Identification of Emerging Novel Psychoactive Substances by Retrospective Analysis of Population-Scale Mass Spectrometry Data Sets.

Over the last two decades, hundreds of new psychoactive substances (NPSs), also known as "designer drugs", have emerged on the illicit drug market. The toxic and potentially fatal effects of these compounds oblige laboratories around the world to screen for NPS in seized materials and biological samples, commonly using high-resolution mass spectrometry. However, unambiguous identification of a NPS by mass spectrometry requires comparison to data from analytical reference materials, acquired on the same instrument. The sheer number of NPSs that are available on the illicit market, and the pace at which new compounds are introduced, means that forensic laboratories must make difficult decisions about which reference materials to acquire. Here, we asked whether retrospective suspect screening of population-scale mass spectrometry data could provide a data-driven platform to prioritize emerging NPSs for assay development. We curated a suspect database of precursor and diagnostic fragment ion masses for 83 emerging NPSs and used this database to retrospectively screen mass spectrometry data from 12,727 urine drug screens from one Canadian province. We developed integrative computational strategies to prioritize the most reliable identifications and tracked the frequency of these identifications over a 3 year study period between August 2019 and August 2022. The resulting data were used to guide the acquisition of new reference materials, which were in turn used to validate a subset of the retrospective identifications. Last, we took advantage of matching clinical reports for all 12,727 samples to systematically benchmark the accuracy of our retrospective data analysis approach. Our work opens up new avenues to enable the rapid detection of emerging illicit drugs through large-scale reanalysis of mass spectrometry data.

Desalkylgidazepam blood concentrations in 63 forensic investigation cases.

Desalkylgidazepam, also known as bromonordiazepam, is the latest designer benzodiazepine to appear in postmortem blood samples in British Columbia. Our laboratory was first alerted to the presence of desalkylgidazepam in seized drug samples in May 2022, and the analyte was added to an in-house library shortly thereafter. Previously acquired spectra from routine death investigation cases were reprocessed using the updated library with the first presumptive identification of desalkylgidazepam occurring in a sample received in April 2022. A standard addition method for the quantitation of desalkylgidazepam in blood samples (from femoral, iliac, jugular and subclavian veins) was validated and consequently used to confirm presence and concentrations of the drug in 63 cases, with an average concentration of 42.2 ± 44.0 ng/mL (median concentration: 24.5 ng/mL; range: 3.7-220.6 ng/mL). Similar to detections of other novel benzodiazepines, co-occurrence of desalkylgidazepam with opioids and/or stimulants was common. To our knowledge, this paper is the first to report desalkylgidazepam concentrations in postmortem blood samples.

Bromazolam Blood Concentrations in Postmortem Cases-A British Columbia Perspective.

Bromazolam is a designer benzodiazepine that was first detected in British Columbia in January 2021. Postmortem cases were analyzed using a comprehensive blood drug screening procedure by liquid chromatography-high-resolution mass spectrometry before being retrospectively analyzed using an in-house novel psychoactive substances data processing method. Bromazolam was detected in 41 postmortem cases in 2021 and quantitatively confirmed by standard addition, using liquid chromatography-tandem mass spectrometry. The mean bromazolam concentration observed was 11.4 ± 53.7 ng/mL (median concentration: 1.6 ng/mL), with a range from 0.5 to 319.3 ng/mL and the majority of cases co-occurring with fentanyl. These low concentrations may be indicative of a presumed enhancement of opioid effects, rather than being used as a stand-alone drug. Bromazolam was always detected with opioids (fentanyl and carfentanil), stimulants (methamphetamine) and/or other benzodiazepines (etizolam and flualprazolam). To our knowledge, this is the first report to provide concentrations of bromazolam in postmortem blood samples in Canada.

Fatal ingestion of Taxus baccata: English yew.

Poisoning from consumption of foraged alternative medicine products is an uncommon yet recognized occurrence. Here, presented is the case of a 40-year-old woman who was witnessed to collapse with labored breathing and subsequently died despite emergency medical personnel attendance and resuscitation efforts. Autopsy revealed the presence of plant matter that was visually identified as leaves from Taxus baccata - the English Yew. Isolation of alkaloids from the plant material and subsequent identification of the same alkaloids in the decedent's blood by liquid chromatography-tandem mass spectrometry indicated a toxicological cause of death. This case illustrates a collaborative team approach among subject matter experts to unexpectedly discover and then confirm the sudden death of this woman from T. baccata toxicity.

Generation of ligand conformations in continuum solvent consistent with protein active site topology: application to thrombin.

Using the crystal structure of an inhibitor complexed with the serine protease thrombin (PDB code ) and the functional group definitions contained within the Catalyst software, a representation of the enzyme's active site was produced (structure-based pharmacophore model). A training set of 16 homologous non-peptide inhibitors whose conformations had been generated in continuum solvent (MacroModel) and clustered into conformational families (XCluster) was regressed against this pharmacophore so as to obtain a 3D-QSAR model. To test the robustness of the resulting QSAR model, the synthesis of a series of non-peptide thrombin inhibitors based on arylsuphonyl derivatives of an aminophenol ring linked to a pyridyl-based S1 binding group was undertaken. These compounds served as a test set (20-24). The crystal structure for the novel symmetrical disulfonyl compound 24, in complex with thrombin, has been solved. Its calculated binding mode is in general agreement with the crystallographically observed one, and the predicted K(i) value is in close accord with the experimental value.