Synthesis, characterisation, detection and quantification of a novel hexyl-substituted synthetic cannabinoid receptor agonist: (S)-N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-hexyl-1H-indazole-3-carboxamide (ADB-HINACA)

Abstract

Synthetic cannabinoid receptor agonists (SCRAs) are a continually evolving family of illicit drugs, with novel analogues frequently being detected. This paper reports the detection of a new N-hexyl-1H-indazole derivative, ADB-HINACA, within a herbal sample seized by law enforcement for the first time in the United Kingdom. The identity of the compound was confirmed via the synthesis of a pure ADB-HINACA reference standard and direct spectral comparison by 1H NMR and GC-EI-MS analysis. A full analytical profiling of ADB-HINACA by nuclear magnetic resonance (NMR), attenuated total reflection Fourier-transform infrared (FTIR) spectroscopy and gas chromatography-electron ionisation-mass spectrometry (GC-EI-MS) is reported and shows good concordance between the seized sample and the reference standard. A validated GC-EI-MS method for the routine quantification of the cannabinoid in seized samples (LOD:1.7 μg/mL, LOQ: 5.8 μg/mL) was also developed and using this method, the seized herbal sample was determined to contain 4.9%w/w ADB-HINACA.