Quantitative analysis of zopiclone, N-desmethylzopiclone, zopiclone N-oxide and 2-amino-5-chloropyridine in urine using LC-MS-MS.

A simple liquid chromatography-tandem mass spectrometry method was validated to allow determination of zopiclone (ZOP), N-desmethylzopiclone (NDZOP), zopiclone N-oxide (ZOPNO) and 2-amino-5-chloropyridine (ACP) in urine at concentrations up to 3,000 ng/mL within 3.5 min. This method was used for quantitative analysis of the analytes in authentic urine samples obtained 10 h after oral administration of zopiclone (Imovane(®)) and in aliquots of the same urine samples after different storage conditions. In addition, pH of each studied urine sample was measured over time. The results showed that formation of ACP occurred at elevated pH and/or temperature by degradation of ZOP, NDZOP and ZOPNO. This method was also applied to samples obtained from two female victims of drug-facilitated assault. One sample had been exposed to long-term storage conditions at different temperatures and at pH >8.2, which resulted in high concentrations of ACP. The other sample, which was exposed to pH <6.5, showed no formation of ACP. ACP is formed both from ZOP and from its metabolites NDZOP and ZOPNO depending on the pH of the urine, time of storage and/or the temperature conditions. For correct interpretation in forensic cases, ZOP, its major metabolites and ACP should be analyzed. When ACP is identified in urine, the concentrations of ZOP, NDZOP and ZOPNO should be interpreted with great caution.

Nilsson GH ，Kugelberg FC ，Ahlner J ，Kronstrand R ... -  《-》

Validation of an LC-MS/MS method for the determination of zopiclone, N-desmethylzopiclone and 2-amino-5-chloropyridine in whole blood and its application to estimate the original zopiclone concentration in stored specimens.

Nilsson GH ，Kugelberg FC ，Ahlner J ，Kronstrand R ... -  《-》

UHPLC-MS/MS and UHPLC-HRMS identification of zolpidem and zopiclone main urinary metabolites and method development for their toxicological determination.

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.

Strano Rossi S ，Anzillotti L ，Castrignanò E ，Frison G ，Zancanaro F ，Chiarotti M ... -  《-》

Detection of 2-amino-5-chloropyridine in urine as a parameter of zopiclone (Imovane) intake using HPLC with diode array detection.

Mannaert E ，Tytgat J ，Daenens P 《JOURNAL OF ANALYTICAL TOXICOLOGY》

[Progress on Determination and Analysis of Zopiclone in Biological Samples].

As a new hypnotic, zopiclone is widely used in clinical treatment. There are many methods for determination of zopiclone, including spectrophotometry, chromatography and chromatography mass spectrum, etc. Present paper reviews different kinds of biological samples associated with zopiclone, extraction and purification methods, and determination and analysis methods, which aims to provide references for the relevant research and practice.

Shu CX ，Gong D ，Zhang LP ，Zhao JX ... -  《-》