title: UHPLC-MS/MS and UHPLC-HRMS identification of zolpidem and zopiclone main urinary metabolites and method development for their toxicological determination.
abstract: Zolpidem and zopiclone (Z-compounds) are non-benzodiazepine hypnotics of new generation that can be used in drug-facilitated sexual assault (DFSA). Their determination in biological fluids, mainly urine, is of primary importance; nevertheless, although they are excreted almost entirely as metabolites, available methods deal mainly with the determination of the unmetabolized drug. This paper describes a method for the determination in urine of Z-compounds and their metabolites by ultra-high-pressure liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) and UHPLC coupled with high resolution/high accuracy Orbitrap® mass spectrometry (UHPLC-HRMS). The metabolic profile was studied on real samples collected from subjects in therapy with zolpidem or zopiclone; the main urinary metabolites were identified and their MS behaviour studied by MS/MS and HRMS. Two carboxy- and three hydroxy- metabolites, that could be also detected by gas chromatography/mass spectrometry (GC-MS) as trimethylsylyl derivatives, have been identified for zolpidem. Also, at least one dihydroxilated metabolite was detected. As for zopiclone, the two main metabolites detected were N-demethyl and N-oxide zopiclone. For both substances, the unmetabolized compounds were excreted in low amounts in urine. In consideration of these data, a UHPLC-MS/MS method for the determination of Z-compounds and their main metabolites after isotopic dilution with deuterated analogues of zolpidem and zopiclone and direct injection of urine samples was set up. The proposed UHPLC-MS/MS method appears to be practically applicable for the analysis of urine samples in analytical and forensic toxicology cases, as well as in cases of suspected DFSA.
authors.affiliation: Institute of Legal Medicine, Catholic University of Sacred Heart, Rome, Italy.
authors.forename: Sabina
authors.initials: S
authors.lastname: Strano Rossi
authors.forename: Luca
authors.initials: L
authors.lastname: Anzillotti
authors.forename: Erika
authors.initials: E
authors.lastname: Castrignanò
authors.forename: Giampietro
authors.initials: G
authors.lastname: Frison
authors.forename: Flavio
authors.initials: F
authors.lastname: Zancanaro
authors.forename: Marcello
authors.initials: M
authors.lastname: Chiarotti
mesh_terms: D053961:Azabicyclo Compounds / Q000378:metabolism* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D006993:Hypnotics and Sedatives / Q000378:metabolism* / Q000652:urine*; D057230:Limit of Detection; D010879:Piperazines / Q000378:metabolism* / Q000652:urine*; D011725:Pyridines / Q000378:metabolism* / Q000652:urine*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D000077334:Zolpidem
chemical_list: D053961:Azabicyclo Compounds; D006993:Hypnotics and Sedatives; D010879:Piperazines; D011725:Pyridines; C515050:zopiclone; D000077334:Zolpidem
keywords: GC-MS; LC-HR-MS; LC-MS/MS; metabolites; zolpidem; zopiclone