Waxy- or Putty-Like Materials as a Novel Drug Preparation for Synthetic Cannabinoid Receptor Agonists: Detection in Prisons and In Vitro Cannabinoid Receptor Activity

After the Scottish Prison Service (SPS) introduced mail photocopying procedures in December 2021, a shift in smuggling methods was observed for synthetic cannabinoid receptor agonists (SCRAs) and other new psychoactive substances (NPS) from drug-infused papers back to traditional sample matrices (e.g., tablets and powders), although new matrices also emerged. This study reports on waxy- or putty-like materials as a novel drug preparation for SCRAs and other drugs seized from UK prisons. In 2023, 22 of these new preparations were seized from Scottish prisons, with eight found in sealed vape pods. The materials were positive for SCRAs, phytocannabinoids, novel benzodiazepines, and/or gabapentinoids. Additionally, 11 preparations were seized from an English prison, all containing the SCRAs MDMB-4en-PINACA and MDMB-INACA. MDMB-INACA was pharmacologically characterized using in vitro CB₁ and CB₂ bioassays, revealing moderate efficacy but low potency at CB₁. Furthermore, the in vitro CB₁ bioassay was also used to evaluate the CB₁ activating potential of extracts from eight seized samples. Six of these showed high CB₁ activity, whereas the samples lacking SCRAs or containing only MDMB-INACA showed no or only weak CB₁ activity, respectively. Lastly, applying the bioassay as an activity-based “untargeted” screening method effectively identified the presence of SCRAs in one waxy preparation, which was initially not detected by gas chromatography–mass spectrometry (GC-MS). This underscores the effectiveness of the bioassay for evaluating these new waxy- or putty-like materials for the presence of SCRAs.