Understanding methiopropamine, a new psychoactive substance: an in-depth review on its chemistry, pharmacology and implications to human health

Methiopropamine or 1-(thiophen-2-yl)-2-methylaminopropane (MPA) is a thiophene ring-based structural analogue of methamphetamine, first synthesized in 1942 but become popular when it started to be available for purchase on websites selling 'legal highs' since 2010. While it is legally controlled in many countries, it remains readily accessible and frequently encountered in recreational settings. The growing prevalence of MPA use results in new therapeutic challenges. Relatively few studies have focused on its pharmacodynamics and pharmacokinetics, making it important to better understand its potential risks and harmful effects in humans in terms of its toxicity. This review provides a comprehensive profiling of MPA toxicological properties, including its chemical properties, analytical methods, prevalence, patterns of use, and legal status. Additionally, it discusses the drug's effects on the central nervous system, its potential for addiction, and its adverse physical and mental health effects. Improving the understanding of safety aspects of MPA and how it imposes health threats for public health will guide the development of therapeutic approach of its intoxication and guide the authorities in deciding its legal status.

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

This study reports the first application of in silico methods to assess the toxicity of 4-chloromethcathinone (4-CMC), a novel psychoactive substance (NPS). Employing advanced toxicology in silico tools, it was possible to predict crucial aspects of the toxicological profile of 4-CMC, including acute toxicity (LD50), genotoxicity, cardiotoxicity, and its potential for endocrine disruption. The obtained results indicate significant acute toxicity with species-specific variability, moderate genotoxic potential suggesting the risk of DNA damage, and a notable cardiotoxicity risk associated with hERG channel inhibition. Endocrine disruption assessment revealed a low probability of 4-CMC interacting with estrogen receptor alpha (ER-α), suggesting minimal estrogenic activity. These insights, derived from in silico studies, are critical in advancing the understanding of 4-CMC properties in forensic and clinical toxicology. These initial toxicological findings provide a foundation for future research and aid in the formulation of risk assessment and management strategies in the context of the use and abuse of NPSs.

Application of liquid chromatography coupled to data-independent acquisition mass spectrometry for the metabolic profiling of N-ethyl heptedrone

We have investigated the metabolic profile of N-ethyl heptedrone, a new designer synthetic stimulant drug, by using data independent acquisition mass spectrometry. Phase I and phase II metabolism was studied by in vitro models, followed by liquid-chromatography coupled to mass spectrometry, to characterize and pre-select the most diagnostic markers of intake. N-ethyl heptedrone was incubated in the presence of pooled human liver microsomes. The contribution of individual enzymatic isoforms in the formation of the phase I and phase II metabolites was further investigated by using human recombinant cDNA-expressed cytochrome P450 enzymesand uridine 5'-diphospho glucuronosyltransferases. The analytical workflow consisted of liquid-liquid extraction with tert-butyl-methyl-ether at alkaline pH, performed before (to investigate the phase I metabolic profile) and after (to investigate the glucuronidation profile) enzymatic hydrolysis. The separation, identification, and determination of the compounds formed in the in vitro experiments were carried out by using liquid chromatography coupled to either high- or low-resolution mass spectrometry. Data independent acquisition method, namely sequential window acquisition of all theoretical fragment-ion spectra (SWATH®) and product ion scan were selected for high-resolution mass spectrometry, whereas multiple reaction monitoring was used for low-resolution mass spectrometry. Thirteen phase-I metabolites were isolated, formed from reactions being catalyzed mainly by CYP1A2, CYP2C9, CYP2C19 and CYP2D6 and, to a lesser degree, by CYP3A4 and CYP3A5. The phase I biotransformation pathways included hydroxylation in different positions, reduction of the ketone group, carbonylation, N-dealkylation, and combinations of the above. Most of the hydroxylated metabolites underwent conjugation reactions to form the corresponding glucurono-conjugated metabolites. Based on our in vitro observation, the metabolic products resulting from reduction of the keto group, N-dealkylation and hydroxylation of the aliphatic chain appear to be the most diagnostic target analytes to be selected as markers of exposure to N-ethyl heptedrone.

Variable Data Independent Acquisition and Data Mining Exploring Feature-Based Molecular Networking Analysis for Untargeted Screening of Synthetic Cannabinoids in Oral Fluid

Novel psychoactive substances (NPS) are constantly emerging in the drug market, and synthetic cannabinoids (SCs) are included in this NPS family. Forensic laboratories often struggle with these continually emerging SCs, forcing them to develop an untargeted workflow to incorporate these psychoactive drugs in their procedures. Usually, forensic laboratories select analytical methods based on targeted mass spectrometry (MS) technologies for strictly tracking already known NPS. The appropriate way to tackle unknown substances is to develop pipelines for untargeted analysis that include LC-HRMS analytical methods and data analysis. Once established, this strategy would allow drug testing laboratories to be always one step ahead of the new trends concerning the "designer drugs" market. To address this challenge an untargeted workflow based on mass spectrometry data acquisition and data analysis was developed to detect SCs in oral fluid (OF) samples at a low concentration range. The samples were extracted by mixed-mode solid-phase extraction and analyzed by Liquid Chromatography - High-Resolution Mass Spectrometry (LC-HRMS). Tandem mass spectra (MS2) were recorded performing a variable isolation width across a mass range of all theoretical precursor ions (vDIA) after the chromatographic separation. After raw data processing with the MSDial software, the deconvoluted features were sent to GNPS for Feature-Based Molecular Networking (FBMN) construction for nontargeted data mining. The FBMN analysis created a unique integrated network for most of the SCs assessed in the OF at a low level (20 ng/mL). These results demonstrate the potential of an untargeted approach to detect different derivatives of SCs at trace levels for forensic applications.

[Determination of Salt Forms of New Psychoactive Substances by Ion Chromatography]

Objective To establish an ion chromatography method for the salt form determination of new psychoactive substances （NPS）. Methods The method of conducting qualitative and quantitative analysis of six types of organic acid ions （acetate ion, tartrate ion, maleate ion, oxalate ion, fumarate ion, citrate ion） and five types of inorganic anions （fluoride ion, chloride ion, nitrate ion, sulfate ion, phosphate ion） in NPS sample by ion chromatography was developed. The salt forms of 222 seized NPS samples （103 samples with synthetic cannabinoids, 81 samples with cathinones, 44 samples with phenylethylamines, 12 samples with tryptamines, 7 samples with phencyclidines, 6 samples with piperazines, 2 samples with aminoindenes, 26 samples with fentanyls and 43 samples with other types of NPS） were analyzed by this method. Results Each anion had good linearity in the corresponding linear range, the correlation coefficients （r） were greater than 0.999, the limits of detection were 0.01-0.05 mg/L, and the limits of quantitative were 0.1-0.5 mg/L. Except that 5F-BEPIRAPIM was hydrochloride, the salt forms of the other 102 synthetic cannabinoids were all base. The salt form of 81 cathinone samples, 44 phenylethylamine samples, 7 phencyclidine samples and 2 aminoindene samples were all hydrochloride. The salt forms of tryptamine samples included base, hydrochloride, fumarate and oxalate. The salt forms of piperazine samples included base and hydrochloride. The salt forms of fentanyl samples and samples of other types included base, hydrochloride and citrate. Conclusion Ion chromatography is a simple, accurate and efficient method for determining the salt form of NPS samples, which makes the qualitative and quantitative conclusions of NPS more scientific and rigorous.

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.

Human Neuronal Cell Lines as An In Vitro Toxicological Tool for the Evaluation of Novel Psychoactive Substances

Novel psychoactive substances (NPS) are synthetic substances belonging to diverse groups, designed to mimic the effects of scheduled drugs, resulting in altered toxicity and potency. Up to now, information available on the pharmacology and toxicology of these new substances is very limited, posing a considerable challenge for prevention and treatment. The present in vitro study investigated the possible mechanisms of toxicity of two emerging NPS (i) 4′-methyl-alpha-pyrrolidinoexanophenone (3,4-MDPHP), a synthetic cathinone, and (ii) 2-chloro-4,5-methylenedioxymethamphetamine (2-Cl-4,5-MDMA), a phenethylamine. In addition, to apply our model to the class of synthetic opioids, we evaluated the toxicity of fentanyl, as a reference compound for this group of frequently abused substances. To this aim, the in vitro toxic effects of these three compounds were evaluated in dopaminergic-differentiated SH-SY5Y cells. Following 24 h of exposure, all compounds induced a loss of viability, and oxidative stress in a concentration-dependent manner. 2-Cl-4,5-MDMA activates apoptotic processes, while 3,4-MDPHP elicits cell death by necrosis. Fentanyl triggers cell death through both mechanisms. Increased expression levels of pro-apoptotic Bax and caspase 3 activity were observed following 2-Cl-4,5-MDMA and fentanyl, but not 3,4-MDPHP exposure, confirming the different modes of cell death.

Biosynthesis and synthetic biology of psychoactive natural products

Psychoactive natural products play an integral role in the modern world. The tremendous structural complexity displayed by such molecules confers diverse biological activities of significant medicinal value and sociocultural impact. Accordingly, in the last two centuries, immense effort has been devoted towards establishing how plants, animals, and fungi synthesize complex natural products from simple metabolic precursors. The recent explosion of genomics data and molecular biology tools has enabled the identification of genes encoding proteins that catalyze individual biosynthetic steps. Once fully elucidated, the "biosynthetic pathways" are often comparable to organic syntheses in elegance and yield. Additionally, the discovery of biosynthetic enzymes provides powerful catalysts which may be repurposed for synthetic biology applications, or implemented with chemoenzymatic synthetic approaches. In this review, we discuss the progress that has been made toward biosynthetic pathway elucidation amongst four classes of psychoactive natural products: hallucinogens, stimulants, cannabinoids, and opioids. Compounds of diverse biosynthetic origin - terpene, amino acid, polyketide - are identified, and notable mechanisms of key scaffold transforming steps are highlighted. We also provide a description of subsequent applications of the biosynthetic machinery, with an emphasis placed on the synthetic biology and metabolic engineering strategies enabling heterologous production.

Application of a simultaneous screening method for the detection of new psychoactive substances in various matrix samples using liquid chromatography/electrospray ionization tandem mass spectrometry and liquid chromatography/quadrupole time-of-flight mass spectrometry

RATIONALE

Recently, new psychoactive substances (NPS) have emerged as a public health risk. Particularly, their chemical structures are modified to avoid detection. Synthetic NPS with effects similar to those of illegal drugs have been recently detected and synthesized worldwide, including MDMB-FUBINACA and APINAC, making it essential to rapidly and accurately detect NPS.

METHODS

Fourteen NPS with similar structures were selected and their structures identified using ¹ H and ¹³ C NMR spectroscopy. Additionally, we proposed the fragmentation pattern of each compound using liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS). A simultaneous analytical method using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was also developed and applied to real samples to detect the 14 NPS. The method was validated based on the specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, matrix effect, and stability according to international validation guidelines.

RESULTS

The established method was used to screen 65 different matrix samples using LC/ESI-MS/MS. By comparing the calculated product ion ratios with those of standards, 2C-B in one of the real samples and 5F-MDMB-PICA in 20 samples were identified. For re-confirmation of detected compounds, the fragmentation pattern of each compound was compared with that of each standard using LC/QTOF-MS.

CONCLUSIONS

In this study, LC/QTOF-MS data were used to elucidate the structures and fragmentation patterns of 14 NPS. A simultaneous method was developed using LC/ESI-MS/MS, which was applied to 65 real samples. The presented method and results can assist in ensuring the safety of public health from illegal adulteration.

Phototransformation of Three Psychoactive Drugs in Presence of Sedimental Water Extractable Organic Matter

Psychoactive drugs are classified as contaminants of emerging concern but there is limited information on their fate in surface waters. Here, we studied the photodegradation of three psychoactive drugs (sertraline, clozapine, and citalopram) in the presence of organic matter (WEOM) extracted under mild conditions from sediment of Lake Pamvotis, Greece. Spectral characterization of WEOM confirmed its humic-like nature. Preliminary experiments using chemical probes showed that WEOM was able to produce oxidant triplet excited state (³WEOM*), singlet oxygen (¹O₂), and hydroxyl radicals under irradiation with simulated solar light. Then, WEOM at 5 mgC L^-1 was irradiated in the presence of the three drugs. It enhanced their phototransformation by a factor of 2, 4.2, and 16 for sertraline, clozapine, and citalopram, respectively. The drastic inhibiting effect of 2-propanol (5 × 10^-3 M) on the reactions demonstrated that hydroxyl radical was the key intermediate responsible for drugs photodegradation. A series of photoproducts were identified by ultra-high performance liquid chromatography (UHPLC) coupled to high resolution mass spectrometry (HR-MS). The photodegradation of the three drugs proceeded through several pathways, in particular oxidations of the rings with or without O atom inclusion, N elimination, and substitution of the halogen by OH. The formation of halogenated aromatics was observed for sertraline. To conclude, sedimental natural organic matter can significantly phototransform the studied antidepressant drugs and these reactions need to be more investigated. Finally, ecotoxicity was estimated for the three target analytes and their photoproducts, using the Ecological Structure Activity Relationships (ECOSAR) computer program.

High-field and benchtop NMR spectroscopy for the characterization of new psychoactive substances

New psychoactive substances (NPS) have become a serious threat to public health in Europe due to their ability to be sold in the street or on the darknet. Regulating NPS is an urgent priority but comes with a number of analytical challenges since they are structurally similar to legal products. A number of analytical techniques can be used for identifying NPS, among which NMR spectroscopy is a gold standard. High field NMR is typically used for structural elucidation in combination with others techniques like GC-MS, Infrared spectroscopy, together with databases. In addition to their strong ability to elucidate molecular structures, high field NMR techniques are the gold standard for quantification without any physical isolation procedure and with a single internal standard. However, high field NMR remains expensive and emerging "benchtop" NMR apparatus which are cheaper and transportable can be considered as valuable alternatives to high field NMR. Indeed, benchtop NMR, which emerged about ten years ago, makes it possible to carry out structural elucidation and quantification of NPS despite the gap in resolution and sensitivity as compared to high field NMR. This review describes recent advances in the field of NMR applied to the characterization of NPS. High-field NMR methods are first described in view of their complementarity with other analytical methods, focusing on both structural and quantitative aspects. The second part of the review highlights how emerging benchtop NMR approaches could act as a game changer in the field of forensics.

Toxicology and Analysis of Psychoactive Tryptamines

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

Examination of the effect of air atmosphere on heterogeneous reactions under surface ionization of psychotropic drug molecules

The results of mass spectrometric studies of surface ionization of molecules of psychotropic drugs such as chlorpromazine, amitriptyline and medazepam in an air atmosphere have been presented. The channels of heterogeneous reactions occurring during the molecule adsorption on the hot surface of the thermoemitter from refractory metal oxides have been revealed, as well as the influence of air atmosphere on these reactions. A strong influence of the air atmosphere on the heterogeneous association reactions with the emission of [M + H]⁺ ions has been found. This ion line is the main in the mass spectra of all the substances under study instead of the characteristic main line in the surface ionization mass spectra obtained in vacuum. The effect of air on the reactions of dehydrogenation and dissociation of adsorbed molecules of organic compounds has been insignificant. In the surface ionization mass spectra of all the substances studied under atmospheric conditions the adduct cluster ions М⋅[М-R]⁺, М⋅[М-Н]⁺ and М⋅[М+Н]⁺ (where М is the molecule, R is the radical, H is the hydrogen atom) up to М⋅[М+Н]⁺⋅HCl. They are probably formed by adhesion of analyte molecules to the primary ions [М-R]⁺, [М-Н]⁺ and [М+Н]⁺. A comparative analysis has been also performed with the data obtained by chromato-mass spectrometry with electron ionization, as well as with the surface ionization data for these preparations obtained under high vacuum.

[Ayahuasca - religion, life-style or drug?]

Ayahuasca is a psychoactive drug which has been used by indigenous cultures in the amazonas basin for hundreds of years for medical and religious purpose. Backpackers who came in contact with ayahuasca exported its use in the western world and increased its popularity. By presenting a case report of a patient seeking medical help due to psychotic symptoms after having attended an ayahuasca ritual we give an short overview of pharmacology, legal status, use and side effects of the substance.

Determination of the chiral status of different novel psychoactive substance classes by capillary electrophoresis and β-cyclodextrin derivatives

Besides the abuse of well‐known illicit drugs, consumers discovered new synthetic compounds with similar effects but minor alterations in their chemical structure. Originally, these so‐called novel psychoactive substances (NPS) have been created to circumvent law of prosecution because of illicit drug abuse. During the past decade, such compounds came up in generations, the most popular compound was a synthetic cathinone derivative named mephedrone. Cathinones are structurally related to amphetamines; to date, more than 120 completely new derivatives have been synthesized and are traded via the Internet. Cathinones possess a chiral center; however, only little is known about the pharmacology of their enantiomers. However, NPS comprise further chiral compound classes such as amphetamine derivatives, ketamines, 2‐(aminopropyl)benzofurans, and phenidines. In continuation of our project, a cheap and easy‐to‐perform chiral capillary zone electrophoresis method for enantioseparation of cathinones presented previously was extended to the aforementioned compound classes. Enantioresolution was achieved by simply adding native β‐cyclodextrin, acetyl‐β‐cyclodextrin, 2‐hydroxypropyl‐β‐cyclodextrin, or carboxymethyl‐β‐cyclodextrin as chiral selector additives to the background electrolyte. Fifty‐one chiral NPS served as analytes mainly purchased from online vendors via the Internet. Using 10 mM of the aforementioned β‐cyclodextrins in a 10 mM sodium phosphate buffer (pH 2.5), overall, 50 of 51 NPS were resolved. However, chiral separation ability of the selectors differed depending on the analyte. Additionally, simultaneous enantioseparations, the determination of enantiomeric migration orders of selected analytes, and a repeatability study were performed successfully. It was proven that all separated NPS were traded as racemic mixtures.

Rapid detection and validated quantification of psychoactive compounds in complex plant matrices by direct analysis in real time-high resolution mass spectrometry - Application to "Kava" psychoactive pepper products

RATIONALE

Classified by the UNODC as a top 20 plant of concern, Piper methysticum (also known as Kava) is being increasingly abused recreationally for its mind-altering effects. It is of significant forensic relevance to establish methods to rapidly identifyand quantify psychoactive compounds, especially those yet to be scheduled ascontrolled substances and which have exhibited various noteworthy health concerns.

METHODS

Direct analysis in real time high-resolution mass spectrometry (DART-HRMS) demonstrated the ability to detect a range of kavalactones in Pipermethysticum derived products and plant material with no sample preparation. Inaddition, a validated method using calibration curves developed with a deuteratedinternal standard was used for the quantification of the psychoactive moleculeyangonin in various products.

RESULTS

DART-HRMS detected the protonated masses of six major kavalactonesand three flavokavains in 18 commercial Kava products. A method consistent withFDA validation guidelines was established for the quantification of yangonin in thevarious complex matrices. Implementation of this method, with an LLOQ of 5 mg/mL, enabled successful quantification of yangonin in 16 Kava products.Concentrations for solid products ranged from 2.71 to 8.99 mg/g, while that forliquid products ranged from 1.03 to 4.59 mg/mL.

CONCLUSIONS

Rapid identification and quantification of psychoactive smallmolecules in plant material can be accomplished using a validated DART-HRMSprotocol. This work illustrates an approach to qualitative and quantitative analysesof a wide variety of complex matrices derived from plants, and demonstrates thatthe commercially available products analyzed are P. methysticum derived and docontain psychoactive yangonin at quantifiable levels.

Mesembrine: The archetypal psycho-active Sceletium alkaloid

(-)-Mesembrine is a chiral alkaloid that features an aryloctahydroindole skeleton and is most commonly found in species of the succulent genus Sceletium. Several Sceletium species are used by various ethnic groups in South Africa to manage disorders of the central nervous system. Binding assays have revealed that mesembrine is a more potent inhibitor of the serotonin transporter (SERT) than fluoxetine (Prozac) which has prompted the commercialization of mesembrine-containing consumer products. The congested all carbon quaternary stereocenter present at the bridgehead of mesembrine has rendered it a compound of interest for research in synthetic chemistry, which has assisted in the absolute configuration of the naturally occurring isomer to be assigned. Accordingly, this review will cover the recent literature pertaining to the distribution, structural elucidation, chemotaxonomy, biosynthesis, organic synthesis, as well as the biological activities of (-)-mesembrine. Recent synthetic procedures of the non-natural enantiomer as well as the racemate are also considered.

Chemical evidence for the use of multiple psychotropic plants in a 1,000-year-old ritual bundle from South America

Over several millennia, various native plant species in South America have been used for their healing and psychoactive properties. Chemical analysis of archaeological artifacts provides an opportunity to study the use of psychoactive plants in the past and to better understand ancient botanical knowledge systems. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to analyze organic residues from a ritual bundle, radiocarbon dated to approximately 1,000 C.E., recovered from archaeological excavations in a rock shelter located in the Lípez Altiplano of southwestern Bolivia. The site is located at an elevation of ∼3,900 m above sea level and contains evidence of intermittent human occupations during the last 4,000 years. Chemical traces of bufotenine, dimethyltryptamine, harmine, and cocaine, including its degradation product benzoylecgonine, were identified, suggesting that at least three plants containing these compounds were part of the shamanic paraphernalia dating back 1,000 years ago, the largest number of compounds recovered from a single artifact from this area of the world, to date. This is also a documented case of a ritual bundle containing both harmine and dimethyltryptamine, the two primary ingredients of ayahuasca. The presence of multiple plants that come from disparate and distant ecological areas in South America suggests that hallucinogenic plants moved across significant distances and that an intricate botanical knowledge was intrinsic to pre-Columbian ritual practices.

Multivariate comparison of photocatalytic properties of thirteen nanostructured metal oxides for water purification

Although the environmental photocatalysis is being developed for many years, the relationships between simple metal oxides have not been explored so far. In this study a multivariate comparison of thirteen nanostructured metal oxides (Bi₂O₃, CeO₂, Co₃O₄, Fe₂O₃, NiO, Pr₆O₁₁, SnO₂, SrTiO₃, TiO₂, WO₃, ZnFe₂O₄, ZnO and ZrO₂) was performed. The solution containing twenty-six psychotropic pharmaceuticals was used as a model mixture. In order to ensure the influence of the dissolved organic matter on the process, all the experiments were conducted in the river water. Simulated solar radiation was applied as the most environmentally relevant. The high-resolution LC-MS profiles, obtained for the photocatalytic samples after 1 h of irradiation, were then submitted to the multivariate chemometric analysis. Graphical representations of principal component analysis and hierarchical cluster analysis enabled visualization of the relationships between the studied oxides. The registered degradation profiles were compared qualitatively and discussed.

Using Ca2+-channel biosensors to profile amphetamines and cathinones at monoamine transporters: electro-engineering cells to detect potential new psychoactive substances

BACKGROUND

The appearance of stimulant-class new psychoactive substances (NPS) is a frequent and significant problem in our society. Cathinone variants are often sold illegally as 3,4-methylenedioxy methamphetamine ("ecstasy") or disguised for legal sale using misleading names such as "bath salts" and carry the risk of promoting disruptive mental states, addiction, and fatal overdose. The principal targets of these recreational drugs are monoamine transporters expressed in catecholaminergic and serotonergic neurons. Some transporter ligands can be transported into cells, where they can promote a massive release of neurotransmitters through reverse transport, and others can block uptake. A ligand's dopamine vs. serotonin transporter selectivity, potency, and activity as a substrate or blocker can help elucidate the abuse liability and subjective effects of a drug.

OBJECTIVES

Here, we describe the discovery, development, and validation of an emerging methodology for compound activity assessment at monoamine transporters.

KEY FINDINGS

Substrates generate inward electrical currents through transporters and can depolarize the plasma membrane, whereas blockers work as a "cork in a bottle" and function as antagonists. Voltage-gated Ca²⁺ channels were co-expressed with monoamine transporters in cultured cells and used to measure fluctuations of the membrane electrical potential. In this system, substrates of monoamine transporters produce reliable dose-dependent Ca²⁺ signals, while blockers hinder them.

DISCUSSION

This system constitutes a novel use of voltage-gated Ca²⁺ channels as biosensors for the purpose of characterizing ligand activity at monoamine transporters using fluorimetry. This approach in combination with in vivo evaluations of drugs' abuse-related effects is a powerful strategy for anticipating potential stimulant-class NPS.

The Evolving Landscape of Designer Drugs

Since 2008 there has been an onslaught of new drugs in the illicit marketplace. Often referred to as "research chemicals," "designer drugs," or "novel psychoactive substances" (NPS), these substances are used for their pharmacological effects which are often similar to more widely known drugs such as ecstasy or heroin. In some cases users specifically seek out these new chemicals, in other cases they are simply purchasing what they believe to be their normal drug of choice from a dealer, but the product is not what it is purported to be. Implementation of national and international systems to monitor the appearance of new compounds enables laboratories to be prepared with validated tests to detect them in biological specimens. The most common classes of NPS are synthetic cannabinoids, novel opioids, novel benzodiazepines, stimulants, and hallucinogens. Within these groups the compounds may be drugs that were originally synthesized for research purposes during the pursuit of new therapeutic agents such as the synthetic cannabinoid JWH-018 and the designer opioid U47700. Others like etizolam are compounds used in other countries but not commonly seen in the USA. Some are drugs synthesized specifically to circumvent legal controls. In all cases, these compounds present a unique challenge to forensic toxicology laboratories which must quickly develop and validate analytical methods for the identification and quantification in biological matrices.This chapter is a condensed and updated version of an article originally published in Clinical and Forensic Toxicology News.

Neurochemical pharmacology of psychoactive substituted N-benzylphenethylamines: High potency agonists at 5-HT2A receptors

The use of new psychoactive substituted 2,5-dimethoxy-N-benzylphenethylamines is associated with abuse and toxicity in the United States and elsewhere and their pharmacology is not well known. This study compares the mechanisms of action of 2-(2,5-dimethoxy-4-methylphenyl)-N-(2-methoxybenzyl)ethanamine (25D-NBOMe), 2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25E-NBOMe), 2-(2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25H-NBOMe), 2-(((4-iodo-2,5-dimethoxyphenethyl)amino)methyl)phenol (25I-NBOH); and 2-(2,5-dimethoxy-4-nitrophenyl)-N-(2-methoxybenzyl)ethanamine) (25N-NBOMe) with hallucinogens and stimulants. Mammalian cells heterologously expressing 5-HT1A, 5-HT2A, 5-HT2B or 5-HT2C receptors, or dopamine, serotonin or norepinephrine transporters (DAT, SERT and NET, respectively) were used to assess drug affinities at radioligand binding sites. Potencies and efficacies were determined using [35S]GTPγS binding assays (5-HT1A), inositol-phosphate accumulation assays (5-HT2A, 5-HT2B and 5-HT2C), and uptake and release assays (transporters). The substituted phenethylamines were very low potency and low efficacy agonists at the 5-HT1A receptor. 25D-NBOMe, 25E-NBOMe, 25H-NBOMe, 25I-NBOH and 25N-NBOMe had very high affinity for, and full efficacy at, 5-HT2A and 5-HT2C receptors. In the 5-HT2A receptor functional assay, 25D-NBOMe, 25E-NBOMe, 25I-NBOH and 25N-NBOMe had subnanomolar to low nanomolar potencies similar to (+)lysergic acid diethylamide (LSD) while 25H-NBOMe had lower potency, similar to serotonin. At the 5-HT2C receptor, four had very high potencies, similar to LSD and serotonin, while 25H-NBOMe had lower potency. At the 5-HT2B receptor, the compounds had lower affinity, potency and efficacy compared to 5-HT2A or 5-HT2C. The phenethylamines had low to mid micromolar affinities and potencies at the transporters. These results demonstrate that these -NBOMe and -NBOH substituted phenethylamines have a biochemical pharmacology consistent with hallucinogenic activity, with little psychostimulant activity.

The DARK Side of Total Synthesis: Strategies and Tactics in Psychoactive Drug Production

Humankind has used and abused psychoactive drugs for millennia. Formally, a psychoactive drug is any agent that alters cognition and mood. The term "psychotropic drug" is neutral and describes the entire class of substrates, licit and illicit, of interest to governmental drug policy. While these drugs are prescribed for issues ranging from pain management to anxiety, they are also used recreationally. In fact, the current opioid epidemic is the deadliest drug crisis in American history. While the topic is highly politicized with racial, gender, and socioeconomic elements, there is no denying the toll drug mis- and overuse is taking on this country. Overdose, fueled by opioids, is the leading cause of death for Americans under 50 years of age, killing ca. 64,000 people in 2016. From a chemistry standpoint, the question is in what ways, if any, did organic chemists contribute to this problem? In this targeted review, we provide brief historical accounts of the main classes of psychoactive drugs and discuss several foundational total syntheses that ultimately provide the groundwork for producing these molecules in academic, industrial, and clandestine settings.

Electrochemical degradation of psychoactive drug caffeine in aqueous solution using graphite electrode

In this study, the electrochemical degradation of caffeine (1,3,7-trimethylxanthine) in aqueous solution by a graphite electrode was investigated. Electrochemical degradation was tested by the cyclic voltametry technique performed in the potential range of -1.0 to +1.0 V versus Ag/AgCl, which confirmed the electro-activity of the selected caffeine. The effects of the treatment process variables, such as initial pH, current density, electrolyte concentration and electrolysis time on the degradation of caffeine, were explored. During the various stages of electrolysis, parameters such as chemical oxygen demand (COD), total organic carbon (TOC) were analysed. The maximum COD and TOC removal efficiencies of 85% and 77% were achieved at neutral pH 7, operated at a current density of 5.1 mA/cm², electrolyte (Na₂SO₄) concentration of 0.1 M and at 240 min electrolysis time. From this study, it can be concluded that the electrochemical treatment process could effectively reduce the COD and TOC from the caffeine in aqueous medium. The degradation of the caffeine was confirmed by UV spectra, IR spectra and HPLC analysis.