Metabolic fate of the new synthetic cannabinoid 4'N-5F-ADB in rat, human, and pooled human S9 studied by means of hyphenated high-resolution mass spectrometry.

New psychoactive substances an important issue in clinical/forensic toxicology. 4'N-5F-ADB, a synthetic cannabinoid derived from 5F-ADB, appeared recently on the market. Up to now, no data about its mass spectral fragmentation pattern, metabolism, and thus suitable targets for toxicological urine screenings is available. Therefore, the aim of this study was to elucidate the metabolic fate of 4'N-5F-ADB in rat, human, and pooled human S9 (pS9). Main human urinary excretion products, which can be used as targets for toxicological screening procedures, were identified by Orbitrap (OT)-based liquid chromatography-high resolution-tandem mass spectrometry (LC-HRMS/MS). In addition, possible differentiation of 4'N-5F-ADB and 5F-ADB via LC-HRMS/MS was studied. Using the vivo and in vitro models for metabolism studies, thirty-six metabolites were tentatively identified. 4'N-5F-ABD was extensively metabolized in rat and human and minor species differences were observed. The unchanged parent compound could be found in human urine but metabolites were far more abundant. The most abundant ones were the hydrolyzed ester (M5), the hydrolyzed ester in combination with hydroxylation of the tertiary butyl part (M11), and the hydrolyzed ester in addition to glucuronidation (M30). Beside the parent compound, these metabolites should be used as targets for urine based toxicological screening procedures. Two urine-paired human plasma samples contained mainly the parent compound (c=205 μg/L, 157 μg/L) and, at a higher abundance, the compound after ester hydrolysis (M5). In pS9 incubations, the parent compound, M5 and M30 were detectable amongst others. Furthermore, a differentiation of both compounds was possible due to different retention times and fragmentation patterns.