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 β-arrestin2 recruitment assays, based on the NanoLuc Binary Technology®. At CB 1 , a potency of 635 nM (EC 50 ) 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 CB 2 , indicative of a clear CB 1 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 EC 50 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.