Differential cannabinoid-like effects and pharmacokinetics of ADB-BICA, ADB-BINACA, ADB-4en-PINACA and MDMB-4en-PINACA in mice: A comparative study

Despite synthetic cannabinoids' (SCs) prevalent use among humans, these substances often lack comprehensive pharmacological data, primarily due to their rapid emergence in the market. This study aimed to discern differences and causal factors among four SCs (ADB-BICA, ADB-BINACA, ADB-4en-PINACA and MDMB-4en-PINACA), with respect to locomotor activity, body temperature and nociception threshold. Adult male C57BL/6 mice received intraperitoneal injections of varying doses (0.5, 0.1 and 0.02 mg/kg) of these compounds. Three substances (including ADB-BINACA, ADB-4en-PINACA and MDMB-4en-PINACA) demonstrated dose- and time-dependent hypolocomotive and hypothermic effects. Notably, 0.1 mg/kg MDMB-4en-PINACA exhibited analgesic properties. However, ADB-BICA did not cause any effects. MDMB-4en-PINACA manifested the most potent and sustained effects, followed by ADB-4en-PINACA, ADB-BINACA and ADB-BICA. Additionally, the cannabinoid receptor 1 (CB1R) antagonist AM251 suppressed the effects induced by acute administration of the substances. Analysis of molecular binding configurations revealed that the four SCs adopted a congruent C-shaped geometry, with shared linker binding pockets conducive to robust steric interaction with CB1R. Essential residues PHE268 , PHE200 and SER173 within CB1R were identified as pivotal contributors to enhancing receptor-ligand associations. During LC-MS/MS analysis, 0.5 mg/kg MDMB-4en-PINACA exhibited the highest plasma concentration and most prolonged detection window post-administration. The study of SCs' pharmacological and pharmacokinetic profiles is crucial for better understanding the main mechanisms of cannabinoid-like effects induced by SCs, interpreting clinical findings related to SC uses and enhancing SCs risk awareness.

Indazole-derived synthetic cannabinoids: Absolute configuration determination and structure characterization by circular dichroism and DFT calculations

An increasing number of products containing synthetic cannabinoids pose a growing crisis to public health worldwide. Recently, a rising number of cases of serious adverse health effects, intoxications, and death cases associated with synthetic cannabinoids were reported. The current study represents the comprehensive structural analysis of three new synthetic cannabinoids (AB-, ADB- and AMB-FUBINACA) in solution investigated by electronic and vibrational circular dichroism together with the conventional methods of infrared and ultraviolet absorption spectroscopy, all supported by the density functional theory (DFT) calculations. The best level of theory to reproduce the experimental wavenumbers and wavelengths was found to be the B3PW91 method with a 6-311++G(d,p) basis set including the implicit solvent effect simulation. Very good agreement between the experimental and simulated spectra allowed us to determine the absolute configuration and a detailed interpretation of the IR absorption, VCD, ECD and UV spectra of AB-, ADB- and AMB-FUBINACA. In addition, the HOMO and LUMO electronic transitions were calculated.

Putative Synthetic Cannabinoids MEPIRAPIM, 5F-BEPIRAPIM (NNL-2), and Their Analogues Are T-Type Calcium Channel (CaV3) Inhibitors

Synthetic cannabinoid receptor agonists (SCRAs) are a large and growing class of new psychoactive substances (NPSs). Two recently identified compounds, MEPIRAPIM and 5F-BEPIRAPIM (NNL-2), have not been confirmed as agonists of either cannabinoid receptor subtype but share structural similarities with both SCRAs and a class of T-type calcium channel (Ca_V3) inhibitors under development as new treatments for epilepsy and pain. In this study, MEPIRAPIM and 5F-BEPIRAPIM and 10 systematic analogues were synthesized, analytically characterized, and pharmacologically evaluated using in vitro cannabinoid receptor and Ca_V3 assays. Several compounds showed micromolar affinities for CB₁ and/or CB₂, with several functioning as low potency agonists of CB₁ and CB₂ in a membrane potential assay. 5F-BEPIRAPIM and four other derivatives were identified as potential Ca_V3 inhibitors through a functional calcium flux assay (>70% inhibition), which was further confirmed using whole-cell patch-clamp electrophysiology. Additionally, MEPIRAPIM and 5F-BEPIRAPIM were evaluated in vivo using a cannabimimetic mouse model. Despite detections of MEPIRAPIM and 5F-BEPIRAPIM in the NPS market, only the highest MEPIRAPIM dose (30 mg/kg) elicited a mild hypothermic response in mice, with no hypothermia observed for 5F-BEPIRAPIM, suggesting minimal central CB₁ receptor activity.

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.

Identification and quantification of 10 indole/indazole carboxamide synthetic cannabinoids in 36 herbal blends by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy

Herbal blends containing synthetic cannabinoids have become popular alternatives to marijuana. The number of synthetic cannabinoids and speed of their emergence enable this group of compounds particularly challenging in terms of detection, monitoring, and responding. In this work, both gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR) methods were developed for the identification and quantification of synthetic cannabinoids in herbal blends. Ten types of indole/indazole carboxamide synthetic cannabinoids, which showed different types of substitutions connected to nitrogen of the indole/indazole carboxamide, were detected in 36 herbal blends. The GC-MS fragmentation routes of indole/indazole carboxamide synthetic cannabinoids were discussed in detail for structure identification purpose. The concentration range of synthetic cannabinoid in 36 herbal blends was 1.9-50.6 mg/g using GC-MS method, while 1.5-49.0 mg/g by NMR method. Nicotine in herbal blends was quantified by NMR method without using reference material, and showed a variation of 5.3-44.7 mg/g. For quantitative analysis, NMR method showed great advantage in the absence of reference material, while GC-MS method showed great merit for multiple-compound analysis when reference material was available. Therefore, for the quantitative analysis of new emerged synthetic cannabinoid in herbal blends, different methods could be chosen by considering whether reference material is available, as well as the number and types of synthetic cannabinoids detected in a single sample.

The key role of mass spectrometry in comprehensive research on new psychoactive substances

New psychoactive substances (NPS) are a wide group of compounds that try to mimic the effects produced by the 'classical' illicit drugs, including cannabis (synthetic cannabinoids), cocaine and amphetamines (synthetic cathinones) or heroin (synthetic opioids), and which health effects are still unknown for most of them. Nowadays, more than 700 compounds are being monitored by official organisms, some of which have been recently identified in seizures and/or intoxication cases. Toxicological analysis plays a pivotal role in NPS research. A comprehensive investigation on NPS, from the first identification of a novel substance until its detection in drug users to help in diagnostics and medical treatment, requires the use of a wide variety of instruments and analytical strategies. This paper illustrates the key role of mass spectrometry (MS) along a comprehensive investigation on NPS. The synthetic cannabinoid XLR-11 and the synthetic cathinone 5-PPDi have been chosen as representative substances of the most consumed NPS families. Moreover, both compounds have been investigated at our laboratory in different stages of the three-step strategy considered in this article. The initial identification and characterisation of the compound in consumption products, the first reported metabolic pathway and the development of analytical methodologies for its determination (and/or their metabolites) in different toxicological samples are described. The analytical strategies and MS instruments are briefly discussed to show the reader the possibilities that MS instrumentation offer to analytical scientists. This publication aims to be a starting point for those interested on the NPS research field from an analytical chemistry point of view.

Understanding the pharmacokinetics of synthetic cathinones: Evaluation of the blood-brain barrier permeability of 13 related compounds in rats

Synthetic cathinones are the second most commonly seized new psychoactive substance family in Europe. These compounds have been related to several intoxication cases, including fatalities. Although the pharmacological effects, metabolism, and pharmacokinetics of cathinones have been studied, there is little information about the permeability of these compounds through the blood-brain barrier (BBB). This is an important parameter to understand the behavior and potency of cathinones. In this work, 13 selected cathinones have been analyzed in telencephalon tissue from Sprague-Dawley rats intraperitoneally dosed at 3 mg/kg. Our results revealed a direct relationship between compound polarity and BBB permeability, with higher permeability for the more polar cathinones. The chemical moieties present in the cathinone had an important impact on the BBB permeability, with lengthening of the α-alkyl chain or functionalization of the aromatic ring with alkyl moieties resulting in lower concentration in telencephalon tissue. Our data suggest that transport of cathinones is a carrier-mediated process, similar to cocaine transport across the BBB.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

In Vitro Metabolic Profile Elucidation of Synthetic Cannabinoid APP-CHMINACA (PX-3)

Indazole carboxamide synthetic cannabinoids remain the most prevalent subclass of new psychoactive substances (NPS) reported internationally. However, the metabolic and pharmacological properties of many of these compounds remain unknown. Elucidating these characteristics allows members of the clinical and forensic communities to identify causative agents in patient samples, as well as render conclusions regarding their toxic effects. This work presents a detailed report on the in vitro phase I metabolism of indazole carboxamide synthetic cannabinoid APP-CHMINACA (PX-3). Incubation of APP-CHMINACA with human liver microsomes, followed by analysis of extracts via high-resolution mass spectrometry, yielded 12 metabolites, encompassing 7 different metabolite classes. Characterization of the metabolites was achieved by evaluating the product ion spectra, accurate mass and chemical formula generated for each metabolite. The predominant biotransformations observed were hydrolysis of the distal amide group and hydroxylation of the cyclohexylmethyl (CHM) substituent. Nine metabolites were amide hydrolysis products, of which five were monohydroxylated, one dihydroxylated and two were ketone products. The metabolites in greatest abundance in the study were products of amide hydrolysis with no further biotransformation (M1), followed by amide hydrolysis with monohydroxylation (M2.1). Three APP-CHMINACA-specific metabolites were generated, all of which were hydroxylated on the CHM group; one mono-, di- and tri-hydroxylated metabolite each was produced, with dihydroxylation (M6) present in the greatest abundance. The authors propose that metabolites M1, M2.1 and M6 are the most appropriate markers to determine consumption of APP-CHMINACA. The methods used in the current study have broad applicability and have been used to determine the in vitro metabolic profiles of multiple synthetic cannabinoids and other classes of NPS. This research can be used to guide analytical scientists in method development, synthesis of reference material, pharmacological testing of proposed metabolites and prediction of metabolic processes of compounds yet to be studied.

Adding more "spice" to the pot: A review of the chemistry and pharmacology of newly emerging heterocyclic synthetic cannabinoid receptor agonists

Synthetic cannabinoid receptor agonists (SCRAs) first appeared on the international recreational drug market in the early 2000s in the form of SCRA-containing herbal blends. Due to the cannabimimetic effects associated with the consumption of SCRAs, they have acquired an ill-informed reputation for being cheap, safe, and legal alternatives to illicit cannabis. Possessing high potency and affinity for the human cannabinoid receptor subtype-1 (CB₁ ) and -2 (CB₂ ), it is now understood that the recreational use of SCRAs can have severe adverse health consequences. The major public health problem arising from SCRA use has pressed legislators around the world to employ various control strategies to curb their recreational use. To circumvent legislative control measures, SCRA manufacturers have created a wide range of SCRA analogs that contain, more recently, previously unencountered azaindole, γ-carbolinone, or carbazole heterocyclic scaffolds. At present, little information is available regarding the chemical syntheses of these newly emerging classes of SCRA, from a clandestine perspective. When compared with previous generations of indole- and indazole-type SCRAs, current research suggests that many of these heterocyclic SCRA analogs maintain high affinity and efficacy at both CB₁ and CB₂ but largely evade legislative control. This review highlights the importance of continued research in the field of SCRA chemistry and pharmacology, as recreational SCRA use remains a global public health issue and represents a serious control challenge for law enforcement agencies.

The chemistry and pharmacology of synthetic cannabinoid SDB-006 and its regioisomeric fluorinated and methoxylated analogs

Synthetic cannabinoids are the largest and most structurally diverse class of new psychoactive substances, with manufacturers often using isomerism to evade detection and circumvent legal restriction. The regioisomeric methoxy- and fluorine-substituted analogs of SDB-006 (N-benzyl-1-pentyl-1H-indole-3-carboxamide) were synthesized and could not be differentiated by gas chromatography-mass spectrometry (GC-MS), but were distinguishable by liquid chromatography-quadrupole time-of-flight-MS (LC-QTOF-MS). In a fluorescence-based plate reader membrane potential assay, SDB-006 acted as a potent agonist at human cannabinoid receptors (CB1 EC50 = 19 nM). All methoxy- and fluorine-substituted analogs showed reduced potency compared to SDB-006, although the 2-fluorinated analog (EC50 = 166 nM) was comparable to known synthetic cannabinoid RCS-4 (EC50 = 146 nM). Using biotelemetry in rats, SDB-006 and RCS-4 evoked comparable reduction in body temperature (~0.7°C at a dose of 10 mg/kg), suggesting lower potency than the recent synthetic cannabinoid AB-CHMINACA (>2°C, 3 mg/kg).

Palladium-catalyzed aminocarbonylation of halo-substituted 7-azaindoles and other heteroarenes using chloroform as a carbon monoxide source

A palladium-catalyzed aminocarbonylation of halo-substituted 7-azaindoles and other heterocycles utilizing CHCl₃ as the carbonyl source has been developed for the straightforward incorporation of an amide functional group.

Quantification of synthetic cannabinoids in herbal smoking blends using NMR

Herbal smoking blends containing synthetic cannabinoids have become popular alternatives to marijuana. These products were previously sold in pre-packaged foil bags, but nowadays seizures usually contain synthetic cannabinoid powders together with unprepared plant materials. A question often raised by the Swedish police is how much smoking blend can be prepared from certain amounts of banned substance, in order to establish the severity of the crime. To address this question, information about the synthetic cannabinoid content in both the powder and the prepared herbal blends is necessary. In this work, an extraction procedure compatible with direct NMR quantification of synthetic cannabinoids in herbal smoking blends was developed. Extraction media, time and efficiency were tested for different carrier materials containing representative synthetic cannabinoids. The developed protocol utilizes a 30 min extraction step in d₄ -methanol in presence of internal standard allowing direct quantitation of the extract using NMR. The accuracy of the developed method was tested using in-house prepared herbal smoking blends. The results showed deviations less than 0.2% from the actual content, proving that the method is sufficiently accurate for these quantifications. Using this method, ten synthetic cannabinoids present in sixty-three different herbal blends seized by the Swedish police between October 2012 and April 2015 were quantified. Obtained results showed a variation in cannabinoid contents from 1.5% (w/w) for mixtures containing MDMB-CHMICA to over 5% (w/w) for mixtures containing 5F-AKB-48. This is important information for forensic experts when making theoretical calculations of production quantities in legal cases regarding "home-made" herbal smoking blends. Copyright © 2016 John Wiley & Sons, Ltd.