In vitro metabolism of the synthetic cannabinoids CUMYL‐PINACA, 5F–CUMYL‐PINACA, CUMYL‐4CN‐BINACA, 5F–CUMYL‐P7AICA and CUMYL‐4CN‐B7AICA

• Published in: Drug testing and analysis 2018-01, Vol.10 (1), p.148-157
• Main Authors: Staeheli, Sandra N., Poetzsch, Michael, Veloso, Veronica P., Bovens, Michael, Bissig, Christian, Steuer, Andrea E., Kraemer, Thomas
• Format: Article
• Language: English
• Subjects: Cannabinoids - chemistry; Cannabinoids - metabolism; Drug testing; Humans; in vitro metabolism; Indazoles - chemistry; Indazoles - metabolism; Metabolic Networks and Pathways - physiology; Metabolism; Metabolites; Microsomes, Liver - metabolism; new psychoactive substances NPS; Street Drugs - metabolism; synthetic cannabinoids
• ISSN: 1942-7603; 1942-7611
• DOI: 10.1002/dta.2298

Synthetic cannabinoid consumption trends underlie fast changes and provide several challenges to clinical and forensic toxicologists. Due to their extensive metabolism, parent compounds are hardly detectable in urine. Therefore, knowledge of the metabolism of synthetic cannabinoids is essential to allow their detection in biological matrices. The aim of the present study was the elucidation of the metabolism of CUMYL‐PINACA, 5F–CUMYL‐PINACA, CUMYL‐4CN‐BINACA, 5F–CUMYL‐P7AICA, and CUMYL‐4CN‐B7AICA with a focus on the analytical and interpretational differentiation of the compounds. Microsomal assay mixtures containing co‐substrates, 10 μg/mL substrate and 1 mg/mL pooled human liver microsomes were incubated for 1 hour at 37°C. Investigation of the metabolites was performed on a Thermo Fischer Ultimate 3000 UHPLC system coupled to a Sciex 6600 QTOF System. Hydroxylation was observed to be a major biotransformation step for all 5 cumyl‐derivatives, followed by dihydroxylation. For CUMYL‐PINACA, a major metabolic pathway was hydroxylation at the pentyl moiety, followed by a second hydroxylation at that pentyl moiety or oxidation to ketone. A major metabolic pathway for the compounds containing a nitrile function was nitrile hydrolysis followed by carboxylation and further hydroxylation. For the fluorinated compounds, oxidative defluorination and carboxylation were abundant metabolic steps. Some of the metabolic transformations lead to structurally identical metabolites, which should not be used as marker for the intake of a particular parent compound. In addition, several constitutional isomers containing either an indazole or azaindole core structure were detected, which should be differentiated by retention time rather than by their mass spectra alone. The aim was the elucidation of the metabolism of the new synthetic cannabinoids CUMYL‐PINACA, 5F‐CUMYL‐PINACA, CUMYL‐4CN‐BINACA, 5F‐CUMYL‐P7AICA, and CUMYL‐4CN‐B7AICA with a focus on the analytical and interpretational differentiation of the compounds. Some of the metabolic transformations lead to structurally identical metabolites, and should not be used as markers for the intake of a particular parent compound. Furthermore, constitutional isomers containing either an indazole or an azaindole core structure should also be differentiated by retention time rather than by their mass spectra alone.