LC-MS/MS method enables simultaneous quantification of zolpidem, zopiclone and metabolites in urine
Investigators developed and validated an LC-MS/MS method coupled with dispersive liquid-liquid microextraction for the simultaneous quantification of zolpidem, zopiclone, and 18 metabolites in human urine. The assay satisfied ICH validation parameters, demonstrating linearity (R² > 0.999), accuracy between 96.29% and 99.56%, and precision with RSD ≤ 3.12%. Pharmacokinetic evaluation in five healthy volunteers revealed that hydroxylated and carboxylated metabolites peaked at 2 to 12 hours and remained detectable for up to 84 hours. The method offers a solvent-efficient, sensitive screening platform for retrospective z-drug exposure in clinical and forensic toxicology laboratories.
The original study
LC-MS/MS Method for Simultaneous Quantification of Zolpidem, Zopiclone, and Their Metabolites in Human Urine and Its Pharmacokinetic Application.
- Authors
- Chauhan V, Sharma M, Taha M, Kumar M, Srivastava S, Shahzad N, et al.
- Journal
- Biomedical chromatography : BMC
- Type
- Journal Article
- PMID
- 42714029
Original abstract
Zolpidem (Z1) and zopiclone (Z2) are widely prescribed for insomnia; but their misuse in drug-facilitated crimes presents significant forensic and clinical challenges. This study aimed to develop and validate a simple and sensitive LC-MS/MS method, coupled with dispersive liquid-liquid microextraction (DLLME), for the simultaneous determination of Z1, Z2, and 18 phase I and phase II metabolites (20 species) in human urine. DLLME employed 1 mL of dichloromethane as extractant and 2 mL of acetonitrile as disperser per 2 mL of urine, reducing halogenated-solvent use compared with conventional liquid-liquid extraction. Chromatographic separation was achieved on a HyPURITY C18 column with water-acetonitrile (70:30, v/v) containing 0.2% formic acid. Z1 and Z2 were validated according to ICH guidelines over 0.1-200 ng/mL, showing linearity (R2 > 0.999), accuracy (96.29%-99.56%), precision (RSD ≤ 3.12%), and recovery (96.12%-98.74%). Because authentic metabolite standards were unavailable, metabolite concentrations were estimated using parent-drug calibration curves and are considered semi-quantitative. In five healthy volunteers, hydroxylated and carboxylated metabolites peaked at 2-12 h and remained detectable up to 84 h. These findings support the method's potential for retrospective urinary screening of Z-drug exposure in forensic and clinical toxicology.