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

"Declarations Conflict of interestThe authors declare that they have no conflict of interest. Ethical approvalThe use of urine samples obtained from an autopsy was approved by the Human Ethics Committee of Nippon Medical School (approval number: 26-13). Conflict of interest The authors declare that they have no conflict of interest."

"This work was supported by JSPS KAKENHI Grant Numbers 24790646, 16K09221, and 20K10566. We are deeply grateful to Mr. Takahiro Goda (Shimadzu Co.) for assistance with structural elucidation of the novel metabolites using LC-QqTOFMS, to Dr. Ryo Takita and Ms. Mio Takagi (Graduate School of Pharmaceutical Sciences, The University of Tokyo) for assistance with the NMR measurements and elemental analysis, and to Dr. Yuko Kazui (National Research Institute of Police Science) for assistance with the NMR measurements."