Elucidating the potential role of microorganisms in postmortem biotransformation: a comparison of clonazolam and its metabolite in postmortem and DUID cases

Abstract

Clonazolam is a designer triazolobenzodiazepine first synthesized in 1971 and primarily used for its anxiolytic and sedative effects. It became a drug of misuse in 2012 and is known for its high potency and long duration of effects. Previous studies of nitrobenzodiazepines such as nitrazepam, clonazepam, flunitrazepam, and their metabolites have demonstrated that bacterial species native to the gastrointestinal tract and active during postmortem (PM) decomposition are capable of affecting positivity and compound-to-metabolite ratios. Further studies have not been performed with clonazolam; however, it possesses the nitro functional group necessary for this biotransformation. To understand whether clonazolam may be similarly affected, PM (n = 288) and driving under the influence of drugs (DUID, n = 54) cases positive for 8-aminoclonazolam reported by NMS Labs from 2020 to 2023 were selected for inclusion in this study. Concentrations of clonazolam and 8-aminoclonazolam were evaluated, and concurrent identification of parent drug and metabolite occurred less frequently in PM cases (n = 1, 0.30% of cases) than in DUID cases (n = 21, 38% of cases). The clonazolam concentration in one PM case was 13 ng/mL. In DUID cases the median clonazolam concentration was 4.0 ng/mL and ranged from 2.0-10 ng/mL. 8-Aminoclonazolam had median concentrations of 13 and 19 ng/mL and ranges of 2.0-580 and 2.8-59 ng/mL for PM and DUID cases, respectively. Due to the everchanging landscape of the DBZD market, in vitro studies of PM microbial biotransformation of clonazolam are unavailable. The data reported herein provide valuable information in the absence of such studies and represent an alternative method of investigating this phenomenon as a potential cause of parent nitrobenzodiazepine to metabolite conversion.