Репозиторий Университета

© 2018 Walter de Gruyter GmbH, Berlin/Boston. Phenazepam (bromdihydrochlorphenylbenzodiazepine) is the original Russian benzodiazepine tranquilizer belonging to 1,4-benzodiazepines. There is still limited knowledge about phenazepam's metabolic liver pathways and other pharmacokinetic features. To determine phenazepam's metabolic pathways, the study was divided into three stages: In silico modeling, in vitro experiment (cell culture study), and in vivo confirmation. In silico modeling was performed on the specialized software PASS and GUSAR to evaluate phenazepam molecule affinity to different cytochromes. The in vitro study was performed using a hepatocytes' cell culture, cultivated in a microbioreactor to produce cytochrome P450 isoenzymes. The culture medium contained specific cytochrome P450 isoforms inhibitors and substrates (for CYP2C9, CYP3A4, CYP2C19, and CYP2B6) to determine the cytochrome that was responsible for phenazepam's metabolism. We also measured CYP3A activity using the 6-betahydroxycortisol/cortisol ratio in patients. According to in silico and in vitro analysis results, the most probable metabolizer of phenazepam is CYP3A4. By the in vivo study results, CYP3A activity decreased sufficiently (from 3.8 [95% CI: 2.94-4.65] to 2.79 [95% CI: 2.02-3.55], p=0.017) between the start and finish of treatment in patients who were prescribed just phenazepam. Experimental in silico and in vivo studies confirmed that the original Russian benzodiazepine phenazepam was the substrate of CYP3A4 isoenzyme.

© 2018 Sklifosovsky Research Institute for Emergency Medicine. All rights reserved. BACKGROUND The relative availability of Phenazepam makes it a frequent cause of overdose, suicide and non-medical use. At the same time, it remains insufficiently studied in chemical and toxicological terms. THE AIM OF STUDY to create an accessible, rapid method for detecting Phenazepam in biological matrices of patients with acute poisoning. MATERIALS AND METHODS We used thin-layer chromatography (TLC), gas chromatography with a mass selective detector (GC-MS), high performance liquid chromatography with a tandem mass-selective detector (LC-MS/MS) and immunochromatographic analysis (ICA). The preparation of samples of intact urine with the addition of standard solutions of Phenazepam and real urine samples of patients with acute poisoning with Phenazepam was carried out using liquid-liquid extraction or precipitation of related components of the sample with acetonitrile. Hydrolysis and derivatization were also added in GC-MS analysis. RESULTS The analysis of statistics of the Department of Acute Poisonings of the N.V. Sklifosovsky Research Institute for Emergency Medicine in 2014–2016 showed that Phenazepam poisonings averaged 9.2% of the total number of admissions and mainly occurred as suicidal attempts. A technique has been developed for the detection of Phenazepam by TLC, which gives more objective results than ICA. For confirmatory analysis, it is advisable to use LC-MS/MS method for the native substance and GC-MS for the products of hydrolysis after derivatization. Compared to confirmatory methods, the developed TLC-screening technique is expressive, does not require the use of expensive high-tech equipment, difficult sample preparation, and makes it possible to reliably detect toxic and lethal concentrations of Phenazepam.