In Vitro and In Vivo Human Metabolism of Synthetic Cannabinoids FDU-PB-22 and FUB-PB-22

In Vitro Metabolic Fate of the Synthetic Cannabinoid Receptor Agonists 2F-QMPSB and SGT-233 Including Isozyme Mapping and Carboxylesterases Activity Testing

Quinolin-8-yl 3-(4,4-difluoropiperidine-1-sulfonyl)-4-methylbenzoate (2F-QMPSB) and 3-(4,4-difluoropiperidine-1-sulfonyl)-4-methyl-N-(2-phenylpropan-2-yl)benzamide (SGT-233) belong to a new group of synthetic cannabinoid receptor agonists containing a sulfamoyl benzoate or sulfamoyl benzamide core structure. 2F-QMPSB was identified in herbal material seized in Europe in 2018. The aims of this study were the identification of in vitro Phase I and II metabolites of 2F-QMPSB and SGT-233 to find analytical targets for toxicological screenings. Furthermore, the contribution of different monooxygenases and human carboxylesterases to Phase I metabolism was investigated. Liquid chromatography coupled to high-resolution tandem mass spectrometry was used for analysis. Ester hydrolysis was found to be an important step in the metabolism of 2F-QMPSB, which was catalyzed mainly by human carboxylesterases (hCES)1 isoforms. Additionally, nonenzymatic ester hydrolysis was observed in case of 2F-QMPSB. Notably, the carboxylic acid product derived from ester hydrolysis and metabolites thereof were only detectable in negative ionization mode. In case of SGT-233, mono- and dihydroxy metabolites were identified, as well as glucuronides. The cytochrome P450 (CYP) isozymes CYP2C8, CYP2C9, CYP2C19, CYP3A4 and CYP3A5 were found to be involved in the hydroxylation of both compounds. The results of these in vitro experiments suggest that the ester hydrolysis products of 2F-QMPSB and their glucuronides are suitable targets for toxicological screenings. In the case of SGT-233, the mono- and dihydroxy metabolites were identified as suitable screening targets. The involvement of various CYP isoforms in the metabolism of both substances reduces the likelihood of drug-drug interactions due to CYP inhibition.

Human Hepatocyte 4-Acetoxy-N,N-Diisopropyltryptamine Metabolite Profiling by Reversed-Phase Liquid Chromatography Coupled with High-Resolution Tandem Mass Spectrometry

Tryptamine intoxications and fatalities are increasing, although these novel psychoactive substances (NPS) are not controlled in most countries. There are few data on the metabolic pathways and enzymes involved in tryptamine biotransformation. 4-acetoxy-N,N-diisopropyltryptamine (4-AcO-DiPT) is a synthetic tryptamine related to 4-hydroxy-N,N-diisopropyltryptamine (4-OH-DiPT), 4-acetyloxy-N,N-dipropyltryptamine (4-AcO-DPT), and 4-acetoxy-N,N-dimethyltryptamine (4-AcO-DMT). The aim of this study was to determine the best 4-AcO-DiPT metabolites to identify 4-AcO-DiPT consumption through human hepatocyte metabolism and high-resolution mass spectrometry. 4-AcO-DiPT metabolites were predicted in silico with GLORYx freeware to assist in metabolite identification. 4-AcO-DiPT was incubated with 10-donor-pooled human hepatocytes and sample analysis was performed with reversed-phase liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS/MS) in positive- and negative-ion modes. Software-assisted LC-HRMS/MS raw data mining was performed. A total of 47 phase I and II metabolites were predicted, and six metabolites were identified after 3 h incubation following ester hydrolysis, O-glucuronidation, O-sulfation, N-oxidation, and N-dealkylation. All second-generation metabolites were derived from the only first-generation metabolite detected after ester hydrolysis (4-OH-DiPT). The metabolite with the second-most-intense signal was 4-OH-iPT-sulfate followed by 4-OH-DiPT-glucuronide, indicating that glucuronidation and sulfation are common in this tryptamine’s metabolic pathway. 4-OH-DiPT, 4-OH-iPT, and 4-OH-DiPT-N-oxide are suggested as optimal biomarkers to identify 4-AcO-DiPT consumption.

Comparison between human liver microsomes and the fungus Cunninghamella elegans for biotransformation of the synthetic cannabinoid JWH-424 having a bromo-naphthyl moiety analysed by high-resolution mass spectrometry

PURPOSE

JWH-424, (8-bromo-1-naphthyl)(1-pentyl-1H-indol-3-yl)methanone, is a synthetic cannabinoid, which is a brominated analogue of JWH-018, one of the best-known synthetic cannabinoids. Despite the structural similarity to JWH-018, little is known about JWH-424 including its metabolism. The aim of the study was to compare human liver microsomes (HLM) and the fungus Cunninghamella elegans as the metabolism catalysts for JWH-424 to better understand the characteristic actions of the fungus in the synthetic cannabinoid metabolism.

METHODS

JWH-424 was incubated with HLM for 1 h and Cunninghamella elegans for up to 72 h. The HLM incubation mixtures were diluted with methanol and fungal incubation mixtures were extracted with dichloromethane and reconstituted in methanol before analyses by liquid chromatography-high-resolution mass spectrometry (LC-HRMS).

RESULTS

HLM incubation resulted in production of ten metabolites through dihydrodiol formation, hydroxylation, and/or ipso substitution of the bromine with a hydroxy group. Fungal incubation led to production of 23 metabolites through carboxylation, dihydrodiol formation, hydroxylation, ketone formation, glucosidation and/or sulfation.

CONCLUSIONS

Generally, HLM models give good predictions of human metabolites and structural analogues are metabolised in a similar fashion. However, major hydroxy metabolites produced by HLM were those hydroxylated at naphthalene instead of pentyl moiety, the major site of hydroxylation for JWH-018. Fungal metabolites, on the other hand, had undergone hydroxylation mainly at pentyl moiety. The metabolic disagreement suggests the necessity to verify the human metabolites in authentic urine samples, while H9 and H10 (hydroxynaphthalene), H8 (ipso substitution), F22 (hydroxypentyl), and F17 (dihydroxypentyl) are recommended for monitoring of JWH-424 in urinalysis.

Simultaneous screening of 239 synthetic cannabinoids and metabolites in blood and urine samples using liquid chromatography-high resolution mass spectrometry

Synthetic cannabinoids (SCs) are new psychoactive substances that function as endocannabinoid CB1 and CB2 receptor agonists. Abuse of SCs can lead to symptoms such as confusion, dizziness, and even death. At present, Synthetic cannabinoids constitute one of the largest groups of new psychoactive substances and become popular recreational drugs of abuse for their psychoactive properties. The continuous transformation of SCs also leads to an endless emergence of new types. An efficient, high-throughput screening method is therefore very important for their identification. This paper describes a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method for simultaneously screening 179 SCs and 80 SC metabolites in blood and urine. Simple acetonitrile was used to precipitate the blood and urine proteins, and the supernatants obtained after centrifugation were analyzed. The LC-HRMS run time was 20 min. The mass spectrometer used an ESI source with a scanning range of m/z 100-1000. LC-HRMS provided accurate mass, retention time, and fragment ions for qualitative analysis. The method validation results showed that the limits of detection (LODs) for over 80% compounds were 5 ng/mL in blood and urine samples. At low concentrations (50 ng/mL), 229 compounds (95.8%) in the blood showed recoveries of more than 50%, and 232 compounds (97.1%) had matrix effects greater than 80%. In the urine, 219 compounds (91.6%) had recoveries above 50%, and the matrix effects of 234 compounds (97.9%) were greater than 80%. This method was successfully applied to actual forensic cases.

Phase I-metabolism studies of the synthetic cannabinoids PX-1 and PX-2 using three different in vitro models

PURPOSE

Synthetic cannabinoids (SCs), highly metabolized substances, are rarely found unmodified in urine samples. Urine screening relies on SC metabolite detection, requiring metabolism knowledge. Metabolism data can be acquired via in vitro assays, e.g., human hepatocytes, pooled human liver microsomes (pHLM), cytochrome P450 isoforms and a fungal model; or in vivo by screening, e.g., authentic human samples or rat urine. This work describes the comprehensive study of PX-1 and PX-2 in vitro metabolism using three in vitro models. 5F-APP-PICA (PX-1) and 5F-APP-PINACA (PX-2) were studied as they share structural similarity with AM-2201, THJ-2201 and 5F-AB-PINACA, the metabolism of which was described in the literature.

METHODS

For SC incubation, pHLM, cytochrome P450 isoenzymes and the fungal model Cunninghamella elegans LENDNER (C. elegans) were used. PX-1 and PX-2 in vitro metabolites were revealed comprehensively by liquid chromatography-high-resolution mass spectrometry measurements.

RESULTS

In total, 30 metabolites for PX 1 and 15 for PX-2 were detected. The main metabolites for PX-1 and PX-2 were the amide hydrolyzed metabolites, along with an indole monohydroxylated (for PX-1) and a defluorinated pentyl-monohydroxylated metabolite (for PX-2).

CONCLUSIONS

CYP isoforms along with fungal incubation results were in good agreement to those obtained with pHLM incubation. CYP2E1 was responsible for many of the metabolic pathways; particularly for PX-1. This study shows that all three in vitro assays are suitable for predicting metabolic pathways of synthetic cannabinoids. To establish completeness of the PX-1 and PX-2 metabolic pathways, it is not only recommended but also necessary to use different assays.

NNL-3: A Synthetic Intermediate or a New Class of Hydroxybenzotriazole Esters with Cannabinoid Receptor Activity?

Synthetic cannabinoid receptor agonists (SCRAs) remain a prolific class of new psychoactive substances (NPS) and continue to expand rapidly. Despite the recent identification of hydroxybenzotriazole (HOBt) containing SCRAs in synthetic cannabis samples, there is currently no information regarding the pharmacological profile of these NPS with respect to human CB₁ and CB₂ receptors. In the current study, a series consisting of seven HOBt indole-, indazole-, and 7-azaindole-carboxylates bearing a range of N-alkyl substituents were synthesized and pharmacologically evaluated. Competitive binding assays at CB₁ and CB₂ demonstrated that all analogues except a 2-methyl-substituted derivative had low affinity for CB₁ (K_i = 3.80-43.7 μM) and CB₂ (K_i = 2.75-18.2 μM). A fluorometric functional assay revealed that 2-methylindole- and indole-derived HOBt carboxylates were potent and efficacious agonists of CB₁ (EC₅₀ = 12.0 and 63.7 nM; E_max = 118 and 120%) and CB₂ (EC₅₀ = 10.9 and 321 nM; E_max = 91 and 126%). All other analogues incorporating indazole and 7-azaindole cores and bearing a range of N1-substituents showed relatively low potency for CB₁ and CB₂. Additionally, a reporter assay monitoring β-arrestin 2 (βarr2) recruitment to the receptor revealed that the 2-methylindole example was the most potent and efficacious at CB₁ (EC₅₀ = 131 nM; E_max = 724%) and the most potent at CB₂ (EC₅₀ = 38.2 nM; E_max = 51%). As with the membrane potential assay, the indazole and other indole HOBt carboxylates were considerably less potent at both receptors, and analogues comprising a 7-azaindole core showed little activity. Taken together, these data suggest that NNL-3 demonstrates little CB1 receptor activity and is unlikely to be psychoactive in humans. NNL-3 is likely an unintended SCRA manufacturing byproduct. However, the synthesis of NNL-3 analogues proved simple and general, and some of these showed potent cannabimetic profiles in vitro, indicating that HOBt esters of this type may represent an emerging class of SCRA NPS.

In Vitro Metabolic Fate of the Synthetic Cannabinoid Receptor Agonists QMPSB and QMPCB (SGT-11) Including Isozyme Mapping and Esterase Activity

Quinolin-8-yl 4-methyl-3-(piperidine-1-sulfonyl)benzoate (QMPSB) and quinolin-8-yl 4-methyl-3-(piperidine-1-carbonyl)benzoate (QMPCB, SGT-11) are synthetic cannabinoid receptor agonists (SCRAs). Knowing their metabolic fate is crucial for the identification of toxicological screening targets and to predict possible drug interactions. The presented study aimed to identify the in vitro phase I/II metabolites of QMPSB and QMPCB and to study the contribution of different monooxygenases and human carboxylesterases by using pooled human liver S9 fraction (pHLS9), recombinant human monooxygenases, three recombinant human carboxylesterases, and pooled human liver microsomes. Analyses were carried out by liquid chromatography high-resolution tandem mass spectrometry. QMPSB and QMPCB showed ester hydrolysis, and hydroxy and carboxylic acid products were detected in both cases. Mono/dihydroxy metabolites were formed, as were corresponding glucuronides and sulfates. Most of the metabolites could be detected in positive ionization mode with the exception of some QMPSB metabolites, which could only be found in negative mode. Monooxygenase activity screening revealed that CYP2B6/CYP2C8/CYP2C9/CYP2C19/CYP3A4/CYP3A5 were involved in hydroxylations. Esterase screening showed the involvement of all investigated isoforms. Additionally, extensive non-enzymatic ester hydrolysis was observed. Considering the results of the in vitro experiments, inclusion of the ester hydrolysis products and their glucuronides and monohydroxy metabolites into toxicological screening procedures is recommended.

A Systematic Study of the In Vitro Pharmacokinetics and Estimated Human In Vivo Clearance of Indole and Indazole-3-Carboxamide Synthetic Cannabinoid Receptor Agonists Detected on the Illicit Drug Market

In vitro pharmacokinetic studies were conducted on enantiomer pairs of twelve valinate or tert-leucinate indole and indazole-3-carboxamide synthetic cannabinoid receptor agonists (SCRAs) detected on the illicit drug market to investigate their physicochemical parameters and structure-metabolism relationships (SMRs). Experimentally derived Log D_7.4 ranged from 2.81 (AB-FUBINACA) to 4.95 (MDMB-4en-PINACA) and all SCRAs tested were highly protein bound, ranging from 88.9 ± 0.49% ((R)-4F-MDMB-BINACA) to 99.5 ± 0.08% ((S)-MDMB-FUBINACA). Most tested SCRAs were cleared rapidly in vitro in pooled human liver microsomes (pHLM) and pooled cryopreserved human hepatocytes (pHHeps). Intrinsic clearance (CL_int) ranged from 13.7 ± 4.06 ((R)-AB-FUBINACA) to 2944 ± 95.9 mL min⁻¹ kg⁻¹ ((S)-AMB-FUBINACA) in pHLM, and from 110 ± 34.5 ((S)-AB-FUBINACA) to 3216 ± 607 mL min⁻¹ kg⁻¹ ((S)-AMB-FUBINACA) in pHHeps. Predicted Human in vivo hepatic clearance (CL_H) ranged from 0.34 ± 0.09 ((S)-AB-FUBINACA) to 17.79 ± 0.20 mL min⁻¹ kg⁻¹ ((S)-5F-AMB-PINACA) in pHLM and 1.39 ± 0.27 ((S)-MDMB-FUBINACA) to 18.25 ± 0.12 mL min⁻¹ kg⁻¹ ((S)-5F-AMB-PINACA) in pHHeps. Valinate and tert-leucinate indole and indazole-3-carboxamide SCRAs are often rapidly metabolised in vitro but are highly protein bound in vivo and therefore predicted in vivo CL_H is much slower than CL_int. This is likely to give rise to longer detection windows of these substances and their metabolites in urine, possibly as a result of accumulation of parent drug in lipid-rich tissues, with redistribution into the circulatory system and subsequent metabolism.

Deep Learning Based Drug Metabolites Prediction

Drug metabolism research plays a key role in the discovery and development of drugs. Based on the discovery of drug metabolites, new chemical entities can be identified and potential safety hazards caused by reactive or toxic metabolites can be minimized. Nowadays, computational methods are usually complementary tools for experiments. However, current metabolites prediction methods tend to have high false positive rates with low accuracy and are usually only used for specific enzyme systems. In order to overcome this difficulty, a method was developed in this paper by first establishing a database with broad coverage of SMARTS-coded metabolic reaction rule, and then extracting the molecular fingerprints of compounds to construct a classification model based on deep learning algorithms. The metabolic reaction rule database we built can supplement chemically reasonable negative reaction examples. Based on deep learning algorithms, the model could determine which reaction types are more likely to occur than the others. In the test set, our method can achieve the accuracy of 70% (Top-10), which is significantly higher than that of random guess and the rule-based method SyGMa. The results demonstrated that our method has a certain predictive ability and application value.

Effects of lipophilicity and functional groups of synthetic cannabinoids on their blood concentrations and urinary excretion

The influence of lipophilicity and functional groups of synthetic cannabinoids (SCs) on their blood concentrations and urinary excretion has been studied by analyzing blood and urine specimens sampled from drivers who were involved in a car crashes under the influence of SCs. A total of 58 specimens (26 urine and 31 blood specimens), sampled within 13h of the occurrence, were analyzed by liquid chromatography-tandem mass spectrometry. Fifteen SCs were detected in those specimens; the SCs detected were categorized as follows: Class 1, Naphthoyl/Benzoyl indole (EAM2201 and three other analogs); Class 2, Indole-3-carboxylate/carboxamide containing naphthol/quinol (5F-PB-22 and four other analogs); and Class 3, Indazole-3-carboxamide containing valine/tert-leucine derivative (5F-AMB and five other analogs). The calculated lipophilicity index log P, the octanol/water participation coefficient, of those SCs in Classes 1, 2, and 3 ranged between 5.01-8.14, 5.80-6.74 and 2.29-3.81, respectively. Class 3 SCs were detectable in 12 out of 13 urine specimens, but those in Classes 1 and 2 were not detected in urine. Our analytical results indicated that the boundary line for their detectability in urine lies between log P 4 and 5. The blood concentrations of Class 3 SCs varied widely (0.0036-31ng/ml) depending on their log P, while much smaller variation was observed among those in Class 2 (0.10-5.0ng/ml).

DARK Classics in Chemical Neuroscience: Synthetic Cannabinoids (Spice/K2)

This Review covers the background, pharmacology, adverse effects, synthesis, pharmacokinetics, metabolism, and history of synthetic cannabinoid compounds. Synthetic cannabinoids are a class of novel psychoactive substances that act as agonists at cannabinoid receptors. This class of compounds is structurally diverse and rapidly changing, with multiple generations of molecules having been developed in the past decade. The structural diversity of synthetic cannabinoids is supported by the breadth of chemical space available for exploitation by clandestine chemists and incentivized by attempts to remain ahead of legal pressures. As a class, synthetic cannabinoid products have a more serious adverse effect profile than that of traditional phytocannabinoids, including notable risks of lethality, as well as a history of dangerous adulteration. Most synthetic cannabinoids are rapidly metabolized to active species with prolonged residence times and peripheral tissue distribution, and analytical confirmation of use of these compounds remains challenging. Overall, the emergence of synthetic cannabinoids serves as a noteworthy example of the pressing public health challenges associated with the increasing development of easily synthesized, structurally flexible, highly potent, psychoactive drugs.

Enzymatic analysis of glucuronidation of synthetic cannabinoid 1-naphthyl 1-(4-fluorobenzyl)-1H-indole-3-carboxylate (FDU-PB-22)

Recently, there has been a rise in abuse of synthetic cannabinoids (SCBs). The consumption of SCBs results in various effects and can induce toxic reactions, including paranoia, seizures, tachycardia and even death. 1-Naphthyl 1-(4-fluorobenzyl)-1H-indole-3-carboxylate (FDU-PB-22) is a third generation SCB whose metabolic pathway has not been fully characterized. In this study, we conducted in vitro pharmacokinetic analysis of FDU-PB-22 metabolism. Metabolic reactions containing FDU-PB-22 and human liver microsomes (HLMs) were independent of NADPH but not UDP-glucuronic acid (UDPGA), suggesting that UDP-glucuronosyltransferases (UGTs) are the primary enzymes involved in this metabolism. It was further determined that the metabolite extensively formed after incubating FDU-PB-22 with UDPGA in HLMs was the glucuronide of FDU-PB-22 3-carboxyindole (FBI-COOH). Various hepatic UGTs showed enzymatic activity for FBI-COOH. A series of UGT inhibitors showed moderate to strong inhibition of FBI-COOH-glucuronidation in HLMs, suggesting that multiple UGT isoforms are involved in FBI-COOH-glucuronidation in the liver. Interestingly, an extra-hepatic isoform, UGT1A10, exhibited the highest activity with a K_m value of 38 µM and a V_max value of 5.90 nmol/min/mg. Collectively, these results suggest that both genetic mutations of and the co-administration of inhibitors for FDU-PB-22-metabolizing UGTs will likely increase the risk of FDU-PB-22-induced toxicity.

New Synthetic Cannabinoids Metabolism and Strategies to Best Identify Optimal Marker Metabolites

Synthetic cannabinoids (SCs) were initially developed as pharmacological tools to probe the endocannabinoid system and as novel pharmacotherapies, but are now highly abused. This is a serious public health and social problem throughout the world and it is highly challenging to identify which SC was consumed by the drug abusers, a necessary step to tie adverse health effects to the new drug's toxicity. Two intrinsic properties complicate SC identification, their often rapid and extensive metabolism, and their generally high potency relative to the natural psychoactive Δ9-tetrahydrocannabinol in cannabis. Additional challenges are the lack of reference standards for the major urinary metabolites needed for forensic verification, and the sometimes differing illicit and licit status and, in some cases, identical metabolites produced by closely related SC pairs, i.e., JWH-018/AM-2201, THJ-018/THJ-2201, and BB-22/MDMB-CHMICA/ADB-CHMICA. We review current SC prevalence, establish the necessity for SC metabolism investigation and contrast the advantages and disadvantages of multiple metabolic approaches. The human hepatocyte incubation model for determining a new SC's metabolism is highly recommended after comparison to human liver microsomes incubation, in silico prediction, rat in vivo, zebrafish, and fungus Cunninghamella elegans models. We evaluate SC metabolic patterns, and devise a practical strategy to select optimal urinary marker metabolites for SCs. New SCs are incubated first with human hepatocytes and major metabolites are then identified by high-resolution mass spectrometry. Although initially difficult to obtain, authentic human urine samples following the specified SC exposure are hydrolyzed and analyzed by high-resolution mass spectrometry to verify identified major metabolites. Since some SCs produce the same major urinary metabolites, documentation of the specific SC consumed may require identification of the SC parent itself in either blood or oral fluid. An encouraging trend is the recent reduction in the number of new SC introduced per year. With global collaboration and communication, we can improve education of the public about the toxicity of new SC and our response to their introduction.

Metabolic profiling of synthetic cannabinoid 5F-ADB by human liver microsome incubations and urine samples using high-resolution mass spectrometry

5F-ADB (methyl 2-{[1-(5-fluoropentyl)-1H-indazole-3-carbonyl] amino}-3,3-dimethylbutanoate) is a frequently abused new synthetic cannabinoid that has been sold since at least the end of 2014 on the drug market and has been classified as an illicit drug in most European countries, as well as Turkey, Japan, and the United States. In this study, the in vitro metabolism of 5F-ADB was investigated by using pooled human liver microsomes (HLMs) assay and liquid chromatography-high-resolution mass spectrometry (LC-HRMS). 5F-ADB (5 μmol/L) was incubated with HLMs for up to 3 hours, and the metabolites were identified using LC-HRMS and software-assisted data mining. The in vivo metabolism was investigated by the analysis of 30 authentic urine samples and was compared to the data received from the in vitro metabolism study. Less than 3.3% of the 5F-ADB parent compound remained after 1 hour of incubation, and no parent drug was detected after 3 hours. We identified 20 metabolites formed via ester hydrolysis, N-dealkylation, oxidative defluorination, hydroxylation, dehydrogenation, further oxidation to N-pentanoic acid and glucuronidation or a combination of these reactions in vitro. In 12 urine samples (n = 30), 5F-ADB was detected as the parent drug. Three of the identified main metabolites 5F-ADB carboxylic acid (M20), monohydroxypentyl-5F-ADB (M17), and carboxypentyl ADB carboxylic acid (M8) were suggested as suitable urinary markers. The screening of 8235 authentic urine samples for identified 5F-ADB metabolites in vitro resulted in 3135 cases of confirmed 5F-ADB consumption (38%).

Investigating the ability of the microbial model Cunninghamella elegans for the metabolism of synthetic tryptamines

Tryptamines can occur naturally in plants, mushrooms, microbes, and amphibians. Synthetic tryptamines are sold as new psychoactive substances (NPS) because of their hallucinogenic effects. When it comes to NPS, metabolism studies are of crucial importance, due to the lack of pharmacological and toxicological data. Different approaches can be taken to study in vitro and in vivo metabolism of xenobiotica. The zygomycete fungus Cunninghamella elegans (C. elegans) can be used as a microbial model for the study of drug metabolism. The current study investigated the biotransformation of four naturally occurring and synthetic tryptamines [N,N-Dimethyltryptamine (DMT), 4-hydroxy-N-methyl-N-ethyltryptamine (4-HO-MET), N,N-di allyl-5-methoxy tryptamine (5-MeO-DALT) and 5-methoxy-N-methyl-N-isoporpoyltryptamine (5-MeO-MiPT)] in C. elegans after incubation for 72 hours. Metabolites were identified using liquid chromatography-high resolution-tandem mass spectrometry (LC-HR-MS/MS) with a quadrupole time-of-flight (QqTOF) instrument. Results were compared to already published data on these substances. C. elegans was capable of producing all major biotransformation steps: hydroxylation, N-oxide formation, carboxylation, deamination, and demethylation. On average 63% of phase I metabolites found in the literature could also be detected in C. elegans. Additionally, metabolites specific for C. elegans were identified. Therefore, C. elegans is a suitable complementary model to other in vitro or in vivo methods to study the metabolism of naturally occurring or synthetic tryptamines.

The ongoing challenge of novel psychoactive drugs of abuse. Part I. Synthetic cannabinoids (IUPAC Technical Report)

In the past decade, the world has experienced a large increase in the number of novel compounds appearing on the illicit drug market for recreational purposes. Such substances are designed to circumvent governmental regulations; the illegal drug manufacturers take a known psychoactive compound reported in the scientific literature and slightly modify its chemical structure in order to produce analogues that will mimic the pharmacological activity of the original substance. Many of these novel substances are sold via the Internet. Among the various chemical classes, synthetic cannabinoid receptor modulators, commonly referred to as “synthetic cannabinoids” have been at the forefront, as demonstrated by the frequency of drug seizures, numerous severe toxic effects, and fatalities associated with some of these substances. This review presents the chemical structures of relevant synthetic cannabinoids and describes their mechanism of action, pharmacological features, metabolic pathways, and structure-activity relationships. It illustrates the approaches used in forensic testing, both for bulk analysis (drug seizures) and for analytical toxicology (biological matrices) and discusses aspects of regulation surrounding this drug class. This report is intended to provide pertinent information for the purposes of informing scientific, medical, social, and governmental bodies about this ever-evolving recreational drug class and the challenges it poses worldwide.

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 metabolism of synthetic cannabinoid AM1220 by human liver microsomes and Cunninghamella elegans using liquid chromatography coupled with high resolution mass spectrometry

Purpose

Identifying intake of synthetic cannabinoids generally requires the metabolism data of the drugs so that appropriate metabolite markers can be targeted in urine testing. However, the continuous appearance of new cannabinoids during the last decade has made it difficult to keep up with all the compounds including {1-[(1-methylpiperidin-2-yl)methyl]-1H-indol-3-yl}(naphthalen-1-yl)methanone (AM1220). In this study, metabolism of AM1220 was investigated with human liver microsomes and the fungus Cunninghamella elegans.

Methods

Metabolic stability of AM1220 was analysed by liquid chromatography–tandem mass spectrometry in multiple reaction monitoring mode after 1 µM incubation in human liver microsomes for 30 min. Tentative structure elucidation of metabolites was performed on both human liver microsome and fungal incubation samples using liquid chromatography–high-resolution mass spectrometry.

Results

Half-life of AM1220 was estimated to be 3.7 min, indicating a high clearance drug. Nine metabolites were detected after incubating human liver microsomes while seven were found after incubating Cunninghamella elegans, leading to 11 metabolites in total (five metabolites were common to both systems). Demethylation, dihydrodiol formation, combination of the two, hydroxylation and dihydroxylation were the observed biotransformations.

Conclusions

Three most abundant metabolites in both human liver microsomes and Cunninghamella elegans were desmethyl, dihydrodiol and hydroxy metabolites, despite different isomers of dihydrodiol and hydroxy metabolites in each model. These abundant metabolites can potentially be useful markers in urinalysis for AM1220 intake.

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.

The Chemistry and Pharmacology of Synthetic Cannabinoid Receptor Agonist New Psychoactive Substances: Evolution

Synthetic cannabinoid receptor agonists (SCRAs) are the largest and most structurally diverse class of new psychoactive substances (NPS). Although the earliest SCRA NPS were simply repurposed from historical academic manuscripts or pharmaceutical patents describing cannabinoid ligands, recent examples bear hallmarks of rational design. SCRA NPS manufacturers have applied traditional medicinal chemistry strategies (such as molecular hybridization, bioisosteric replacement, and scaffold hopping) to existing cannabinoid templates in order to generate new molecules that circumvent structure-based legislation. Most SCRAs potently activate cannabinoid type 1 and type 2 receptors (CB₁ and CB₂, respectively), with the former contributing to the psychoactivity of these substances. SCRAs are generally more toxic than the Δ⁹-tetrahydrocannabinol (Δ⁹-THC) found in cannabis, and this may be due to ligand bias, metabolism, or off-target activity. This chapter will chart the evolution of recently identified SCRA NPS chemotypes, as well as their putative manufacturing by-products and thermolytic degradants, and describe structure-activity relationships within each class.

UPLC-HR-MS/MS-based determination study on the metabolism of four synthetic cannabinoids, ADB-FUBICA, AB-FUBICA, AB-BICA and ADB-BICA, by human liver microsomes

Since 2012, several cannabimimetic indazole and indole derivatives with valine amino acid amide residue have emerged in the illicit drug market, and have gradually replaced the old generations of synthetic cannabinoids (SCs) with naphthyl or adamantine groups. Among them, ADB-FUBICA [N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indole-3-carboxamide], AB-FUBICA [N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indole-3-carboxamide], AB-BICA [N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-benzyl-1H-indole-3-carboxamide] and ADB-BICA [N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-benzyl-1H-indole-3-carboxamide] were detected in China recently, but unfortunately no information about their in vitro human metabolism is available. Therefore, biomonitoring studies to screen their consumption lack any information about the potential biomarkers (e.g. metabolites) to target. To bridge this gap, we investigated their phase I metabolism by incubating with human liver microsomes, and the metabolites were identified by ultra-performance liquid chromatography-high resolution-tandem mass spectrometry. Metabolites generated by N-dealkylation and hydroxylation on the 1-amino-alkyl moiety were found to be predominant for all these four substances, and others which underwent hydroxylation, amide hydrolysis and dehydrogenation were also observed in our investigation. Based on our research, we recommend that the N-dealkylation and hydroxylation metabolites are suitable and appropriate analytical markers for monitoring their intake.

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

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.

Human Hepatocyte Metabolism of Novel Synthetic Cannabinoids MN-18 and Its 5-Fluoro Analog 5F-MN-18

BACKGROUND

In 2014, 2 novel synthetic cannabinoids, MN-18 and its 5-fluoro analog, 5F-MN-18, were first identified in an ongoing survey of novel psychoactive substances in Japan. In vitro pharmacological assays revealed that MN-18 and 5F-MN-18 displayed high binding affinities to human CB₁ and CB₂ receptors, with K_i being 1.65-3.86 nmol/L. MN-18 and 5F-MN-18 were scheduled in Japan and some other countries in 2014. Despite increasing prevalence, no human metabolism data are currently available, making it challenging for forensic laboratories to confirm intake of MN-18 or 5F-MN-18.

METHODS

We incubated 10 μmol/L of MN-18 and 5F-MN-18 in human hepatocytes for 3 h and analyzed the samples on a TripleTOF 5600⁺ high-resolution mass spectrometer to identify appropriate marker metabolites. Data were acquired via full scan and information-dependent acquisition-triggered product ion scans with mass defect filter.

RESULTS

In total, 13 MN-18 metabolites were detected, with the top 3 abundant metabolites being 1-pentyl-1H-indazole-3-carboxylic acid, pentyl-carbonylated MN-18, and naphthalene-hydroxylated MN-18. For 5F-MN-18, 20 metabolites were observed, with the top 3 abundant metabolites being 5'-OH-MN-18, MN-18 pentanoic acid, and 1-(5-fluoropentyl)-1H-indazole-3-carboxylic acid.

CONCLUSIONS

We have characterized MN-18 and 5F-MN-18 metabolism with human hepatocytes and high-resolution mass spectrometry, and we recommend characteristic major metabolites for clinical and forensic laboratories to identify MN-18 and 5F-MN-18 intake and link observed adverse events to these novel synthetic cannabinoids.

New psychoactive substances: Studies on the metabolism of XLR-11, AB-PINACA, FUB-PB-22, 4-methoxy-α-PVP, 25-I-NBOMe, and meclonazepam using human liver preparations in comparison to primary human hepatocytes, and human urine

New psychoactive substances (NPS) are an increasing problem in clinical and forensic toxicology. The knowledge of their metabolism is important for toxicological risk assessment and for developing toxicological urine screenings. Considering the huge numbers of NPS annually appearing on the market, metabolism studies should be realized in a fast, simple, cost efficient, and reliable way. Primary human hepatocytes (PHH) were recommended to be the gold standard for in vitro metabolism studies as they are expected to contain natural enzyme clusters, co-substrates, and drug transporters. In addition, they were already successfully used for metabolism studies of NPS. However, they also have disadvantages such as high costs and limited applicability without special equipment. The aims of the present study were therefore first to investigate exemplarily the phase I and phase II metabolism of six NPS (XLR-11, AB-PINACA, FUB-PB-22, 4-methoxy-α-PVP, 25-I-NBOMe, and meclonazepam) from different drug classes using pooled human S9 fraction (pS9) or pooled human liver microsomes combined with cytosol (pHLM/pHLC) after addition of the co-substrates for the main metabolic phase I and II reactions. Second to compare results to published data generated using primary human hepatocytes and human urine samples. Results of the incubations with pS9 or pHLM/pHLC were comparable in number and abundance of metabolites. Formation of metabolites, particularly after multi-step reactions needed a longer incubation time. However, incubations using human liver preparations resulted in a lower number of total detected metabolites compared to PHH, but they were still able to allow the identification of the main human urinary excretion products. Human liver preparations and particularly the pooled S9 fraction could be shown to be a sufficient and more cost-efficient alternative in context of metabolism studies also for developing toxicological urine screenings. It might be recommended to use the slightly cheaper pS9 fraction instead of a pHLM/pHLC combination. As formation of some metabolites needed a long incubation time, two sampling points at 60 and 360min should be recommended.

In Vitro Metabolite Profiling of ADB-FUBINACA, A New Synthetic Cannabinoid

Metabolite profiling of novel psychoactive substances (NPS) is critical for documenting drug consumption. N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1H-indazole-3-carboxamide (ADB-FUBINACA) is an emerging synthetic cannabinoid whose toxicological and metabolic data are currently unavailable. We aimed to determine optimal markers for identifying ADB-FUBINACA intake. Metabolic stability was evaluated with human liver microsome incubations. Metabolites were identified after 1 and 3 h incubation with pooled human hepatocytes, liquid chromatography- high resolution mass spectrometry in positive-ion mode (5600+ TripleTOF®, Sciex) and several data mining approaches (MetabolitePilot™, Sciex). Metabolite separation was achieved on an Ultra Biphenyl column (Restek®); full-scan TOF-MS and information-dependent acquisition MS/MS data were acquired. ADB-FUBINACA microsomal half-life was 39.7 min, with a predicted hepatic clearance of 9.0 mL/min/kg and a 0.5 extraction ratio (intermediate-clearance drug). Twenty-three metabolites were identified. Major metabolic pathways were alkyl and indazole hydroxylation, terminal amide hydrolysis, subsequent glucuronide conjugations, and dehydrogenation. We recommend ADB-FUBINACA hydroxyalkyl, hydroxydehydroalkyl and hydroxylindazole metabolites as ADB-FUBINACA intake markers. N-dealkylated metabolites are not specific ADB-FUBINACA metabolites and should not be used as definitive markers of consumption. This is the first ADB-FUBINACA in vitro metabolism study; in vivo experiments enabling pharmacokinetic and pharmacodynamics studies or urine from authentic clinical/forensic cases are needed to confirm our results.

In vitro and in vivo human metabolism of a new synthetic cannabinoid NM-2201 (CBL-2201)

In 2014, NM-2201 (CBL-2201), a novel synthetic cannabinoid (SC), was detected by Russian and United States laboratories. It was already added to the scheduled drugs list in Japan, Sweden and Germany. Unfortunately, no human metabolism data are currently available, making it challenging to confirm its intake because all previous investigated SCs were extensively metabolized. The present study aims to recommend appropriate marker metabolites by investigating NM-2201 metabolism in human hepatocytes and confirm the results in authentic human urine specimens. For the metabolic stability assay, 1 μM NM-2201 was incubated in human liver microsomes (HLMs) for up to 1 h; for metabolite profiling, 10 μM of NM-2201 was incubated in human hepatocytes for 3 h. Two authentic urine specimens from NM-2201 positive cases were analyzed after β-glucuronidase hydrolysis. Metabolite identification in hepatocyte samples and urine specimens was achieved with high-resolution mass spectrometry via information-dependent acquisition. NM-2201 was quickly metabolized in HLMs with an 8.0 min half-life. In human hepatocyte incubation samples, a total of thirteen NM-2201 metabolites were identified, generated mainly from ester hydrolysis and further hydroxylation, oxidative defluorination and subsequent glucuronidation. M13 (5-fluoro PB-22 3-carboxyindole) was the major metabolite. In the urine specimens, the parent drug NM-2201 was not detected; M13 was the predominant metabolite after β-glucuronidase hydrolysis. Therefore, based on our study, we recommend the M13 as a suitable urinary marker metabolite for confirming NM-2201 and/or 5F-PB-22 intake.

Spectroscopic studies of anthracyclines: Structural characterization and in vitro tracking

A broad spectroscopic characterization, using ultraviolet-visible (UV-vis) and Fourier transform infrared absorption as well as Raman scattering, of two commonly used anthracyclines antibiotics (DOX) daunorubicin (DNR), their epimers (EDOX, EDNR) and ten selected analogs is presented. The paper serves as a comprehensive spectral library of UV-vis, IR and Raman spectra of anthracyclines in the solid state and in solution. The particular advantage of Raman spectroscopy for the measurement and analysis of individual antibiotics is demonstrated. Raman spectroscopy can be used to monitor the in vitro uptake and distribution of the drug in cells, using both 488nm and 785nm as source wavelengths, with submicrometer spatial resolution, although the cellular accumulation of the drug is different in each case. The high information content of Raman spectra allows studies of the drug-cell interactions, and so the method seems very suitable for monitoring drug uptake and mechanisms of interaction with cellular compartments at the subcellular level.

New psychoactive substances: an overview on recent publications on their toxicodynamics and toxicokinetics

This review article covers English-written and PubMed-listed review articles and original studies published between January 2015 and April 2016 dealing with the toxicodynamics and toxicokinetics of new psychoactive substances. Compounds covered include stimulants and entactogens, synthetic cannabinoids, tryptamines, NBOMes, phencyclidine-like drugs, benzodiazepines, and opioids. First, an overview and discussion is provided on timely review articles followed by an overview and discussion on recent original studies. Both sections are then concluded by an opinion on these latest developments. This review shows that the NPS market is still highly dynamic and that the data published on their toxicodynamics and toxicokinetics can hardly keep pace with the appearance of new entities. However, data available are very helpful to understand and predict how NPS may behave in severe intoxication. The currently best-documented parameter is the in vitro metabolism of NPS, a prerequisite to allow detection of NPS in biological matrices in cases of acute intoxications or chronic consumption. However, additional data such as their chronic toxicity are still lacking.

Detection of synthetic cannabinoids using GC-EI-MS, positive GC-CI-MS, and negative GC-CI-MS

Recently, various synthetic cannabinoid (SC) compounds that have been slightly modified at the functional groups have been identified in Japan. However, the structural elucidation of these new compounds using conventional approaches such as gas chromatography-electron impact-mass spectrometry (GC-EI-MS) is difficult. As such, indole and indazole SCs were scanned using GC-MS-EI, positive GC-chemical ionization (CI)-MS, and negative GC-chemical ionization-MS, allowing for efficient structural elucidation of unknown SC compounds. Pure substances have been employed for the study.

High-resolution mass spectrometry in toxicology: current status and future perspectives

This paper reviews high-resolution mass spectrometry (HRMS) approaches using time-of-flight or Orbitrap techniques for research and application in various toxicology fields, particularly in clinical toxicology and forensic toxicology published since 2013 and referenced in PubMed. In the introduction, an overview on applications of HRMS in various toxicology fields is given with reference to current review articles. Papers concerning HRMS in metabolism, screening, and quantification of pharmaceuticals, drugs of abuse, and toxins in human body samples are critically reviewed. Finally, a discussion on advantages as well as limitations and future perspectives of these methods is included.

Metabolic profiling of new synthetic cannabinoids AMB and 5F-AMB by human hepatocyte and liver microsome incubations and high-resolution mass spectrometry

RATIONALE

AMB (methyl (1-pentyl-1H-indazole-3-carbonyl)-L-valinate)) and its fluoro analog 5F-AMB (methyl (1-(5-fluoropentyl)-1H-indazole-3-carbonyl)-L-valinate) are two new synthetic cannabinoids that are structural analogs of AB-PINACA and 5F-AB-PINACA, respectively. 5F-AMB is scheduled as an illicit drug in China, Germany, Singapore and Japan, and no metabolism data are currently available for either drug. The aim of the present work was to investigate the metabolism of AMB and 5F-AMB and propose appropriate markers to identify their intake in clinical or forensic cases.

METHODS

AMB and 5F-AMB were incubated in human hepatocytes (10 μmol/L) to generate phase I and II metabolites, which were identified with a TripleTOF 5600(+) high-resolution mass spectrometer. AMB and 5F-AMB metabolic stability studies also were performed with human liver microsomes (HLM) to evaluate metabolic clearances, and to adequately design the human hepatocyte experiment.

RESULTS

AMB and 5F-AMB were quickly metabolized in HLM with a 1.1 ± 0.1 and 1.0 ± 0.2 min T1/2, respectively. The predominant metabolic pathway for AMB and 5F-AMB in hepatocytes was ester hydrolysis, and further oxidation and/or glucuronidation. In total, 19 metabolites were identified for AMB and 17 for 5F-AMB. We describe metabolites to differentiate AMB from 5F-AMB, and metabolites that are common to both analytes due to oxidative defluorination of 5F-AMB.

CONCLUSIONS

For the first time, AMB and 5F-AMB metabolism profiles were characterized, providing valuable data for identifying these two novel psychoactive substances. The difficulties of differentiating AMB and 5F-AMB from AB-PINACA/5F-AB-PINACA metabolites also were examined. These data improve the interpretation of urinary markers after AMB and 5F-AMB intake. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

Strategies to distinguish new synthetic cannabinoid FUBIMINA (BIM-2201) intake from its isomer THJ-2201: metabolism of FUBIMINA in human hepatocytes

Since 2013, a new drugs-of-abuse trend attempts to bypass drug legislation by marketing isomers of scheduled synthetic cannabinoids (SCs), e.g., FUBIMINA (BIM-2201) and THJ-2201. It is much more challenging to confirm a specific isomer’s intake and distinguish it from its structural analog because the isomers and their major metabolites usually have identical molecular weights and display the same product ions. Here, we investigated isomers FUBIMINA and THJ-2201 and propose strategies to distinguish their consumption. THJ-2201 was scheduled in the US, Japan, and Europe; however, FUBIMINA is easily available on the Internet. We previously investigated THJ-2201 metabolism in human hepatocytes, but human FUBIMINA metabolism is unknown. We aim to characterize FUBIMINA metabolism in human hepatocytes, recommend optimal metabolites to confirm its consumption, and propose strategies to distinguish between intakes of FUBIMINA and THJ-2201. FUBIMINA (10 μM) was incubated in human hepatocytes for 3 h, and metabolites were characterized with high-resolution mass spectrometry (HR-MS). We identified 35 metabolites generated by oxidative defluorination, further carboxylation, hydroxylation, dihydrodiol formation, glucuronidation, and their combinations. We recommend 5′-OH-BIM-018 (M34), BIM-018 pentanoic acid (M33), and BIM-018 pentanoic acid dihydrodiol (M7) as FUBIMINA specific metabolites. THJ-2201 produced specific metabolite markers 5′-OH-THJ-018 (F26), THJ-018 pentanoic acid (F25), and hydroxylated THJ-2201 (F13). Optimized chromatographic conditions to achieve different retention times and careful selection of specific product ion spectra enabled differentiation of isomeric metabolites, in this case FUBIMINA from THJ-2201. Our HR-MS approach should be applicable for differentiating future isomeric SCs, which is especially important when different isomers have different legal status.