In vitro metabolic studies and machine learning analysis of mass spectrometry data: A dual strategy for differentiating alpha-pyrrolidinohexiophenone (α-PHP) and alpha-pyrrolidinoisohexanophenone (α-PiHP) in urine analysis.

Synthetic cathinones are some of the most prevalent new psychoactive substances (NPSs) globally, with alpha-pyrrolidinoisohexanophenone (α-PiHP) being particularly noted for its widespread use in the United States, Europe, and Taiwan. However, the analysis of isomeric NPSs such as α-PiHP and alpha-pyrrolidinohexiophenone (α-PHP) is challenging owing to similarities in their retention times and mass spectra. This study proposes a dual strategy based on in vitro metabolic experiments and machine learning-based classification modelling for differentiating α-PHP and α-PiHP in urine samples: (1) in vitro metabolic experiments using pooled human liver microsomes and liquid chromatography tandem quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) were conducted to identify the key metabolites of α-PHP and α-PiHP from the high-resolution MS/MS spectra. After 5 h incubation, 71.4 % of α-PHP and 64.7 % of α-PiHP remained unmetabolised. Nine phase I metabolites were identified for each compound, including primary ß-ketone reduction (M1) metabolites. Comparing the metabolites and retention times confirmed the efficacy of in vitro metabolic experiments for differentiating NPS isomers. Subsequently, analysis of seven real urine samples revealed the presence for various metabolites, including M1, that could be used as suitable detection markers at low concentrations. The aliphatic hydroxylation (M2) metabolite peak counts and metabolite retention times were used to determine α-PiHP use. (2) Classification models for the parent compounds and M1 metabolites were developed using principal component analysis for feature extraction and logistic regression for classification. The training and test sets were devised from the spectra of standard samples or supernatants from in vitro metabolism experiments with different incubation times. Both models had classification accuracies of 100 % and accurately identified α-PiHP and its M1 metabolite in seven real urine samples. The proposed methodology effectively distinguished between such isomers and confirmed their presence at low concentrations. Overall, this study introduces a novel concept that addresses the complexities in analysing isomeric NPSs and suggests a path towards enhancing the accuracy and reliability of NPS detection.

The synthetic cathinones MDPHP and MDPV: Comparison of the acute effects in mice, in silico ADMET profiles and clinical reports.

The 3,4-methylenedioxy-alpha-pyrrolidinohexanophenone (MDPHP) is a synthetic cathinone closely related to 3,4-methylenedioxypyrovalerone (MDPV), one of the most common synthetic cathinones present in the "bath salts". MDPHP has recently gained attention due to increasing seizures and involvement in human intoxications which occurred in Europe and Italy in the last years, but currently there is a lack of information about its pharmaco-toxicological effects. With the aim at filling this gap, the present study is endeavoured to (i) evaluate the effects of acute administration of MDPHP (0.01-20 mg/kg; i.p.) on behaviour, cardiorespiratory and cardiovascular parameters in CD-1 male mice, comparing them to those observed after administration of MDPV; (ii) predict the ADMET profile of the two analogues using the Plus ADMET Predictor®; (iii) present clinical data related to MDPHP and MDPV-induced intoxications recorded between 2011 and 2023 by the Pavia Poison Control Centre (PCC) - National Toxicology Information Centre (Istituti Clinici Scientifici Maugeri, IRCCS Pavia, Italy). Our results substantiated that MDPHP and MDPV similarly affect sensorimotor and behavioural responses in mice, importantly increased locomotion and induced aggressive behaviour, and, at higher dosage, increased heart rate and blood pressure. These findings are in line with those observed in humans, revealing severe toxidromes typically characterized by Central Nervous System (CNS) alterations (behavioural/neuropsychiatric symptoms), including psychomotor agitation and aggressiveness, cardiovascular and respiratory disorders (e.g. tachycardia, hypertension, dyspnoea), and other peripheral symptoms (e.g. hyperthermia, acidosis, rhabdomyolysis).

N,N-dimethylpentylone poisoning: Clinical manifestations, analytical detection, and metabolic characterization.

INTRODUCTION: The proliferation of new psychoactive substances (NPS) poses a significant challenge to clinical and forensic toxicology laboratories. N,N-dimethylpentylone, a novel synthetic cathinone, has emerged as a public health concern. The aims of this study are to describe the clinical presentation of N,N-dimethylpentylone poisoning, to describe detection methods, and to deduce its metabolic pathways. METHODS: Clinical data was collected and reviewed retrospectively from patients with confirmed N,N-dimethylpentylone exposure. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify N,N-dimethylpentylone and its metabolites in urine samples. The metabolic pathway was characterised by comparison of the detected substances with reference standards. RESULTS: Eight cases were included in the case series. Seven different metabolites of N,N-dimethylpentylone were identified in in vivo patient urine samples, where the two major metabolic pathways were proposed to be opening of the 5-membered ring and reduction of carboxide. All patients presented with neuropsychiatric and/or cardiovascular symptoms. Co-ingestion with other substances was reported in all cases. One patient requiring intensive care was described in detail. All patients eventually recovered. The analytical method allowed the simultaneous identification of N,N-dimethylpentylone, pentylone and bisdesmethyl-N,N-dimethylpentylone, as well as other drugs of abuse in patient samples. CONCLUSION: N,N-dimethylpentylone appears to be less potent than its metabolite pentylone. Co-ingestion with other drugs of abuse is common. Poisoning cases have neuropsychiatric and cardiovascular manifestations. An updated and comprehensive laboratory method is needed for its detection.

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

Synthetic cathinones represent one of the largest and most abused new psychoactive substance classes, and have been involved in numerous intoxications and fatalities worldwide. Methcathinone analogues like 3-methylmethcathinone (3-MMC), 3-chloromethcathinone (3-CMC), and 4-CMC currently constitute most of synthetic cathinone seizures in Europe. Documenting their consumption in clinical/forensic casework is therefore essential to tackle this trend. Targeting metabolite markers is a go-to to document consumption in analytical toxicology, and metabolite profiling is crucial to support investigations. We sought to identify 3-CMC, 4-CMC, and 4-bromomethcathinone (4-BMC) human metabolites. The substances were incubated with human hepatocytes; incubates were screened by liquid chromatography-high-resolution tandem mass spectrometry and data were mined with Compound Discoverer (Themo Scientific). 3-CMC-positive blood, urine, and oral fluid and 4-CMC-positive urine and saliva from clinical/forensic casework were analyzed. Analyses were supported by metabolite predictions with GLORYx freeware. Twelve, ten, and ten metabolites were identified for 3-CMC, 4-CMC, and 4-BMC, respectively, with similar transformations occurring for the three cathinones. Major reactions included ketoreduction and N-demethylation. Surprisingly, predominant metabolites were produced by combination of N-demethylation and ω-carboxylation (main metabolite in 3-CMC-positive urine), and combination of ß-ketoreduction, oxidative deamination, and O-glucuronidation (main metabolite in 4-CMC-positive urine). These latter metabolites were detected in negative-ionization mode only and their non-conjugated form was not detected after glucuronide hydrolysis; this metabolic pathway was never reported for any methcathinone analogue susceptible to undergo the same transformations. These results support the need for comprehensive screening strategies in metabolite identification studies, to avoid overlooking significant metabolites and major markers of consumption.

Investigation of cathinone analogs targeting human dopamine transporter using molecular modeling.

In a step towards understanding the structure-property relationship among Synthetic Cathinones (SCs), a combined methodology based on Density Functional Theory (DFT), Administration, Distribution, Metabolism, Excretion, and Toxicity (ADMET) predictions, docking and molecular dynamics simulations have been applied to correlate physicochemical descriptors of various SCs to their biological activity. The results from DFT and molecular docking studies correlate well with each other explaining the biological activity trends of the studied SCs. Quantum mechanical descriptors viz. polarizability, electron affinity, ionization potential, chemical hardness, electronegativity, molecular electrostatic potential, and ion interaction studies unravel the distinguishingly reactive nature of Group D (pyrrolidine substituted) and Group E (methylenedioxy and pyrrolidine substituted) compounds. According to ADMET analysis, Group D and Group E molecules have a higher probability of permeating through the blood-brain barrier. Molecular docking results indicate that Phe76, Ala77, Asp79, Val152, Tyr156, Phe320, and Phe326 constitute the binding pocket residues of hDAT in which the most active ligands MDPV, MDPBP, and MDPPP are bound. Finally, to validate the derived quantum chemical descriptors and docking results, Molecular Dynamics (MD) simulations are performed with homology-modelled hDAT (human dopamine transporter). The MD simulation results revealed that the majority of SCs remain stable within the hDAT protein's active sites via non-bonded interactions after 100 ns long simulations. The findings from DFT, ADMET analysis, molecular docking, and molecular dynamics simulation studies complement each other suggesting that pyrrolidine-substituted SCs (Group D and E), specifically, MPBP and PVN are proven potent SCs along with MDPV, validating various experimental observations.Communicated by Ramaswamy H. Sarma.

The neuropharmacological properties of α-pyrrolidinobutiothiophenone, a new synthetic cathinone, in rodents; role of the dopaminergic system.

BACKGROUND AND PURPOSE: α-Pyrrolidinobutiothiophenone (α-PBT) is a chemical derivative of cathinone, a structural analogue of amphetamine. Until now, there have been a few previous neurochemical or neurobehavioural studies on the abuse potential of α-PBT. EXPERIMENTAL APPROACH: We examined the abuse potential of α-PBT by measuring psychomotor, rewarding, and reinforcing properties and methamphetamine-like discriminative stimulus effects in rodents using locomotor activity, conditioned place preference, self-administration, and drug discrimination studies. To clarify the underlying neuropharmacological mechanisms, we measured dopamine levels and neuronal activation in the dorsal striatum. In addition, we investigated the role of the dopamine D1 receptor or D2 receptors in α-PBT-induced hyperlocomotor activity, conditioned place preference, and the methamphetamine-like discriminative stimulus effect of α-PBT in rodents. KEY RESULTS: α-PBT promoted hyperlocomotor activity in mice. α-PBT induced drug-paired place preference in mice and supported self-administration in rats. In a drug discrimination experiment, α-PBT fully substituted for the discriminative stimulus effects of methamphetamine in rats. Furthermore, α-PBT increased dopamine levels and c-Fos expression in the dorsal striatum of mice, which was associated with these behaviours. Finally, pretreatment with the D1 receptor antagonist SCH23390 or the D2 receptors antagonist eticlopride significantly attenuated acute or repeated α-PBT-induced hyperlocomotor activity, place preference, and the methamphetamine-like discriminative stimulus effects in rodents. CONCLUSIONS AND IMPLICATIONS: These findings suggest that α-PBT has abuse potential at the highest dose tested via enhanced dopaminergic transmission in the dorsal striatum of rodents. The results provide scientific evidence for the legal restrictions of the recreational use of α-PBT.

Short- and long-term stability of synthetic cathinones and dihydro-metabolites in human urine samples.

PURPOSE: Synthetic cathinones constitute the second largest group of new psychoactive substances, which are often used for recreational purposes and reported in toxicological analysis. Various factors may influence the stability of synthetic cathinones between sampling and analysis, and therefore, stability studies are required to determine the best storage conditions as well as extend the period of detection. METHODS: This study involved sixteen synthetic cathinones and ten dihydro-metabolites spiked in human urine to evaluate the stability under common storage conditions to imitate real forensic toxicology samples. The samples were stored at either room temperature (22-23 °C) for up to 3 days, refrigerated (4 °C) for up to 14 days or frozen (-40 °C) for up to 12 months, and analyzed in triplicate using a validated liquid chromatography-tandem mass spectrometry method. RESULTS: Analytes' concentrations decreased over time, although slower when stored frozen. All analytes remained stable (> 80%) for 1 month when stored frozen before losses in content were more apparent for some compounds, depending on their chemical structure. Under all storage conditions, the highest instability was observed for analytes containing halogens (i.e., chlorine or fluorine). Thus, halogenated analytes were further investigated by using liquid chromatography coupled to quadruple time-of-flight mass spectrometry to attempt identifying degradation products. CONCLUSIONS: Irrespective of parent analytes, dihydro-metabolites had improved stability at each tested temperature, which highlights their importance as appropriate urine biomarkers when retesting is required after a long period of storage.

The psychomotor, reinforcing, and discriminative stimulus effects of synthetic cathinone mexedrone in male mice and rats.

The chronic use of the novel synthetic cathinone mexedrone, like other psychoactive drugs, can be considered addictive, with a high potential for abuse and the ability to cause psychological dependence in certain users. However, little is known about the neurobehavioral effects of mexedrone in association with its potential for abuse. We investigated the abuse potential for mexedrone abuse through multiple behavioral tests. In addition, serotonin transporter (SERT) levels were measured in the synaptosome of the dorsal striatum, and serotonin (5-HT) levels were measured in the dorsal striatum of acute mexedreone (50 mg/kg)-treated mice. To clarify the neuropharmacological mechanisms underlying the locomotor response of mexedrone, the 5-HT2A receptor antagonist M100907 (0.5 or 1.0 mg/kg) was administered prior to the acute injection of mexedrone in the locomotor activity experiment in mice. Mexedrone (10-50 mg/kg) produced a significant place preference in mice and mexedrone (0.1-0.5 mg/kg/infusion) maintained self-administration behavior in rats in a dose-dependent manner. In the drug discrimination experiment, mexedrone (5.6-32 mg/kg) was fully substituted for the discriminative stimulus effects of cocaine in rats. Mexedrone increased locomotor activity, and these effects were reversed by pretreatment with M100907. Acute mexedrone significantly increased c-Fos expression in the dorsal striatum and decreased SERT levels in the synaptosome of the dorsal striatum of mice, resulting in an elevation of 5-HT levels. Taken together, our results provide the possibility that mexedrone has abuse potential, which might be mediated, at least in part, by the activation of the serotonergic system in the dorsal striatum.

Metabolic profile of N-ethylhexedrone, N-ethylpentedrone, and 4-chloromethcathinone in urine samples by UHPLC-QTOF-HRMS.

Forensic laboratories are constantly required to identify new drugs and their metabolites. N-ethylhexedrone (NEH, HEXEN), N-Ethylpentedrone (NEP), and 4-Chloromethcathinone (4-CMC, clephedrone) are synthetic substances structurally related to natural cathinone, alkaloid present in the leaves of the Catha edulis (Khat) plant. These synthetic cathinones (SC) are members of the heterogenous family of new psychoactive substances (NPS) that raised major concerns in scientific and forensic communities over the past years due to their widespread consumption. In this context, we investigated their metabolic profile using of UHPLC-QTOF-HRMS to elucidate the distribution of the parent drug and its metabolites in urine samples over time. Initially, both male and female volunteers were divided into three groups and eight subjects of each group were administered intranasally or orally with one SC (20-40 mg of NEH or NEP intranasal, 100-150 mg of 4-CMC oral). Urine samples were collected at 0-2 and 2-4 or 2-5 h. Urine (50 µL) was diluted 1:2 with acetonitrile/methanol (95:5) and injected into the UHPLC-QTOF-HRMS. Phase-I and phase-II metabolites were identified on the basis of fragmentation patterns and exact masses. Several phase-I and glucuronide-phase-II metabolites were identified in urine samples. Keto group reduction, hydroxylation and dealkylation were the common metabolic pathways identified for all cathinones and the presence of NEH-glucuronide, NEP-glucuronide and 4-CMC-glucuronide was also relevant. Significant is the slower metabolite formation for 4-CMC, which was detected at high concentrations in its original form even 5 h after administration, due to its long half-life and low intrinsic clearance compared to the other SCs. UHPLC-QTOF-HRMS demonstrated a considerable capability to semi-quantify the three synthetic cathinones and identify the target metabolites with high reliability. The introduction of new target compounds improves the efficiency of toxicological screening analysis on real samples and extends the window of detection of the SCs in biological matrices.

Clinical manifestations and analytical reports for MDPHP acute intoxication cases.

MDPHP is a synthetic cathinone (SC) belonging to α-pyrrolidinophenone derivatives. It is a central nervous system stimulant and may induce hallucinations, paranoia, tachycardia, hypertension, chest pain, and rhabdomyolysis. In literature, a few cases of intoxication have been reported. In the present study, 17 cases of MDPHP intake were described including the analytical findings and clinical manifestations. MDPHP was quantified by liquid chromatography-tandem mass spectrometry in blood (range 1.26-73.30 ng/mL) and urine (range 19.31-8769.64 ng/mL) samples. In three cases the presence of α-PHP was observed. In one case, MDPHP was the only detected substance. Concomitant use of MDPHP with other substances, particularly psychostimulants, was common and it was difficult to describe the peculiar clinical characteristics of this SC. Most of the symptoms overlapped those expected, some of them were unusual and all of them particularly severe thus inducing the research of NPS in laboratory tests. We demonstrated the presence of psychiatric, neurological, and respiratory symptoms, as well as the possible presence of rhabdomyolysis and cardiotoxicity associated with the use of MDPHP. ED admissions were also more frequent in patients with addiction problems. In some cases, MDPHP intake required intensive supportive care. A multidisciplinary approach, including specialist consultation, is recommended for patients showing challenging features. Moreover, we demonstrated that the adoption of advanced analytical techniques, i.e., liquid chromatography-tandem mass spectrometry, is necessary to detect these molecules. Further studies are needed to understand MDPHP intake patterns and associated symptoms. It is essential to raise awareness in addiction treatment centers and among potential users, especially young people, and chemsex addicted.

Pharmacological profile, phase I metabolism, and excretion time profile of the new synthetic cathinone 3,4-Pr-PipVP.

1-(2,3-Dihydro-1H-inden-5-yl)-2-(piperidin-1-yl)pentan-1-one (3,4-Pr-PipVP), a novel synthetic cathinone (SCat), was first identified in 2022 in Germany. The product was marketed as 1-(bicyclo[4.2.0]octa-1,3,5-trien-3-yl)-2-(pyrrolidin-1-yl)pentan-1-one (3,4-EtPV), a substance not covered by the German New Psychoactive Substances Act (NpSG). Although originally intended to be an exploratory new synthetic cathinone containing the novel bicyclo[4.2.0]octatrienyl function, the compound was subsequently confirmed to contain an indanyl ring system scheduled under generic legislation like the NpSG. However, it is one of only a few marketed SCats carrying a piperidine ring. Inhibition experiments involving norepinephrine, dopamine, and serotonin transporters showed that 3,4-Pr-PipVP was a low potency blocker at all three monoamine transporters compared to related substances such as MDPV. Additionally, pharmacokinetic data were collected from pooled human liver microsomes incubations and from the analysis of authentic urine samples received after oral administration of 5 mg 3,4-Pr-PipVP hydrochloride. Phase I metabolites were tentatively identified in vitro and in vivo using liquid chromatography-time-of-flight mass spectrometry. Main metabolites were formed by metabolic reduction of the carbonyl function with and without additional hydroxylations at the propylene bridge of the molecule. Keto-reduced H2 -3,4-Pr-PipVP and H2 -piperidine-OH-3,4-Pr-PipVP as well as aryl-OH-3,4-Pr-PipVP, and indanyl-OH-piperidine-OH-3,4-Pr-PipVP are suggested as most suitable biomarkers for the detection of 3,4-Pr-PipVP since they were detected for much longer than the parent compound. 3,4-Pr-PipVP could be detected for up to 21 h whereas its metabolites were detectable for up to about 4 days.

Metabolism of dipentylone in zebrafish and human liver microsomes determined by liquid chromatography-high resolution mass spectrometry.

The consumption of novel psychoactive substances (NPS) is exceedingly prevalent in society, as these substances are sold and distributed as "legal highs." One novel synthetic cathinone emerging in the market is 1-(1,3-benzodioxol-5-yl)-2-(dimethylamino) pentan-1-one (dipentylone). The goal of this work was to study the in vivo and in vitro metabolism of dipentylone in zebrafish and human liver microsomes (HLMs) by liquid chromatography-high resolution mass spectrometry (LC-HRMS). The zebrafish and HLM samples contained 14 dipentylone metabolites, specifically 12 phase Ⅰ metabolites and 2 phase Ⅱ metabolites. The main metabolic pathways included monohydroxylation (M1 and M2), N-dealkylation (M3), hydroxylation of the aromatic ring and dealkoxylation of M3 (M4), O-dealkylation (M5), N-dealkylation of M5 (M6), reduction of carboxide (M7), monohydroxylation of M5 (M8), dehydrogenation (M9), dealkoxylation (M10), N-dealkylation of M10 (M11), dealkoxylation of M9 (M12), glucuronidation of M5 (M13), and sulfation (M14). The monohydroxylated metabolite (M2) can be recommended as metabolic markers for dipentylone. This study is the first to identify a target compound for monitoring the abuse of dipentylone and to determine the essential chemical structure of the metabolites for further toxicological research.

The differentiation of N-butyl pentylone isomers using GC-EI-MS and NMR.

Forensic laboratories are faced with an ever-expanding seized drug landscape including the increasing prevalence of novel psychoactive substances (NPS), such as synthetic cathinones, that have varying potencies and scheduling. This study demonstrates a combined gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) and nuclear magnetic resonance (NMR) spectroscopy approach for the differentiation of N-butyl pentylone isomers based on distinct retention times, characteristic EI mass spectra, and NMR characterization. Retention time reproducibility was assessed from 60 replicate measurements for each isomer over the course of a month. In addition, the effect of the mass spectrometer tune and the stability of an identified characteristic ion ratio using spectral data from ± 1 scan on either side of the peak apex were also statistically assessed using Welch's ANOVA testing. The presence of diastereomers for N-sec-butyl pentylone was identified using the developed GC-EI-MS method, which was confirmed using one-dimensional and two-dimensional NMR spectroscopy. The retention time reproducibility of the chromatographic method was ± 0.076% or less over the course of a month. An identified characteristic ion ratio between the abundance of the fragment ion at m/z 128 and the fragment ion at m/z 72 enabled the differentiation of the four N-butyl pentylone isomers, even when accounting for the effect of the mass spectrometer tune and mass spectral scans used to calculate the characteristic ion ratio. The 95% confidence interval mean abundance ratio of the fragment ions at m/z 128 and m/z 72 was 17.14 ± 0.14 for N-butyl pentylone, 6.44 ± 0.05 for N-isobutyl pentylone, 3.38 ± 0.02 for N-sec-butyl pentylone, and 0.75 ± 0.01 for N-tert-butyl pentylone. These results highlight the capabilities of a combined GC-EI-MS and NMR approach for the differentiation and characterization of synthetic cathinone isomers.

Assessment of the Permeability of 3,4-Methylenedioxypyrovalerone (MDPV) across the Caco-2 Monolayer for Estimation of Intestinal Absorption and Enantioselectivity.

3,4-Methylenedioxypyrovalerone (MDPV) is a widely studied synthetic cathinone heterocycle mainly concerning its psychoactive effects. It is a chiral molecule and one of the most abused new psychoactive substances worldwide. Enantioselectivity studies for MDPV are still scarce and the extent to which it crosses the intestinal membrane is still unknown. Herein, an in vitro permeability study was performed to evaluate the passage of the enantiomers of MDPV across the Caco-2 monolayer. To detect and quantify MDPV, a UHPLC-UV method was developed and validated. Acceptable values within the recommended limits were obtained for all evaluated parameters (specificity, linearity, accuracy, limit of detection (LOD), limit of quantification (LOQ) and precision). The enantiomers of MDPV were found to be highly permeable across the Caco-2 monolayer, which can indicate a high intestinal permeability. Enantioselectivity was observed for the Papp values in the basolateral (BL) to apical (AP) direction. Furthermore, efflux ratios are indicative of efflux through a facilitated diffusion mechanism. To the best of our knowledge, determination of the permeability of MDPV across the intestinal epithelial cell monolayer is presented here for the first time.

Relative reinforcing effects of dibutylone, ethylone, and N-ethylpentylone: self-administration and behavioral economics analysis in rats.

RATIONALE: Following the emergence of methylone as one of the most popular synthetic cathinones, this group of novel psychoactive substance with names ending in "-lone," such as dibutylone, ethylone, and N-ethylpentylone, appeared on the recreational drug market. The pharmacological mechanisms of dibutylone, ethylone, and N-ethylpentylone are well understood; however, to date, the reinforcing effects of dibutylone, ethylone, and N-ethylpentylone are still unclear. OBJECTIVES: This study aimed to examine the self-administration of dibutylone, ethylone, and N-ethylpentylone relative to methamphetamine (METH) and to quantify their relative reinforcing effectiveness using behavioral economic analysis. METHODS: Male Sprague-Dawley rats were trained to self-administer METH (0.05 mg/kg) under a fixed-ratio 1 (FR1) schedule. Following the training, dose substitution was used to generate full dose-response curves for METH and the three synthetic cathinones. According to the first doses on the descending limb of the dose-response curves, rats were trained to self-administer METH (0.05 mg/kg), dibutylone (0.1 mg·kg-1·infusion-1), ethylone (0.4 mg·kg-1·infusion-1), or N-ethylpentylone (0.1 mg·kg-1·infusion-1) under an FR1 schedule, and a behavioral economic evaluation of their reinforcing effectiveness was then performed. RESULTS: Dibutylone, ethylone, and N-ethylpentylone functioned as reinforcers, and the inverted U-shaped dose-response curves were obtained. The rank order of reinforcing potency in this procedure was METH > N-ethylpentylone ≈ dibutylone > ethylone. In the economic analysis, the comparisons of the essential value (EV) transformed from demand elasticity (α) indicated that the rank order of efficacy as reinforcers was METH (EV = 7.93) ≈ dibutylone (EV = 7.81) > N-ethylpentylone (EV = 5.21) ≈ ethylone (EV = 4.19). CONCLUSIONS: These findings demonstrated that dibutylone, ethylone, and N-ethylpentylone function as reinforcers and have addictive potential, suggesting that the modification of α-alkyl and N-alkyl side chains may affect their reinforcing efficacy.

A fatal case of intoxication from a single use of eutylone: Clinical symptoms and quantitative analysis results.

Eutylone is a synthetic cathinone that is becoming an increasingly popular drug in the US and Europe. This report describes a fatal case of eutylone intoxication. A 32-year-old man went into cardiac arrest after several minutes of abnormal behavior. Rectal temperature was 37.0 °C at 5 h after death. Autopsy revealed no remarkable injuries apart from several small abrasions and no signs of rhabdomyolysis. Toxicological examination revealed only aripiprazole in the therapeutic range and eutylone. The eutylone concentration in cardiac blood was 4290 ng/g. This case is valuable because it involved fatal intoxication from a single use of eutylone and quantitative analysis, whereas most previous reports of eutylone intoxication have involved a mixture of drugs with limited quantitative analysis.

Comparison of clinical characteristics between meth/amphetamine and synthetic cathinone users presented to the emergency department.

BACKGROUND: Synthetic cathinones (SC) are popular new psychoactive substances that produce sympathomimetic toxicity. Meth/amphetamine and SC have similar chemical structures and pharmacological effects. We aimed to compare the clinical characteristics between meth/amphetamine and SC users presenting to the emergency department (ED). METHODS: This retrospective observational cohort study included patients who presented to six EDs from May 2017 to April 2021 with symptoms that related to recreational drug use and whose urine toxicology tests were positive only for meth/amphetamine or SC through liquid chromatography-tandem mass spectrometry. RESULTS: There were 379 patients who tested positive only for meth/amphetamine (MA group), and 87 patients tested positive only for SC (SC groups). Patients in the MA group were older than those in the SC group (median (IQR); MA: 37.0 (30-43.7), SC: 25.0 (21.0-32.7), p < 0.001). There were no significant between-group differences in the sex distribution and initial chief complaints. Compared with the MA group, the SC group had more cases of tachycardia (≥ 135/min; MA: 29 (8.2%), SC:16 (19.0%), p = 0.0031) and hyperthermia (≥ 38 °C; MA: 31 (8.2%), SC:18 (20.7%), p = 0.001). Besides, the SC group had significantly higher levels of creatinine kinase (CK, IU/L; MA: 263 (115-601), SC: 497 (206-9216), p = 0.008) as well as a higher risk of rhabdomyolysis (CK > 1000; MA:32 (8.4%), SC: 16 (18.4%), p = 0.006) and severe rhabdomyolysis (CK > 10,000; MA:10 (2.6%), SC:10 (11.5%), p = 001). Multivariable logistic regression analyses indicated SC group in comparison with the MA group (adjusted odds ratio: 2.732, 95% confidence interval: 1. 250-5.972, p = 0.012) was an association with the risk of rhabdomyolysis. CONCLUSION: Our findings demonstrate that tachycardia, hyperthermia, and rhabdomyolysis were more common among cathinone users than among meth/amphetamine users presented to EDs.

3F-α-pyrrolydinovalerophenone (3F-α-PVP) in vitro human metabolism: Multiple in silico predictions to assist in LC-HRMS/MS analysis and targeted/untargeted data mining.

Synthetic cathinones (SCs) constitute a heterogenous class of new psychoactive substances (NPS), structurally related to cathinone. SCs represent the widest NPS class, second to synthetic cannabinoids, accounting for approximately 160 different analogues with substitution at the phenyl group, the amine group, or the alkyl chain. In 2020, α-pyrrolidonophenone analogues were the most trafficked SCs, and were involved in many fatalities and intoxication cases. In particular, 3F-α-pyrrolidinovalerophenone (3F-α-PVP) was the cause of the highest number of SC-related fatal intoxications in Sweden in 2018. Minor structural modifications are used to avoid legal controls and analytical detection, but may also induce different toxicological profile. Therefore, the identification of specific markers of consumption is essential to discriminate SCs in clinical and forensic toxicology. In this study, we assessed 3F-α-PVP metabolic profile. 3F-α-PVP was incubated with 10-donor-pooled human hepatocytes, LC-HRMS/MS analysis, and software-assisted data mining. This well-established workflow was completed by in silico metabolite predictions using three different freeware. Ten metabolites were identified after 3 h incubation, including hydrogenated, hydroxylated, oxidated, and N-dealkylated metabolites. A total of 51 phase I and II metabolites were predicted, among which 7 were detected in the incubations. We suggest 3F-α-PVP N-butanoic acid, 3F-α-PVP pentanol, and 3F-α-PVP 2-ketopyrrolidinyl-pentanol as specific biomarkers of 3F-α-PVP consumption. This is the first time that an N-ethanoic acid is detected in the metabolic pathway of a pyrrolidine SC, demonstrating the importance of a dual targeted/untargeted data mining strategy.

The Illicit Supply of New Psychoactive Substances Within and From China: A Descriptive Analysis.

Although China has played a significant role in the emergence and expansion of new psychoactive substances (NPS) worldwide, little research has specifically focused on the illicit supply of NPS within China and smuggling from China. In this study, data were extracted from sentencing files obtained from closed criminal cases to develop an objective understanding of the NPS supply chain in China. The sample consisted of 341 major cases concerning the illicit supply of three groups of NPS (ketamine, synthetic cathinone, and fentanyl) and five categories of offense, including manufacturing, distributing, retailing, transporting, and manufacturing-retailing. Significant differences between these categories of offense in terms of offenders' profiles, behaviors, and supply patterns were observed. Our results suggest the existence of a dynamic and complex supply network both in China and in terms of smuggling routes from China.

Synthetic drugs of abuse.

Synthetic drugs of abuse contain various psychoactive substances. These substances have recently emerged as novel drugs of abuse in public; thus, they are known as novel psychoactive substances (NPS). As these compounds are artificially synthesized in a laboratory, they are also called designer drugs. Synthetic cannabinoids and synthetic cathinones are the two primary classes of NPS or designer drugs. Synthetic cannabinoids, also known as "K2" or "Spice," are potent agonists of the cannabinoid receptors. Synthetic cathinones, known as "Bath salts," are beta-keto amphetamine derivatives. These compounds can cause severe intoxication, including overdose deaths. NPS are accessible locally and online. NPS are scheduled in the US and other countries, but the underground chemists keep modifying the chemical structure of these compounds to avoid legal regulation; thus, these compounds have been evolving rapidly. These drugs are not detectable by traditional drug screening, and thus, these substances are mainly abused by young individuals and others who wish to avoid drug detection. These compounds are analyzed primarily by mass spectrometry.