Early warning systems detect new psychoactive substances (NPS), while dedicated monitoring programs and routine drug and toxicology testing identify fluctuations in prevalence. We report the increasing prevalence of the synthetic cannabinoid receptor agonist (SCRA) ADB‐BUTINACA (N‐[1‐amino‐3,3‐dimethyl‐1‐oxobutan‐2‐yl]‐1‐butyl‐1H‐indazole‐3‐carbox‐amide). ADB‐BUTINACA was first detected in a seizure in Sweden in 2019, and we report its detection in 13 routine Swedish forensic toxicology cases soon after. In January 2021, ADB‐BUTINACA was detected in SCRA‐infused papers seized in Scottish prisons and has rapidly increased in prevalence, being detected in 60.4% of the SCRA‐infused papers tested between January and July 2021. In this work, ADB‐BUTINACA was incubated with human hepatocytes (HHeps), and 21 metabolites were identified in vitro, 14 being detected in authentic case samples. The parent drug and metabolites B9 (mono‐hydroxylation on the n‐butyl tail) and B16 (mono‐hydroxylation on the indazole ring) are recommended biomarkers in blood, while metabolites B4 (dihydrodiol formation on the indazole core), B9, and B16 are suitable biomarkers in urine. ADB‐4en‐PINACA (N‐[1‐amino‐3,3‐dimethyl‐1‐oxobutan‐2‐yl]‐1‐[pent‐4‐en‐1‐yl]‐1H‐indazole‐3‐carboxamide) was detected in Scottish prisons in December 2020, but, unlike ADB‐BUTINACA, prevalence has remained low. ADB‐4en‐PINACA was incubated with HHeps, and 11 metabolites were identified. Metabolites E3 (dihydrodiol formed in the tail moiety) and E7 (hydroxylation on the linked/head group) are the most abundant metabolites in vitro and are suggested as urinary biomarkers. The in vitro potencies of ADB‐BUTINACA (EC₅₀, 11.5 nM and ADB‐4en‐PINACA (EC₅₀, 11.6 nM) are similar to that of MDMB‐4en‐PINACA (EC₅₀, 4.3 nM). A third tert‐leucinamide SCRA, ADB‐HEXINACA was also detected in prison samples and warrants further investigation.

Semi‐synthetic cannabinoids (SSCs) including hexahydrocannabinol (HHC) are emerging on the drug market and sold openly as purportedly legal replacements for cannabis and Δ⁹‐THC. By the beginning of 2024, 24 European countries had identified HHC, often sold openly in edibles (foods/candy), vapes and low‐THC cannabis flowers and resins. The SSC market is developing rapidly, with HHC acetate (HHC‐O), hexahydrocannabiphorol (HHC‐P) and others recently identified. These developments may mark the first major change in the market for ‘legal’ replacements to cannabis since ‘Spice’ containing synthetic cannabinoids, such as JWH‐018, emerged in 2008. Currently, there are some data available on the pharmacology of SSCs, which is crucial for understanding their effects, evaluating health risks and informing public health responses. This study focused on characterizing the in vitro activation of the human CB₁ receptor by the (R)‐ and (S)‐epimers of HHC, HHC‐P and HHC‐O. Using recombinant CHO‐K1 cells expressing the human CB₁ receptor, the potency (EC₅₀) and efficacy were determined. It was established that (9R)‐HHC and (9R)‐HHC‐P activated the CB₁ receptor as partial agonists and with five and two times lower potency compared to JWH‐018, respectively, while the (S)‐epimers exhibited even lower potency. The (R)‐epimer of HHC‐O activate the CB₁ receptor to even lesser extent and the (S)‐epimer showed no activation. For HHC and HHC‐P, all epimers exhibited similar level of efficacy. This available evidence suggests cannabimimetic effects of the tested SSC with the exception for the acetates that likely function as pro‐drugs in vivo.

Many new psychoactive substances (NPS) are stimulants, and information about their potency and abuse potential is often lacking. To start addressing this need, a method measuring the inhibition of the dopamine, serotonin, and norepinephrine transporters (DAT, SERT, and NET) by stimulant drugs was developed. The use of a proprietary fluorescent dye mixture and three cell lines (CHO‐K1, HEK 293, and MDCK), each expressing a single transporter, allowed for a semiautomated, one‐pot determination of inhibition in a 384‐well format. The method was validated using well characterized stimulants, including cocaine, amphetamine, 3,4‐methylenedioxymethamphetamine (MDMA), α‐PVP, and fluoxetine and performed similarly to other methods. Seven synthetic cathinones all showed highest potency for DAT inhibition, followed by NET and SERT. The rank potency for DAT inhibition IC₅₀ (nM) was MPHP (4.53) > 4Cl‐α‐PVP (8.05) > 3F‐α‐PVP (12.7) > α‐PiHP (13.4) > N‐ethylpentylone (16.9) > N‐ethylhexedrone (44.5) > 4‐methylpentedrone (261). All but 4‐methylpentedrone were more potent than amphetamine (257) and cocaine (111). The DAT/SERT inhibition ratio for the cathinones was in the range from 5.02 for 4‐methylpentedrone to >3730 for α‐PiHP, compared to 1.64 for cocaine and >4030 for α‐PVP. All seven substances had inhibition profiles similar to those of potent stimulants with high abuse potential.

1‐(2,3‐Dihydro‐1H‐inden‐5‐yl)‐2‐(piperidin‐1‐yl)pentan‐1‐one (3,4‐Pr‐PipVP), a novel synthetic cathinone (SCat), was first identified in 2022 in Germany. The product was marketed as 1‐(bicyclo[4.2.0]octa‐1,3,5‐trien‐3‐yl)‐2‐(pyrrolidin‐1‐yl)pentan‐1‐one (3,4‐EtPV), a substance not covered by the German New Psychoactive Substances Act (NpSG). Although originally intended to be an exploratory new synthetic cathinone containing the novel bicyclo[4.2.0]octatrienyl function, the compound was subsequently confirmed to contain an indanyl ring system scheduled under generic legislation like the NpSG. However, it is one of only a few marketed SCats carrying a piperidine ring. Inhibition experiments involving norepinephrine, dopamine, and serotonin transporters showed that 3,4‐Pr‐PipVP was a low potency blocker at all three monoamine transporters compared to related substances such as MDPV. Additionally, pharmacokinetic data were collected from pooled human liver microsomes incubations and from the analysis of authentic urine samples received after oral administration of 5 mg 3,4‐Pr‐PipVP hydrochloride. Phase I metabolites were tentatively identified in vitro and in vivo using liquid chromatography−time‐of‐flight mass spectrometry. Main metabolites were formed by metabolic reduction of the carbonyl function with and without additional hydroxylations at the propylene bridge of the molecule. Keto‐reduced H₂–3,4‐Pr‐PipVP and H₂‐piperidine‐OH‐3,4‐Pr‐PipVP as well as aryl‐OH‐3,4‐Pr‐PipVP, and indanyl‐OH‐piperidine‐OH‐3,4‐Pr‐PipVP are suggested as most suitable biomarkers for the detection of 3,4‐Pr‐PipVP since they were detected for much longer than the parent compound. 3,4‐Pr‐PipVP could be detected for up to 21 h whereas its metabolites were detectable for up to about 4 days.