Postmortem Metabolomics: Strategies to Assess Time-Dependent Postmortem Changes of Diazepam, Nordiazepam, Morphine, Codeine, Mirtazapine and Citalopram

Abstract

Postmortem redistribution (PMR) can result in artificial drug concentration changes following death and complicate forensic case interpretation. Currently, no accurate methods for PMR prediction exist. Hence, alternative strategies were developed investigating the time-dependent postmortem behavior of diazepam, nordiazepam, morphine, codeine, mirtazapine and citalopram. For 477 authentic postmortem cases, femoral blood samples were collected at two postmortem time-points. All samples were quantified for drugs of abuse (targeted; liquid chromatography-tandem mass spectrometry LC-MS/MS) and characterized for small endogenous molecules (untargeted; gas chromatography-high resolution MS (GC-HRMS). Trends for significant time-dependent concentration decreases (diazepam (n = 137), nordiazepam (n = 126)), increases (mirtazapine (n = 55), citalopram (n = 50)) or minimal median postmortem changes (morphine (n = 122), codeine (n = 92)) could be observed. Robust mathematical mixed effect models were created for the generalized postmortem behavior of diazepam and nordiazepam, which could be used to back-calculate drug concentrations towards a time-point closer to the estimated time of death (caution: inter-individual variability). Significant correlations between time-dependent concentration changes of morphine, mirtazapine and citalopram with individual endogenous molecules could be determined; no correlation was deemed strong enough for successful a posteriori estimation on the occurrence of PMR for specific cases. The current dataset did successfully lead to a significant knowledge gain in further understanding the time-dependent postmortem behavior of the studied drugs (of abuse).

A bibliometric analysis of the recent advances in diazepam from 2012 to 2021

“…In inhibitory synapses, the Gephyrin is one of the most studied proteins, belongs to the core scaffolding proteins, and plays an important role in synaptic anchoring with GABAR subtypes ( Hoffmann and Milovanovic, 2021 ). Gephyrin participates in the anchoring of GABAARs in the postsynaptic region, affects the aggregation and diffusion of synaptic GABAARs, regulates the number of gephyrins, and regulates inhibitory synaptic plasticity ( Bai et al, 2021 ; Brockbals et al, 2021 ; Hoffmann and Milovanovic, 2021 ). Gephyrin and GABAA are interdependent, studies have shown that knocking out gephyrin will destroy GABAAR clusters without affecting their overall protein levels.…”

“…Diazepam can be abused for entertainment or in other situations. Determination of diazepam levels in whole blood, serum, plasma, oral samples hair, and urine by UPLC-MS/MS is helpful to study of the pharmacokinetics of diazepam and has forensic significance ( Laloup et al, 2007 ; Wang et al, 2017 ; Brockbals et al, 2021 ).…”

Post‐mortem redistribution of drugs and other factors affecting interpretation: A review

“…Variable changes from the admission blood to that taken later has also been seen in a number of time series studies from the Zurich Institute of Forensic Medicine for morphine and number of other opioids, anti‐depressants, anti‐psychotics, and benzodiazepines. On average most drugs showed only small net increases (Brockbals et al, 2018; Brockbals, Staeheli, et al, 2021; Brockbals, Wartmann, et al, 2021; Staeheli et al, 2017).…”

Postmortem redistribution of morphine in humans: Important variables that might be influencing the central blood/peripheral blood ratio

“…It is now widely acknowledged that, although peripheral blood is less prone to postmortem changes in drug concentrations, these changes in fact occur [14][15][16][17][18][19][20][21][22].…”