Oxidative Metabolism and Comparative Analysis of Synthetic Cannabinoid N‐(1‐adamantyl)‐1‐(5‐fluoropentyl)indazole‐3‐carboxamide (5F‐AKB‐48) and the Unfluorinated Analog AKB‐48

Abstract

Recently, the rising frequency in the abuse of synthetic cannabinoids (SCBs) has resulted in the occurrence of numerous severe adverse effects. We have previously shown that several early generations of SCBs undergo extensive metabolism by cytochrome P450s (P450s) and that their metabolites retain biological activity at CB1 and CB2 receptors. In this study, we examined the oxidative metabolism of 5F‐AKB‐48, one of a new structural generation of SCBs. Activity towards 5F‐AKB‐48 was investigated using various human microsomes followed by studies utilizing multiple recombinant human P450s. Screening with these enzymes showed that only 4, CYP2D6, −2J2, −3A4, and −3A5, biosynthesized the 2 major products, mono‐ and dihydroxylated 5F‐AKB‐48, with activities in the range of 2–5 pmol/min/pmol CYP. CYP3A5 formed the most dihydroxylated metabolite, whereas CYP2J2, highly expressed in cardiovascular tissues, showed the biosynthesized the most monohydroxylated derivative. CYP2D6 produced only monohydroxylated derivatives whereas CYP3A4 produced mostly dihydroxylated ones. To elucidate the roles of CYP3A4 and CYP3A5, additional enzymatic reactions utilized genotyped HLMs containing normal activity for CYP3A4 but low or high activities of CYP3A5. Those experiments resulted in significantly different patterns of oxidized metabolites. An UPLC equipped with UV/Vis detector and/or MS/MS were used to analyze the reactions. The profiles of the products biosynthesized were significantly different between the fluorinated and unfluorinated analogs. As this structural difference is known to increase potency for CB1 receptors, understanding the involved mechanism is essential. In conclusion, extensive metabolic studies of SCBs, including investigation of the mechanism(s) of action leading to toxicity, could result in the development of life saving, efficacious treatments for SCB abuse.Support or Funding Information(INBRE 117‐1006096 2018 AP and NIH/NIDA DA039143 to ARP and PLP)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.