:Humans; D008297:Male
D014151:Anti-Anxiety Agents; D001570:Benzodiazepinones; D001569:Benzodiazepines; C039103:2-oxoquazepam; D005479:Flurazepam; C025130:quazepam; C020965:norflutoprazepam