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Forensic Toxicology

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Open Access 04-01-2022 | Zolpidem | Original Article

Qualitative analysis of 7- and 8-hydroxyzolpidem and discovery of novel zolpidem metabolites in postmortem urine using liquid chromatography–tandem mass spectrometry

Authors: Koji Yamaguchi, Hajime Miyaguchi, Youkichi Ohno, Yoshimasa Kanawaku

Published in: Forensic Toxicology | Issue 2/2022

Abstract

Purpose

Zolpidem (ZOL) is a hypnotic sometimes used in drug-facilitated crimes. Understanding ZOL metabolism is important for proving ZOL intake. In this study, we synthesized standards of hydroxyzolpidems with a hydroxy group attached to the pyridine ring and analyzed them to prove their presence in postmortem urine. We also searched for novel ZOL metabolites in the urine sample using liquid chromatography–triple quadrupole mass spectrometry (LC-QqQMS) and liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QqTOFMS).

Methods

7- and 8-Hydroxyzolpidem (7OHZ and 8OHZ, respectively) were synthesized and analyzed using LC-QqQMS. Retention times were compared between the synthetic standards and extracts of postmortem urine. To search for novel ZOL metabolites, first, the urine extract was analyzed with data-dependent acquisition, and the peaks showing the characteristic fragmentation pattern of ZOL were selected. Second, product ion spectra of these peaks at various collision energies were acquired and fragments that could be used for multiple reaction monitoring (MRM) were chosen. Finally, MRM parameters were optimized using the urine extract. These peaks were also analyzed using LC-QqTOFMS.

Results

The presence of 7OHZ and 8OHZ in urine was confirmed. The highest peak among hydroxyzolpidems was assigned to 7OHZ. The novel metabolites found were zolpidem dihydrodiol and its glucuronides, cysteine adducts of ZOL and dihydro(hydroxy)zolpidem, and glucuronides of hydroxyzolpidems.

Conclusions

The presence of novel metabolites revealed new metabolic pathways, which involve formation of an epoxide on the pyridine ring as an intermediate.

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Title: Qualitative analysis of 7- and 8-hydroxyzolpidem and discovery of novel zolpidem metabolites in postmortem urine using liquid chromatography–tandem mass spectrometry
Authors: Koji Yamaguchi
Hajime Miyaguchi
Youkichi Ohno
Yoshimasa Kanawaku
Publication date: 04-01-2022
Publisher: Springer Nature Singapore
Keyword: Zolpidem
Published in: Forensic Toxicology / Issue 2/2022
Print ISSN: 1860-8965
Electronic ISSN: 1860-8973
DOI: https://doi.org/10.1007/s11419-021-00611-9

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Springer Medicine

Qualitative analysis of 7- and 8-hydroxyzolpidem and discovery of novel zolpidem metabolites in postmortem urine using liquid chromatography–tandem mass spectrometry

Abstract

Purpose

Methods

Results

Conclusions

At a glance: The ONWARDS insulin icodec trials

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Abstract

Purpose

Methods

Results

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