Postmortem metabolomics: influence of time since death on the level of endogenous compounds in human femoral blood. Necessary to be considered in metabolome study planning?

INTRODUCTION: The (un)targeted analysis of endogenous compounds has gained interest in the field of forensic postmortem investigations. The blood metabolome is influenced by many factors, and postmortem specimens are considered particularly challenging due to unpredictable decomposition processes. OBJECTIVES: This study aimed to systematically investigate the influence of the time since death on endogenous compounds and its relevance in designing postmortem metabolome studies. METHODS: Femoral blood samples of 427 authentic postmortem cases, were collected at two time points after death (854 samples in total; t1: admission to the institute, 1.3-290 h; t2: autopsy, 11-478 h; median ∆t = 71 h). All samples were analyzed using an untargeted metabolome approach, and peak areas were determined for 38 compounds (acylcarnitines, amino acids, phospholipids, and others). Differences between t2 and t1 were assessed by Wilcoxon signed-ranked test (p < 0.05). Moreover, all samples (n = 854) were binned into time groups (6 h, 12 h, or 24 h intervals) and compared by Kruskal-Wallis/Dunn's multiple comparison tests (p < 0.05 each) to investigate the effect of the estimated time since death. RESULTS: Except for serine, threonine, and PC 34:1, all tested analytes revealed statistically significant changes between t1 and t2 (highest median increase 166%). Unpaired analysis of all 854 blood samples in-between groups indicated similar results. Significant differences were typically observed between blood samples collected within the first and later than 48 h after death, respectively. CONCLUSIONS: To improve the consistency of comprehensive data evaluation in postmortem metabolome studies, it seems advisable to only include specimens collected within the first 2 days after death.

Identification of clobromazolam in Australian emergency department intoxications using data-independent high-resolution mass spectrometry and the HighResNPS.com database.

The proliferation of novel psychoactive substances (NPSs) continues to challenge toxicology laboratories. In particular, the United Nations Office on Drugs and Crime considers designer benzodiazepines to be a current primary threat among all NPSs. Herein, we report detection of a new emerging designer benzodiazepine, clobromazolam, using high-resolution mass spectrometry and untargeted data acquisition in combination with a "suspect screening" method built from the crowd-sourced HighResNPS.com database. Our laboratory first detected clobromazolam in emergency department presenting intoxications included within the Emerging Drugs Network of Australia-Victoria project in the state of Victoria, Australia, from April 2022 to March 2023. Clobromazolam was the most frequent designer benzodiazepine detected in this cohort (100/993 cases, 10%). No patients reported intentional administration of clobromazolam, although over half reported exposure to alprazolam, which was detected in only 7% of cases. Polydrug use was prevalent (98%), with phenazepam (45%), methylamphetamine (71%) and other benzodiazepines (60%) most frequently co-detected. This is the first case series published in the literature concerning clobromazolam in clinical patients. The identification of clobromazolam in patients presenting to emergency departments in Victoria demonstrates how high-resolution mass spectrometry coupled with the HighResNPS.com database can be a valuable tool to assist toxicology laboratories in keeping abreast of emerging psychoactive drug use.

Quantitative analysis of tetrahydrocannabinol isomers and other toxicologically relevant drugs in blood.

A multi-analyte liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is described, involving the separation of delta-9-tetrahydrocannabinol (delta-9-THC) and delta-8-THC in addition to other commonly encountered drugs and metabolites. Briefly, sample preparation involved an alkaline liquid-liquid extraction (methyl tert-butyl ether) of blood (100 µl). The solvent layer was transferred, evaporated to dryness, reconstituted, and samples then separated on an Agilent Poroshell 120 EC-C18 100 Å (50 mm × 3.0 mm, 2.7 µm) analytical column using a multi-step gradient elution of 50 mM ammonium formate in water (pH 3.5) and 0.1% formic acid in methanol over 14 min. A SCIEX Triple Quad 6500+ system operating in scheduled multiple reaction monitoring and positive electrospray ionization was used for detection. There were no interferences, and matrix effects were generally acceptable (±20% of neat response). Linearity was achieved within the calibration range, including methylamphetamine (MA) (10-1000 ng/ml), 3,4-methylenedioxy-N-methylamphetamine (MDMA) (10-1,000 ng/ml), cocaine (10-1000 ng/ml), and two THC isomers (1-100 ng/ml). Accuracies of MA, MDMA, cocaine, and two THC isomers were 3.6 to 8.9%, -1.2 to 4%, -5.3 to 5.8%, and -11 to 14%, respectively; while precision estimates of the same were 1.6 to 5.4%, 1.7 to 5.3%, 1.2 to 4.5%, and 2 to 10%, respectively. Autosampler stability and dilution integrity were within acceptable limits, and no carryover was detected at the limit of detection. This validated LC-MS/MS method made the routine identification of both delta-9-THC and delta-8-THC in blood possible.

Monitoring for fentanyl within Australian supervised injecting facilities: Findings from feasibility testing of novel methods and collaborative workshops.

BACKGROUND: Australia is yet to see widespread fentanyl-contaminated heroin, despite the established presence of fentanyl in other countries. International mortality trends alongside a local cluster of fentanyl-related deaths prompted interest in developing methods to monitor for fentanyl and other potentially harmful novel psychoactive substances (NPS) in Australia. METHODS: We tested novel methods to monitor for fentanyl and other NPS. From 2017-2021, clients from supervised injecting facilities (SIFs) in Melbourne and Sydney, Australia, contributed urine screens (UDS) with BTNX Rapid Response™ fentanyl test strips (FTS) paired with surveys, and injecting equipment associated with opioid overdoses for laboratory analysis. A single site piloted drug checking using FTS with laboratory confirmation. Two workshops were conducted with SIF staff, content experts and people with lived experience to determine how results can inform practices within SIFs. RESULTS: Of the 911 UDS with FTS conducted, less than 1% (n=8) yielded positive results that were not explained by self-reported pharmaceutical fentanyl use, with two laboratory confirmed fentanyl positive results. Injecting equipment from 59 overdoses was tested and neither fentanyl nor other NPS were identified. Drug checking with FTS (n=34) indicated the presence of fentanyl on three tests. Two specimens were subsequently sent for laboratory testing and classified as false positives as the presence of fentanyl was not confirmed. Workshop participants (n=21) felt routine monitoring with FTS currently had limited value. A process for using pre-defined signals to trigger surveillance was developed. CONCLUSION: The high false positive rates with FTS, relative to the small number of positive results and potential for them to undermine confidence in FTS emphasised the need for confirmatory testing. The role of routine surveillance was unclear within the current low-fentanyl context, however, a process was developed to upscale testing should signals of increased fentanyl prevalence in the Australian heroin market emerge.

Diagnostic accuracy for self-reported methamphetamine use versus oral fluid test as the reference standard in a methamphetamine-dependent intervention trial population.

AIMS: Treatment of methamphetamine dependence requires monitoring of recent use or abstinence. Self-report is commonly used for routine monitoring, but the accuracy of self-report is not established. For the treating clinician, the key accuracy statistic is the negative predictive value (NPV). The study aim was to estimate the NPV of self-reported non-use of methamphetamine compared with an oral fluid reference standard. DESIGN, SETTING AND PARTICIPANTS: This study was a secondary (subgroup) analysis from a randomized controlled pharmacotherapy trial. Three Australian outpatient addiction services took part. Particpants were 139 people dependent on methamphetamine. MEASUREMENTS: Weekly oral fluid samples over 12 weeks to determine methamphetamine (and amphetamine) concentrations were used as the reference standard. Self-report of any methamphetamine use in the previous 7 days by the time-line follow-back method was the index test. Standard diagnostic accuracy statistics were calculated for all available paired episodes (n = 1134). Three NPV values were calculated: unadjusted NPV and NPV adjusted for clustering of observations through logistic regression and generalized estimating equation (GEE). We also calculated the NPVs for a range of prevalence rates of methamphetamine use, for the calculated levels of sensitivity and specificity. FINDINGS: Sensitivity was 96.4% [95% confidence interval (CI) = 95-97.5], specificity was 63.7% (95% CI = 57.3-69.8) and positive predictive value (PPV) was 90.8% (95% CI = 88.8-92.6). The unadjusted NPV was 82.7% (95% CI = 76.5-87.9), adjusted NPV by logistic regression 82.7% (95% CI = 73.9-91.5) and GEE 76.8% (95% CI = 66.8-86.8). At a methamphetamine use prevalence of 5%, the estimated NPV would be 99.7% (95% CI = 99.6-99.9) and at 95% prevalence, 48.2% (95% CI = 39.6-57.0). CONCLUSIONS: Self-report of no recent methamphetamine use appears to be sufficiently accurate to be clinically useful at the expected prevalence rates of methamphetamine use in clinical treatment settings. If generalizable to clinical settings, where these tests are routinely conducted, this may permit a reduction in the frequency and cost of oral fluid assays.

Fatal Intoxications from a Combination of 4-Fluoroamphetamine and 25C-NBOMe.

Six fatalities have occurred from the ingestion of a combination of new psychoactive substances (NPSs), 4-fluoroamphetamine (4FA) and 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25C-NBOMe) over a 9-month period. Four of these fatalities (one older female and three young males) were from direct adverse effects of drugs, and one each from a fall while being intoxicated and during restraint. All cases were subject to full postmortem examinations that included collection of femoral blood. The four drug-caused fatalities had postmortem blood concentrations for 4FA and 25C-NBOMe of 330-682 ng/L (median 417) and 1.4-12 ng/mL (median 4.3), respectively. The other two cases (both young males) where death was considered to have been caused indirectly by drug intoxication had 4FA and 25C-NBOMe postmortem concentrations of 21 and 123 ng/mL, and 1.8 and 4.5 ng/mL, respectively. None of these cases showed concentrations of drugs that suggested use of high recreational doses. In one drug-caused death, capsules and a brown powder obtained from the scene were found to contain a mixture of these two NPSs. With the exception of one drug-caused death, other drugs were detected; however, the effects of the two NPSs together were regarded as the primary triggers for the deaths. There were no consistent symptoms or pathology in these cases; however, agitation/aggression was observed in two cases prior to their collapse, with seizures in possibly three cases. Pulmonary and/or cerebral edema was noted in three cases. Potentially significant natural disease (a mildly enlarged heart) was only observed in one drug-caused case. These cases illustrate a possible increased risk of sudden death with this combination of drugs, both of which can elevate serotonin concentrations as well as act as strong stimulants. These cases also illustrate the difficulty in detecting NPS in cases where no prior information is available that might suggest their use.

Infrequent detection of unintentional fentanyl use via urinalysis among people who regularly inject opioids in Sydney and Melbourne, Australia.

BACKGROUND AND AIM: The current phase of the North American 'opioid crisis' is characterised by illicit fentanyl use; however, the presence of illicit fentanyl in Australia is unknown. This study aimed to monitor unintentional fentanyl consumption in Australia. DESIGN: Rapid urine drug screens (UDS) paired with surveys conducted within supervised injecting facilities (SIFs) and confirmatory laboratory testing. SETTING: Sydney and Melbourne, Australia. PARTICIPANTS: Clients who used heroin within the past 2 days (n = 911 tests, 2017-2021). Participants were demographically similar to the overall client base (median age 43, 72% male). MEASUREMENTS: UDS were conducted using BTNX Rapid Response fentanyl urine strip tests with cross-reactivity to numerous fentanyl analogues. Positive urine samples were analysed using liquid chromatography coupled with tandem mass spectrometry. Surveys covered past 3 day drug use and lifetime report of fentanyl in heroin. FINDINGS: Two percent of participants reported intentional use of fentanyl, mostly through fentanyl patches. Of the 911 rapid UDS conducted, 17 (1.9%) yielded positive results. Eight of these (all from Melbourne) were not explained by survey-reported fentanyl use in the past 3 days. Of these 8 unexplained positives, confirmatory laboratory analysis was conducted on 6, with 4 deemed to be false positives, and 2 confirmed for the presence of fentanyl. This represents the first confirmation of unintended use of fentanyl type substances in this population. CONCLUSION: There is limited evidence of unintentional fentanyl use among people in Sydney and Melbourne, Australia who regularly inject heroin, suggesting that, currently, there is very little illicit fentanyl in Australian drug markets accessed by supervised injecting facilities attendees. This study demonstrates the feasibility of quick onsite testing to cost-effectively screen large samples for fentanyl; however, the high false positive rate emphasises the need for confirmation of positive tests through advanced analytical techniques.

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

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).

High Throughput Detection of 327 Drugs in Blood by LC-MS-MS with Automated Data Processing.

The described procedure provides a rapid technique for the detection and semi-quantitation of a large number of drugs in blood. This procedure uses a minimal sample volume and employs a one-step liquid extraction and automated data processing to yield rapid turnaround times. A total of 327 of the most commonly used medicinal and illicit drugs in Australia were selected including various amphetamines, anesthetics, antidepressants, antipsychotics, anticonvulsants, benzodiazepines, beta blockers, opioid and nonopioid analgesics, stimulants, THC and a large number of synthetic cannabinoids and other novel psychoactive substances. The extracts were subject to 5-minute chromatography using a Kinetex C18 50 × 4.6 mm 2.6 µm solid-core analytical column and analyzed using a Sciex 3200 Q-TRAP MS-MS (+ ESI, MRM mode, two transitions per analyte). The method was fully validated in accordance with international guidelines. Matrix effects and extraction efficiencies were acceptable with most analytes showing > 80% response and low variation (within 25%RSD). Cannabinoids were most affected by the matrix and yielded poorest recovery values but were still detectable. Precision, accuracy, repeatability and multipoint linearity were assessed for all analytes. The method has been used in routine practice in the forensic toxicology service at the Victorian Institute of Forensic Medicine in over 6000 coronial investigations using both postmortem and clinical blood specimens. This technique has greatly increased throughput, reduced turnaround times and allowed for rapid same-day analysis of results when needed. The method is routinely used in routine overnight testing with results reported to pathologists within 4 h of data acquisition. This rapid toxicological technique is used in conjunction with other investigative processes such as full-body CT imaging, review of case circumstances and medical histories to provide an efficient death investigation process.

Time-Dependent Changes in THC Concentrations in Deceased Persons.

Changes in the concentrations of Δ9-tetrahydrocannabinol (THC) in the postmortem period were investigated in a series of cases by comparing concentrations in blood taken on receipt of the body in the mortuary (admission specimen, AD) with the concentrations obtained in blood taken at autopsy some time later and also from blood specimens taken antemortem. Overall, the median THC concentration in AD blood was 13.7 ng/mL (n = 239, range LOQ-220), while the median concentration at autopsy was 13.8 ng/mL (n = 106, range LOQ-810) and 1.9 ng/mL (n = 147, range LOQ-48) antemortem. Fourteen cases had all three specimens taken from the same decedent. The corresponding AM, AD and PM median concentrations were 4.0 (range LOQ-48), 15.5 (range 4.0-176) and 4.4 ng/mL (LOQ-56), respectively. The median elapsed times from AM to AD and AD to PM were 33 and 97.5 h, respectively. In contrast, acetaminophen showed no change in blood concentration from AM to AD (6.8 and 6.0 mg/L, respectively). These data show large increases in THC concentration in the early postmortem period, followed by a decline, although the median blood concentrations at autopsy were similar to that obtained antemortem. In contrast, when blood was taken from the femoral region, subclavian and heart ventricles sites, in the same case, the THC concentrations, while variable, showed overall no significant difference. These dynamic changes reflect complex phenomenon occurring in deceased persons and will further serve to increase the uncertainty over any interpretation of postmortem THC concentrations.

Postmortem Drug Redistribution: A Compilation of Postmortem/Antemortem Drug Concentration Ratios.

Postmortem drug redistribution (PMR) is a well-known phenomenon in forensic toxicology with implications for medico-legal death investigations. Paired antemortem (AM) specimen and postmortem (PM) mortuary admission femoral blood drug concentrations from 811 coronial cases were used to construct a retrospective compilation of PM/AM drug concentration ratios for 42 parent drugs and metabolites. The median PM/AM ratios for all antidepressants were > 1 and consistent with PMR In contrast, the median PM/AM ratios of most benzodiazepines were < 1. The antipsychotics were varied (0.63-3.3) and suggest the mixed effects of PMR and drug instability. Amphetamines exhibited no trends (0.90-0.95) and are likely confounded by many factors. The PM/AM ratios of cardiovascular drugs, opioids and other drugs are also reported. This research represents an expansive retrospective compilation of paired AM and PM drug concentrations for many toxicologically relevant drugs. While the median PM/AM ratios demonstrate some drug-dependent trends, there was no obvious relationship between AM specimens and PM femoral blood taken at mortuary admission.

Identification of a thermal degradation product of CUMYL-PEGACLONE and its detection in biological samples.

The structural diversity of synthetic cannabinoids makes it a challenging task to have a comprehensive screening method for this class of drugs. The difficulty is increased by the fact that some synthetic cannabinoids undergo thermal decomposition during common routes of administration, such as smoking or vaping. CUMYL-PEGACLONE is a relatively new synthetic cannabinoid which has a structural variant from most other synthetic cannabinoids: a γ-carbolinone core. To investigate its thermal stability, CUMYL-PEGACLONE was heated in an oven at temperatures ranging from 200 to 350o C, and a major thermal degradation product, N-pentyl-γ-carbolinone, was subsequently identified. Unlike some other synthetic cannabinoids, the thermal degradation product of CUMYL-PEGACLONE is not one of its known metabolites, nor were any known metabolites detected during the thermal stability experiments. The degradation product was formed in significant amounts at temperatures above 250°C, and has been detected (along with CUMYL-PEGACLONE) in case samples, including post-mortem blood and urine, and residue found at a scene.

LC-MSMS characterisations of scymnol and oxoscymnol biotransformations in incubation mixtures of rat liver microsomes.

The bile alcohol 5ß-scymnol ([24R]-(+)-5ß-cholestan-3α,7α,12α,24,26,27-hexol) is a therapeutic nutraceutical derived from marine sources, however very little is known about its potential for biotransformation as a xenobiotic in higher vertebrates. In this study, biotransformation products of scymnol catalysed by liver microsomes isolated from normal and streptozotocin (STZ)-treated male Wistar rats were characterised by liquid chromatography-tandem mass spectroscopy (LC-MSMS). In order of increasing polarity relative to the reversed phase sorbent, structural assignments were made for four biotransformation products, namely 3-oxoscymnol (5ß-cholestan-3-one-7α,12α,24,26,27-pentol); 7-oxoscymnol (5ß-cholestan-7-one-3α,12α,24,26,27-pentol); 3ß-scymnol (5ß-cholestan-3ß,7α,12α,24,26,27-hexol) and 6ß-hydroxyscymnol (5ß-cholestan-3α,6ß,7α,12α,24,26,27-heptol). In addition, a total of eight biotransformation products were characterised from microsomal incubations of crude oxoscymnol compounds, namely 7ß-scymnol; 3,12-dioxoscymnol; 3,7-dioxoscymnol; 7,12-dioxoscymnol; 12-oxo-3ß-scymnol; 7-oxo-3ß-scymnol; 6ß-hydroxy-12-oxoscymnol and 6ß-hydroxy-7-oxoscymnol. Collectively, the results indicate hepatic enzyme-catalysed hydroxylation, dehydrogenation and epimerisation reactions on the steroid nucleus of scymnol, and provide an insight into biotransformation pathways for scymnol use as a therapeutic nutraceutical in higher vertebrates.

Hydroxysteroid dehydrogenase transformations of 5ß-scymnol and identification of oxoscymnol transformation products by liquid chromatography-tandem mass spectroscopy.

A new and sensitive high performance liquid chromatography (HPLC) separation procedure coupled with tandem mass spectroscopy (MS and MS(2)) detection was developed to identify for the first time the oxidation products of 5ß-scymnol [(24R)-(+)-5ß-cholestan-3α,7α,12α,24,26,27-hexol] catalysed by bacterial hydroxysteroid dehydrogenase (HSD) reactions in vitro. The authentic scymnol (MW 468) standard yielded a protonated molecular ion [M+H](+) at m/z 469 Da, and higher mass adduct ions attributed to [M+NH(4)](+) (m/z 486), [M+H+CH(3)OH](+) (m/z 501) and [M+H+CH(3)COOH](+) (m/z 530). (24R)-(+)-5ß-Cholestan-3-one-7α,12α,24,26,27-pentol (3-oxoscymnol, m/z 467 Da, relative retention time (RRT)=0.89) was identified as the principle molecular species of scymnol in the reaction with 3α-HSD pure enzyme. [S](0.5) for the reaction of 3α-HSD with scymnol as substrate was 0.7292 mM. (24R)-(+)-5ß-cholestan-7-one-3α,12α,24,26,27-pentol (7-oxoscymnol, m/z 467 Da, RRT=0.79) and (24R)-(+)-5ß-cholestan-12-one-3α,7α,24,26,27-pentol (12-oxoscymnol, m/z 467 Da, RRT=0.81) were similarly identified as principle molecular species in the respective 7α-HSD and 12α-HSD reactions. Polarity of the oxoscymnol species was established as 7-oxoscymnol>12-oxoscymnol>3-oxoscymnol>scymnol (in order from most polar to least polar). Confirmation that 5ß-scymnol is an oxidative substrate for steroid-metabolising enzymes was made possible by the use of sophisticated liquid chromatography-mass spectrometry (LC-MS) techniques that will likely provide the basis for further exploration of scymnol as a therapeutic compound.