Metabolic stability and metabolite profiling of emerging synthetic cathinones

Abstract

Synthetic cathinones constitute the second largest groups of new psychoactive substances (NPS), which are especially popular among adolescents and young adults. Due to their potential toxicity, the recreational use of these NPS constitute a serious worldwide public health problem. However, their fast appearance in the market renders the continuous updating of NPS information highly challenging for forensic authorities. The unavailability of pharmacokinetic data for emerging NPS is critical for forensic and clinical verifications. With the ultimate goal of having a proactive approach towards the NPS issue, high resolution mass spectrometry was used in the current work to assess preliminary pharmacokinetic data for 8 selected cathinones: 4 reported substances (4-CIC, 3-CMC, 4-CMC and 4-MEAP) and 4 previously unreported ones (3-CIC, 4-MDMB, 4-MNEB and 4-MDMP) for which the emergence on the NSP market is expected to be eminent, were also included in this study. Based on the calculation of pharmacokinetic parameters, half-life and intrinsic clearance, 4-CMC and 4-MDMB are low and high clearance compounds, respectively, and all the remaining cathinones included in this study are intermediate clearance compounds. This fact anticipates the key role of metabolites as suitable biomarkers to extend detection windows beyond those provided by the parent cathinones. Reduction of the keto group and hydroxylation on the alkyl chains were the common metabolic pathways identified for all cathinones. However, the relative importance of these metabolic transformations is dependent on the cathinone substituents. The glucuronic acid conjugation to metabolites stemming for keto group reduction constituted the sole Phase II transformation identified. To our knowledge, this study constitutes the first metabolite profiling of the already reported synthetic cathinones 4-CIC, 3-CMC and 4-CMC. Noteworthy is the fact that 3-CMC accounts for almost a quarter of the quantity of powders seized during 2020. The analytical methods developed, and the metabolites characterized, are now available to be included in routine screening methods to attest the consumption of the 8 cathinones studied.

3-CMC, 4-CMC, and 4-BMC Human Metabolic Profiling: New Major Pathways to Document Consumption of Methcathinone Analogues?

“…FullMS settings were: range, m/z 100-500; resolution at full width at half maximum at m/z 200, 70,000; automatic gain control (AGC) target, 10 6 ; and maximum injection time (IT), 200 ms. ddMS 2 settings were: AGC target, 2 × 10 5 ; maximum IT, 64 ms; isolation window, m/z 1.2; resolution, 17,500; and stepped normalized collision energy (NCE), 20, 80, and 100 a.u. A maximum number of five ddMS 2 scans were triggered for each FullMS scan (minimum intensity, 10 4 ; dynamic exclusion, 2.0 s) depending on an inclusion list of putative metabolites based on in silico predictions and postulation (Supplementary Table S1) (5,16,18). Due to 4-BMC isotopic distribution, the 3-h incubate with hepatocytes was reinjected with two different inclusion lists using 79 Br or 81 Br isotope to increase the chances to obtain non-interfered HRMS/MS spectra.…”

“…However, they can also cause several adverse effects such as agitation, accelerated heart rate, high blood pressure, unconsciousness, and hallucination (3,4). These effects are attributed to the SC affinity for dopamine, norepinephrine, and serotonin transporters, increasing the concentration of catecholamines in the central nervous system (1,5).…”

“…Due to their extensive metabolic degradation, detection of new emerging SCs challenges analytical toxicologists (5,17). The detection of metabolites is therefore a go-to to prove consumption in clinical and forensic casework.…”

“…4-FMC human metabolism was previously assessed (17). 3-and 4-CMC metabolic transformations have been recently studied, although the investigations were partial (5,16,18). To the best of our knowledge, 4-BMC metabolism has not been studied.…”

Toxicity of the New Psychoactive Substance (NPS) Clephedrone (4-Chloromethcathinone, 4-CMC): Prediction of Toxicity Using In Silico Methods for Clinical and Forensic Purposes

“…To date, no clinical data on this compound are available. Only a few studies have been published that focused on its determination in biological samples by GC-MS or CE [ 3 ] and its toxicokinetics, involving the identification of metabolites in human liver microsomes and investigations of metabolic pathways [ 5 ]. Furthermore, limited information is available regarding the physicochemical properties of this substance.…”