Prevalence and co-existence of active components of 'legal highs'

Chemical composition of Ecstasy tablets seized in Poland between 2005 and 2020

PURPOSE

The most commonly associated substance found in Ecstasy tablets is MDMA (3,4-methylenedioxymethamphetamine). In our study, we showed how the composition of psychoactive ingredients in Ecstasy tablets seized on the drug market in Poland has changed in the years 2005-2020.

METHODS

The study material consisted of nearly 20,000 single Ecstasy tablets seized by representatives of law enforcement (the police, prosecutors) from 2005 to 2020 and analysed by the Institute of Forensic Research, Krakow, Poland. The analysis of the tablets was carried out by gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography with diode array detection (HPLC-DAD) and ultra-high-performance liquid chromatography with photodiode array detection (UHPLC-PDA).

RESULTS

Currently, new types of MDMA tablets are introduced onto the market, available in various colours and shapes. Our study showed that tablets sold on the street as Ecstasy have variable purity and sometimes contain little or no MDMA. The mean content of MDMA in one tablet seized in 2005-2011 decreased from 90 to 50 mg. In 2013, Ecstasy tablets with a very high MDMA content (average 195 mg per tablet) appeared on the market, but in the next 2 years, the MDMA content decreased again. From 2016, the average MDMA content began to rise again, ranging from 60 to 280 mg.

CONCLUSION

Tablets sold as Ecstasy also contained completely different psychoactive substances, including new psychoactive substances (NPS) (found in almost 20% of all examined tablets sold as Ecstasy) belonging to different chemical groups or their dangerous combinations (i.e. phenylethylamines, piperazines, tryptamines, cathinones, arylalkylamines, arylcyclohexylamines and piperidines). Such a large variety of psychoactive substances in Ecstasy tablets is associated with a high risk for users unaware of their composition.

Identification of three unexpected new psychoactive substances at an Australian drug checking service

Drug checking is a harm reduction measure that provides people with the opportunity to confirm the identity and purity of substances before consumption. The CanTEST Health and Drug Checking Service is Australia's first fixed-site drug checking service, where clients can learn about the contents of the samples they provide while receiving tailored harm reduction and health advice. Three samples were recently presented to the service with the expectation of 4-fluoromethylphenidate (4F-MPH) 1, methoxetamine (MXE) 2 and 3-methylmethcathinone (3-MMC) 3. The identity of all three samples did not meet these expectations and remained unknown on-site, as no high confidence identifications were obtained. However, further analysis by nuclear magnetic resonance spectroscopy, high resolution gas chromatography-electron ionisation-mass spectrometry and liquid chromatography-electrospray ionisation-mass spectrometry at the nearby Australian National University allowed for the structure elucidation of the three samples as 4-fluoro-α-pyrrolidinoisohexanophenone (4F-α-PiHP) 4, 1-(4-fluorobenzyl)-4-methylpiperazine (4F-MBZP) 5 and N-propyl-1,2-diphenylethylamine (propylphenidine) 6, respectively. Given all three samples were not of the expected identity and have not yet been described as new psychoactive substances in the literature, this study presents a full characterisation of each compound. As exemplified by this rapid identification of three unexpected new psychoactive substances, drug checking can be used as an effective method to monitor the unregulated drug market.

Comparison of Psychiatric and Clinical Profiles Between People Who Use Synthetic Cathinones and Methamphetamine: A Matched Case-Control Study

BACKGROUND

Synthetic cathinones are the most used novel psychoactive substances in Taiwan because they exhibit psychoactive effects similar to those of methamphetamine, inducing acute psychosis, violence, and self-harm. However, the differences in the clinical characteristics of patients with synthetic cathinone and methamphetamine intoxication admitted to psychiatric emergency departments (EDs) remain unclear.

METHODS

This study recruited patients with stimulant intoxication who were admitted to a psychiatric ED from April 2019 to May 2020. Sociodemographic, lifestyle, and psychopathological data were collected through face-to-face interviews and evaluated. Immunoassay tests and liquid chromatography-quadrupole time-of-flight mass spectrometry were performed to detect substances in urine specimens. The patients were matched by sex and age (in 5-year intervals). The associations between the 2 groups and physical complications were analyzed through logistic regression.

RESULTS

Twenty-four patients with synthetic cathinone intoxication were identified and matched with 48 patients with methamphetamine intoxication. The 2 groups exhibited similar clinical severity of psychotic symptoms and high risks of violence and self-harm. Both groups were predominated by unmarried patients, unemployed patients, and habitual smokers and drinkers. However, family histories of substance use and criminal records were less prevalent among the patients with synthetic cathinone intoxication, but they had a higher rate of physical complications (odds ratio, 8.55; 95% confidence interval, 2.15-34.03), compared with patients with methamphetamine intoxication.

CONCLUSIONS

Compared with patients intoxicated with methamphetamine, those intoxicated with synthetic cathinones may have similar tendencies toward psychosis, violence, and self-harm but higher risks of physical complications, which are prioritized in psychiatric EDs.

Toxicological Analysis of Cases of Mixed Poisonings with Synthetic Cathinones and Other Drugs of Abuse

Some of the most commonly used new psychoactive substances (NPSs) are synthetic cathinones (SCs). The literature increasingly indicates that SCs have a significant addictive potential and pose a high risk to human health and life. The vast majority of SC users take a number of substances simultaneously. This article lists the detected concentrations in 26 fatal and 2 non-fatal real cases, in which SCs or an SC along with other substances were determined in blood and other biological materials. The following SCs were found most often: α-pyrrolidinohexiophenone, α-pyrrolidinopentiophenone, N-ethylpentedrone (NEP), 4-methyl-α-ethylaminopentiophenone and N-ethylhexedrone. In addition to detected SCs, the analyzed samples showed the presence of conventional drugs such as methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine, amphetamine and NPSs from groups other than SCs, such as synthetic cannabinoids (UR-144 and 5F-AMB), synthetic opioids (AH-7921, U-47700 and 4-fluorobutyrfentanyl) and others (desoxypipradrol and etizolam). The quantitative analyses were carried out by liquid chromatography with tandem mass spectrometry (LC-MS-MS). This study presents pioneering data on concentrations and effects of 4-ethylmethcathinone, NEP, N-ethylbuphedrone and mexedrone. Also noteworthy are the data on SCs that until now have rarely been described in the literature together with specified blood concentrations. The analyzed cases of taking SCs were associated with fatal intoxication (n = 26), driving under the influence of drugs (n = 2) and death caused by beating (n = 1). Taking SCs has serious side effects that can lead to multiple organ failure and death. The use of more than one psychoactive substance simultaneously (including at least one SC) contributes to increased SC toxicity. These data could be valuable for further interpretation of other results from toxicological analyses.

Synthetic Cathinones: Recent Developments, Enantioselectivity Studies and Enantioseparation Methods

New psychoactive substances represent a public health threat since they are not controlled by international conventions, are easily accessible online and are sold as a legal alternative to illicit drugs. Among them, synthetic cathinones are widely abused due to their stimulant and hallucinogenic effects. To circumvent the law, new derivatives are clandestinely synthesized and, therefore, synthetic cathinones keep emerging on the drug market, with their chemical and toxicological properties still unknown. In this review, a literature assessment about synthetic cathinones is presented focusing on the recent developments, which include more than 50 derivatives since 2014. A summary of their toxicokinetic and toxicodynamic properties are also presented. Furthermore, synthetic cathinones are chiral compounds, meaning that they can exist as two enantiomeric forms which may present different biological and toxicological activities. To analyze the enantiomers, the development of enantiomeric resolution methods for synthetic cathinones is crucial. Many methods have been reported over the years that include mostly chromatographic and electromigration techniques, with liquid chromatography using chiral stationary phases being the technique of choice. This review intended to present an overview of enantioselectivity studies and enantioseparation analysis regarding synthetic cathinones, highlighting the relevance of chirality and current trends.

Application of dose-addition analyses to characterize the abuse-related effects of drug mixtures

Polysubstance use makes up a majority of drug use, yet relatively few studies investigate the abuse-related effects of drug mixtures. Dose-addition analyses provide a rigorous and quantitative method to determine the nature of the interaction (i.e., supraadditive, additive, or subadditive) between two or more drugs. As briefly reviewed here, studies in rhesus monkeys have applied dose-addition analyses to group level data to characterize the nature of the interaction between the reinforcing effects of stimulants and opioids (e.g., mixtures of cocaine + heroin). Building upon these foundational studies, more recent work has applied dose-addition analyses to better understand the nature of the interaction between caffeine and illicit stimulants such as MDPV and methamphetamine in rats. In addition to utilizing a variety of operant procedures, including drug discrimination, drug self-administration, and drug-primed reinstatement, these studies have incorporated potency and effectiveness ratios as a method for both statistical analysis and visualization of departures from additivity at both the group and individual subject level. As such, dose-addition analyses represent a powerful and underutilized approach to quantify the nature of drug-drug interactions that can be applied to a variety of abuse-related endpoints in order to better understand the behavioral pharmacology of polysubstance use.

Prevalence of cathinones and other new psychoactive substances in hair of parents and children of families with known or suspected parental abuse of conventional illegal drugs

BACKGROUND

Hair analysis of parents and their children was regularly used since 2011 as a diagnostic tool in a social support project for families with known or suspected abuse of conventional illegal drugs and revealed a high incidence of cocaine, cannabinoids, amphetamines, ecstasy and heroin. In this context, the prevalence of new psychoactive substances (NPS) in these families should be important for a realistic estimate of the situation.

METHODS

The extracts of 1537 hair samples from 318 children (age 1-14 years), 44 adolescents and 611 adults, which were collected and tested for conventional drugs between June 2016 and April 2021 and frozen at -20 °C, were reanalyzed by a validated LC-MS/MS method (limits of quantitation 5-24 pg/mg) for 33 cathinones, 10 phenylethylamines, 5 piperazines including the antidepressant trazodone, 2 tryptamines, 9 designer benzodiazepines, 4 synthetic opioids and 4 ketamine-like substances including phencyclidine.

RESULTS

Between one and up to five from 42 of these substances were detected in 227 samples (14.8%). The most frequently detected substances were benzedrone (62x), α-pyrrolidinovalerophenone (41x), N-ethylamphetamine (29x), dimethyltryptamine (13x) and pyrovalerone (11x). The quantification was possible only for 34 results of 15 drugs and the remaining majority of the results were unambiguously identified below LLOQ. The relative frequency of conventional drugs in the 227 NPS positive samples was higher than in all 1310 NPS negative samples for cocaine (69.6% vs. 56.0%), heroin (6-acetylmorphine 8.8% vs. 4.9%), amphetamine (16.3% vs. 7.7%) and MDMA (16.3% vs. 7.0%) but was similar for THC (38.3% vs. 36.3%) and benzodiazepines (1.8% vs. 1.7%). The high prevalence of N-ethylamphetamine can be explained as a byproduct of the illicit amphetamine synthesis from benzaldehyde and nitroethane rather than as a separate drug or as a combined metabolite of amphetamine and ethanol. The isolated appearance of 3-trifluoromethylphenylpiperazine in 9 hair samples collected in January 2017 can be caused either by its use as an NPS or by its formation as a metabolite of the medical drug flibanserin. The results were compared within 17 families whose members were tested at the same time and showed positive NPS results. The detected drugs agreed between both parents only in about half of the cases whereas the drugs found in children's hair was always detected also in hair of one or both parents.

CONCLUSION

The re-testing of hair extracts for NPS after long-time storage in frozen state enables an impression about the relative high prevalence in the tested population group, despite the limitation by partial degradation of the substances and the corresponding impossibility in quantitative assessments. In addition to conventional drugs, the hair test for these substances should be useful in unclear cases of child's welfare endangerment and in family law.

Prevalence and concentrations of new designer stimulants, synthetic opioids, benzodiazepines, and hallucinogens in postmortem hair samples: A 13-year retrospective study

Hair samples are frequently analyzed in order to characterize consumption patterns of drugs. However, the interpretation of new psychoactive substance (NPS) findings in hair remains difficult because of lacking data for comparison. In this study, selected postmortem hair samples (n = 1203) from 2008 to 2020 were reanalyzed for synthetic cathinones, piperazines, phenethylamines, hallucinogens, benzodiazepines and opioids to evaluate prevalence data and concentration ranges. Hair samples were extracted using a two-step extraction procedure and analyzed using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Overall NPSs were detected in 381 cases (31.6%). Many cases were tested positive for more than one NPS in the same time span. A variety of NPS with a large range of concentrations was observed. For better comparability and interpretation of positive cases in routine work, quantitation data for 13 NPS were calculated as percentiles. The most frequently detected NPS in this study were N-ethylamphetamine, α-pyrrolidinovalerophenone, mephedrone, benzedrone, metamfepramone, and 4-fluoroamphetamine. In conclusion, a high prevalence of these drugs was observed from postmortem hair samples. The results show a growing use of many different NPSs by mainly young drug-using adults. Consequently, NPS screening procedures should be included in forensic toxicology. Our quantitative data may support other toxicologists in their assessment of NPS hair concentrations.

The Pharmacological Profile of Second Generation Pyrovalerone Cathinones and Related Cathinone Derivative

Pyrovalerone cathinones are potent psychoactive substances that possess a pyrrolidine moiety. Pyrovalerone-type novel psychoactive substances (NPS) are continuously detected but their pharmacology and toxicology are largely unknown. We assessed several pyrovalerone and related cathinone derivatives at the human norepinephrine (NET), dopamine (DAT), and serotonin (SERT) uptake transporters using HEK293 cells overexpressing each respective transporter. We examined the transporter-mediated monoamine efflux in preloaded cells. The receptor binding and activation potency was also assessed at the 5-HT_1A, 5-HT_2A, 5-HT_2B, and 5-HT_2C receptors. All pyrovalerone cathinones were potent DAT (IC₅₀ = 0.02-8.7 μM) and NET inhibitors (IC₅₀ = 0.03-4.6 μM), and exhibited no SERT activity at concentrations < 10 μM. None of the compounds induced monoamine efflux. NEH was a potent DAT/NET inhibitor (IC₅₀ = 0.17-0.18 μM). 4F-PBP and NEH exhibited a high selectivity for the DAT (DAT/SERT ratio = 264-356). Extension of the alkyl chain enhanced NET and DAT inhibition potency, while presence of a 3,4-methylenedioxy moiety increased SERT inhibition potency. Most compounds did not exhibit any relevant activity at other monoamine receptors. In conclusion, 4F-PBP and NEH were selective DAT/NET inhibitors indicating that these substances likely produce strong psychostimulant effects and have a high abuse liability.

Analysis of Google Trends to monitor new psychoactive substance. Is there an added value?

The past decade has seen an increase in the development and availability of a broad category of drugs, known as new psychoactive substances (NPS). NPS are challenging for public health authorities, therefore the two major drug monitoring bodies - the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and the United Nations Office on Drugs and Crime (UNODC) - have implemented the EU Early Warning System (EWS) and Early Warning Advisory (EWA), respectively. While these monitoring systems are informative, it is difficult to keep up with the constant and rapid developmental rate of NPS. The EMCDDA has recognised the need for an alternative and technologically derived early warning system. The aim of this research is to determine whether Google Trends and drug discussion forum data can be used to complement early warning systems for NPS. Forty-eight substances were used in this study and classed into groups based on their chemical structure, following the UNODC classification system. Google Trends data (time range: 2004-2019) and drug forum data (time range: 2003-2018) were extracted for each substance and visual trend profiles were created for class groups as well as individual substances. Analysis was conducted to determine when a substance first appeared on Google Trends and a drug discussion forum as well as their trends over time. This date of first appearance was then compared to the date the substance was first reported to UNODC. Of the three data sources utilised, substances were most likely to appear on Google Trends first. Amongst the different classes of NPS, discernible trends ('block', 'successive', and 'generational' trends) were observed. These trends reflect the evolution of the manufacture of substances or generations of substances that has been observed in the literature. For example, in the synthetic cannabinoids' category, a generational trend is observed that corresponds to the different generations of synthetic cannabinoids. When comparing Google Trends and Drugs-Forum directly, the order of appearance and duration of presence for substances aligns accurately for most classes. Google Trends showed the emergence, persistence, or transient nature of substances, which could direct the focus of law enforcement, health organisation and laboratory resources towards a limited number of substances. When one considers the reliance of individual information seeking on the Web as well as the prominence of NPS on the Web, it becomes clear that Google Trends and drug discussion forums could be used as a complement to current early warning systems.

An updated review on synthetic cathinones

Cathinone, the main psychoactive compound found in the plant Catha edulis Forsk. (khat), is a β-keto analogue of amphetamine, sharing not only the phenethylamine structure, but also the amphetamine-like stimulant effects. Synthetic cathinones are derivatives of the naturally occurring cathinone that largely entered the recreational drug market at the end of 2000s. The former "legal status", impressive marketing strategies and their commercial availability, either in the so-called "smartshops" or via the Internet, prompted their large spread, contributing to their increasing popularity in the following years. As their popularity increased, the risks posed for public health became clear, with several reports of intoxications and deaths involving these substances appearing both in the social media and scientific literature. The regulatory measures introduced thereafter to halt these trending drugs of abuse have proved to be of low impact, as a continuous emergence of new non-controlled derivatives keep appearing to replace those prohibited. Users resort to synthetic cathinones due to their psychostimulant properties but are often unaware of the dangers they may incur when using these substances. Therefore, studies aimed at unveiling the pharmacological and toxicological properties of these substances are imperative, as they will provide increased expertise to the clinicians that face this problem on a daily basis. The present work provides a comprehensive review on history and legal status, chemistry, pharmacokinetics, pharmacodynamics, adverse effects and lethality in humans, as well as on the current knowledge of the neurotoxic mechanisms of synthetic cathinones.

Reinforcing effects of synthetic cathinones in rhesus monkeys: Dose-response and behavioral economic analyses

The abuse of synthetic cathinones ("bath salts") with psychomotor stimulant and/or entactogenic properties emerged as a public health concern when they were introduced as "legal" alternatives to drugs of abuse such as cocaine or MDMA. In this study, experiments were conducted in nonhuman primates to examine how differences in transporter selectivity might impact the reinforcing effects of synthetic cathinones. Rhesus monkeys (N = 5) were trained to respond for intravenous injections under a fixed-ratio (FR) 30, timeout 60-s schedule of reinforcement. The reinforcing effects of selected cathinones (e.g., MDPV, αPVP, MCAT, and methylone) with a range of pharmacological effects at dopamine and serotonin transporters were compared to cocaine and MDMA using dose-response analysis under a simple FR schedule and behavioral economic procedures that generated demand curves for two doses of each drug. Results show that one or more doses of all drugs were readily self-administered in each subject and, excepting MDMA (21 injections/session), peak levels of self-administration were similar across drugs (between 30 and 40 injections/session). Demand elasticity for the peak and the peak + 1/2-log dose of each drug did not significantly differ, and when data for the two doses were averaged for each drug, the following rank-order of reinforcing strength emerged: cocaine > MCAT = MDPV = methylone > αPVP = MDMA. These results indicate that the reinforcing strength of synthetic cathinones are not related to their selectivity in binding dopamine or serotonin transporter sites.

Simultaneous determination of 10 new psychoactive piperazine derivatives in urine using ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction combined with gas chromatography-tandem mass spectrometry

With the rapid development of synthetic drugs, novel piperazine derivatives, as an increasingly important class of new psychoactive substances (NPS), have attracted global attention owing to their increasing demand in the illicit drug market. In this study, ten piperazine derivatives were analyzed in urine samples after pre-treatment with ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction (UA-LDS-DLLME) combined with gas chromatography-tandem mass spectrometry (GC-MS/MS). This simple approach involved the use of urine samples (1 mL) adjusted to pH 12, which was added to 100 µL of n-hexane and subjected to ultrasonication for 3 min to completely disperse the sample in the n-hexane solution. The resulting turbid suspension was centrifuged at 10,000 rpm for 3 min, and the supernatant was extracted and analyzed using GC-MS/MS. Under the optimized conditions presented in this study, the linear relationship between the analytes was good within 10-1500 ng/mL, and the correlation coefficient (r) was between .9914 and .9983. The limit of detection (LOD) was 0.3-2 ng/mL (S/N = 3), and the lower limit of quantification (LLOQ) was 10 ng/mL (S/N = 10) with the recovery of the analytes of interest from the spiked samples being 76.3%-93.3%. This method has been used to analyze real-world samples; our study shows that the UA-LDS-DLLME approach can be used for rapid analysis while consuming minimal solvent for the simultaneous determination of a range of analytes. This method has the potential for use in clinical analyses and forensic toxicology.

Exploring the Baseline Knowledge and Experience of Healthcare Professionals in the United Kingdom on Novel Psychoactive Substances

Objective: This survey aimed to explore knowledge and experience on novel psychoactive substances (NPS) of healthcare professionals (HCPs). The study also aimed to assess how HCPs would like to improve their knowledge of NPS. Methods: Seventy paper questionnaires were disseminated in 2017 within continuing education events to pharmacists, nurses and general practitioners (GPs). Additionally, 127 online surveys were completed using the Qualtrics platform by other HCPs and mental health nurses in six United Kingdom (UK) independent mental health hospitals long-stay in-patient rehabilitation services. Two educational sessions involving pharmacists and GPs were also held in late 2017 and mid-2018. Knowledge of NPS by HCPs was evaluated prior to the start of the educational events. Evaluation forms were handed out post-sessions to garner feedback, especially on areas for improvement for future sessions. Statistical analysis of data was undertaken using SPSS (V.25). Results: Most HCPs reported only ‘basic’ to ‘intermediate’ NPS knowledge. Substance misuse service staff felt more informed, were more often consulted and had greater confidence regarding NPS compared to hospital and primary care professionals. A negative association was found between the age of the HCP and knowledge of NPS. Most participants expressed a need for regular training and updates as insufficient NPS-related information is currently received. Conclusions: An improvement within the self-reported knowledge of HCPs on NPS is evident in comparison to previous studies. Continued education of HCPs on NPS is fundamental for the provision of improved harm reduction services, which can enhance overall care for NPS service users.

Synthetic Cathinones Induce Cell Death in Dopaminergic SH-SY5Y Cells via Stimulating Mitochondrial Dysfunction

Increasing reports of neurological and psychiatric complications due to psychostimulant synthetic cathinones (SCs) have recently raised public concern. However, the precise mechanism of SC toxicity is unclear. This paucity of understanding highlights the need to investigate the in-vitro toxicity and mechanistic pathways of three SCs: butylone, pentylone, and 3,4-Methylenedioxypyrovalerone (MDPV). Human neuronal cells of SH-SY5Y were cultured in supplemented DMEM/F12 media and differentiated to a neuronal phenotype using retinoic acid (10 μM) and 12-O-tetradecanoylphorbol-13-acetate (81 nM). Trypan blue and lactate dehydrogenase assays were utilized to assess the neurotoxicity potential and potency of these three SCs. To investigate the underlying neurotoxicity mechanisms, measurements included markers of oxidative stress, mitochondrial bioenergetics, and intracellular calcium (Ca²⁺), and cell death pathways were evaluated at two doses (EC₁₅ and EC₄₀), for each drug tested. Following 24 h of treatment, all three SCs exhibited a dose-dependent neurotoxicity, characterized by a significant (p < 0.0001 vs. control) production of reactive oxygen species, decreased mitochondrial bioenergetics, and increased intracellular Ca²⁺ concentrations. The activation of caspases 3 and 7 implicated the orchestration of mitochondrial-mediated neurotoxicity mechanisms for these SCs. Identifying novel therapeutic agents to enhance an altered mitochondrial function may help in the treatment of acute-neurological complications arising from the illicit use of these SCs.

The phenomenon of para-Fluorophenylpiperazine (pFPP) in combination with the synthetic cannabinoid AMB-FUBINACA in seized plant material in New Zealand

New psychoactive substances have emerged as a vast and diverse group of illicit drugs over the past decade, with synthetic cannabinoids comprising the largest of the categories. Commonly, a single synthetic cannabinoid is applied to plant material, creating a product that is designed to be smoked by the user. The clandestine preparation process can result in an unevenly distributed product, with varying concentration within and between plant materials. This investigation describes the novel co-detection of the synthetic cannabinoid AMB-FUBINACA, with the piperazine para-fluorophenylpiperazine (pFPP), in a number of plant material samples analysed in New Zealand in 2017. Of 157 samples of plant material containing AMB-FUBINACA, pFPP was detected in 55 of them. A range of pFPP concentrations was observed between the plant material samples, as well as intra-batch variation. The presence of both drugs may be designed to enhance, prolong or balance the psychoactive effects caused from smoking the plant material. However the intended purpose has not been verified. This is the first reported combination of a synthetic cannabinoid and a piperazine in plant material.

Synthetic cathinones: an evolving class of new psychoactive substances

Synthetic cathinones (SCat) are amphetamine-like psychostimulants that emerged onto drug markets as "legal" alternatives to illicit drugs such as ecstasy, cocaine, and amphetamines. Usually they are sold as "bath salts," "plant food," or "research chemicals," and rapidly gained popularity amongst drugs users due to their potency, low cost, and availability. In addition, internet drug sales have been replacing the old way of supplying drugs of abuse, contributing to their rapid spread. Despite the legislative efforts to control SCat, new derivatives continue to emerge on the recreational drugs market and their abuse still represents a serious public health issue. To date, about 150 SCat have been identified on the clandestine drugs market, which are one of the largest groups of new psychoactive substances (NPS) monitored by the United Nations Office on Drugs and Crime and the European Monitoring Center for Drugs and Drug Addiction. Similar to the classical stimulants, SCat affect the levels of catecholamines in the central nervous system, which results in their psychological, behavioral and toxic effects. Generally, the effects of SCat greatly differ from drug to drug and relatively little information is available about their pharmacology. The present work provides a review on the development of SCat as substances of abuse, current patterns of abuse and their legal status, chemical classification, known mechanisms of action, and their toxicological effects.

Effects of MDPV on dopamine transporter regulation in male rats. Comparison with cocaine

RATIONALE

MDPV (3,4-methylenedioxypyrovalerone) is a synthetic cathinone present in bath salts. It is a powerful psychostimulant and blocker of the dopamine transporter (DAT), like cocaine. It is known that acute exposure to psychostimulants induces rapid changes in DAT function.

OBJECTIVES

To investigate the effects of MDPV on DAT function comparing with cocaine.

METHODS

Binding of [³H]WIN 35428 was performed on PC 12 cells treated with MDPV and washed. Rat striatal synaptosomes were incubated with MDPV or cocaine (1 μM) for 1 h and [³H]dopamine (DA) uptake was performed. Also, different treatments with MDPV or cocaine were performed in Sprague-Dawley rats to assess locomotor activity and ex vivo [³H]DA uptake.

RESULTS

MDPV increased surface [³H]WIN 35428 binding on PC 12 cells. In vitro incubation of synaptosomes with MDPV produced significant increases in V_max and K_M for [³H]DA uptake. In synaptosomes from MDPV- (1.5 mg/kg, s.c.) and cocaine- (30 mg/kg, i.p.) treated rats, there was a significantly higher and more persistent increase in [³H]DA uptake in the case of MDPV than cocaine. Repeated doses of MDPV developed tolerance to this DAT upregulation and 24 h after the 5-day treatment with MDPV, [³H]DA uptake was reduced. However, a challenge with the same drugs after withdrawal recovered the DAT upregulation by both drugs and showed an increased response to MDPV vs the first dose. At the same time, animals were sensitized to the stereotypies induced by both psychostimulants.

CONCLUSIONS

MDPV induces a rapid and reversible functional upregulation of DAT more powerfully and lasting than cocaine.

The synthetic cathinones, butylone and pentylone, are stimulants that act as dopamine transporter blockers but 5-HT transporter substrates

RATIONALE

Synthetic cathinones continue to emerge in recreational drug markets worldwide. 1-(1,3-Benzodioxol-5-yl)-2-(methylamino)butan-1-one (butylone) and 1-(1,3-benzodioxol-5-yl)-2-(methylamino)pentan-1-one (pentylone) are derivatives of the cathinone compound, 1-(1,3-benzodioxol-5-yl)-2-(methylamino)propan-1-one (methylone), that are being detected in drug products and human casework.

OBJECTIVES

The purpose of the present study was to examine the neuropharmacology of butylone and pentylone using in vitro and in vivo methods.

METHODS

In vitro uptake and release assays were carried out in rat brain synaptosomes and in cells expressing human dopamine transporters (DAT) and 5-HT transporters (SERT). In vivo microdialysis was performed in the nucleus accumbens of conscious rats to assess drug-induced changes in neurochemistry.

RESULTS

Butylone and pentylone were efficacious uptake blockers at DAT and SERT, though pentylone was more DAT-selective. Both drugs acted as transporter substrates that evoked release of [³H]5-HT at SERT, while neither evoked release at DAT. Consistent with the release data, butylone and pentylone induced substrate-associated inward currents at SERT but not DAT. Administration of butylone or pentylone to rats (1 and 3 mg/kg, i.v.) increased extracellular monoamines and motor activity, but pentylone had weaker effects on 5-HT and stronger effects on motor stimulation.

CONCLUSIONS

Our data demonstrate that increasing the α-carbon chain length of methylone creates "hybrid" transporter compounds which act as DAT blockers but SERT substrates. Nevertheless, butylone and pentylone elevate extracellular dopamine and stimulate motor activity, suggesting both drugs possess significant risk for abuse.

Behavioral economic analysis of the reinforcing effects of "bath salts" mixtures: studies with MDPV, methylone, and caffeine in male Sprague-Dawley rats

RATIONALE

"Bath salts" preparations often contain combinations of synthetic cathinones (e.g., 3,4-methylenedioxymethcathinone [methylone], 3,4-methylenedioxypyrovalerone [MDPV]), and caffeine, and evidence suggests that mixtures of synthetic cathinones and caffeine (e.g., MDPV + caffeine or methylone + caffeine) can be more potent and/or effective reinforcers than predicted for an additive interaction.

OBJECTIVE

To use demand curve analyses to compare the reinforcing effectiveness of MDPV and methylone to mixtures of MDPV + caffeine and methylone + caffeine.

METHODS

Male Sprague-Dawley rats acquired methylone self-administration (0.32 mg/kg/inf) under a fixed ratio (FR) 1 schedule of reinforcement and generated full dose-response curves for methylone (0.01-1 mg/kg/inf) under an FR5 schedule of reinforcement. Demand curves were then obtained for methylone, MDPV, caffeine, and methylone + caffeine and MDPV + caffeine mixtures by increasing the FR across sessions according to the following series: 3, 10, 18, 32, 56, 100, 178, etc. RESULTS: Self-administration of methylone was rapidly acquired by 87.5% of rats and was maintained across a range of doses, producing an inverted U-shaped dose-response curve. Rank order demand for the individual constituents was MDPV > methylone > caffeine. Demand for the 3:1 (but not 10:1) methylone + caffeine mixture was greater than that for methylone alone, and demand for MDPV alone was similar to both MDPV + caffeine mixtures evaluated.

CONCLUSIONS

These studies provide additional evidence that although methylone is an effective reinforcer, combining methylone with caffeine results in an enhanced reinforcing effectiveness compared to methylone alone. Thus, abused "bath salts" preparations containing synthetic cathinones and caffeine may have higher abuse liability than preparations containing only synthetic cathinones.

Change in the new psychoactive substances associated with Emergency Department acute toxicity presentations associated with the introduction of the UK 2016 Psychoactive Substances Act

OBJECTIVES

In May 2016, the Psychoactive Substances Act (PSA) came into effect in UK making it an offence to produce or supply new psychoactive substances (NPS). The aim of this study was to determine whether this was associated with a change in Emergency Department (ED) presentations with acute NPS toxicity.

METHOD

ED presentations to our inner-city hospital in London, UK, with acute NPS toxicity in the 12 months before and after the PSA introduction [June 2015-May 2016 (2015/2016) and June 2016-May 2017 (2016/2017)] were obtained from our database. The following data were extracted: (i) demographics; (ii) NPS(s) self-reported [categorized as synthetic cannabinoids (SC), cathinones, and "other NPS")]; and (iii) month of presentation.

RESULTS

There were 1884 presentations with recreational drug toxicity, 447 (23.7%) involved NPS. There was no difference in the overall proportion of presentations involving an NPS in 2015/2016 [n = 196 (22.3%)] and 2016/2017 [251 (24.9%); (p = .48)]. There were a mean ± SD of 16.3 ± 3.7 NPS-related presentations per month in 2015/2016 and 20.9 ± 9.2 in 2016/2017; there was no significant change in overall monthly NPS-related presentations between these periods (p = .15). However, mean ± SD monthly SC-related presentations increased from 2015/2016 (5.9 ± 2.5) to 2016/2017 (17 ± 9.8); p = .004. Mean monthly cathinone-related presentations decreased from 2015/2016 (8.8 ± 4.2) to 2016/2017 (3.8 ± 2.7); p = .001. There was no significant change in monthly mean "other NPS" presentations from 2015/2016 (1.8 ± 2.2) to 2016/2017 (0.5 ± 0.8); p = .062. Between 2015/2016 and 2016/2017, SCs as a proportion of NPS-related presentations increased (r = .90) whilst cathinones decreased (r = -0.82).

CONCLUSION

NPS present front-line health services with unique challenges, and the PSA 2016 represents a major legislative effort in UK to limit their availability and supply. The burden of NPS use on this inner-city  ED remains large 12 months after this legislation has come into force, with evolving patterns of NPS use.

Synthetic and Non-synthetic Cannabinoid Drugs and Their Adverse Effects-A Review From Public Health Prospective

There is a growing use of novel psychoactive substances containing synthetic cannabinoids. Synthetic cannabinoid products have effects similar to those of natural cannabis, yet, these drugs are more potent and dangerous, and have been associated with dangerous adverse effects. Here, we review current literature on the epidemiology, acute, and chronic effects of synthetic and natural cannabinoid-based drugs. Synthetic drugs contain a mixture of psychoactive compounds that mostly bind cannabinoid receptors with high potency. These synthetic drugs replicate the effects of natural cannabis and Δ9-tetrahydrocannabinol but they induce more severe adverse effects including respiratory difficulties, hypertension, tachycardia, chest pain, muscle twitches, acute renal failure, anxiety, agitation, psychosis, suicidal ideation, and cognitive impairment. Chronic use of synthetic cannabinoids has been associated with serious psychiatric and medical conditions and even death. Given the growing popularity in the use of cannabinoid-based drugs and their harmful potential, there is a need for further research in this field.

Reinforcing Effects of Binary Mixtures of Common Bath Salt Constituents: Studies with 3,4-Methylenedioxypyrovalerone (MDPV), 3,4-Methylenedioxymethcathinone (methylone), and Caffeine in Rats

Bath salts use is associated with high rates of abuse, toxicity, and death. Bath salt preparations often contain mixtures of drugs including multiple synthetic cathinones (eg, 3,4-methylenedioxypyrovalerone (MDPV) or 3,4-methylenedioxymethcathinone (methylone)) or synthetic cathinones and caffeine; however, little is known about whether interactions among bath salt constituents contribute to the abuse-related effects of bath salts preparations. This study used male Sprague-Dawley rats responding under a progressive ratio schedule to quantify the reinforcing effectiveness of MDPV, methylone, and caffeine, administered alone and as binary mixtures (n=12 per mixture). Each mixture was evaluated at four ratios (10 : 1, 3 : 1, 1 : 1, and 1 : 3) relative to the mean ED₅₀ for each drug alone. Dose-addition analyses were used to determine the predicted, additive effect for each dose pair within each drug mixture. MDPV, methylone, and caffeine maintained responding in a dose-dependent manner, with MDPV being the most potent and effective, and caffeine being the least potent and effective of the three bath salts constituents. High levels of responding were also maintained by each of the bath salts mixtures. Although the nature of the interactions tended toward additivity for most bath salts mixtures, supra-additive (3 : 1 MDPV : caffeine, and 3 : 1 and 1 : 1 methylone : caffeine) and sub-additive (3 : 1, 1 : 1, and 1 : 3 MDPV : methylone) interactions were also observed. Together, these findings demonstrate that the composition of bath salts preparations can have an impact on both their reinforcing potency and effectiveness, and suggest that such interactions among constituent drugs could contribute to the patterns of use and effects reported by human bath salts users.

Intended and unintended use of cathinone mixtures

INTRODUCTION

Cathinones are one of the most popular categories of new psychoactive substances (NPS) consumed. Cathinones have different pharmacological activities and receptor selectivity for monoamine transporters based on their chemical structures. They are incorporated into NPS mixtures and used with other NPS or 'traditional' drugs. Cathinone use represents significant health risks to individuals and is a public health burden.

METHODS

Evidence of poly-NPS use with cathinones, seizure information, and literature analyses results on NPS mixtures was systematically gathered from online database sources, including Google Scholar, Scopus, Bluelight, and Drugs-Forum.

RESULTS AND DISCUSSION

Results highlight the prevalence of NPS with low purity, incorporation of cathinones into NPS mixtures since 2008, and multiple members of the cathinone family being present in individual UK-seized samples. Cathinones were identified as adulterants in NPS marketed as being pure NPS, drugs of abuse, branded products, herbal blends, and products labelled "not for human consumption." Toxicity resulting from cathinone mixtures is unpredictable because key attributes remain largely unknown. Symptoms of intoxication include neuro-psychological, psychiatric, and metabolic symptoms. Proposed treatment includes holistic approaches involving psychosocial, psychiatric and pharmacological interventions.

CONCLUSION

Raising awareness of NPS, education, and training of health care professionals are paramount in reducing harms related to cathinone use.

Exposure of adolescent mice to 3,4-methylenedioxypyrovalerone increases the psychostimulant, rewarding and reinforcing effects of cocaine in adulthood

BACKGROUND AND PURPOSE

3,4-Methylenedioxypyrovalerone (MDPV) is a synthetic cathinone with powerful psychostimulant effects. It selectively inhibits the dopamine transporter (DAT) and is 10-50-fold more potent as a DAT blocker than cocaine, suggesting a high abuse liability. The main objective of the present study was to assess the consequences of an early (adolescence) MDPV exposure on the psychostimulant, rewarding and reinforcing effects induced by cocaine in adult mice.

EXPERIMENTAL APPROACH

Twenty-one days after MDPV pretreatment (1.5 mg·kg^-1 , s.c., twice daily for 7 days), adult mice were tested with cocaine, using locomotor activity, conditioned place preference and self-administration (SA) paradigms. In parallel, dopamine D₂ receptor density and the expression of c-Fos and ΔFosB in the striatum were determined.

KEY RESULTS

MDPV treatment enhanced the psychostimulant and conditioning effects of cocaine. Acquisition of cocaine SA was unchanged in mice pretreated with MDPV, whereas the breaking point achieved under a progressive ratio programme and reinstatement after extinction were higher in this group of mice. MDPV decreased D₂ receptor density but increased ΔFosB expression three-fold. As expected, acute cocaine increased c-Fos expression, but MDPV pretreatment negatively influenced its expression. ΔFosB accumulation declined during MDPV withdrawal, although it remained elevated in adult mice when tested for cocaine effects.

CONCLUSION AND IMPLICATIONS

MDPV exposure during adolescence induced long-lasting adaptive changes related to enhanced responsiveness to cocaine in the adult mice that seems to lead to a higher vulnerability to cocaine abuse. This particular behaviour correlated with increased expression of ΔFosB.

The new stimulant designer compound pentedrone exhibits rewarding properties and affects dopaminergic activity

Cathinone derivatives are new recreational drugs known to produce psychostimulant effects. However, unlike other psychostimulants, the addictive potential of cathinone derivatives has not been widely studied. Here, we investigated the effects of pentedrone, a type of cathinone derivative, on the dopaminergic system using reverse transcription polymerase chain reaction and Western blot. We also evaluated the addictive potential of pentedrone using conditioned place preference and self-administration. We found that pentedrone increased the mRNA expression of dopamine 1 receptor, dopamine 2 receptor and dopamine transporter, as well as induced phosphorylation of cAMP response element-binding protein in PC-12 cells. Additionally, pentedrone at 3 and 10 mg/kg significantly increased conditioned place preference in mice, while pentedrone at 0.3 mg/kg/infusion significantly increased self-administration in rats. Finally, we found that acute administration of pentedrone enhanced locomotor activity in a dose-dependent manner. Collectively, these data suggest that the addictive properties of pentedrone may be due to its effects on the dopaminergic system.

The Presence of Stimulant Drugs in Wastewater from Krakow (Poland): A Snapshot

An analysis of wastewater from Krakow (Poland) for the presence of controlled and uncontrolled stimulant drugs of abuse was performed. Samples were collected from the Plaszow wastewater treatment plant, Krakow, Poland, and prepared by solid phase extraction. The LC-QTOFMS method was applied for identification and quantification of popular stimulants: MDMA, mephedrone, 4-MEC, MDPV and mCPP. Environmental loads of illicit drugs were calculated; the WWTP discharged loads ranging from 3.6 to 6.7 mg day(-1) 1000 inhabitants(-1) of MDMA, 3.6 to 7.1 mg day(-1) 1000 inhabitants(-1) of mephedrone and 4.8 to 5.8 mg day(-1) 1000 inhabitants(-1) of 4-MEC. The results confirmed the growing popularity of new psychoactive substances in Poland.

Discriminative Stimulus Effects of Binary Drug Mixtures: Studies with Cocaine, MDPV, and Caffeine

Illicit drug preparations often include more than one pharmacologically active compound. For example, cocaine and synthetic cathinones [e.g., 3,4-methylenedioxypyrovalerone (MDPV)] are often mixed with caffeine before sale. Caffeine is likely added to these preparations because it is inexpensive and legal; however, caffeine might also mimic or enhance some of the effects of cocaine or MDPV. In these studies, male Sprague-Dawley rats were trained to discriminate 10 mg/kg cocaine from saline, and the discriminative stimulus effects of cocaine, caffeine, and MDPV were evaluated alone and as binary mixtures (cocaine and caffeine, MDPV and caffeine, and cocaine and MDPV) at fixed-dose ratios of 3:1, 1:1, and 1:3 relative to the dose of each drug that produced 50% cocaine-appropriate responding. Dose-addition analyses were used to determine the nature of the drug-drug interactions for each mixture (e.g., additive, supra-additive, or subadditive). Although additive interactions were observed for most mixtures, supra-additive interactions were observed at the 50% effect level for the 1:1 mixture of cocaine and caffeine and at the 80% effect level for all three mixtures of cocaine and caffeine, as well as for the 3:1 and 1:3 mixtures of cocaine and MDPV. These results demonstrate that with respect to cocaine-like discriminative stimulus effects, caffeine can function as a substitute in drug preparations containing either cocaine or MDPV, with enhancements of cocaine-like effects possible under certain conditions. Further research is needed to determine whether similar interactions exist for other abuse-related or toxic effects of drug preparations, including cocaine, synthetic cathinones, and caffeine.

3,4-Methylenedioxypyrovalerone (MDPV): in vitro mechanisms of hepatotoxicity under normothermic and hyperthermic conditions

Synthetic cathinones have emerged in recreational drug markets as legal alternatives for classical amphetamines. Though currently banned in several countries, 3,4-methylenedioxypyrovalerone (MDPV) is one of the most commonly abused cathinone derivatives worldwide. We have recently reported the potential of MDPV to induce hepatocellular damage, but the underlying mechanisms responsible for such toxicity remain to be elucidated. Similar to amphetamines, a prominent toxic effect of acute intoxications by MDPV is hyperthermia. Therefore, the present in vitro study aimed to provide insights into cellular mechanisms involved in MDPV-induced hepatotoxicity and also evaluate the contribution of hyperthermia to the observed toxic effects. Primary cultures of rat hepatocytes were exposed to 0.2-1.6 mM MDPV for 48 h, at 37 or 40.5 °C, simulating the rise in body temperature that follows MDPV intake. Cell viability was measured through the MTT reduction and LDH leakage assays. Oxidative stress endpoints and cell death pathways were evaluated, namely the production of reactive oxygen and nitrogen species (ROS and RNS), intracellular levels of reduced (GSH) and oxidized (GSSG) glutathione, adenosine triphosphate (ATP) and free calcium (Ca(2+)), as well as the activities of caspases 3, 8 and 9, and nuclear morphological changes with Hoechst 33342/PI double staining. At 37 °C, MDPV induced a concentration-dependent loss of cell viability that was accompanied by GSH depletion, as one of the first signs of toxicity, observed already at low concentrations of MDPV, with negligible changes on GSSG levels, followed by accumulation of ROS and RNS, depletion of ATP contents and increases in intracellular Ca(2+) concentrations. Additionally, activation of caspases 3, 8, and 9 and apoptotic nuclear morphological changes were found in primary rat hepatocytes exposed to MDPV, indicating that this cathinone derivative activates both intrinsic and extrinsic apoptotic death pathways. The cytotoxic potential of MDPV and all the studied endpoints were markedly aggravated under hyperthermic conditions (40.5 °C). In conclusion, these data suggest that MDPV toxicity in primary rat hepatocytes is mediated by oxidative stress, subsequent to GSH depletion and increased ROS and RNS accumulation, mitochondrial dysfunction, and impairment of Ca(2+) homeostasis. Furthermore, the rise in body temperature subsequent to MDPV abuse greatly exacerbates its hepatotoxic potential.

4F-PBP (4'-fluoro-α-pyrrolidinobutyrophenone), a new substance of abuse: Structural characterization and purity NMR profiling

The rapidly growing problem of new psychoactive substances (NPS) makes the time management for international control a real challenge, with the traditional detection methods becoming increasingly inadequate. NPS screening technologies, such as NMR, which allows multiple substances to be detected, characterized and quantified simultaneously from a single sample, offers a rapid solution to this problem. This study describes the application of NMR to the simultaneous detection, characterization and quantification of samples of white powders seized by the Portuguese Police. 4F-PBP (4'-fluoro-α-pyrolidinobutyrophenone) a new synthetic psychoactive cathinone cut with myo-inositol was found in two seized products. The structural characterization of 4F-PBP was elucidated in the mixture, and confirmed after isolation from the matrix by (1)H, (13)C, (19)F NMR and MS. Myo-inositol was found for the first time as a cutting agent of cathinones. Furthermore another seized product was characterized as being MDPBP, with a high degree of purity, and its spectroscopic elucidation enabled the correction of (13)C NMR literature assignments.

Quantitative structure-activity relationship analysis of the pharmacology of para-substituted methcathinone analogues

BACKGROUND AND PURPOSE

Methcathinone (MCAT) is a potent monoamine releaser and parent compound to emerging drugs of abuse including mephedrone (4-CH3 MCAT), the para-methyl analogue of MCAT. This study examined quantitative structure-activity relationships (QSAR) for MCAT and six para-substituted MCAT analogues on (a) in vitro potency to promote monoamine release via dopamine and serotonin transporters (DAT and SERT, respectively), and (b) in vivo modulation of intracranial self-stimulation (ICSS), a behavioural procedure used to evaluate abuse potential. Neurochemical and behavioural effects were correlated with steric (Es ), electronic (σp ) and lipophilic (πp ) parameters of the para substituents.

EXPERIMENTAL APPROACH

For neurochemical studies, drug effects on monoamine release through DAT and SERT were evaluated in rat brain synaptosomes. For behavioural studies, drug effects were tested in male Sprague-Dawley rats implanted with electrodes targeting the medial forebrain bundle and trained to lever-press for electrical brain stimulation.

KEY RESULTS

MCAT and all six para-substituted analogues increased monoamine release via DAT and SERT and dose- and time-dependently modulated ICSS. In vitro selectivity for DAT versus SERT correlated with in vivo efficacy to produce abuse-related ICSS facilitation. In addition, the Es values of the para substituents correlated with both selectivity for DAT versus SERT and magnitude of ICSS facilitation.

CONCLUSIONS AND IMPLICATIONS

Selectivity for DAT versus SERT in vitro is a key determinant of abuse-related ICSS facilitation by these MCAT analogues, and steric aspects of the para substituent of the MCAT scaffold (indicated by Es ) are key determinants of this selectivity.

"Legal Highs"--An Emerging Epidemic of Novel Psychoactive Substances

During the last decade, there has been an increase in the availability and use of novel psychoactive substances (NPS), also known as "legal highs," across the world. They include a wide range of products, from natural plant-originated substances to synthetic compounds, that can be purchased both online and from high street retailers. "Legal highs" mimic psychoactive effects of illicit drugs of abuse. However, they are claimed to consist of compounds that are legal to sell, possess, and use, often labeled as "not for human consumption" to circumvent drug abuse legislation. Based on the spectrum of their actions on cognitive processes, mood, and behavior, "legal highs" can be classified into four basis categories: amphetamine- and ecstasy-like stimulants, synthetic cannabinoids (SCs), hallucinogenic/dissociative, and opioid-like compounds. NPS may, however, exhibit a combination of these actions due to their designed chemical structure. Although the prevalence and pattern of NPS use differ between various countries, the most popular groups are SCs and psychostimulants, described in this chapter. Currently, there is limited information available on the potential acute toxicity (harms) associated with the use of these substances. However, the number of intoxicated people presenting with emergencies is constantly increasing, providing evidence that negative health and social consequences may indeed seriously affect recreational and chronic users.

Monoamine transporter and receptor interaction profiles of novel psychoactive substances: para-halogenated amphetamines and pyrovalerone cathinones

The pharmacology of novel psychoactive substances is mostly unknown. We evaluated the transporter and receptor interaction profiles of a series of para-(4)-substituted amphetamines and pyrovalerone cathinones. We tested the potency of these compounds to inhibit the norepinephrine (NE), dopamine (DA), and serotonin (5-HT) transporters (NET, DAT, and SERT, respectively) using human embryonic kidney 293 cells that express the respective human transporters. We also tested the substance-induced efflux of NE, DA, and 5-HT from monoamine-loaded cells, binding affinities to monoamine receptors, and 5-HT2B receptor activation. Para-(4)-substituted amphetamines, including 4-methylmethcathinone (mephedrone), 4-ethylmethcathinone, 4-fluoroamphetamine, 4-fluoromethamphetamine, 4-fluoromethcatinone (flephedrone), and 4-bromomethcathinone, were relatively more serotonergic (lower DAT:SERT ratio) compared with their analogs amphetamine, methamphetamine, and methcathinone. The 4-methyl, 4-ethyl, and 4-bromo groups resulted in enhanced serotonergic properties compared with the 4-fluoro group. The para-substituted amphetamines released NE and DA. 4-Fluoramphetamine, 4-flouromethamphetamine, 4-methylmethcathinone, and 4-ethylmethcathinone also released 5-HT similarly to 3,4-methylenedioxymethamphetamine. The pyrovalerone cathinones 3,4-methylenedioxypyrovalerone, pyrovalerone, α-pyrrolidinovalerophenone, 3,4-methylenedioxy-α-pyrrolidinopropiophenone, and 3,4-methylenedioxy-α-pyrrolidinobutiophenone potently inhibited the NET and DAT but not the SERT. Naphyrone was the only pyrovalerone that also inhibited the SERT. The pyrovalerone cathinones did not release monoamines. Most of the para-substituted amphetamines exhibited affinity for the 5-HT2A receptor but no relevant activation of the 5-HT2B receptor. All the cathinones exhibited reduced trace amine-associated receptor 1 binding compared with the non-β-keto-amphetamines. In conclusion, para-substituted amphetamines exhibited enhanced direct and indirect serotonergic agonist properties and are likely associated with more MDMA-like effects. The pharmacological profile of the pyrovalerone cathinones predicts pronounced stimulant effects and high abuse liability.

Fatal intoxication with 3-methyl-N-methylcathinone (3-MMC) and 5-(2-aminopropyl)benzofuran (5-APB)

The emergence of a large number of new psychoactive substances (NPSs) in recent years poses a serious problem to clinical and forensic toxicologists. Here we report a patient who administrated ca. 500mg of 3-MMC (3-methyl-N-methylcathinone) and 400mg of 5-APB (5-(2-aminopropyl)benzofuran) in combination with 80g of ethyl alcohol. The clinical manifestations included agitation, seizures, hypertension, tachycardia, hyperthermia and bradycardia. The patient did not recover and died around 4h after the use of drugs. The cause of death was acute cardiovascular collapse that occurred following mixed intoxication with NPSs and alcohol. Toxicological analysis of post-mortem blood revealed 3-MMC and 5-APB in concentrations of 1.6μg/mL and 5.6μg/mL, respectively. Moreover, the serum alcohol concentration was 1.4g/L in ante-mortem sample collected 1h after admission to the hospital. This is the first report on blood concentration of 3-MMC and 5-APB in fatal intoxication.