Analytical characterization of N,N-diallyltryptamine (DALT) and 16 ring-substituted derivatives

Serotonin 1A Receptors Modulate Serotonin 2A Receptor-Mediated Behavioral Effects of 5-Methoxy-N,N-dimethyltryptamine Analogs in Mice

5-methoxy-N,N-dimethyltrytpamine (5-MeO-DMT) analogs are used as recreational drugs, but they are also being developed as potential medicines, warranting further investigation into their pharmacology. Here, we investigated the neuropharmacology of 5-MeO-DMT and several of its N-alkyl, N-allyl, and 2-methyl analogs, with three major aims: 1) to determine in vitro receptor profiles for the compounds, 2) to characterize in vitro functional activities at serotonin (5-HT) 2A receptors (5-HT2A) and 1A receptors (5-HT1A), and 3) to examine the influence of 5-HT1A on 5-HT2A-mediated psychedelic-like effects in the mouse head twitch response (HTR) model. In vitro receptor binding and functional assays showed that all 5-MeO-DMT analogs bind with high affinity and activate multiple targets (e.g., 5-HT receptor subtypes, alpha adrenergic receptors), including potent effects at 5-HT2A and 5-HT1A. In C57Bl/6J mice, subcutaneous injection of the analogs induced HTRs with varying potencies (ED50 range = 0.2-1.8 mg/kg) and maximal effects (Emax range = 20-60 HTRs/30 min), while inducing hypothermia and hypolocomotion at higher doses (ED50 range = 3.2-20.6 mg/kg). 5-HT2A antagonist pretreatment blocked drug-induced HTRs, whereas 5-HT1A antagonist pretreatment enhanced HTRs. In general, N,N-dialkyl and N-isopropyl derivatives displayed HTR activity, while the N-methyl, N-ethyl, and 2-methyl analogs did not. Importantly, blockade of 5-HT1A unmasked latent HTR activity for the N-ethyl analog and markedly increased maximal responses for other HTR-active compounds (40-90 HTRs/30 min), supporting the notion that 5-HT1A agonist activity can dampen 5-HT2A-mediated HTRs. Suppression of 5-HT2A-mediated HTRs by 5-HT1A only occurred after high 5-MeO-DMT doses, suggesting involvement of other receptors in modulating psychedelic-like effects. Overall, our findings provide key information about the receptor target profiles for 5-MeO-DMT analogs, the structure-activity relationships for inducing psychedelic-like effects, and the critical role of 5-HT1A agonism in modulating acute psychoactive effects of 5-HT2A agonists.

UPLC-LTQ-Orbitrap Study on Rat Urinary Metabolites of 5-Methoxy-Alpha-Methyltryptamine

OBJECTIVE

5-Methoxy-α-Methyltryptamine (5-MeO-AMT) is a new psychoactive substance which is abused due to its hallucinogenic and euphoric effects. This study aimed to study the metabolic characteristics of 5-MeO-AMT.

METHODS

Five rats were given intraperitoneal injection at a dose of 50 mg/kg of 5-MeO-AMT, and their urine was subsequently collected at different times within 7 days. Ultra-high performance liquid chromatographytandem high-resolution mass spectrometry (UPLC-LTQ-Orbitrap) was used to detect the precise molecular weight and fragment ions of 5-MeO-AMT and its possible metabolites in the urine sample extracted with benzene-ethyl acetate.

RESULTS

Three metabolites, including OH-5-MeO-AMT, α-Me-5-HT, and N-Acetyl-5-MeO-AMT were identified in rats' urine. The major metabolic pathways involved O-demethylation, hydroxylation of indole ring, and Acetylation on aliphatic amines.

CONCLUSION

The results of this study are an important reference for the identification and screening of toxicants of 5-MeO-AMT.

Toxicology and Analysis of Psychoactive Tryptamines

Our understanding of tryptamines is poor due to the lack of data globally. Tryptamines currently are not part of typical toxicology testing regimens and their contribution to drug overdoses may be underestimated. Although their prevalence was low, it is increasing. There are few published data on the many new compounds, their mechanisms of action, onset and duration of action, toxicity, signs and symptoms of intoxication and analytical methods to identify tryptamines and their metabolites. We review the published literature and worldwide databases to describe the newest tryptamines, their toxicology, chemical structures and reported overdose cases. Tryptamines are 5-HT2A receptor agonists that produce altered perceptions of reality. Currently, the most prevalent tryptamines are 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DiPT), 5-methoxy-N,N- diallyltryptamine (5-MeO-DALT) and dimethyltryptamine (DMT). From 2015 to 2020, 22 new analytical methods were developed to identify/quantify tryptamines and metabolites in biological samples, primarily by liquid chromatography tandem mass spectrometry. The morbidity accompanying tryptamine intake is considerable and it is critical for clinicians and laboratorians to be informed of the latest data on this public health threat.

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.

Study of the in vitro and in vivo metabolism of 4-HO-MET

4-Hydroxy-N-methyl-N-ethyltryptamine (4-HO-MET) is a new psychoactive substance (NPS) of the chemical class of tryptamines. It shows structural similarities to the endogenous neurotransmitter serotonin, and is a serotonergic hallucinogen, affecting emotional, motoric, and cognitive functions. The knowledge about its biotransformation is mandatory to confirm the abuse of the substance by urine analysis in forensic cases. Therefore, phase I metabolites were generated by the use of the pooled human liver microsomes (pHLM) in vitro model and analyzed by high-performance liquid chromatography high-resolution tandem mass spectrometry with information-dependent acquisition (HPLC-IDA-HR-MS/MS). Furthermore, three authentic urine samples was analyzed and results were compared: 12 different in vitro and 4 in vivo metabolites were found. The predominant biotransformation steps observed in vitro were mono- or dihydroxylation of 4-HO-MET, besides demethylation, demethylation in combination with monohydroxylation, formation of a carboxylic acid, deethylation, and oxidative deamination. In vivo, monohydroxylation, and glucuronidation were detected. A metabolic pathway based on these results was proposed. For the analysis of urine samples in forensic cases, the N-oxide metabolite and the HO-alkyl metabolite are recommended as target compounds, besides the glucuronides of 4-HO-MET and the parent compound 4-HO-MET itself.

Receptor binding profiles and behavioral pharmacology of ring-substituted N,N-diallyltryptamine analogs

Substantial effort has been devoted toward understanding the psychopharmacological effects of tryptamine hallucinogens, which are thought to be mediated by activation of 5-HT_2A and 5-HT_1A receptors. Recently, several psychoactive tryptamines based on the N,N-diallyltryptamine (DALT) scaffold have been encountered as recreational drugs. Despite the apparent widespread use of DALT derivatives in humans, little is known about their pharmacological properties. We compared the binding affinities of DALT and its 2-phenyl-, 4-acetoxy-, 4-hydroxy-, 5-methoxy-, 5-methoxy-2-methyl-, 5-fluoro-, 5-fluoro-2-methyl-, 5-bromo-, and 7-ethyl-derivatives at 45 receptor and transporter binding sites. Additionally, studies in C57BL/6 J mice examined whether these substances induce the head twitch response (HTR), a 5-HT_2A receptor-mediated response that is widely used as a behavioral proxy for hallucinogen effects in humans. Most of the test drugs bound to serotonin receptors, σ sites, α₂-adrenoceptors, dopaminergic D₃ receptors, histaminergic H₁ receptors, and the serotonin transporter. DALT and several of the ring-substituted derivatives were active in the HTR assay with the following rank order of potency: 4-acetoxy-DALT > 5-fluoro-DALT > 5-methoxy-DALT > 4-hydroxy-DALT > DALT > 5-bromo-DALT. 2-Phenyl-DALT, 5-methoxy-2-methyl-DALT, 5-fluoro-2-methyl-DALT, and 7-ethyl-DALT did not induce the HTR. HTR potency was not correlated with either 5-HT_1A or 5-HT_2A receptor binding affinity, but a multiple regression analysis indicated that 5-HT_2A and 5-HT_1A receptors make positive and negative contributions, respectively, to HTR potency (R² = 0.8729). In addition to supporting the established role of 5-HT_2A receptors in the HTR, these findings are consistent with evidence that 5-HT_1A activation by tryptamine hallucinogens buffers their effects on HTR. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.

Metabolism of the tryptamine-derived new psychoactive substances 5-MeO-2-Me-DALT, 5-MeO-2-Me-ALCHT, and 5-MeO-2-Me-DIPT and their detectability in urine studied by GC-MS, LC-MSn , and LC-HR-MS/MS

Many N,N-dialkylated tryptamines show psychoactive properties and were encountered as new psychoactive substances. The aims of the presented work were to study the phase I and II metabolism and the detectability in standard urine screening approaches (SUSA) of 5-methoxy-2-methyl-N,N-diallyltryptamine (5-MeO-2-Me-DALT), 5-methoxy-2-methyl-N-allyl-N-cyclohexyltryptamine (5-MeO-2-Me-ALCHT), and 5-methoxy-2-methyl-N,N-diisopropyltryptamine (5-MeO-2-Me-DIPT) using gas chromatography-mass spectrometry (GC-MS), liquid chromatography coupled with multistage accurate mass spectrometry (LC-MSⁿ ), and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). For metabolism studies, urine was collected over a 24 h period after administration of the compounds to male Wistar rats at 20 mg/kg body weight (BW). Phase I and II metabolites were identified after urine precipitation with acetonitrile by LC-HR-MS/MS. 5-MeO-2-Me-DALT (24 phase I and 12 phase II metabolites), 5-MeO-2-Me-ALCHT (24 phase I and 14 phase II metabolites), and 5-MeO-2-Me-DIPT (20 phase I and 11 phase II metabolites) were mainly metabolized by O-demethylation, hydroxylation, N-dealkylation, and combinations of them as well as by glucuronidation and sulfation of phase I metabolites. Incubations with mixtures of pooled human liver microsomes and cytosols (pHLM and pHLC) confirmed that the main metabolic reactions in humans and rats might be identical. Furthermore, initial CYP activity screenings revealed that CYP1A2, CYP2C19, CYP2D6, and CYP3A4 were involved in hydroxylation, CYP2C19 and CYP2D6 in O-demethylation, and CYP2C19, CYP2D6, and CYP3A4 in N-dealkylation. For SUSAs, GC-MS, LC-MSⁿ , and LC-HR-MS/MS were applied to rat urine samples after 1 or 0.1 mg/kg BW doses, respectively. In contrast to the GC-MS SUSA, both LC-MS SUSAs were able to detect an intake of 5-MeO-2-Me-ALCHT and 5-MeO-2-Me-DIPT via their metabolites following 1 mg/kg BW administrations and 5-MeO-2-Me-DALT following 0.1 mg/kg BW dosage. Copyright © 2017 John Wiley & Sons, Ltd.