Metabolic characterization of (1-(5-fluoropentyl)-1H-indol-3-yl)(4-methyl-1-naphthalenyl)-methanone (MAM-2201) using human liver microsomes and cDNA-overexpressed cytochrome P450 enzymes

Metabolic profiling of a new synthetic cannabinoid receptor agonist, ADMB-FUBIATA, with human liver microsomes, human primary hepatocytes and human recombinant CYP450 enzymes using LC-quadrupole-orbitrap MS

A novel synthetic cannabinoid receptor agonist (SCRA), ADMB-FUBIATA, featuring an acetamide-linked structure, has emerged on the illicit drug market. To provide dependable verification of its consumption and identify reliable biomarkers, we investigated an in vitro metabolism study of ADMB-FUBIATA incubated with human primary hepatocytes (HPHs) for the first time and correlated our findings with those from human liver microsomes (HLMs). In this work, ADMB-FUBIATA (10 μM) was incubated with HLM and HPH for 1 and 5 h, respectively, and then subjected to LC-quadrupole-orbitrap MS. A total of 25 metabolites across 8 metabolic pathways were identified after incubation with HLM and HPH, respectively. Monohydroxylation and N-dealkylation were the major metabolic pathways, and formation to ketone was first identified. In addition, the metabolism of ADMB-FUBIATA were found to be mediated by multiple CYP450 enzymes, predominantly CYP2C19, 2D6, and 3A4. This research also initially characterized the fragmentation patterns of the metabolites of ADMB-FUBIATA, elaborating on their structural relationship with ADMB-FUBIATA analogs. To effectively monitor ADMB-FUBIATA abuse, metabolites M4 and M1 were proposed as reliable biomarkers by cross-validating the HLM and HPH incubation results.

Comparative metabolism of aschantin in human and animal hepatocytes

Aschantin, a tetrahydrofurofuran lignan with a 1,3-benzodioxole group derived from Flos Magnoliae, exhibits antioxidant, anti-inflammatory, cytotoxic, and antimicrobial activities. This study compared the metabolic profiles of aschantin in human, dog, mouse, and rat hepatocytes using liquid chromatography-high-resolution mass spectrometry. The hepatic extraction ratio of aschantin among the four species was 0.46-0.77, suggesting that it undergoes a moderate-to-extensive degree of hepatic metabolism. Hepatocyte incubation of aschantin produced 4 phase 1 metabolites, including aschantin catechol (M1), O-desmethylaschantin (M2 and M3), and hydroxyaschantin (M4), and 14 phase 2 metabolites, including O-methyl-M1 (M5 and M6) via catechol O-methyltransferase (COMT), six glucuronides of M1, M2, M3, M5, and M6, and six sulfates of M1, M2, M3, M5, and M6. Enzyme kinetic studies using aschantin revealed that the production of M1, a major metabolite, via O-demethylenation is catalyzed by cytochrome 2C8 (CYP2C8), CYP2C9, CYP2C19, CYP3A4, and CYP3A5 enzymes; the formation of M2 (O-desmethylaschantin) is catalyzed by CYP2C9 and CYP2C19; and the formation of M4 is catalyzed by CYP3A4 enzyme. Two glutathione (GSH) conjugates of M1 were identified after incubation of aschantin with human and animal liver microsomes in the presence of nicotinamide adenine dinucleotide phosphate and GSH, but they were not detected in the hepatocytes of all species. In conclusion, aschantin is extensively metabolized, producing 18 metabolites in human and animal hepatocytes catalyzed by CYP, COMT, UDP-glucuronosyltransferase, and sulfotransferase. These results can help in clarifying the involvement of metabolizing enzymes in the pharmacokinetics and drug interactions of aschantin and in elucidating GSH conjugation associated with the reactive intermediate formed from M1 (aschantin catechol).

Comparative metabolism of fargesin in human, dog, monkey, mouse, and rat hepatocytes

Fargesin, a bioactive lignan derived from Flos Magnoliae, possesses anti-inflammatory, anti-oxidative, anti-melanogenic, and anti-apoptotic effects. This study compared the metabolic profiles of fargesin in human, dog, monkey, mouse, and rat hepatocytes using liquid chromatography-high resolution mass spectrometry. In addition, we investigated the human cytochrome P450 (CYP), UDP-glucuronosyltransferase (UGT), and sulfotransferase (SULT) enzymes responsible for fargesin metabolism. The hepatic extraction ratio of fargesin among the five species ranged from 0.59 to 0.78, suggesting that it undergoes a moderate-to-extensive degree of hepatic metabolism. During metabolism, fargesin generates three phase 1 metabolites, including fargesin catechol (M1) and O-desmethylfargesin (M2 and M3), and 11 phase 2 metabolites, including O-methyl-M1 (M4 and M5) via catechol O-methyltransferase (COMT), glucuronides of M1, M2, M4, and M5, and sulfates of M1-M5. The production of M1 from fargesin via O-demethylenation is catalyzed by CYP2C9, CYP3A4, CYP2C19, and CYP2C8 enzymes, whereas the formation of M2 and M3 (O-desmethylfargesin) is catalyzed by CYP2C9, CYP2B6, CYP2C19, CYP3A4, CYP1A2, and CYP2D6 enzymes. M4 is metabolized to M4 glucuronide by UGT1A3, UGT1A8, UGT1A10, UGT2B15, and UGT2B17 enzymes, whereas M4 sulfate is generated by multiple SULT enzymes. Fargesin is extensively metabolized in human hepatocytes by CYP, COMT, UGT, and SULT enzymes. These findings help to elucidate the pharmacokinetics and drug interactions of fargesin.

MAM-2201 acute administration impairs motor, sensorimotor, prepulse inhibition, and memory functions in mice: a comparison with its analogue AM-2201

RATIONALE

1-[(5-fluoropentyl)-1H-indol-3-yl](4-methyl-1-naphthalenyl) methanone (MAM-2201) is a potent synthetic cannabinoid receptor agonist illegally marketed in "spice" products and as "synthacaine" for its psychoactive effects. It is a naphthoyl-indole derivative which differs from its analogue 1-[(5-Fluoropentyl)-1H-indol-3-yl](1-naphthylenyl) methanone (AM-2201) by the presence of a methyl substituent on carbon 4 (C-4) of the naphthoyl moiety. Multiple cases of intoxication and impaired driving have been linked to AM-2201 and MAM-2201 consumption.

OBJECTIVES

This study aims to investigate the in vitro (murine and human cannabinoid receptors) and in vivo (CD-1 male mice) pharmacodynamic activity of MAM-2201 and compare its effects with those induced by its desmethylated analogue, AM-2201.

RESULTS

In vitro competition binding studies confirmed that MAM-2201 and AM-2201 possess nanomolar affinity for both CD-1 murine and human CB₁ and CB₂ receptors, with preference for the CB₁ receptor. In agreement with the in vitro binding data, in vivo studies showed that MAM-2201 induces visual, acoustic, and tactile impairments that were fully prevented by pretreatment with CB₁ receptor antagonist/partial agonist AM-251, indicating a CB₁ receptor mediated mechanism of action. Administration of MAM-2201 also altered locomotor activity and PPI responses of mice, pointing out its detrimental effect on motor and sensory gating functions and confirming its potential use liability. MAM-2201 and AM-2201 also caused deficits in short- and long-term working memory.

CONCLUSION

These findings point to the potential public health burden that these synthetic cannabinoids may pose, with particular emphasis on impaired driving and workplace performance.

Study on the metabolic process of synthetic cannabinoids 4F-MDMB-BINACA and 4F-MDMB-BICA in human liver microsome and zebrafish model via UHPLC-QE Orbitrap MS

In order to address the increasing abuse of synthetic cannabinoids, on July 1, 2021, China listed the whole category of synthetic cannabinoids in the Supplementary Catalog for the Control of Non-medicinal Narcotic Drugs and Psychotropic Substances. Because synthetic cannabinoids metabolize rapidly, techniques are urgently needed to identify the phase I metabolites of new synthetic cannabinoids, as well as the symbol metabolites, which can be used for detection in real cases. In this study, we used pooled human liver microsome (pHLM) and zebrafish combined with ultra-high-performance liquid chromatography (UHPLC) Q Exactive Orbitrap MS to identify the phase I metabolites of two new synthetic cannabinoids 4F-MDMB-BICA and 4F-MDMB-BINACA in vitro and in vivo, respectively. We studied the toxicokinetics of 4F-MDMB-BICA and 4F-MDMB-BINACA by sampling from a pHLM incubation system at different time points to study the change in metabolites over time. We detected a total of 14 metabolites of 4F-MDMB-BINACA and 16 metabolites of 4F-MDMB-BICA in this study. Metabolites of 4F-MDMB-BICA were detected in vitro for the first time. One metabolite of 4F-MDMB-BINACA, M05, was discovered for the first time. Based on the toxicokinetics results, we recommend three metabolites (M03, M11, M12) of 4F-MDMB-BINACA and three metabolites (M10, M12, M14) of 4F-MDMB-BICA as their symbol metabolites. The results showed that these two structurally similar synthetic cannabinoids 4F-MDMB-BINACA and 4F-MDMB-BICA had similar metabolic processes, as well as similar structures of their main symbol metabolites.

Urinary Metabolite Biomarkers for the Detection of Synthetic Cannabinoid ADB-BUTINACA Abuse

BACKGROUND

(S)-N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-butyl-1H-indazole-3carboxamide (ADB-BUTINACA) is an emerging synthetic cannabinoid that was first identified in Europe in 2019 and entered Singapore's drug scene in January 2020. Due to the unavailable toxicological and metabolic data, there is a need to establish urinary metabolite biomarkers for detection of ADB-BUTINACA consumption and elucidate its biotransformation pathways for rationalizing its toxicological implications.

METHODS

We characterized the metabolites of ADB-BUTINACA in human liver microsomes using liquid chromatography Orbitrap mass spectrometry analysis. Enzyme-specific inhibitors and recombinant enzymes were adopted for the reaction phenotyping of ADB-BUTINACA. We further used recombinant enzymes to generate a pool of key metabolites in situ and determined their metabolic stability. By coupling in vitro metabolism and authentic urine analyses, a panel of urinary metabolite biomarkers of ADB-BUTINACA was curated.

RESULTS

Fifteen metabolites of ADB-BUTINACA were identified with key biotransformations being hydroxylation, N-debutylation, dihydrodiol formation, and oxidative deamination. Reaction phenotyping established that ADB-BUTINACA was rapidly eliminated via CYP2C19-, CYP3A4-, and CYP3A5-mediated metabolism. Three major monohydroxylated metabolites (M6, M12, and M14) were generated in situ, which demonstrated greater metabolic stability compared to ADB-BUTINACA. Coupling metabolite profiling with urinary analysis, we identified four urinary biomarker metabolites of ADB-BUTINACA: 3 hydroxylated metabolites (M6, M11, and M14) and 1 oxidative deaminated metabolite (M15).

CONCLUSIONS

Our data support a panel of four urinary metabolite biomarkers for diagnosing the consumption of ADB-BUTINACA.

MAM-2201, One of the Most Potent-Naphthoyl Indole Derivative-Synthetic Cannabinoids, Exerts Toxic Effects on Human Cell-Based Models of Neurons and Astrocytes

Considering the consequences on human health, in general population and workplace, associated with the use of new psychoactive substances and their continuous placing on the market, novel in vitro models for neurotoxicology research, applying human-derived CNS cells, may provide a means to understand the mechanistic basis of molecular and cellular alterations in brain. Cytotoxic effects of MAM-2201, a potent-naphthoyl indole derivative-synthetic cannabinoid, have been evaluated applying a panel of human cell-based models of neurons and astrocytes, testing different concentrations (1-30 µM) and exposure times (3-24-48 h). MAM-2201 induced toxicity in primary neuron-like cells (hNLCs), obtained from transdifferentiation of mesenchymal stem cells derived from human umbilical cord. Effects occurred in a concentration- and time-dependent manner. The lowest concentration affecting cell viability, metabolic function, apoptosis, morphology, and neuronal markers (MAP-2, NSE) was 5 μM, and even 1 μM induced apoptosis. Effects appeared early (3 h) and persisted after 24 and 48 h. Similar behavior was evidenced for human D384-astrocytes treated with MAM-2201. Differently, human SH-SY5Y-neurons, both differentiated and undifferentiated, were not sensitive to MAM-2201. On D384, the different altered endpoints were reversed, attenuated, or not antagonized by AM251 indicating that CB1 receptors may partially mediate MAM-2201-induced cytotoxicity. While in hNLCs, all toxic effects caused by MAM-2201 were apparently unrelated to CB-receptors since they were not evidenced by immunofluorescence. The present in vitro findings demonstrate the cytotoxicity of MAM-2201 on human primary neurons (hNLCs) and astrocytes cell line (D384), and support the use of these cellular models as species-specific in vitro tools suitable to clarify the neurotoxicity mechanisms of synthetic cannabinoids.

In Vitro Metabolism and Hepatic Intrinsic Clearance of the Synthetic Cannabinoid Receptor Agonist JWH-122 and Its Four ω-Halogenated Analogues

The number of new psychoactive substances (NPS) emerging on the illicit drug market has increased over the last decade. Halogenation of existing illicit drugs is a particular trend, with the purpose of both circumventing the law and altering the toxicodynamic and toxicokinetic profiles of the compounds. This study investigates the in vitro impact of JWH-122 ω-halogenation (fluoro, chloro, bromo and iodo) on the metabolism, apparent intrinsic hepatic clearance and analytical targets for detecting drug consumption. Metabolite profiling was conducted with pooled human liver microsomes, suspended rat hepatocytes and pooled human hepatocytes. The in vitro half-life was also determined in pooled human hepatocytes. All samples were analysed by liquid chromatography/high-resolution mass spectrometry. All compounds, except for JWH-122, showed high formation rates of phase I metabolites, predominantly ω-COOH and methylnaphthyl hydroxylation metabolites. Phase II metabolites were ω-O-glucuronides, methylnaphthyl O-glucuronides and ω-glutathione conjugates. The relative ion intensity of the glutathione conjugates increased with the ω-halogen size, with I-JWH-122 having the highest intensity. Stability studies gave a low half-life and a high intrinsic hepatic clearance for JWH-122 (1305 mL/min/kg) and MAM-2201 (1408 mL/min/kg). Cl-, Br- and I-JWH-122 showed increasing half-life with increasing ω-halogen size, with intrinsic clearance values of 235-502 mL/min/kg. The recommended analytical targets for consumption of JWH-122 or ω-halogenated JWH-122 analogues are the ω-COOH metabolites for unspecific profiling and the methylnaphthyl hydroxylated metabolites to distinguish the compounds. Furthermore, ω-halogenation with larger halogens appears to increase the intrinsic hepatic stability, thereby prolonging exposure and possibly the duration of action.

Synthetic cannabinoids are substrates and inhibitors of multiple drug-metabolizing enzymes

Synthetic cannabinoids, a new class of psychoactive substances, are potent agonists of cannabinoid receptors, which mimic the psychoactive effects of the principal psychoactive component of cannabis, ∆9-tetrahydrocannabinol. Despite governmental scheduling as illicit drugs, new synthetic cannabinoids are being produced. The abuse of synthetic cannabinoids with several drugs containing different chemical groups has resulted in large numbers of poisonings. This has increased the urgency for forensic and public health laboratories to identify the metabolites of synthetic cannabinoids and apply this knowledge to the development of analytical methods and for toxicity prediction. It is necessary to determine whether synthetic cannabinoids are involved in drug-metabolizing enzyme-mediated drug-drug interactions. This review describes the metabolic pathways of 13 prevalent synthetic cannabinoids and various drug-metabolizing enzymes responsible for their metabolism, including cytochrome P450 (CYP), UDP-glucuronosyltransferases (UGTs), and carboxylesterases. The inhibitory effects of synthetic cannabinoids on CYP and UGT activities are also reviewed to predict the potential of synthetic cannabinoids for drug-drug interactions. The drug-metabolizing enzymes responsible for metabolism of synthetic cannabinoids should be characterized and the effects of synthetic cannabinoids on CYP and UGT activities should be determined to predict the pharmacokinetics of synthetic cannabinoids and synthetic cannabinoid-induced drug-drug interactions in the clinic.

In Vitro Inhibitory Effects of Synthetic Cannabinoid EAM-2201 on Cytochrome P450 and UDP-Glucuronosyltransferase Enzyme Activities in Human Liver Microsomes

EAM-2201, a synthetic cannabinoid, is a potent agonist of the cannabinoid receptors that is widely abused as an illicit recreational drug in combination with other drugs. To evaluate the potential of EAM-2201 as a perpetrator of drug–drug interactions, the inhibitory effects of EAM-2201 on major drug-metabolizing enzymes, cytochrome P450s (CYPs) and uridine 5′-diphospho-glucuronosyltransferases (UGTs) were evaluated in pooled human liver microsomes using liquid chromatography–tandem mass spectrometry (LC-MS/MS). EAM-2201 at doses up to 50 µM negligibly inhibited the activities of eight major human CYPs (1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6 and 3A4) and five UGTs (1A1, 1A4, 1A6, 1A9 and 2B7) in human liver microsomes. EAM-2201 exhibited time-dependent inhibition of CYP2C8-catalyzed amodiaquine N-deethylation, CYP2C9-catalyzed diclofenac 4′-hydroxylation, CYP2C19-catalyzed [S]-mephenytoin 4′-hydroxylation and CYP3A4-catalyzed midazolam 1′-hydroxylation with K_i values of 0.54 µM (k_inact: 0.0633 min⁻¹), 3.0 µM (k_inact: 0.0462 min⁻¹), 3.8 µM (k_inact: 0.0264 min⁻¹) and 4.1 µM (k_inact: 0.0250 min⁻¹), respectively and competitively inhibited UGT1A3-catalyzed chenodeoxycholic acid 24-acyl-glucuronidation, with a K_i value of 2.4 µM. Based on these in vitro results, we conclude that EAM-2201 has the potential to trigger in vivo pharmacokinetic drug interactions when co-administered with substrates of CYP2C8, CYP2C9, CYP2C19, CYP3A4 and UGT1A3.

Targeted and non-targeted metabolite identification of MAM-2201 in human, mouse, and rat hepatocytes

MAM-2201 is a fluorinated naphthoylindole synthetic cannabinoid with potent psychoactive properties that has been detected as an active ingredient in herbal incense blends. To gain a greater understanding of MAM-2201 metabolism and to compare its metabolic fate in humans with those in animals, the metabolism of MAM-2201 in human, mouse, and rat hepatocytes was investigated using liquid chromatography-high-resolution mass spectrometry combined with targeted and non-targeted metabolite profiling approaches. Nineteen phase I metabolites (M1-M19) reported previously in human liver microsomes and 13 novel metabolites were identified in human, mouse, and rat hepatocytes: 1 phase I metabolite (M20) and 12 phase II metabolites including 6 glucuronides (G1-G6), 1 sulfate (S1), and 5 glutathione (GSH) conjugates (GS1-GS5) of MAM-2201 metabolites. G3 was human-specific, but M20, G1, G2, and 5 GSH conjugates were rat-specific, indicating species-related differences in MAM-2201 metabolism. The findings in the present study can be useful for the experimental design and assessment of metabolism-mediated toxic risk of MAM-2201.

Inhibition of cytochrome P450 and uridine 5'-diphospho-glucuronosyltransferases by MAM-2201 in human liver microsomes

MAM-2201, a synthetic cannabinoid, is a potent agonist of the cannabinoid receptors and is increasingly used as an illicit recreational drug. The inhibitory effects of MAM-2201 on major drug-metabolizing enzymes such as cytochrome P450s (CYPs) and uridine 5'-diphospho-glucuronosyltransferases (UGTs) have not yet been investigated although it is widely abused, sometimes in combination with other drugs. We evaluated the inhibitory effects of MAM-2201 on eight major human CYPs (CYPs 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4) and six UGTs (UGTs 1A1, 1A3, 1A4, 1A6, 1A9, and 2B7) of pooled human liver microsomes; we thus explored potential MAM-2201-induced drug interactions. MAM-2201 potently inhibited CYP2C9-catalyzed diclofenac 4'-hydroxylation, CYP3A4-catalyzed midazolam 1'-hydroxylation, and UGT1A3-catalyzed chenodeoxycholic acid 24-acyl-glucuronidation, with K _i values of 5.6, 5.4 and 5.0 µM, respectively. MAM-2201 exhibited mechanism-based inhibition of CYP2C8-catalyzed amodiaquine N-de-ethylation with K _i and k _inact values of 1.0 µM and 0.0738 min^-1, respectively. In human liver microsomes, MAM-2201 (50 µM) negligibly inhibited CYP1A2, CYP2A6, CYP2B6, CYP2C19, CYP2D6, UGT1A1, UGT1A4, UGT1A6, UGT1A9, and UGT2B7. Based on these in vitro results, we conclude that MAM-2201 has the potential to trigger in vivo pharmacokinetic drug interactions when co-administered with substrates of CYP2C8, CYP2C9, CYP3A4, and UGT1A3.