The next generation of synthetic cannabinoids: Detection, activity, and potential toxicity of pent-4en and but-3en analogues including MDMB-4en-PINACA

Identification of ADB-5'Br-BINACA in plant material and analytical characterization using GC-MS, LC-QTOF-MS, NMR and ATR-FTIR

Synthetic cannabinoids are a class of novel psychoactive substances that emerged in the drug market in the early 2010s. Since then, a wide range of different synthetic cannabinoids has been detected in drug materials and in biological specimens collected from intoxication cases. In general, synthetic cannabinoids are reported first in seized materials. In this study, the identification of the novel synthetic cannabinoid, ADB-5'Br-BINACA is reported. A plant material suspected to contain a synthetic cannabinoid was extracted and analyzed. Analyses were performed using gas chromatography-mass spectrometry (GC-MS), liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and one dimensional and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. An aliquot of the sample was extracted using methanol and deuterated chloroform, and analyzed via GC-MS and NMR, respectively. Further dilution of the methanolic extract was analyzed via LC-QTOF-MS. For ATR-FTIR analyses, a few drops of the extract in deuterated chloroform were analyzed. GC-MS, LC-QTOF-MS, and 1H NMRwere successfully used to elucidate and confirm the structure of ADB-5'Br-BINACA in the drug sample. ATR-FTIR and 13C NMR analyses of the extracts did not result in significant information for the confirmation of ADB-5'Br-BINACA in the plant material likely due to low amount of drug material and high background noise. The chemical characterization of ADB-5'Br-BINACA in an authentic sample is reported herein, and chromatographic, mass spectrometric and spectroscopic data are provided for use in future analysis of this drug in suspected samples.

Identification of phase-I and phase-II metabolites and the metabolic pathway of the novel synthetic cannabinoid 5F-EDMB-PICA in vitro

5F-EDMB-PICA is a newly emerged synthetic cannabinoid which has been characterized in relevant literature in recent years. Although phase-I metabolites of 5F-EDMB-PICA have been partly reported, the phase-II metabolism of this synthetic cannabinoid has not been studied yet. In this study, we established a phase-I and phase-II metabolism model in vitro by using pooled human liver microsomes, NADPH regeneration system, and UGT incubation system, with 1 mg/ml 5F-EDMB-PICA added and incubated at 37 °C for 60 min. The metabolites were analyzed by Q Exactive™ Hybrid Quadrupole-Orbitrap™ Mass Spectrometer, via which we discovered and identified 14 phase-I metabolites and 4 phase-II metabolites of 5F-EDMB-PICA, involving pathways such as ester hydrolysis, dehydrogenation, hydrolytic defluorination, hydroxylation, dihydroxylation, glucuronidation, and combinations of the pathways mentioned above. We recommend considering the monohydroxylation metabolites (M9, M10) with higher content and intact ester and 5-fluoropentyl structures as potential biomarkers of 5F-EDMB-PICA.

New trends of drug abuse in custodial settings: A systematic review on the misuse of over-the-counter drugs, prescription-only-medications, and new psychoactive substances

The article presents a systematic literature review on the use and the psychiatric implications of over-the-counter drugs (OTC), prescription-only-medications (POM), and new psychoactive substances (NPS) within custodial settings. The searches wer carried out on 2 November 2022 on PubMed, Scopus, and Web of Science in line with PRISMA guidelines. A total of 538 records were identified, of which 37 met the inclusion criteria. Findings showed the most prevalent NPS and OTC and POM classes reported in prisons were synthetic cannabinoids receptor agonists (SCRAs) and opioids, respectively. NPS markets were shown to be in constant evolution following the pace of legislations aimed to reduce their spread. The use of such substances heavily impacts the conditions and rehabilitation of persons in custody, with consequent physical and mental health risks. It is important to raise awareness of the use and misuse of such substances in prisons (i) from an early warning perspective for law enforcement and policy makers (ii) to prompt doctors to cautiously prescribe substances that may be misused (iii) to improve and increase access to treatment provided (iv) to add such substances to routine toxicological screening procedures (v) to improve harm reduction programmes.

MDMB-4en-PINACA-Related Deaths in Cook County Jail: Awareness and Preventive Measures

ABSTRACT

Since January 2023, a series of fatalities has occurred in the Cook County Jail. Upon reviewing surveillance videos, in some cases, the inmates shared paper strips, and it was followed by the onset of labored breathing and loss of consciousness. Scene investigation revealed burnt paper strips near the body in 3 cases. No trauma was observed during autopsy. The expanded toxicology panels did not detect any illegal drugs in the postmortem blood samples. However, additional analysis specifically targeting synthetic cannabinoids revealed the presence of MDMB-4en-PINACA [methyl 3,3-dimethyl-2-{[1-(pent-4-en-1-yl)-1H-indazole-3-carbonyl]amino}butanoate], a synthetic cannabinoid associated with a wide range of adverse effects, including cardiovascular complications such as tachycardia and hypertension, respiratory depression, and acute kidney injury. There is limited research on the lethality of MDMB-4en-PINACA. This case series suggests that even isolated use can potentially lead to death. This study aims to raise public awareness regarding MDMB-4en-PINACA, highlighting its unpredictable effects and potential for severe adverse reactions, and to facilitate the development of effective prevention and harm reduction strategies. Implementing screening methods in correctional facilities is crucial to prevent the circulation of potentially fatal substances.

Pharmacological evaluation of new generation OXIZID synthetic cannabinoid receptor agonists

Synthetic cannabinoid receptor agonists (SCRAs) remain one the largest classes of new psychoactive substances, and are increasingly associated with severe adverse effects and death compared to the phytocannabinoid Δ9-tetrahydrocannabinol (THC). In the attempt to circumvent the rapid emergence of novel SCRAs, several nations have implemented 'generic' legislations, or 'class-wide' bans based on common structural scaffolds. However, this has only encouraged the incorporation of new chemical entities, including distinct core and linker structures, for which there is a dearth of pharmacological data. The current study evaluated five emergent OXIZID SCRAs for affinity and functional activity at the cannabinoid CB1 receptor (CB1) in HEK 293 cells, as well as pharmacological equivalence with THC in drug discrimination in mice. All OXIZID compounds behaved as agonists in Gαi protein activation and β-arrestin 2 translocation assays, possessing low micromolar affinity at CB1. All ligands also substituted for THC in drug discrimination, where potencies broadly correlated with in vitro activity, with the methylcyclohexane analogue BZO-CHMOXIZID being the most potent. Notably, MDA-19 (BZO-HEXOXIZID) exhibited partial efficacy in vitro, generating an activity profile most similar to that of THC, and partial substitution in vivo. Overall, the examined OXIZIDs were comparatively less potent and efficacious than previous generations of SCRAs. Further toxicological data will elucidate whether the moderate cannabimimetic activity for this series of SCRAs will translate to severe adverse health effects as seen with previous generations of SCRAs.

Synthesis and Functional Evaluation of Synthetic Cannabinoid Receptor Agonists Related to ADB-HEXINACA

ADB-HEXINACA has been recently reported as a synthetic cannabinoid receptor agonist (SCRA), one of the largest classes of new psychoactive substances (NPSs). This compound marks the entry of the n-hexyl tail group into the SCRA landscape, which has continued in the market with recent, newly detected SCRAs. As such, a proactive characterization campaign was undertaken, including the synthesis, characterization, and pharmacological evaluation of ADB-HEXINACA and a library of 41 closely related analogues. Two in vitro functional assays were employed to assess activity at CB1 and CB2 cannabinoid receptors, measuring Gβγ-coupled agonism through a fluorescence-based membrane potential assay (MPA) and β-arrestin 2 (βarr2) recruitment via a live cell-based nanoluciferase complementation reporter assay. ADB-HEXINACA was a potent and efficacious CB1 agonist (CB1 MPA pEC50 = 7.87 ± 0.12 M; Emax = 124 ± 5%; βarr2 pEC50 = 8.27 ± 0.14 M; Emax = 793 ± 42.5), as were most compounds assessed. Isolation of the heterocyclic core and alkyl tails allowed for the comprehensive characterization of structure-activity relationships in this compound class, which were rationalized in silico via induced fit docking experiments. Overall, most compounds assessed are possibly emerging NPSs.

Investigating selectivity and bias for G protein subtypes and β-arrestins by synthetic cannabinoid receptor agonists at the cannabinoid CB1 receptor

The cannabinoid CB1 receptor (CB1) is a G protein-coupled receptor (GPCR) with widespread expression in the central nervous system. This canonically G⍺i/o-coupled receptor mediates the effects of Δ9-tetrahydrocannabinol (THC) and synthetic cannabinoid receptor agonists (SCRAs). Recreational use of SCRAs is associated with serious adverse health effects, making pharmacological research into these compounds a priority. Several studies have hypothesised that signalling bias may explain the different toxicological profiles between SCRAs and THC. Previous studies have focused on bias between G protein activation measured by cyclic adenosine monophosphate (cAMP) inhibition and β-arrestin translocation. In contrast, the current study characterises bias between G⍺ subtypes of the G⍺i/o family and β-arrestins; this method facilitates a more accurate assessment of ligand bias by assessing signals that have not undergone major amplification. We have characterised G protein dissociation and translocation of β-arrestin 1 and 2 using real-time BRET reporters. The responses produced by each SCRA across the G protein subtypes tested were consistent with the responses produced by the reference ligand AMB-FUBINACA. Ligand bias was probed by applying the operational analysis to determine biases within the G⍺i/o family, and between G protein subtypes and β-arrestins. Overall, these results confirm SCRAs to be balanced, high-efficacy ligands compared to the low efficacy ligand THC, with only one SCRA, 4CN-MPP-BUT7IACA, demonstrating statistically significant bias in one pathway comparison (towards β-arrestin 1 when compared with G⍺oA/oB). This suggests that the adverse effects caused by SCRAs are due to high potency and efficacy at CB1, rather than biased agonism.

Narrative Review of the Pharmacodynamics, Pharmacokinetics, and Toxicities of Illicit Synthetic Cannabinoid Receptor Agonists

BACKGROUND

Synthetic cannabinoid receptor agonists (SCRAs) are the most diverse class of new psychoactive substances worldwide, with approximately 300 unique SCRAs identified to date. While the use of this class of drug is not particularly prevalent, SCRAs are associated with several deaths every year due to their severe toxicity.

METHODS

A thorough examination of the literature identified 15 new SCRAs with a significant clinical impact between 2015 and 2021.

RESULTS

These 15 SCRAs have been implicated in 154 hospitalizations and 209 deaths across the US, Europe, Asia, and Australasia during this time period.

CONCLUSION

This narrative review provides pharmacodynamic, pharmacokinetic, and toxicologic data for SCRAs as a drug class, including an in-depth review of known pharmacological properties of 15 recently identified and emerging SCRAs for the benefit of researchers, policy makers, and clinicians who wish to be informed of developments in this field.

Evaluating signaling bias for synthetic cannabinoid receptor agonists at the cannabinoid CB2 receptor

The rapid structural evolution and emergence of novel synthetic cannabinoid receptor agonists (SCRAs) in the recreational market remains a key public health concern. Despite representing one of the largest classes of new psychoactive substances, pharmacological data on new SCRAs is limited, particularly at the cannabinoid CB2 receptor (CB2 ). Hence, the current study aimed to characterize the molecular pharmacology of a structurally diverse panel of SCRAs at CB2 , including 4-cyano MPP-BUT7AICA, 4F-MDMB-BUTINACA, AMB-FUBINACA, JWH-018, MDMB-4en-PINACA, and XLR-11. The activity of SCRAs was assessed in a battery of in vitro assays in CB2 -expressing HEK 293 cells: G protein activation (Gαi3 and GαoB ), phosphorylation of ERK1/2, and β-arrestin 1/2 translocation. The activity profiles of the ligands were further evaluated using the operational analysis to identify ligand bias. All SCRAs activated the CB2 signaling pathways in a concentration-dependent manner, although with varying potencies and efficacies. Despite the detection of numerous instances of statistically significant bias, compound activities generally appeared only subtly distinct in comparison with the reference ligand, CP55940. In contrast, the phytocannabinoid THC exhibited an activity profile distinct from the SCRAs; most notably in the translocation of β-arrestins. These findings demonstrate that CB2 is able to accommodate a structurally diverse array of SCRAs to generate canonical agonist activity. Further research is required to elucidate whether the activation of CB2 contributes to the toxicity of these compounds.

Fatal Overdose with the Cannabinoid Receptor Agonists MDMB-4en-PINACA and 4F-ABUTINACA: A Case Report and Review of the Literature

A case of a 26-year-old male who died from consuming synthetic cannabinoid receptor agonists MDMB-4en-PINACA and 4F-ABUTINACA is reported. MDMB-4en-PINACA and 4F-ABUTINACA are potent synthetic cannabinoid receptor agonists (SCRAs). This is the first detailed reporting of MDMB-4-en-PINACA and 4F-ABUTINACA associated fatality, which can help the routine forensic work. The scientific literature on the symptoms associated with these substances are evaluated, along with the pharmacological properties and possible mechanism of death. A forensic autopsy was performed according to Recommendation No. R (99)3 of the Council of Europe on medico-legal autopsies. Histological samples were stained with hematoxylin and eosin (HE). Complement component C9 immunohistochemistry was applied to all heart samples. Toxicological analyses were carried out by supercritical fluid chromatography coupled with tandem mass spectrometry (SFC-MS/MS) and headspace gas chromatography with a flame ionization detector (HS-GC-FID). The literature was reviewed to identify reported cases of MDMB-4en-PINACA and 4F-ABUTINACA use. Autopsy findings included brain edema, internal congestion, petechial bleeding, pleural ecchymoses, and blood fluidity. Toxicological analyses determined 7.2 ng/mL of MDMB-4en-PINACA and 9.1 ng/mL of 4F-ABUTINACA in the peripheral blood. MDMB-4en-PINACA and 4F-ABUTINACA are strong, potentially lethal SCRA, and their exact effects and outcome are unpredictable.

Fatal Thyroid Storm in the Setting of Untreated Graves Disease and Use of the Synthetic Cannabinoid MDMB-4en-PINACA

ABSTRACT

Thyroid storm, or thyrotoxic crisis, is a rare but well-described and potentially lethal exacerbation of thyrotoxicosis, characterized by multisystem effects due to failure of the hypothalamic-pituitary-thyroid axis. Thyroid storm is seen most frequently in the setting of inadequately treated Graves disease; however, it may also be triggered or exacerbated by infection, trauma, childbirth, radioiodine treatment, and pharmacologic agents. While there are rare reports of cases in which illicit drug use may have triggered or exacerbated thyroid storm, none specifically involving synthetic cannabinoids have been previously described. We present the case of a 25-year-old man who presented with thyroid storm in the setting of poorly controlled Graves disease and synthetic cannabinoid use.

Toxicity of Synthetic Cannabinoids in K2/Spice: A Systematic Review

(1) Background: Synthetic cannabinoids (SCs) are emerging drugs of abuse sold as 'K2', 'K9' or 'Spice'. Evidence shows that using SCs products leads to greater health risks than cannabis. They have been associated with greater toxicity and higher addiction potential unrelated to the primary psychoactive component of marijuana, Δ9-tetrahydrocannabinol (Δ9-THC). Moreover, early cases of intoxication and death related to SCs highlight the inherent danger that may accompany the use of these substances. However, there is limited knowledge of the toxicology of Spice ingredients. This systematic review intends to analyze the toxicity of SCs compounds in Spice/K2 drugs. (2) Methods: Studies analyzing synthetic cannabinoid toxicity and dependence were included in the present review. We searched the PubMed database of the US National Library of Medicine, Google Scholar, CompTox Chemicals, and Web of Science up to May 2022. (3) Results: Sixty-four articles reporting the effects of synthetic cannabinoids in humans were included in our review. Ten original papers and fifty-four case studies were also included. Fourteen studies reported death associated with synthetic cannabinoid use, with AB-CHMINACA and MDMB-CHMICA being the main reported SCs. Tachycardia and seizures were the most common toxicity symptoms. The prevalence of neuropsychiatric symptoms was higher in third-generation SCs. (4) Conclusion: SCs may exhibit higher toxicity than THC and longer-lasting effects. Their use may be harmful, especially in people with epilepsy and schizophrenia, because of the increased risk of the precipitation of psychiatric and neurologic disorders. Compared to other drugs, SCs have a higher potential to trigger a convulsive crisis, a decline in consciousness, and hemodynamic changes. Therefore, it is crucial to clarify their potential harms and increase the availability of toxicology data in both clinical and research settings.

Synthetic cannabinoid receptor agonists are monoamine oxidase-A selective inhibitors

Synthetic cannabinoid receptor agonists (SCRAs) are one of the fastest growing classes of recreational drugs. Despite their growth in use, their vast chemical diversity and rapidly changing landscape of structures make understanding their effects challenging. In particular, the side effects for SCRA use are extremely diverse, but notably include severe outcomes such as cardiac arrest. These side effects appear at odds with the main putative mode of action, as full agonists of cannabinoid receptors. We have hypothesized that SCRAs may act as MAO inhibitors, owing to their structural similarity to known monoamine oxidase inhibitors (MAOI's) as well as matching clinical outcomes (hypertensive crisis) of 'monoaminergic toxicity' for users of MAOIs and some SCRA use. We have studied the potential for SCRA-mediated inhibition of MAO-A and MAO-B via a range of SCRAs used commonly in the UK, as well as structural analogues to prove the atomistic determinants of inhibition. By combining in silico and experimental kinetic studies we demonstrate that SCRAs are MAO-A-specific inhibitors and their affinity can vary significantly between SCRAs, most notably affected by the nature of the SCRA 'head' group. Our data allow us to posit a putative mechanism of inhibition. Crucially our data demonstrate that SCRA activity is not limited to just cannabinoid receptor agonism and that alternative interactions might account for some of the diversity of the observed side effects and that these effects can be SCRA-specific.

New Psychoactive Substances Intoxications and Fatalities during the COVID-19 Epidemic

In January 2020, the World Health Organization (WHO) issued a Public Health Emergency of International Concern, declaring the COVID-19 outbreak a pandemic in March 2020. Stringent measures decreased consumption of some drugs, moving the illicit market to alternative substances, such as New Psychoactive Substances (NPS). A systematic literature search was performed, using scientific databases such as PubMed, Scopus, Web of Science and institutional and government websites, to identify reported intoxications and fatalities from NPS during the COVID-19 pandemic. The search terms were: COVID-19, SARS-CoV-2, severe acute respiratory syndrome coronavirus 2, coronavirus disease 2019, intox*, fatal*, new psychoactive substance, novel psychoactive substance, smart drugs, new psychoactive substance, novel synthetic opioid, synthetic opioid, synthetic cathinone, bath salts, legal highs, nitazene, bath salt, legal high, synthetic cannabinoid, phenethylamine, phencyclidine, piperazine, novel benzodiazepine, benzodiazepine analogue, designer benzodiazepines, tryptamine and psychostimulant. From January 2020 to March 2022, 215 NPS exposures were reported in Europe, UK, Japan and USA. Single NPS class intoxications accounted for 25, while mixed NPS class intoxications represented only 3 cases. A total of 130 NPS single class fatalities and 56 fatalities involving mixed NPS classes were published during the pandemic. Synthetic opioids were the NPS class most abused, followed by synthetic cathinones and synthetic cannabinoids. Notably, designer benzodiazepines were frequently found in combination with fentalogues. Considering the stress to communities and healthcare systems generated by the pandemic, NPS-related information may be underestimated. However, we could not define the exact impacts of COVID-19 on processing of toxicological data, autopsy and death investigations.

Photochemical Fingerprinting Is a Sensitive Probe for the Detection of Synthetic Cannabinoid Receptor Agonists; toward Robust Point-of-Care Detection

With synthetic cannabinoid receptor agonist (SCRA) use still prevalent across Europe and structurally advanced generations emerging, it is imperative that drug detection methods advance in parallel. SCRAs are a chemically diverse and evolving group, which makes rapid detection challenging. We have previously shown that fluorescence spectral fingerprinting (FSF) has the potential to provide rapid assessment of SCRA presence directly from street material with minimal processing and in saliva. Enhancing the sensitivity and discriminatory ability of this approach has high potential to accelerate the delivery of a point-of-care technology that can be used confidently by a range of stakeholders, from medical to prison staff. We demonstrate that a range of structurally distinct SCRAs are photochemically active and give rise to distinct FSFs after irradiation. To explore this in detail, we have synthesized a model series of compounds which mimic specific structural features of AM-694. Our data show that FSFs are sensitive to chemically conservative changes, with evidence that this relates to shifts in the electronic structure and cross-conjugation. Crucially, we find that the photochemical degradation rate is sensitive to individual structures and gives rise to a specific major product, the mechanism and identification of which we elucidate through density-functional theory (DFT) and time-dependent DFT. We test the potential of our hybrid "photochemical fingerprinting" approach to discriminate SCRAs by demonstrating SCRA detection from a simulated smoking apparatus in saliva. Our study shows the potential of tracking photochemical reactivity via FSFs for enhanced discrimination of SCRAs, with successful integration into a portable device.

Fatal cases involving new psychoactive substances and trends in analytical techniques

New psychoactive substances (NPS) are an emerging public health issue and deaths are commonly associated with polydrug abuse. Moreover, the number of new substances available is constantly increasing, causing intoxications in low doses, characteristics that impose to toxicology and forensic laboratories to keep routine methods up to date, with high detectability and constantly acquiring new analytical standards. Likewise, NPS metabolites and respective elimination pathways are usually unknown, making it difficult the detection and confirmation of the drug involved in the fatal case in an analytical routine. A literature search was performed on PubMed, Scopus and Web of Science databases for papers related to chromatographic analyses from fatal cases related to NPS use published from 2016 to 2021. A total of 96 papers were retrieved and reviewed in this study. Opioids, synthetic cathinones, phenethylamines/amphetamines and cannabinoids were the NPS classes most found in the fatal cases. In many cases, multiple compounds were detected in the biological samples, including prescription and other illegal drugs. Liquid chromatography-tandem mass spectrometry, an alternative to overcome the gas chromatography-mass spectrometry limitations for some compounds, was the analytical technique most used in the studies, and high resolution mass spectrometry was often applied to NPS metabolite investigation and structural characterization and identification of unknown compounds. Toxicological screening and quantitation methods need to be continuously updated to include new substances that are emerging on the drug market that can be fatal at very low doses.

Fourth Generation of Synthetic Cannabinoid Receptor Agonists: A Review on the Latest Insights

BACKGROUND

Over the past few years, an emerging number of new psychoactive substances (NPSs) entered the illicit market. NPSs are designed to resemble the effects of classical drugs of abuse, reinforcing their effects and duration. Among the most abused NPS, synthetic cannabinoids are cannabinoid receptor agonists (SCRAs) that mimic the effect of the main psychotropic phytocannabinoid Δ9-tetrahydrocannabinol (THC).

METHODS

We herein reviewed the international literature to provide available information on the newest SCRAs generation.

RESULTS

Compared to the previous SCRAs generations, the structures of the last generation result in increased affinity for and efficacy at cannabinoid CB₁ receptors, which are thought to be mainly responsible for the psychoactive effects of THC and its analogues. Accordingly, these more potent cannabimimetic effects may increase the number of adverse reactions such as neurological disorders (e.g., psychosis, agitation, irritability, paranoia, confusion, and anxiety), psychiatric episodes (e.g., hallucinations, delusions, self-harm), other physical conditions (e.g., tachycardia, hypertension, arrhythmia, chest pain, nausea, vomiting, and fever) and deaths. In the last decade, more than a hundred SCRAs from different chemical classes emerged on the illicit web market. SCRAs have been thoroughly studied: they were physico-chemically characterized, and pharmaco-toxicological characteristics were investigated. The last SCRAs generations include increasingly potent and toxic compounds, posing a potential health threat to consumers.

CONCLUSION

From November 2017 to February 2021, at least 20 new "fourth-generation" SCRAs were formally reported to international drug agencies. Our understanding of the neurotoxicity of these compounds is still limited due to the lack of global data, but their potency and their toxicity are likely higher than those of the previous generations.

Biosynthetic origins of unusual cannabimimetic phytocannabinoids in Cannabis sativa L: A review

Plants of Cannabis sativa L. (Cannabaceae) produce an array of more than 160 isoprenylated resorcinyl polyketides, commonly referred to as phytocannabinoids. These compounds represent molecules of therapeutic importance due to their modulation of the human endocannabinoid system (ECS). While understanding of the biosynthesis of the major phytocannabinoids Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD) has grown rapidly in recent years, the biosynthetic origin and genetic regulation of many potentially therapeutically relevant minor phytocannabinoids remain unknown, which limits the development of chemotypically elite varieties of C. sativa. This review provides an up-to-date inventory of unusual phytocannabinoids which exhibit cannabimimetic-like activities and proposes putative metabolic origins. Metabolic branch points exploitable for combinatorial biosynthesis and engineering of phytocannabinoids with augmented therapeutic activities are also described, as is the role of phytocannabinoid remodelling to accelerate the therapeutic portfolio expansion in C. sativa.

Metabolic profiles and screening tactics for MDMB-4en-PINACA in human urine and serum samples

MDMB-4en-PINACA (Methyl 3,3-dimethyl-2-[1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido] butanoate) is a potent agonist of the CB1 receptor. In 2021, it was one of the most common synthetic cannabinoid receptor agonists (SCRAs) seized by the Beijing Drug Control Agency. MDMB-4en-PINACA can be hard to detect in biological specimens because of ester hydrolysis. In this work, a highly sensitive liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method was developed for the detection of MDMB-4en-PINACA metabolites in urine, serum, and hair samples. Metabolites from authentic samples were compared with those from human liver microsomes (HLMs) in vitro and in zebrafish in vivo. A total of 75 metabolites, including 44 previously unreported metabolites, were identified from urine samples. We found that 11 metabolic pathways were involved in MDMB-4en-PINACA metabolism, including acetylation, a novel metabolic pathway for SCRAs. Our results revealed that ester hydrolysis and hydroxylation were to the major metabolic pathways involved in MDMB-4en-PINACA metabolism. Using serum samples, we detected 9 metabolites along with the parent drug. Only the parent drug was detected using hair samples. The existence of ADB-4en-PINACA makes the currently used biomarkers for MDMB-4enPINACA not very specific for the intake of MDMB-4en-PINACA. Therefore, based on the identified metabolites and their structural features, we propose more sensitive screening tactics for MDMB-4en-PINACA using urine and serum samples.

Defining Steric Requirements at CB1 and CB2 Cannabinoid Receptors Using Synthetic Cannabinoid Receptor Agonists 5F-AB-PINACA, 5F-ADB-PINACA, PX-1, PX-2, NNL-1, and Their Analogues

Synthetic cannabinoid receptor agonists (SCRAs) are a diverse class of new psychoactive substances (NPS). They commonly comprise N-alkylated indole, indazole, or 7-azaindole scaffolds with amide-linked pendant amino acid groups. To explore the contribution of the amino acid side chain to the cannabinoid pharmacology of SCRA NPS, a systematic library of side chain-modified SCRAs was prepared based on the recent detections of amino acid derivatives 17 (5F-AB-PINACA), 18 (5F-ADB-PINACA), 15 (PX-1), 19 (PX-2), and 20 (NNL-1). In vitro binding affinities and functional activities at cannabinoid type 1 and 2 receptors (CB₁ and CB₂, respectively) were determined for all the library members using radioligand competition experiments and a fluorescence-based membrane potential assay. Binding affinities and functional activities varied widely across compounds (K_i = 0.32 to >10 000 nM, EC₅₀ = 0.24-1259 nM), with several clear structure-activity relationships (SARs) emerging. Affinity and potency at CB₁ changed as a function of the heterocyclic core (indazole > indole > 7-azaindole) and the pendant amino acid side chain (tert-butyl > iso-propyl > iso-butyl > benzyl > ethyl > methyl > hydrogen). Ensemble docking at CB₁ revealed a clear steric basis for observed SAR trends. Interestingly, although 15 (PX-1) and 19 (PX-2) have been detected in recreational drug markets, they failed to induce centrally CB₁-mediated effects (e.g., hypothermia) in mice using radiobiotelemetry. Together, these data provide insights regarding structural contributions to the cannabimimetic profiles of 17 (5F-AB-PINACA), 18 (5F-ADB-PINACA), 15 (PX-1), 19 (PX-2), 20 (NNL-1), and other SCRA NPS.

NPS detection in Prison: a Systematic Literature Review of Use, Drug Form, and Analytical Approaches

This paper presents a systematic literature review on the detection of new psychoactive substances (NPS) in prison settings. It includes the most frequently reported NPS classes, the routes and forms used for smuggling, and the methods employed to analyze biological and non-biological samples. The search was carried out using MEDLINE (EBSCO), Scopus (ELSEVIER), PubMed (NCBI) and Web of Science (Clarivate) databases, along with reports from the grey literature in line with the PRISMA-S guidelines. A total of 2708 records were identified, of which 50 met the inclusion criteria. Findings showed the most prevalent NPS class reported in prison was synthetic cannabinoids (SCs). The most frequently reported SCs in non-biological samples were 4F-MDMB-BINACA, MDMB-4en-PINACA, and 5F-ADB. These were smuggled mainly through the postal services deposited on paper or herbal matrices. Concentrations of SCs detected on seized paper ranged between 0.05-1.17 mg/cm² . The SCs most frequently reported in biological specimens (i.e., urine, blood, saliva, and wastewater) were 5F-MDMB-PICA, 4F-MDMB-BINACA and MDMB-4en-PINACA. Concentrations of SCs reported in femoral blood and serum were 0.12-0.48 ng/ml and 34-17 ng/ml, respectively. Hyphenated techniques were predominantly employed and generally successful for the detection of NPS in biological (i.e., LC-HRMS/MS) and non-biological samples (i.e., LC-HRMS/MS and GC-MS. The on-site technique IMS showed promise for detecting SCs in various forms, however immunoassays were not recommended. Future work should focus on accurate in-field detection of SCs deposited on paper and in urine and saliva to improve real-time decision-making, as well as wastewater and air monitoring for overall drug use trends.

Structure-activity relationships for 5F-MDMB-PICA and its 5F-pentylindole analogs to induce cannabinoid-like effects in mice

Synthetic cannabinoid receptor agonists (SCRAs) are an evolving class of new psychoactive substances found on recreational drug markets worldwide. The indole-containing compound, 5F-MDMB-PICA, is a popular SCRA associated with serious medical consequences, including overdose and hospitalizations. In vitro studies reveal that 5F-MDMB-PICA is a potent agonist at cannabinoid type 1 receptors (CB₁), but little information exists regarding in vivo pharmacology of the drug. To this end, we examined the in vitro and in vivo cannabinoid-like effects produced by 5F-MDMB-PICA and related 5F-pentylindole analogs with differing composition of the head group moiety (i.e., 5F-NNEI, 5F-SDB-006, 5F-CUMYL-PICA, 5F-MMB-PICA). In mouse brain membranes, 5F-MDMB-PICA and its analogs inhibited binding to [³H]rimonabant-labeled CB₁ and displayed agonist actions in [³⁵S]GTPγS functional assays. 5F-MDMB-PICA exhibited the highest CB₁ affinity (K_i = 1.24 nM) and functional potency (EC₅₀ = 1.46 nM), but head group composition markedly influenced activity in both assays. For example, the 3,3-dimethylbutanoate (5F-MDMB-PICA) and cumyl (5F-CUMYL-PICA) head groups engendered high CB₁ affinity and potency, whereas a benzyl (5F-SDB-006) head group did not. In C57BL/6J mice, all 5F-pentylindole SCRAs produced dose- and time-dependent hypothermia, catalepsy, and analgesia that were reversed by rimonabant, indicating CB₁ involvement. In vitro K_i and EC₅₀ values were positively correlated with in vivo ED₅₀ potency estimates. Our findings demonstrate that 5F-MDMB-PICA is a potent SCRA, and subtle alterations to head group composition can have profound influence on pharmacological effects at CB₁. Importantly, measures of CB₁ binding and efficacy in mouse brain tissue seem to accurately predict in vivo drug potency in this species.

In-depth comparison of the metabolic and pharmacokinetic behaviour of the structurally related synthetic cannabinoids AMB-FUBINACA and AMB-CHMICA in rats

Synthetic cannabinoids receptor agonists (SCRAs) are often almost completely metabolised, and hence their pharmacokinetics should be carefully evaluated for determining the most adequate biomarker in toxicological analysis. Two structurally related SCRAs, AMB-FUBINACA and AMB-CHMICA, were selected to evaluate their in vivo metabolism and pharmacokinetics using male Sprague-Dawley rats. Brain, liver, kidney, blood (serum) and urine samples were collected at different times to assess the differences in metabolism, metabolic reactions, tissue distribution and excretion. Both compounds experimented O-demethyl reaction, which occurred more rapidly for AMB-FUBINACA. The parent compounds and O-demethyl metabolites were highly bioaccumulated in liver, and were still detected in this tissue 48 h after injection. The different indazole/indole N-functionalisation produced diverse metabolic reactions in this moiety and thus, different urinary metabolites were formed. Out of the two compounds, AMB-FUBINACA seemed to easily cross the blood-brain barrier, presenting higher brain/serum concentrations ratio than AMB-CHMICA.

Synthetic cannabinoids are amongst the most widely used psychoactive drugs which are tightly controlled by government agencies around the world. Here, pharmacokinetics of two synthetic cannabinoids in rats are evaluated along with their metabolites and tissue distribution, aiding in identifying distinct biomarkers that reflect the consumption of synthetic cannabinoids based on the tissue.

Cocaine esterase occurrence in global wastewater microbiomes and potential for biotransformation of novel psychoactive substances

The analysis of drugs in wastewater for forensic purposes has been constantly increasing and the investigation of the potential interaction between drugs or metabolites and sewage microbiota is important. The results demonstrated that cocaine esterase genes were widely distributed in 1142 global wastewater samples collected from 64 countries and linked to several bacterial species. In addition, in silico predictions indicated that carfentanil, 4F-MDMB-BINACA, 5F-MDMB-PICA, MDMB-4en-PINACA and mitragynine might also undergo microbial hydrolysis, in a similar fashion of cocaine degradation by cocaine esterase. In conclusion, it was demonstrated the microbial potential to hydrolyze drugs of abuse in wastewater environments, contributing to the critical evaluation of potential metabolites as biomarkers for microbial and human transformation of drugs in wastewater.

Adulteration of low-THC products with synthetic cannabinoids: Results from drug checking services

Since late 2019, low‐delta‐9‐tetrahydrocannabinol (THC) preparations adulterated with synthetic cannabinoids (SCs) have been frequently observed in Switzerland. The unawareness of users concerning the presence of SCs and the typically higher potency and toxicity of SCs, when compared with THC, can result in increased health risks. In Switzerland, low‐THC (<1%) cannabis products, except hashish, are legal. These products can act as carrier materials for SCs. In this study, cannabis samples and user self‐reports received through three drug checking services were collected and analysed, to gain deeper insight into this new phenomenon. Samples were collected from January 2020 to July 2021. Liquid chromatography coupled with high‐resolution mass spectrometry was used for the qualitative screening and semi‐quantification of SCs, while gas chromatography with flame ionization detector was applied for the quantification of THC and cannabidiol levels. Reported adverse effects were compared between users who consumed adulterated (SC‐group) and non‐adulterated (THC‐group) products. Of a total 94 samples, 50% contained up to three different SCs. MDMB‐4en‐PINACA was most often detected. All adulterated cannabis flowers contained ≤1% THC. Adulterated hashish also typically presented low THC‐levels (median: 0.8%). The SC‐group was associated with higher numbers of adverse events (p = 0.041). Furthermore, psychologic (p = 0.0007) and cardiologic (p = 0.020) adverse effects were more profound in the SC‐group than in the THC‐group. Drug checking services enabled the timely detection and monitoring of new and potentially dangerous trends. Furthermore, due to user‐reports, additional valuable information was gained on adverse events associated with the consumption of novel SCs.

A Comparison of Acute Neurocognitive and Psychotomimetic Effects of a Synthetic Cannabinoid and Natural Cannabis at Psychotropic Dose Equivalence

Due to differences in potency, efficacy, and affinity for CB1 receptors, similarities and differences in psychoactive effect profiles of natural cannabis and synthetic cannabinoids (SCs) cannot reliably be derived from equipotent dose comparisons. Instead, the current study proposes to compare the intrinsic psychoactive effects of natural cannabis (THC) and an SC, JWH-018, at psychotropic dose equivalence. Participants from two placebo-controlled studies were matched for their levels of subjective high to compare neurocognitive and psychotomimetic effects of THC and JWH-018. At equal subjective intoxication levels, both drugs impaired psychomotor, divided attention, and impulse control, with no significant difference between the two drugs. Both drugs also caused significant psychotomimetic effects, but dissociative effects were considerably more pronounced for JWH-018 than THC. We conclude that psychotropic dose equivalence provides a uniform approach for comparing the neurocognitive and psychotomimetic profiles of CB1 agonists, which can also be applied to other drug classes.

Involuntary MDMB-4en-PINACA intoxications following cannabis consumption: clinical and analytical findings

BACKGROUND AND AIMS

MDMB-4en-PINACA is a synthetic cannabinoid receptor agonist (SCRA) that has recently emerged. Data regarding clinical presentations in the event of intoxication is scarce. This study presents MDMB-4en-PINACA identification in cannabis consumers with clinical and analytical descriptions.

METHODS

Between November 2020 and March 2021, all patients with unexpected or unusually severe effects and Poisoning Severity Score (PSS) greater than or equal to 2 after cannabis consumption were included. Blood and/or urine samples were collected for toxicological analysis. When available, drug material samples were also collected for analysis.

RESULTS

Between November 2020 and March 2021, 13 patients were included. All cases typically presented with altered mental status (n = 13), and nearly all had returned to a normal or quasi-normal state after around 11 h of observation. Neurological symptoms included headaches (n = 3), hallucinations (3), mydriasis (3), amnesia (2) and seizures (5). Psychiatric symptoms were paranoia (6) and anxiety (2). Digestive symptoms were nausea (2) and vomiting (6). No deaths were recorded. All patients were positive for the SCRA MDMB-4en-PINACA in urine, blood and/or drug material sample. Results from toxicology testing paired with case history showed the potential for MDMB-4en-PINACA to cause or contribute to different clinical disorders. Conclusions: This study highlights the risk of intoxication by SCRAs when taking low-THC cannabis products. Forensic scientists, public health and public safety officials, law enforcement personnel and clinicians should be aware of the impact that these emergent SCRAs may have in their work, especially MDMB-4en-PINACA.

The metabolism of the synthetic cannabinoids ADB-BUTINACA and ADB-4en-PINACA and their detection in forensic toxicology casework and infused papers seized in prisons

Early warning systems detect new psychoactive substances (NPS), while dedicated monitoring programs and routine drug and toxicology testing identify fluctuations in prevalence. We report the increasing prevalence of the synthetic cannabinoid receptor agonist (SCRA) ADB-BUTINACA (N-[1-amino-3,3-dimethyl-1-oxobutan-2-yl]-1-butyl-1H-indazole-3-carbox-amide). ADB-BUTINACA was first detected in a seizure in Sweden in 2019, and we report its detection in 13 routine Swedish forensic toxicology cases soon after. In January 2021, ADB-BUTINACA was detected in SCRA-infused papers seized in Scottish prisons and has rapidly increased in prevalence, being detected in 60.4% of the SCRA-infused papers tested between January and July 2021. In this work, ADB-BUTINACA was incubated with human hepatocytes (HHeps), and 21 metabolites were identified in vitro, 14 being detected in authentic case samples. The parent drug and metabolites B9 (mono-hydroxylation on the n-butyl tail) and B16 (mono-hydroxylation on the indazole ring) are recommended biomarkers in blood, while metabolites B4 (dihydrodiol formation on the indazole core), B9, and B16 are suitable biomarkers in urine. ADB-4en-PINACA (N-[1-amino-3,3-dimethyl-1-oxobutan-2-yl]-1-[pent-4-en-1-yl]-1H-indazole-3-carboxamide) was detected in Scottish prisons in December 2020, but, unlike ADB-BUTINACA, prevalence has remained low. ADB-4en-PINACA was incubated with HHeps, and 11 metabolites were identified. Metabolites E3 (dihydrodiol formed in the tail moiety) and E7 (hydroxylation on the linked/head group) are the most abundant metabolites in vitro and are suggested as urinary biomarkers. The in vitro potencies of ADB-BUTINACA (EC₅₀ , 11.5 nM and ADB-4en-PINACA (EC₅₀ , 11.6 nM) are similar to that of MDMB-4en-PINACA (EC₅₀ , 4.3 nM). A third tert-leucinamide SCRA, ADB-HEXINACA was also detected in prison samples and warrants further investigation.

Metabolism of third generation synthetic cannabinoids using zebrafish larvae

Synthetic cannabinoids are the second largest group of new psychoactive substances reported by the United Nations Office on Drugs and Crime in the last decade and case reports bring attention to its high potency effects and its severe toxicity, including fatalities. Moreover, synthetic cannabinoids are usually entirely metabolized and metabolic pathways for many new generation synthetic cannabinoids are still unknown. In this study, the metabolism of five third generation synthetic cannabinoids was evaluated using zebrafish (Danio rerio) larvae as 24-h in vivo model studied within 5 days after fertilization. The studied synthetic cannabinoids were MMB-CHMICA, ADB-CHMICA, ADB-CHMINACA, MDMB-CHMCZCA, and NNL-3, and the respective metabolites were identified by liquid chromatography-high resolution tandem mass spectrometry. Eleven, six, fourteen, eleven, and four metabolites were identified for MMB-CHMICA, ADB-CHMICA, ADB-CHMINACA, MDMB-CHMCZCA, and NNL-3, respectively, and metabolic pathways have been proposed. The use of zebrafish larvae, with a high degree of physiological and genetic homology to humans, is an emerging tool very useful for the identification of metabolic pathways of psychoactive substances. Results obtained in this study compared well with metabolites obtained previously for the same target molecules or structural analogous after in vitro incubation with human or rat hepatocytes. Thus, potential biomarkers for the evaluated compounds are the O-demethylated metabolite for MMB-CHMICA; the oxidative deamination to hydroxyl metabolite for ADB-CHMICA; hydroxyl metabolites at cyclohexylmethyl, tert-butyl, and indazole moieties for ADB-CHMINACA; hydroxyl metabolites at carbazole core, tert-butyl, or cyclohexylmethyl tail moieties for MDMB-CHMCZCA; and amide hydrolyzed, defluorinated, and dihydroxilated metabolite for NNL-3.

Variable Data Independent Acquisition and Data Mining Exploring Feature-Based Molecular Networking Analysis for Untargeted Screening of Synthetic Cannabinoids in Oral Fluid

Novel psychoactive substances (NPS) are constantly emerging in the drug market, and synthetic cannabinoids (SCs) are included in this NPS family. Forensic laboratories often struggle with these continually emerging SCs, forcing them to develop an untargeted workflow to incorporate these psychoactive drugs in their procedures. Usually, forensic laboratories select analytical methods based on targeted mass spectrometry (MS) technologies for strictly tracking already known NPS. The appropriate way to tackle unknown substances is to develop pipelines for untargeted analysis that include LC-HRMS analytical methods and data analysis. Once established, this strategy would allow drug testing laboratories to be always one step ahead of the new trends concerning the "designer drugs" market. To address this challenge an untargeted workflow based on mass spectrometry data acquisition and data analysis was developed to detect SCs in oral fluid (OF) samples at a low concentration range. The samples were extracted by mixed-mode solid-phase extraction and analyzed by Liquid Chromatography - High-Resolution Mass Spectrometry (LC-HRMS). Tandem mass spectra (MS2) were recorded performing a variable isolation width across a mass range of all theoretical precursor ions (vDIA) after the chromatographic separation. After raw data processing with the MSDial software, the deconvoluted features were sent to GNPS for Feature-Based Molecular Networking (FBMN) construction for nontargeted data mining. The FBMN analysis created a unique integrated network for most of the SCs assessed in the OF at a low level (20 ng/mL). These results demonstrate the potential of an untargeted approach to detect different derivatives of SCs at trace levels for forensic applications.

Cytotoxicity, metabolism, and isozyme mapping of the synthetic cannabinoids JWH-200, A-796260, and 5F-EMB-PINACA studied by means of in vitro systems

Intake of synthetic cannabinoids (SC), one of the largest classes of new psychoactive substances, was reported to be associated with acute liver damage but information about their hepatotoxic potential is limited. The current study aimed to analyze the hepatotoxicity including the metabolism-related impact of JWH-200, A-796260, and 5F-EMB-PINACA in HepG2 cells allowing a tentative assessment of different SC subclasses. A formerly adopted high-content screening assay (HCSA) was optimized using a fully automated epifluorescence microscope. Metabolism-mediated effects in the HCSA were additionally investigated using the broad CYP inhibitor 1-aminobenzotriazole. Furthermore, phase I metabolites and isozymes involved were identified by in vitro assays and liquid chromatography–high-resolution tandem mass spectrometry. A strong cytotoxic potential was observed for the naphthoylindole SC JWH-200 and the tetramethylcyclopropanoylindole compound A-796260, whereas the indazole carboxamide SC 5F-EMB-PINACA showed moderate effects. Numerous metabolites, which can serve as analytical targets in urine screening procedures, were identified in pooled human liver microsomes. Most abundant metabolites of JWH-200 were formed by N-dealkylation, oxidative morpholine cleavage, and oxidative morpholine opening. In case of A-796260, most abundant metabolites included an oxidative morpholine cleavage, oxidative morpholine opening, hydroxylation, and dihydroxylation followed by dehydrogenation. Most abundant 5F-EMB-PINACA metabolites were generated by ester hydrolysis plus additional steps such as oxidative defluorination and hydroxylation. To conclude, the data showed that a hepatotoxicity of the investigated SC cannot be excluded, that metabolism seems to play a minor role in the observed effects, and that the extensive phase I metabolism is mediated by several isozymes making interaction unlikely.

Systematic evaluation of a panel of 30 synthetic cannabinoid receptor agonists structurally related to MMB-4en-PICA, MDMB-4en-PINACA, ADB-4en-PINACA, and MMB-4CN-BUTINACA using a combination of binding and different CB1 receptor activation assays: Part I-Synthesis, analytical characterization, and binding affinity for human CB1 receptors

Synthetic cannabinoid receptor agonists (SCRAs) are one of the largest and most structurally diverse classes of new psychoactive substances (NPS). Despite this, pharmacological data are often lacking following the identification of a new SCRA in drug markets. In this first of a three-part series, we describe the synthesis, analytical characterization, and binding affinity of a proactively generated, systematic library of 30 indole, indazole, and 7-azaindole SCRAs related to MMB-4en-PICA, MDMB-4en-PINACA, ADB-4en-PINACA, and MMB-4CN-BUTINACA featuring a 4-pentenyl (4en-P), butyl (B/BUT), or 4-cyanobutyl (4CN-B/BUT) tail and a methyl l-valinate (MMB), methyl l-tert-leucinate (MDMB), methyl l-phenylalaninate (MPP), l-valinamide (AB), l-tert-leucinamide (ADB), l-phenylalaninamide (APP), adamantyl (A), or cumyl head group. Competitive radioligand binding assays demonstrated that the indazole core conferred the highest CB₁ binding affinity (K_i  = 0.17-39 nM), followed by indole- (K_i  = 0.95-160 nM) and then 7-azaindole-derived SCRAs (K_i  = 5.4-271 nM). Variation of the head group had the greatest effect on binding, with tert-leucine amides and methyl esters (K_i  = 0.17-14 nM) generally showing the greatest affinities, followed by valine derivatives (K_i  = 0.72-180 nM), and then phenylalanine derivatives (K_i  = 2.5-271 nM). Adamantyl head groups (K_i  = 8.8-59 nM) were suboptimal for binding, whereas the cumyl analogues consistently conferred high affinity (K_i  = 0.62-36 nM). Finally, both butyl (K_i  = 3.1-163 nM) and 4-cyanobutyl (K_i  = 5.5-44 nM) tail groups were less favorable for CB₁ binding than their corresponding 4-pentenyl counterparts (K_i  = 0.72-25 nM).

New synthetic cannabinoids carrying a cyclobutyl methyl side chain: Human Phase I metabolism and data on human cannabinoid receptor 1 binding and activation of Cumyl-CBMICA and Cumyl-CBMINACA

Synthetic cannabinoids (SCs) represent a large group of new psychoactive substances (NPS), sustaining a high prevalence on the drug market since their first detection in 2008. Cumyl-CBMICA and Cumyl-CBMINACA, the first representatives of a new subclass of SCs characterized by a cyclobutyl methyl (CBM) moiety, were identified in July 2019 and February 2020. This work aimed at evaluating basic pharmacological characteristics and human Phase I metabolism of these compounds. Human Phase I metabolites were tentatively identified by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QToF-MS) of urine samples and confirmed by a pooled human liver microsome (pHLM) assay. The basic pharmacological evaluation was performed by applying a competitive ligand binding assay and a functional activation assay (GTPγS) using cell membranes carrying the human cannabinoid receptor 1 (hCB₁ ). Investigation of the human Phase I metabolism resulted in the identification of specific urinary markers built by monohydroxylation or dihydroxylation. Although Cumyl-CBMICA was primarily hydroxylated at the indole ring, hydroxylation of Cumyl-CBMINACA mainly occurred at the CBM moiety. Both substances acted as agonists at the hCB₁ receptor, although substantial differences could be observed. Cumyl-CBMINACA showed higher binding affinity (K_i  = 1.32 vs. 29.3 nM), potency (EC₅₀  = 55.4 vs. 497 nM), and efficacy (E_max  = 207% vs. 168%) than its indole counterpart Cumyl-CBMICA. This study confirms that substitution of an indole by an indazole core tends to increase in vitro potency, which is potentially reflected by higher in vivo potency. The emergence and disappearance of SCs distributed via online shops carrying a CBM moiety once more demonstrate the "cat-and-mouse" game between manufacturers and legislation.

Systematic evaluation of a panel of 30 synthetic cannabinoid receptor agonists structurally related to MMB-4en-PICA, MDMB-4en-PINACA, ADB-4en-PINACA, and MMB-4CN-BUTINACA using a combination of binding and different CB1 receptor activation assays-Part II: Structure activity relationship assessment via a β-arrestin recruitment assay

Synthetic cannabinoid receptor agonists (SCRAs) are the second largest class of new psychoactive substances (NPS) and are associated with serious adverse effects and even death. Despite this, little pharmacological data are available for many of the most recent SCRAs. This study consists of three different parts, aiming to systematically evaluate a panel of 30 SCRAs using binding and different in vitro human cannabinoid 1 receptor (CB₁ ) activation assays. The present Part II investigated the SCRA analogs for their CB₁ activation via a β-arrestin recruitment assay. The panel was systematically designed to include key structural sub-features of recent SCRAs. Thus, the 4-pentenyl tail of MMB-4en-PICA and MDMB-4en-PINACA was retained while incorporating varying head groups from other prevalent SCRAs, including amides and esters of L-valine, L-tert-leucine, and L-phenylalanine, and adamantyl and cumyl moieties. All 30 SCRAs activated CB₁ , with indazoles generally showing the greatest potency (EC₅₀  = 1.88-281 nM), followed by indoles (EC₅₀  = 11.5-2293 nM), and the corresponding 7-azaindoles (EC₅₀  = 62.4-9251 nM). Several subunit-linked structure-activity relationships were identified: (i) tert-leucine-functionalized SCRAs were more potent than the corresponding valine derivatives; (ii) no major difference in potency or efficacy was observed between tert-leucine/valine-derived amides and the corresponding methyl esters; however, phenylalanine analogs were affected by this change; and (iii) minor structural changes to the 4-pentenyl substituent had little influence on activity. These findings elucidate structural features that modulate the CB₁ activation potential of currently prevalent SCRAs and a systematic panel of analogs, some of which may appear in NPS markets in future.

Comprehensive analytical and structural characteristics of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA)

Purpose

The purpose of the study was to evaluate a complete analytical and structural characterization of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA), a novel synthetic cannabinoid being the analogue of 5F-ADB.

Methods

The compound was analyzed by gas chromatography–mass spectrometry (GC–MS), high-resolution liquid chromatography–mass spectrometry (LC–MS), X-ray diffraction and spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies. To derive MDMB-4en-PINACA molecular geometry and to assign infrared absorption bands, quantum calculations with the employment of density functional theory were also used.

Results

We present a wide range of chromatographic and spectroscopic data supported with theoretical calculations allowing to identify MDMB-4en-PINACA.

Conclusions

To our knowledge, this is the first report presenting a comprehensive analytical and structural characterization of MDMB-4en-PINACA obtained by 1D and 2D NMR, GC–MS, LC–MS(/MS), attenuated total reflection-FTIR spectroscopy, powder X-ray diffraction and quantum chemical calculations. The presented results not only broaden the knowledge about this psychoactive substance but also are useful for forensic and clinical purposes.

Synthesis and in Vitro Cannabinoid Receptor 1 Activity of Recently Detected Synthetic Cannabinoids 4F-MDMB-BICA, 5F-MPP-PICA, MMB-4en-PICA, CUMYL-CBMICA, ADB-BINACA, APP-BINACA, 4F-MDMB-BINACA, MDMB-4en-PINACA, A-CHMINACA, 5F-AB-P7AICA, 5F-MDMB-P7AICA, and 5F-AP7AICA

Synthetic cannabinoid receptor agonists (SCRAs) are an evolving class of new psychoactive substances (NPS) with structurally diverse compounds emerging each year. Due to the rapid pace at which these drugs enter the market, there is often little or nil information regarding the pharmacology of these substances despite widespread human use. In this study, 12 recently emerged SCRAs (reported between 2018 and 2020) were synthesized, analytically characterized, and pharmacologically evaluated using a live cell-based nanoluciferase complementation reporter assay that monitors in vitro cannabinoid receptor type 1 (CB1) activation via its interaction with β-arrestin 2 (βarr2). All synthesized SCRAs acted as agonists of CB1, although differences in potency (EC₅₀ = 2.33-5475 nM) and efficacy (E_max = 37-378%) were noted, and several structure-activity relationships were identified. SCRAs featuring indazole cores (EC₅₀ = 2.33-159 nM) were generally of equal or greater potency than indole analogues (EC₅₀ = 32.9-330 nM) or 7-azaindole derivatives (EC₅₀ = 64.0-5475 nM). Interestingly, with the exception of APP-BINACA (E_max = 75.7%) and 5F-A-P7AICA (E_max = 37.4%), all SCRAs showed greater efficacy than the historical SCRA JWH-018 to which responses were normalized (E_max = 142-378%). The most potent CB1 agonists in the study were ADB-BINACA (EC₅₀ = 6.36 nM), 4F-MDMB-BINACA (EC₅₀ = 7.39 nM), and MDMB-4en-PINACA (EC₅₀ = 2.33 nM). Notably, all of these SCRAs featured an indazole core as well as a "bulky" tert-butyl moiety in the pendant amino acid side chain. This study confirms that recently detected SCRAs 4F-MDMB-BICA, 5F-MPP-PICA, MMB-4en-PICA, CUMYL-CBMICA, ADB-BINACA, APP-BINACA, 4F-MDMB-BINACA, MDMB-4en-PINACA, A-CHMINACA, 5F-AB-P7AICA, 5F-MDMB-P7AICA, and 5F-AP7AICA were all able to activate the CB1 receptor in vitro, albeit to different extents, and are potentially psychoactive in vivo. These results indicate that further evaluation of these widely used NPS is warranted to better understand the risks associated with human consumption of these drugs.

Shape matters: The application of activity-based in vitro bioassays and chiral profiling to the pharmacological evaluation of synthetic cannabinoid receptor agonists in drug-infused papers seized in prisons

Synthetic cannabinoid receptor agonists (SCRAs) elicit many of their psychoactive effects via type-1 human cannabinoid (CB₁ ) receptors. Enantiomer pairs of eight tert-leucinate or valinate indole- and indazole-3-carboxamide SCRAs were synthesized and their CB₁ potency and efficacy assessed using an in vitro β-arrestin recruitment assay in a HEK239T stable cell system. A chiral high-performance liquid chromatography method with photodiode array and/or quadrupole time-of-flight-mass spectrometry detection (HPLC-PDA and HPLC-PDA-QToF-MS) was applied to 177 SCRA-infused paper samples seized in Scottish prisons between 2018 and 2020. In most samples, SCRAs were almost enantiopure (S)-enantiomer (>98% of total chromatographic peak area), although in some (n = 18), 2% to 16% of the (R)-enantiomer was detected. (S)-enantiomers are consistently more potent than (R)-enantiomers and often more efficacious. The importance of SCRA-CB₁ receptor interactions in the "head" or "linked group" moiety is demonstrated, with the conformation of the "bulky" tert-leucinate group greatly affecting potency (by up to a factor of 374), significantly greater than the difference observed between valinate SCRA enantiomers. (S)-MDMB-4en-PINACA, (S)-4F-MDMB-BINACA, and (S)-5F-MDMB-PICA are currently the most prevalent SCRAs in Scottish prisons, and all have similar high potency (EC₅₀ , 1-5 nM) and efficacy. Infused paper samples were compared using estimated intrinsic efficacy at the CB₁ receptor (EIE_CB1 ) to evaluate samples with variable SCRA content. Given their similar potency and efficacy, any variation in CB₁ receptor-mediated psychoactive effects are likely to derive from variation in dose, mode of use, pharmacokinetic differences, and individual factors affecting the user, rather than differences in the specific SCRA present.

Identifying New/Emerging Psychoactive Substances at the Time of COVID-19; A Web-Based Approach

COVID-19-related disruptions of people and goods' circulation can affect drug markets, especially for new psychoactive substances (NPSs). Drug shortages could cause a change in available NPS, with the introduction of new, unknown, substances. The aims of the current research were to use a web crawler, NPSfinder®, to identify and categorize emerging NPS discussed on a range of drug enthusiasts/psychonauts' websites/fora at the time of the pandemic; social media for these identified NPS were screened as well. The NPSfinder® was used here to automatically scan 24/7 a list of psychonaut websites and NPS online resources. The NPSs identified in the time frame between January and August 2020 were searched in both the European Monitoring Center for Drugs and Drug Addictions (EMCDDA)/United Nations Office on Drugs and Crime (UNODC) databases and on social media (Facebook, Twitter, Instagram, Pinterest, and YouTube) as well, with a content qualitative analysis having been carried out on reddit.com. Of a total of 229 NPSs being discussed at the time of the pandemic, some 18 NPSs were identified for the first time by the NPSfinder®. These included six cathinones, six opioids, two synthetic cannabinoid receptor agonists (SCRAs), two phenylcyclohexylpiperidine (PCP)-like molecules, and two psychedelics. Of these NPSs, 10 were found to be previously unreported to either the UNODC or the EMCDDA. Of these 18 NPSs, opioids and cathinones were the most discussed on social media/reddit, with the highest number of threads associated. Current findings may support the use of both automated web crawlers and social listening approaches to identify emerging NPSs; the pandemic-related imposed restrictions may somehow influence the demand for specific NPS classes.