4,4'-DMAR: chemistry, pharmacology and toxicology of a new synthetic stimulant of abuse

Genotoxicological Characterization of (±)cis-4,4'-DMAR and (±)trans-4,4'-DMAR and Their Association

The novel psychoactive substance (NPS) 4-Methyl-5-(4-methylphenyl)-4,5-dihydroxazol-2-amine (4,4′-DMAR) shows psychostimulant activity. Data on the acute toxicity of 4,4′-DMAR are becoming increasingly available, yet the long-term effects are still almost unknown. In particular, no data on genotoxicity are available. Therefore, the aim of the present study was to evaluate its genotoxic potential using the “In Vitro Mammalian Cell Micronucleus Test” (MNvit) on (±)cis-4,4′-DMAR and (±)trans-4,4′-DMAR and their associations. The analyses were conducted in vitro on human TK6 cells. To select suitable concentrations for MNvit, we preliminarily evaluated cytotoxicity and apoptosis. All endpoints were analysed by flow cytometry. The results reveal the two racemates’ opposite behaviours: (±)cis-4,4′-DMAR shows a statistically significant increase in micronuclei (MNi) frequency that (±)trans-4,4′-DMAR is completely incapable of. This contrast confirms the well-known possibility of observing opposite biological effects of the cis- and trans- isomers of a compound, and it highlights the importance of testing single NPSs that show even small differences in structure or conformation. The genotoxic capacity demonstrated stresses an additional alarming toxicological concern related to this NPS. Moreover, the co-treatments indicate that consuming both racemates will magnify the genotoxic effect, an aspect to consider given the unpredictability of illicit drug composition.

Metabolic profile of the synthetic drug 4,4′-dimethylaminorex in urine by LC–MS-based techniques: selection of the most suitable markers of its intake

Purpose

In this study, the phase I and II metabolic pathways of 4,4′-dimethylaminorex were characterized to select the marker(s) of intake allowing the unequivocal identification of this novel psychoactive substance in urine samples.

Methods

The metabolic profile of 4,4′-dimethylaminorex was characterized using both in vitro and in vivo models. In detail, for the in vitro experiments, either pooled human liver microsomes or recombinant cytochrome P450 isoforms were selected, whereas the in vivo investigation was performed on male mice ICR (CD-1®). Sample preparation included enzymatic hydrolysis followed by liquid/liquid extraction. The instrumental analysis was performed by ultra-high-performance liquid chromatography coupled to either high- or low-resolution tandem mass spectrometry.

Results

Five metabolic products were isolated only for the cis-isomer: the phase I metabolic reactions included hydrolysis, carboxylation, hydroxylation, and carbonylation. CYP2D6 was the principal isoenzyme involved, and the incubation in the presence of different allelic variants showed significant alteration on the metabolic profile. Once formed, the phase I metabolites underwent extensive conjugation. Not only the most abundant compounds detected, but also those with the most extended window of detection, were the carboxylated and the hydroxylated metabolites. These analytes together with the parent compound were selected as the most suitable markers of intake.

Conclusions

Knowledge of the metabolic profiles of the new drugs is essential for their fast identification. Phase I and phase II metabolites of 4,4′-dimethylaminorex were identified and selected as markers of intake, to be considered as the most suitable analytical targets in forensic toxicology.

DARK Classics in Chemical Neuroscience: Aminorex Analogues

Aminorex (5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) and 4-methylaminorex (4-methyl-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) are psychostimulants that have long been listed in Schedules IV and I of the UN Convention on Psychotropic Substances of 1971. However, a range of psychoactive analogues exist that are not internationally controlled and therefore often classified as new psychoactive substances (NPS). Aminorex analogues encompass failed pharmaceuticals that reemerged as drugs of abuse, and newly synthesized substances that were solely designed for recreational use by clandestine chemists. NPS, sometimes also referred to as "designer drugs" in alignment with a phenomenon arising in the early 1980s, serve as alternatives to controlled drugs. Aminorex and its derivatives interact with monoaminergic neurotransmission by interfering with the function of monoamine transporters. Hence, these compounds share pharmacological and neurochemical similarities with amphetamines and cocaine. The consumption of aminorex, 4-methylaminorex and 4,4'-dimethylaminorex (4-methyl-5-(4-methylphenyl)-4,5-dihydro-1,3-oxazol-2-amine) has been associated with adverse events including death, bestowing an inglorious fame on aminorex-derived drugs. In this Review, a historical background is presented, as well as an account of the pharmacodynamic and pharmacokinetic properties of aminorex and various analogues. Light is shed on their misuse as drug adulterants of well-established drugs on the market. This Review not only provides a detailed overview of an abused substance-class, but also emphasizes the darkest aspect of the NPS market, i.e., deleterious side effects that arise from the ingestion of certain NPS, as knowledge of the pharmacology, the potency, or the identity of the active ingredients remains obscure to NPS users.

4,4'-Dimethylaminorex ("4,4'-DMAR"; "Serotoni") misuse: A Web-based study

BACKGROUND

4,4'-DMAR (4,4'-dimethylaminorex; "Serotoni") is a potent stimulant drug that has recently been associated with a number of fatalities in Europe. Over the last few years, online communities have emerged as important resources for disseminating levels of technical knowledge on novel psychoactive substances.

OBJECTIVE

Analysing the information provided by the fora communities on 4,4'-DMAR use, additionally critical reviewing the available evidence-based literature on this topic.

METHODS

Different website drug fora were identified. A critical review of the existing evidence-based literature was undertaken. Individuation and analysis of qualitative data from the identified website fora were performed.

RESULTS

The combined search results identified six website fora from which a range of qualitative data on recurring themes was collected. These themes included routes of administration and doses; desired effects; adverse effects; comparison with other drugs; association with other drugs; medications self-administered to reverse 4,4'-DMAR action; overall impression; and provision of harm-reduction advice.

CONCLUSIONS

Although being characterized by a number of methodological limitations, the social networks' Web monitoring approach (netnography) may be helpful to better understand some of the clinical and psychopharmacological issues pertaining to a range of novel psychoactive substances, including 4,4'-DMAR, for which only extremely little, if any, scientific knowledge is available.

New psychoactive substances: an overview on recent publications on their toxicodynamics and toxicokinetics

This review article covers English-written and PubMed-listed review articles and original studies published between January 2015 and April 2016 dealing with the toxicodynamics and toxicokinetics of new psychoactive substances. Compounds covered include stimulants and entactogens, synthetic cannabinoids, tryptamines, NBOMes, phencyclidine-like drugs, benzodiazepines, and opioids. First, an overview and discussion is provided on timely review articles followed by an overview and discussion on recent original studies. Both sections are then concluded by an opinion on these latest developments. This review shows that the NPS market is still highly dynamic and that the data published on their toxicodynamics and toxicokinetics can hardly keep pace with the appearance of new entities. However, data available are very helpful to understand and predict how NPS may behave in severe intoxication. The currently best-documented parameter is the in vitro metabolism of NPS, a prerequisite to allow detection of NPS in biological matrices in cases of acute intoxications or chronic consumption. However, additional data such as their chronic toxicity are still lacking.