A new cannabinoid receptor 1 selective agonist evading the 2021 China ban: ADB-FUBIATA

Following the class-wide ban of synthetic cannabinoid receptor agonists (SCRAs) in China, SCRAs carrying new core and linker structures, aimed at circumventing the recent Chinese generic legislation, have appeared on the recreational drug market. A very recent example is (S)-2-(2-(1-(4-fluorobenzyl)-1H-indol-3-yl)acetamido)-3,3-dimethylbutanamide (ADB-FUBIATA), which is structurally closely related to the potent SCRA ADB-FUBICA, but carries an additional methylene in the linker region of the molecule. ADB-FUBIATA has recently been identified in seized materials in China, Russia, the United States, and also Belgium; however, its pharmacological characteristics were unknown. The aim of this study was to evaluate the intrinsic cannabinoid receptor (hCB(1) and hCB(2)) activation potential of this previously unknown substance via two distinct yet similar in vitro beta-arrestin2 recruitment assays, based on the NanoLuc Binary Technology (R). At CB1, a potency of 635 nM (EC50) was found, with an efficacy (E-max) of 141% relative to the reference compound CP55,940. On the other hand, ADB-FUBIATA had almost no activity at CB2, indicative of a clear CB1 selectivity. Interestingly, this activation pattern differs markedly from that observed for ADB-FUBICA, which was previously found to be potent and efficacious at both cannabinoid receptors. Additionally, the bioassays were applied to a seized powder containing ADB-FUBIATA, as analytically confirmed by high-performance liquid chromatography coupled to diode-array detection (HLPC-DAD), gas chromatography coupled to mass spectrometry (GC-MS), liquid chromatography couple to time-of-flight mass spectrometry (LC-QTOF-MS), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). The EC50 and E-max values obtained for this powder were very similar to those of the ADB-FUBIATA analytical standard, suggesting a high purity of the powder, although analytical techniques did reveal that the sample was not entirely pure.

Automated summary

After the ban of synthetic cannabinoid receptor agonists (SCRAs) in China, new SCRAs carrying new core and linker structures are being introduced to avoid the recent generic legislation. This study evaluated the activity and selectivity of the previously unknown substance ADB-FUBIATA, which has been found in seized materials in multiple countries. The bioassays confirmed the potency and selectivity of ADB-FUBIATA, which differs from the previously known ADB-FUBICA.