Identification and quantification of metabolites of AB-CHMINACA in a urine specimen of an abuser

Indole‐ and indazole‐based synthetic cannabinoid receptor agonists (SCRAs), featuring valine or tert‐leucine substituents, are commonly abused new psychoactive substances (NPS). A major metabolic pathway for these SCRAs is hydrolysis of the terminal amide or methylester functionalities. Although these hydrolysis products were already detected as main ingredients in some “legal highs,” these metabolites are often poorly characterized. Here, we report a systematic investigation of the activity of 7 common hydrolysis metabolites of 15 SCRAs featuring scaffolds based on L‐valine or L‐tert‐leucine in direct comparison to their parent compounds. An activity‐based cannabinoid receptor 1 (CB1) bio‐assay was used for activity profiling of SCRAs and their metabolites in a stable HEK293T cell system. The recruitment of β‐arrestin2 to the activated CB1 (each fused to one part of a split Nanoluciferase) was provoked by adding the (putative) SCRAs. Luminescence of the functionally complemented luciferase was monitored by a 96‐well plate‐reader. The major hydrolysis metabolites of 5F‐AB‐PINACA, ADB‐CHMICA, ADB‐CHMINACA, ADB‐FUBICA, and their methyl‐ and ethylester derivatives showed no detectable CB1 activation at concentrations up to 1 μM. On the other hand, metabolites of 5F‐ADB‐PINACA, AB‐CHMINACA, and ADB‐FUBINACA did retain activity, although significantly reduced as compared to the parent compounds (EC50 values >100 nM). Activity‐based characterization of SCRAs and their metabolites at CB1 may not only allow a better insight into the complex interplay between SCRAs and their metabolites in intoxications, but may also allow application of the concept of “activity equivalents” present in biological fluids or, alternatively, in confiscated materials.

Section: Resultssupporting

confidence: 85%

Functional evaluation of carboxy metabolites of synthetic cannabinoid receptor agonists featuring scaffolds based on L‐valine or L‐tert‐leucine

Wouters

Mogler

Cannaert

et al. 2019

“…Different applications exist for the identification of suitable metabolites in urine. Urine case samples can be used for metabolite identification but are not entirely sufficient for this purpose because of inter‐individual variations . In addition, human liver microsomes (HLMs) and hepatocytes can be used for in vitro identification, but their application is insufficient when they are used alone .…”

Section: Introductionsupporting

confidence: 91%

“…Major in vivo metabolites cannot always be predicted by in vitro methods. However, robust and specific metabolite identification can be achieved by combining applications . For example, in vitro identified metabolites can be confirmed by using case samples to identify major metabolites.…”

Section: Introductionmentioning

confidence: 99%

Detection of metabolites of the new synthetic cannabinoid CUMYL‐4CN‐BINACA in authentic urine samples and human liver microsomes using high‐resolution mass spectrometry

Öztürk¹,

Yeter²,

Öztürk³

et al. 2017

CUMYL-4CN-BINACA(1-(4-cyanobutyl)-N-(2-phenylpropan-2-yl)-1H-indazole-3-carboxamide) is a recently introduced indazole-3-carboxamide-type synthetic cannabinoid (SC) that was detected in herbal incense seized by of the Council of Forensic Medicine, Istanbul Narcotics Department, in May 2016 in Turkey. Recently introduced SCs are not detected in routine toxicological analysis; therefore, analytical methods to measure these compounds are in demand. The present study aims to identify urinary marker metabolites of CUMYL-4CN-BINACA by investigating its metabolism in human liver microsomes and to confirm the results in authentic urine samples (n = 80). In this study, 5 μM CUMYL-4CN-BINACA was incubated with human liver microsomes (HLMs) for up to 3 hours, and metabolites were identified using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Less than 21% of the CUMYL-4CN-BINACA parent compound remained after 3 hours of incubation. We identified 18 metabolites that were formed via monohydroxylation, dealkylation, oxidative decyanation to aldehyde, alcohol, and carboxylic acid formation, glucuronidation or reaction combinations. CUMYL-4CN-BINACA N-butanoic acid (M16) was found to be major metabolite in HLMs. In urine samples CUMYL-4CN-BINACA was not detected; CUMYL-4CN-BINACA N-butanoic acid (M16) was major metabolite after β-glucuronidase hydrolysis. Based on these findings, we recommend using M16 (CUMYL-4CN-BINACA N-butanoic acid), M8 and M11 (hydroxylcumyl CUMYL-4CN-BINACA) as urinary marker metabolites to confirm CUMYL-4CN-BINACA intake.

“…Erratico et al also reported in vitro and in vivo metabolism of AB‐CHMINACA; they detected 26 metabolites by in vitro incubation of AB‐CHMINACA with human liver microsomes, but the in vitro results did not include a metabolite dihydroxylated in the 4‐position of the cyclohexyl moiety and also at the isopropyl moiety in the amide linker. The absence of such a dihydroxylated metabolite of AB‐CHMINACA was also true for a urine sample of an abuser . It is of great interest that such a minor difference in their structures, i.e.…”

Section: Resultsmentioning

confidence: 89%

Identification and quantification of predominant metabolites of synthetic cannabinoid MAB‐CHMINACA in an authentic human urine specimen

Hasegawa

Minakata

Gonmori

et al. 2017

Self Cite

An autopsy case in which the cause of death was judged as drug poisoning by two synthetic cannabinoids, including MAB-CHMINACA, was investigated. Although unchanged MAB-CHMINACA could be detected from solid tissues, blood and stomach contents in the case, the compound could not be detected from a urine specimen. We obtained six kinds of reference standards of MAB-CHMINACA metabolites from a commercial source. The MAB-CHMINACA metabolites from the urine specimen of the abuser were extracted using a QuEChERS method including dispersive solid-phase extraction, and analyzed by liquid chromatography-tandem mass spectrometry with or without hydrolysis with β-glucuronidase. Among the six MAB-CHMINACA metabolites tested, two predominant metabolites could be identified and quantified in the urine specimen of the deceased. After hydrolysis with β-glucuronidase, an increase of the two metabolites was not observed. The metabolites detected were a 4-monohydroxycyclohexylmethyl metabolite M1 (N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-((4-hydroxycyclohexyl)methyl)-1H-indazole-3-carboxamide) and a dihydroxyl (4-hydroxycyclohexylmethyl and tert-butylhydroxyl) metabolite M11 (N-(1-amino-4-hydroxy-3,3-dimethyl-1-oxobutan-2-yl)-1-((4-hydroxycyclohexyl)methyl)-1H-indazole-3-carboxamide). Their concentrations were 2.17 ± 0.15 and 10.2 ± 0.3 ng/mL (n = 3, each) for M1 and M11, respectively. Although there is one previous in vitro study showing the estimation of metabolism of MAB-CHMINACA using human hepatocytes, this is the first report dealing with in vivo identification and quantification of MAB-CHMINACA metabolites in an authentic human urine specimen.