Development and preliminary application of high-performance liquid chromatographic assay of urinary metabolites of diazepam in humans.
A simple high-performance liquid chromatographic method for the measurement of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP) in urine was developed. Preliminary studies of DZP metabolism were also undertaken in four healthy volunteers after administration of a single oral dose (4 mg) of DZP. The assay allowed the simultaneous determination of all analytes in 1 ml of urine and the detection limit was 2 ng/ml with a signal-to-noise ratio of 3. None of 22 drugs and 17 metabolites, except for mianserin, maprotiline and imipramine N-oxide, interfered with the detection of DZP metabolites. Recoveries of the analytes and the internal standard (prazepam) were > 82%. Intra- and inter-assay coefficients of variation for all analytes were < 5.5 and 4.1%, respectively. The mean (+/- S.D.) cumulative urinary excretions of DMDZP, TZP and OZP over 96 h after a single oral administration of DZP were 3.9 +/- 0.4, 6.6 +/- 1.4 and 2.8 +/- 0.6% of the dose, respectively. The urinary excretion of DZP was under the detection limit.
Chiba
K
K
Department of Clinical Pharmacology, International Medical Center of Japan, Tokyo.
Horii
H
H
Chiba
T
T
Kato
Y
Y
Hirano
T
T
Ishizaki
T
T
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003975:Diazepam / Q000493:pharmacokinetics*; D006801:Humans; D003708:Nordazepam / Q000652:urine*; D010076:Oxazepam / Q000652:urine*; D012016:Reference Values; D015203:Reproducibility of Results; D013693:Temazepam / Q000652:urine*
D003708:Nordazepam; D010076:Oxazepam; D013693:Temazepam; D003975:Diazepam