Chemical and toxicological examination of zaleplon and its metabolites in urine

Relevance. Benzodiazepine derivatives are psychoactive substances, modulators of gamma-aminobutyric acid (GABA) receptors, exhibiting hypnotic, sedative, anxiolytic and anticonvulsant effects. Based on this mechanism of action, the use of benzodiazepine receptor agonists of the non-benzodiazepine series is widely used in medical practice. Non-benzodiazepine anxiolytics include the so-called "Z-drugs", after the name of the first drugs from this group (zopiclone, zolpidem, zaleplon). According to the mechanism of action, they are selective agonists of the omega-1 subtype (zopiclone, zolpidem) and the omega-2 subtype (zaleplon) of benzodiazepine receptors of the macromolecular GABA receptor complex. Currently, zaleplon is the most affordable of this group of drugs in Russia. The aim of the study is to develop a technique for detecting zaleplon and its metabolites in urine by HPLC-MS with BP using Orbitrap technology for the purposes and tasks of forensic medical examination. Material and methods. Morning urine was taken from patients who took therapeutic concentrations of zaleplon as prescribed by a doctor. The active substance zaleplon was studied as an alcohol solution with a content of 1 mg/ml of the substance under study. For the study, high-resolution HPLC-MS was used using Orbitrap technology on the instrument. Since the symptoms of side effects in zaleplon are similar to benzodiazepine derivatives when sent for forensic examination for chemical and toxicological examination, the sample preparation was carried out according to the generally accepted scheme for compounds of this group. Results. A technique for identifying zaleplon in urine extracts by HPLC-MS with BP using Orbitrap technology as a confirmatory method during forensic chemical and chemical-toxicological examination of urine has been developed. Retention times of the 5-oxosaleplone metabolite after oral administration were detected and established, and characteristic ions for use in identification were determined. Conclusion. A validation evaluation of the developed methodology was carried out, which indicates the suitability of the proposed methodology for forensic chemical and chemical-toxicological analysis. The relative standard deviation (RSD,%) in assessing the convergence and intra-laboratory reproducibility of retention times did not exceed 5% for a biological object - urine.