Characterization of the hepatic cytochrome P450 enzymes involved in the metabolism of 25I‐NBOMe and 25I‐NBOH

Abstract

The dimethoxyphenyl-N-((2-methoxyphenyl)methyl)ethanamine (NBOMe) compounds are potent serotonin 5-HT2A receptor agonists and have recently been subject to recreational use due to their hallucinogenic effects. Use of NBOMe compounds has been known since 2011, and several non-fatal and fatal intoxication cases have been reported in the scientific literature. The aim of this study was to determine the importance of the different cytochrome P450 enzymes (CYP) involved in the metabolism of 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2methoxybenzyl)ethanamine (25I-NBOMe) and 2-[[2-(4-iodo-2,5dimethoxyphenyl)ethylamino]methyl]phenol (25I-NBOH) and to characterize the metabolites. The following approaches were used to identify the main enzymes involved in primary metabolism: incubation with a panel of CYP and monoamine oxidase (MAO) enzymes and incubation in pooled human liver microsomes (HLM) with and without specific CYP chemical inhibitors. The study was further substantiated by an evaluation of 25I-NBOMe and 25I-NBOH metabolism in single donor HLM. The metabolism pathways of 25I-NBOMe and 25I-NBOH were NADPHdependent with intrinsic clearance values of (CLint) of 70.1 and 118.7 mL/min/kg, respectively. The biotransformations included hydroxylation, O-demethylation, N-dealkylation, dehydrogenation, and combinations thereof. The most abundant metabolites were all identified by retention time and spectrum matching with synthesized reference standards. The major CYP enzymes involved in the metabolism of 25I-NBOMe and 25INBOH were identified as CYP3A4 and CYP2D6, respectively. The compound 25I-NBOH was also liable to direct glucuronidation, which may diminish the impact of CYP2D6 genetic polymorphism. Users of 25I-NBOMe may be subject to drug-drug interactions (DDI) if 25I-NBOMe is taken with a strong CYP3A4 inhibitor. Copyright © 2016 John Wiley & Sons, Ltd.

25C‐NBOMe and 25I‐NBOMe metabolite studies in human hepatocytes, in vivo mouse and human urine with high‐resolution mass spectrometry

“…Given the small number of samples in both studies, individual differences, such as enzyme polymorphisms, might have played a role. This would be consistent with Nielsen et al’s findings that equal amounts of the 2’‐ and 5’‐desmethyl metabolite are found in pooled HLM, but different amounts in incubations with recombinant CYP enzymes, namely CYP2C9, CYP2D6 and CYP3A4 . For 25B‐NBOMe, Leth‐Petersen et al showed dominance of the 5’‐desmethyl metabolite .…”

“…In vitro incubation with human liver microsomes (HLM), cytosol, S9 fraction or recombinant CYP isoenzymes confirmed the main phase I reactions. Presence of the 2’‐ and 5’‐desmethyl 25I‐NBOMe and 4‐hydroxy 25I‐NBOMe was later confirmed with a reference standard . A 25I‐NBOMe metabolism study in fresh mouse liver microsomes and two human urine specimens identified 15 metabolites .…”

“…Our data, case reports, and other metabolism studies provide considerable proof that all three compounds follow the same metabolic pathways differing only in preference of the site of attack. Major phase I biotransformations are demethylation, di‐demethylation and hydroxylation; a minor pathway is NBOMe ring N‐dealkylation . The major phase II reaction is glucuronidation, but sulfation also occurs.…”

25I-NBOH: a new potent serotonin 5-HT2A receptor agonist identified in blotter paper seizures in Brazil

“…The ions detected at m/z 107.0491 and 308.0142 are produced by the cleavage of the C–N bond corresponding to o-cresol and 2C-I, respectively. The ion recorded at m/z 290.9876 is formed after the loss of the amine from the 2C-I fragment [9], and it corresponds to the most abundant ion in the CID spectrum of 25I-NBOH. The presented results suggest that 2C-I ( m/z 308.0142) is a fragment of the 25I-NBOH, explaining the presence of this compound in the high-energy production spectra of this drug.

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In vitro studies on flubromazolam metabolism and detection of its metabolites in authentic forensic samples

“…[14] After 10 min of pre-incubation of the compound with pHLM, the reactions were then started by addition of the NADPH regenerating system consisting of Glucuronidation in pHLM was investigated by following a previously published procedure. [15] Here, the enzymatic reactions were commenced by the addition of UDPGA and alamethicin at the final concentrations of 2 mM and 25 µg/mL, respectively, with and without presence of NADPH.…”