title: Quantitative analysis of quazepam and its metabolites in human blood, urine, and bile by liquid chromatography-tandem mass spectrometry.
abstract: Quazepam (QZP), which is a long-acting benzodiazepine-type hypnotic, and its 4 metabolites, 2-oxoquazepam, N-desalkyl-2-oxoquazepam (DOQ), 3-hydroxy-2-oxoquazepam (HOQ), and 3-hydroxy-N-desalkyl-2-oxoquazepam, in human blood, urine, and bile were quantitatively analyzed by liquid chromatography-tandem mass spectrometry. The analytes were extracted from blood by protein precipitation followed by solid phase extraction, and from urine and bile by liquid-liquid extraction and cleanup using a PSA solid phase extraction cartridge. This method was applied to a medico-legal autopsy case, in which the deceased had been prescribed QZP approximately 3 weeks before his death. In blood, the concentrations of free DOQ (160±7 ng/mL for heart blood and 181±12 ng/mL for femoral blood) were the highest of all the analytes and in agreement with the concentration at a steady state. This indicates that the deceased consecutively received QZP for at least several days until the concentrations reached approximately the same level as that in the steady state. An extremely high concentration of total HOQ (the sum of conjugated and free HOQ) in bile was also found (56,200±1900 ng/mL). This accumulation of HOQ in bile is probably due to enterohepatic circulation. This study demonstrates that the combination of the concentrations of QZP and its metabolites in biological matrices can provide more information about the amount and frequency of QZP administration.
authors.affiliation: Department of Forensic Science, Zhejiang Police College, Hangzhou, PR China; Department of Legal Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Legal Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan. Electronic address: yamakoji@nms.ac.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Legal Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Youkichi
authors.initials: Y
authors.lastname: Ohno
mesh_terms: D001569:Benzodiazepines / Q000032:analysis* / Q000493:pharmacokinetics; D001570:Benzodiazepinones / Q000032:analysis; D001646:Bile / Q000737:chemistry; D002853:Chromatography, Liquid; D005479:Flurazepam / Q000031:analogs & derivatives / Q000032:analysis; D053593:Forensic Toxicology; D006801:Humans; D006993:Hypnotics and Sedatives / Q000032:analysis* / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D015394:Molecular Structure; D053719:Tandem Mass Spectrometry
chemical_list: C584129:3-hydroxy-2-oxoquazepam; D001570:Benzodiazepinones; D006993:Hypnotics and Sedatives; D001569:Benzodiazepines; C049294:3-hydroxy-N-desalkyl-2-oxoquazepam; C039103:2-oxoquazepam; D005479:Flurazepam; C025130:quazepam; C020965:norflutoprazepam
keywords: Liquid chromatography; Mass spectrometry; Metabolites; Quantification; Quazepam