Search

The emergence of new synthetic cannabinoid receptor agonists (SCRAs) onto the illicit drugs market continues to cause harm, and the overall availability of physicochemical and pharmacokinetic data for new psychoactive substances is lacking. The lipophilicity of 23 SCRAs and the plasma protein binding (PPB) of 11 SCRAs was determined. Lipophilicity was determined using a validated chromatographic hydrophobicity index (CHI) log D method; tested SCRAs showed moderate to high lipophilicity, with experimental log D7.4 ranging from 2.48 (AB-FUBINACA) to 4.95 (4F-ABUTINACA). These results were also compared to in silico predictions generated using seven commercially available software packages and online tools (Canvas; ChemDraw; Gastroplus; MoKa; PreADMET; SwissADME; and XlogP). Licenced, dedicated software packages provided more accurate lipophilicity predictions than those which were free or had prediction as a secondary function; however, the latter still provided competitive estimates in most cases. PPB of tested SCRAs, as determined by equilibrium dialysis, was in the upper range of the lipophilicity scale, ranging from 90.8% (ADB-BUTINACA) to 99.9% (BZO-HEXOXIZID). The high PPB of these drugs may contribute to reduced rate of clearance and extended durations of pharmacological effects compared to lesser-bound SCRAs. The presented data improve understanding of the behaviour of these drugs in the body. Ultimately, similar data and predictions may be used in the prediction of the structure and properties of drugs yet to emerge on the illicit market.

Following the enactment of a generic ban in China in 2021, the synthetic cannabinoid market has been evolving, now encompassing even wider structural diversity. Compounds carrying a brominated core such as ADB-5 Br-BUTINACA (ADMB-B-5Br-INACA) and tail-less analogs, such as ADB-5 Br-INACA (ADMB-5Br-INACA), MDMB-5 Br-INACA, and ADB-INACA (ADMB-INACA), have been detected since late 2021. This study investigated the cannabinoid receptor (CB) activation potential of synthesized (S)-enantiomers of these substances, as well as of two predicted analogs MDMB-5 Br-BUTINACA (MDMB-B-5Br-INACA) and ADB-5 F-BUTINACA (ADMB-B-5F-INACA), using CB1 and CB2 beta-arrestin 2 recruitment assays and a CB1 intracellular calcium release assay. Surprisingly, the tail-less (S)-ADB-5 Br-INACA and (S)-MDMB-5 Br-INACA retained CB activity, albeit with a decreased potency compared to their tailed counterparts (S)-ADB-5 Br-BUTINACA and (S)-MDMB-5 Br-BUTINACA, respectively, which were potent and efficacious CB1 agonists. Also, at CB2, tail-less analogs showed a lower potency but increased efficacy. Removing the bromine substitution ((S)-ADB-INACA) resulted in a reduced activity at CB1; however, this effect was less prominent at CB2. Looking at tailed analogs, replacing the bromine with a fluorine substitution ((S)-ADB-5 F-BUTINACA) resulted in an increased potency and efficacy at both receptors. Furthermore, as ADB-5 Br-INACA and MDMB-5 Br-INACA have been frequently detected together in Scottish prisons, this study also evaluated the CB1 receptor activation potential of different mixtures of their respective reference standards, showing no unexpected cannabimimetic effect of combining both substances. Lastly, two powders seized by Belgian Customs and confirmed to contain ADB-5 Br-INACA and MDMB-5 Br-INACA, respectively, were assessed for CB activity. Based on the comparison with their reference standards, varying degrees of purity were suspected. The enactment of the Chinese generic ban (2021) has, Funding Agencies|Research Foundation Flanders (FWO) [1S54521N]; NPS-REFORM project; Strategic Research Area in Forensic Sciences (Linkoeping University); Leverhulme Trust [RC-2015-011]; Scottish Prison Service

Synthetic cannabinoid receptor agonists (SCRAs) remain a major public health concern, with their use implicated in intoxications and drug-related deaths worldwide. Increasing our systematic understanding of SCRA metabolism supports clinical and forensic toxicology casework, facilitating the timely identification of analytical targets for toxicological screening procedures and confirmatory analysis. This is particularly important as new SCRAs continue to emerge on the illicit drug market. In this work, the metabolism of ADB-HEXINACA (ADB-HINACA, N-[1-amino-3,3-dimethyl-1-oxobutan-2-yl]-1-hexyl-1H-indazole-3-carboxamide), which has increased in prevalence in the United Kingdom and other jurisdictions, was investigated using in vitro techniques. The (S)-enantiomer of ADB-HEXINACA was incubated with pooled human hepatocytes over 3 hours to identify unique and abundant metabolites using liquid chromatography-quadrupole time-of-flight mass spectrometry. In total, 16 metabolites were identified, resulting from mono-hydroxylation, di-hydroxylation, ketone formation (mono-hydroxylation then dehydrogenation), carboxylic acid formation, terminal amide hydrolysis, dihydrodiol formation, glucuronidation and combinations thereof. The majority of metabolism took place on the hexyl tail, forming ketone and mono-hydroxylated products. The major metabolite was the 5-oxo-hexyl product (M9), while the most significant mono-hydroxylation product was the 4-hydroxy-hexyl product (M8), both of which were confirmed by comparison to in-house synthesized reference standards. The 5-hydroxy-hexyl (M6) and 6-hydroxy-hexyl (M7) metabolites were not chromatographically resolved, and the 5-hydroxy-hexyl product was the second largest mono-hydroxylated metabolite. The structures of the terminal amide hydrolysis products without (M16, third largest metabolite) and with the 5-positioned ketone (M13) were also confirmed by comparison to synthesized reference standards, along with the 4-oxo-hexyl metabo, Funding Agencies|Eurostars-2 joint programme [E! 113377]; Eurostars-3 [E! 2297]; European Union [201903566]; Strategic Research Area in Forensic Sciences (Styrkeomradet forensiska vetenskaper) at Linkoeping University; Leverhulme Trust [RC-2015-01]

A new class of synthetic cannabinoids termed OXIZIDs has recently emerged on the recreational drug market. In order to continue the detection of new drugs in biological specimens, the identification of metabolites is essential. The aim of this study was to elucidate the metabolites of BZO-4en-POXIZID produced in human liver microsomes (HLMs) and human hepatocyte incubations and to compare the results with closely related analogs using the same experimental setup. Each drug was incubated for 1 h in HLM and BZO-4en-POXIZID was also incubated in human hepatocytes for up to 3 h. Subsequently, the incubates were analyzed by liquid chromatography-high-resolution mass spectrometry. BZO-4en-POXIZID metabolites were obtained in the incubation with HLMs and human hepatocytes, via the metabolic pathways of dihydrodiol formation, hydroxylation, reduction of the alkene bond and glucuronidation. The major metabolic pathway was found to be dihydrodiol formation at the pentenyl tail moiety. BZO-POXIZID, 5 F-BZO-POXIZID, BZO-HEXOXIZID and BZO-CHMOXIZID underwent similar metabolism to those reported in the literature, via the metabolic pathways of N-dealkylation, hydroxylation, ketone formation and oxidative defluorination (to alcohol or carboxylic acid). The results suggest that OXIZIDs are mainly metabolized at the N-alkyl moiety and the major metabolic pathways are hydroxylation when the N-alkyl moiety is a simple hydrocarbon, whereas functional-group-specific pathways (dihydrodiol formation and oxidative defluorination) are preferred when the moiety contains specific functional groups (alkene or fluoro), as has been observed for other synthetic cannabinoids. The major metabolites generated via these major metabolic pathways should serve as useful analytical targets for urine analysis. Furthermore, the higher abundance of glucuronidated metabolite suggests that enzymatic hydrolysis of glucuronides may be necessary for urine analysis to increase phase I metabolite concentration and, Funding Agencies|Japan Society for the Promotion of Science (KAKENHI) [21K17329]; Eurostars-2 joint programme [E! 113377]; European Union [2019-03566]; Strategic Research Area in Forensic Sciences (Styrkeomradet forensiska vetenskaper) at Linkoping University; Leverhulme Trust [RC-2015-01]

Synthetic cannabinoid receptor agonists (SCRAs) are a diverse class of new psychoactive substances (NPS) and new structural scaffolds have emerged on the recreational drug market since the enactment of Chinese SCRA analog controls in 2021. This study reports the first SCRAs to be detected with a bromide at the 5 position (5 ' Br) on the phenyl ring of the indazole core and without a tail moiety. ADB-5 ' Br-INACA (ADMB-5 ' Br-INACA) and MDMB-5 ' Br-INACA were detected in seized samples from Scottish prisons, Belgian customs, and US forensic casework. The brominated analog with a tail moiety, ADB-5 ' Br-BUTINACA (ADMB-5 ' Br-BUTINACA), was also detected in Scottish prisons and US forensic casework. The metabolites of these compounds and the predicted compound MDMB-5 ' Br-BUTINACA were identified through incubation with primary human hepatocytes to aid in their toxicological identification. The bromide on the indazole remains intact on metabolites, allowing these compounds to be easily distinguished in toxicological samples from their non-brominated analogs. Glucuronidation was more common for tail-less analogs than their butyl tail-containing counterparts. Forensic toxicologists are advised to update their analytical methods with the characteristic ions for these compounds, as well as their anticipated urinary markers: amide hydrolysis and monoOH at tert-butyl metabolites (after beta-glucuronidase treatment) for ADB-5 ' Br-INACA; monoOH at tert-butyl and amide hydrolysis metabolites for ADB-5 ' Br-BUTINACA; and ester hydrolysis metabolites with additional metabolites for MDMB-5 ' Br-INACA and MDMB-5 ' Br-BUTINACA. Toxicologists should remain vigilant to the emergence of new SCRAs with halogenation of the indazole core and tail-less analogs, which have already started to emerge. This study reports the detection of the new synthetic cannabinoids ADB-5 ' Br-INACA and MDMB-5 ' Br-INACA in Scotland, Belgium, and the US, and ADB-5 ' Br-BUTINACA in Scotland and the US. These, Funding Agencies|Fonds Wetenschappelijk Onderzoek; Leverhulme Trust [RC-2015-01]; National Institute of Justice [2020-DQ-BX-0007]; Sweden's Innovation Agency [2019-03566]; European Commission; European Union's Horizon 2020; Linkoping University; Scottish Prison Service; Office of Justice Programs; US Department of Justice; Research Foundation Flanders [1S54521N]

The emergence of new synthetic cannabinoid receptor agonists (SCRAs) onto the illicit drugs market continues to cause harm, and the overall availability of physicochemical and pharmacokinetic data for new psychoactive substances is lacking. The lipophilicity of 23 SCRAs and the plasma protein binding (PPB) of 11 SCRAs was determined. Lipophilicity was determined using a validated chromatographic hydrophobicity index (CHI) log D method; tested SCRAs showed moderate to high lipophilicity, with experimental log D-7.4 ranging from 2.48 (AB-FUBINACA) to 4.95 (4F-ABUTINACA). These results were also compared to in silico predictions generated using seven commercially available software packages and online tools (Canvas; ChemDraw; Gastroplus; MoKa; PreADMET; SwissADME; and XlogP). Licenced, dedicated software packages provided more accurate lipophilicity predictions than those which were free or had prediction as a secondary function; however, the latter still provided competitive estimates in most cases. PPB of tested SCRAs, as determined by equilibrium dialysis, was in the upper range of the lipophilicity scale, ranging from 90.8% (ADB-BUTINACA) to 99.9% (BZO-HEXOXIZID). The high PPB of these drugs may contribute to reduced rate of clearance and extended durations of pharmacological effects compared to lesser-bound SCRAs. The presented data improve understanding of the behaviour of these drugs in the body. Ultimately, similar data and predictions may be used in the prediction of the structure and properties of drugs yet to emerge on the illicit market., Funding Agencies|Engineering and Physical Sciences Research Council [EP/N509962/1]; Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Partnership; Leverhulme Trust [RC-2015-011]; Leverhulme Research Centre for Forensic Science