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Acetylbenzylfentanyl, benzoylbenzylfentanyl, 3‐fluoro‐methoxyacetylfentanyl, and 3‐phenylpropanoylfentanyl are fentanyl analogs that have been reported to the European Monitoring Centre for Drugs and Drug Addiction in recent years. The aim of this study was to identify metabolic pathways and potential biomarker metabolites of these fentanyl analogs. The compounds were incubated (5 μM) with cryopreserved hepatocytes for up to 5 h in vitro. Metabolites were analyzed with liquid chromatography–quadrupole time of flight–high‐resolution mass spectrometry (LC‐QTOF‐HRMS). The experiments showed that acetylbenzylfentanyl, benzoylbenzylfentanyl, and 3‐phenylpropanoylfentanyl were mainly metabolized through N‐dealkylation (forming nor‐metabolites) and 3‐fluoro‐methoxyacetylfentanyl mainly through demethylation. Other observed metabolites were formed by mono‐/dihydroxylation, dihydrodiol formation, demethylation, dehydrogenation, amide hydrolysis, and/or glucuronidation. The experiments showed that a large number of metabolites of 3‐phenylpropanoylfentanyl were formed. The exact position of hydroxy groups in formed monohydroxy metabolites could not be established solely based upon recorded MSMS spectra of hepatocyte samples. Therefore, potential monohydroxy metabolites of 3‐phenylpropanoylfentanyl, with the hydroxy group in different positions, were synthesized and analyzed together with the hepatocyte samples. This approach could reveal that the β position of the phenylpropanoyl moiety was highly favored; β‐OH‐phenylpropanoylfentanyl was the most abundant metabolite after the nor‐metabolite. Both metabolites have the potential to serve as biomarkers for 3‐phenylpropanoylfentanyl. The nor‐metabolites of acetylbenzylfentanyl, benzoylbenzylfentanyl, and 3‐fluoro‐methoxyacetylfentanyl do also seem to be suitable biomarker metabolites, as do the demethylated metabolite of 3‐fluoro‐methoxyacetylfentanyl. Identified metabolic pathways and formed metabolites were in agreement with findings in previous studies of similar fentanyl analogs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: About one third of all patients with epilepsy have pharmacoresistant seizures. Thus there is a need for better pharmacological treatments. The human voltage‐gated potassium (hKV) channel hKV7.2/7.3 is a validated antiseizure target for compounds that activate this channel. In a previous study we have shown that resin acid derivatives can activate the hKV7.2/7.3 channel. In this study we investigated if these channel activators have the potential to be developed into a new type of antiseizure drug. Thus we examined their structure‐activity relationships and the site of action on the hKV7.2/7.3 channel, if they have unwanted cardiac and cardiovascular effects, and their potential antiseizure effect. Methods: Ion channels were expressed in Xenopus oocytes or mammalian cell lines and explored with two‐electrode voltage‐clamp or automated patch‐clamp techniques. Unwanted vascular side effects were investigated with isometric tension recordings. Antiseizure activity was studied in an electrophysiological zebrafish‐larvae model. Results: Fourteen resin acid derivatives were tested on hKV7.2/7.3. The most efficient channel activators were halogenated and had a permanently negatively charged sulfonyl group. The compounds did not bind to the sites of other hKV7.2/7.3 channel activators, retigabine, or ICA‐069673. Instead, they interacted with the most extracellular gating charge of the S4 voltage‐sensing helix, and the effects are consistent with an electrostatic mechanism. The compounds altered the voltage dependence of hKV7.4, but in contrast to retigabine, there were no effects on the maximum conductance. Consistent with these data, the compounds had less smooth muscle–relaxing effect than retigabine. The compounds had almost no effect on the voltage dependence of hKV11.1, hNaV1.5, or hCaV1.2, or on the amplitude of hKV11.1. Finally, several resin acid derivatives had clear antiseizure effects in a zebrafish‐larvae model. Significance: The described resin acid derivatives hold promise for new antiseizure medications, with reduced risk for adverse effects compared with retigabine. [ABSTRACT FROM AUTHOR]

MMB022 (methyl 3‐methyl‐2‐[1‐(pent‐4‐en‐1‐yl)‐1H‐indole‐3‐carboxamido]butanoate) is a new synthetic cannabinoid with an alkene at the pentenyl side chain, a rare functional group for synthetic cannabinoids. Metabolite identification is an important step for the detection of synthetic cannabinoids in humans, since they are generally extensively metabolized. The aims of the study were to tentatively identify in vitro phase I metabolites, to confirm major metabolites using synthesized metabolites, to examine metabolic pathways thoroughly, to study metabolic stability and to suggest metabolites appropriate for urine screening. MMB022 and its synthesized metabolites were incubated with human liver microsomes (HLM) and the supernatants were analyzed by liquid chromatography‐quadrupole time‐of‐flight mass spectrometry. Sixteen metabolites were identified, which were generated via dehydrogenation, dihydrodiol formation, ester hydrolysis, hydroxylation, and combinations thereof. A major biotransformation of the alkene at the pentenyl side chain was confirmed to be dihydrodiol formation. The major metabolites were ester hydrolysis (M15) and dihydrodiol (M8) metabolites, whereas the metabolite derived from the combination of ester hydrolysis and dihydrodiol (M5) was the fourth most abundant metabolite. The metabolic pathways were investigated using synthesized metabolites and revealed that M5 is an end product of the pathways, indicating that it might become a more abundant metabolite in vivo depending on the rate of metabolism in humans. The major pathway of MMB022 to M5 was determined to be via M8 formation. Intrinsic clearance of MMB022 was determined to be 296 mL/min/kg and t1/2 was 2.1 min, indicating a low metabolic stability. M15, M8, and potentially M5 are suggested as suitable urinary targets. [ABSTRACT FROM AUTHOR]

We revisited the Congo red analogue 2,5‐bis(4′‐hydroxy‐3′‐carboxy‐styryl)benzene (X‐34) to develop this highly fluorescent amyloid dye for imaging Alzheimer's disease (AD) pathology comprising Aβ and Tau fibrils. A selection of ligands with distinct optical properties were synthesized by replacing the central benzene unit of X‐34, with other heterocyclic moieties. Full photophysical characterization was performed, including recording absorbance and fluorescence spectra, Stokes shift, quantum yield and fluorescence lifetimes. All ligands displayed high affinity towards recombinant amyloid fibrils of Aβ1‐42 (13–300 nm Kd) and Tau (16–200 nm Kd) as well as selectivity towards the corresponding disease‐associated protein aggregates in AD tissue. We observed that these ligands efficiently displaced X‐34, but not Pittsburgh compound B (PiB) from recombinant Aβ1‐42 amyloid fibrils, arguing for retained targeting of the Congo red type binding site. We foresee that the X‐34 scaffold offers the possibility to develop novel high‐affinity ligands for Aβ pathology found in human AD brain in a different mode compared with PiB, potentially recognizing different polymorphs of Aβ fibrils. [ABSTRACT FROM AUTHOR]

A Suzuki–Miyaura coupling reaction of ortho‐hydroxyaromatic bromide 8 with isopropenylboronic acid pinacol ester has been investigated. It was found that the catalyst of Pd2(dba)3/PCy3 in dioxan‐water gave good yield by suppressing the formation of isomeric side product 14. (+)‐Callitrisic acid was synthesized from (+)‐podocarpic acid using this condition with an overall yield of 54 % in about five steps. (+)‐Callitrisic acid was found to be almost three times more potent than dehydroabietic acid to open a voltage‐gated potassium channel. [ABSTRACT FROM AUTHOR]

25C-NBOMe and 25I-NBOMe are potent hallucinogenic drugs that recently emerged as new psychoactive substances. To date, a few metabolism studies were conducted for 25I-NBOMe, whereas 25C-NBOMe metabolism data are scarce. Therefore, we investigated the metabolic profile of these compounds in human hepatocytes, an in vivo mouse model and authentic human urine samples from forensic cases. Cryopreserved human hepatocytes were incubated for 3 h with 10 μM 25C-NBOMe and 25I-NBOMe; samples were analyzed by liquid chromatography high-resolution mass spectrometry (LC-HRMS) on an Accucore C18 column with a Thermo QExactive; data analysis was performed with Compound Discoverer software (Thermo Scientific). Mice were administered 1.0 mg drug/kg body weight intraperitoneally, urine was collected for 24 h and analyzed (with or without hydrolysis) by LC-HRMS on an Acquity HSS T3 column with an Agilent 6550 QTOF; data were analyzed manually and with WebMetabase software (Molecular Discovery). Human urine samples were analyzed similarly. In vitro and in vivo results matched well. 25C-NBOMe and 25I-NBOMe were predominantly metabolized by O-demethylation, followed by O-di-demethylation and hydroxylation. All methoxy groups could be demethylated; hydroxylation preferably occurred at the NBOMe ring. Phase I metabolites were extensively conjugated in human urine with glucuronic acid and sulfate. Based on these data and a comparison with synthesized reference standards for potential metabolites, specific and abundant 25C-NBOMe urine targets are 5'-desmethyl 25C-NBOMe, 25C-NBOMe and 5-hydroxy 25C-NBOMe, and for 25I-NBOMe 2' and 5'-desmethyl 25I-NBOMe and hydroxy 25I-NBOMe. These data will help clinical and forensic laboratories to develop analytical methods and to interpret results. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this work, emergence patterns of synthetic cannabinoids were utilized in an attempt to predict those that may appear on the drug market in the future. Based on this information, two base structures of the synthetic cannabinoid analogues - (1 H-indol-3-yl(2,2,3,3-tetramethylcyclopropyl)methanone and 1 H-indol-3-yl(adamantan-1-yl)methanone) - together with three substituents - butyl, 4-fluorobutyl and ethyl tetrahydropyran - were selected for synthesis. This resulted in a total of six synthetic cannabinoid analogues that to the authors' knowledge have not yet appeared on the drug market. Spectroscopic data, including nuclear magnetic resonance (NMR), mass spectrometry (MS), and Fourier transform infrared (FTIR) spectroscopy (solid and gas phase), are presented for the synthesized analogues and some additional related cannabinoids. In this context, the suitability of the employed techniques for the identification of unknowns is discussed and the use of GC-FTIR as a secondary complementary technique to GC-MS is addressed. Examples of compounds that are difficult to differentiate by their mass spectra, but can be distinguished based upon their gas phase FTIR spectra are presented. Conversely, structural homologues where mass spectra are more powerful than gas phase FTIR spectra for unambiguous assignments are also exemplified. This work further emphasizes that a combination of several techniques is the key to success in structural elucidations. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]