Developments in high-resolution mass spectrometric analyses of new psychoactive substances

Cyclic Ion Mobility of Isomeric New Psychoactive Substances Employing Characteristic Arrival Time Distribution Profiles and Adduct Separation

Analysis of new psychoactive substances (NPS), which is essential for toxicological and forensic reasons, can be made complicated by the presence of isomers. Ion mobility has been used as a standalone technique or coupled to mass spectrometry to detect and identify NPS. However, isomer separation has so far chiefly relied on chromatography. Here we report on the determination of isomeric ratios using cyclic ion mobility-mass spectrometry without any chromatographic separation. Isomers were distinguished by mobility separation of lithium adducts. Alternatively, we used arrival time distribution (ATD) profiles that were characteristic of individual isomers and were acquired for protonated molecules or fragment ions. Both approaches provided comparable results. Calculations were used to determine the structures and collision cross sections of both protonated and lithiated isomers that accurately characterized their ion mobility properties. The applicability of ATD profiles to isomer differentiation was demonstrated using direct infusion and flow injection analysis with electrospray of solutions, as well as desorption electrospray of solid samples. Data processing was performed by applying multiple linear regression to the ATD profiles. Using the proposed ATD profile-based approach, the relationships between the determined and given content of isomers showed good linearity with coefficients of determination typically greater than 0.99. Flow injection analysis using an autosampler allowed us to rapidly determine isomeric ratios in a sample containing two isomeric pairs with a minor isomer of 10% (determined 9.3% of 3-MMC and 11.0% of 3-FMC in a mixture with buphedrone and 4-FMC). The proposed approach is not only useful for NPS, but also may be applicable to small isomeric molecules analyzed by ion mobility when complete separation of isomers is not achieved.

Detecting novel psychoactive substances around the world

PURPOSE OF REVIEW

The worldwide spread of novel psychoactive substances (NPS) in the illicit drug market and their continuous increase in number and type, for the purpose of bypassing controlled substance legislation, represents a continuing challenge for forensic scientists, clinicians and enforcement authorities. We aim to provide information regarding the most urgent harms related to NPS consumption in different world regions and the current state of the art for NPS analysis.

RECENT FINDINGS

Unfortunately, the identification of NPS in biological samples is controversial, especially when samples are limited, or the drug is promptly and extensively metabolized. This causes a lack of information on their real diffusion in different parts of the world and in different populations. New technologies and instrumental detection of NPS in alternative samples are offering comprehensive information about NPS use.

SUMMARY

The lack of detection and underreporting of NPS in biological samples makes it difficult to obtain complete qualitative and quantitative information about NPS prevalence. The most innovative strategies that have been proposed in the last 2 years to assist NPS analysis and possibly facilitate the understanding of the NPS diffusion around the world are presented.

Predicting the new psychoactive substance activity of antitussives and evaluating their ecotoxicity to fish

The misuse of antitussives preparations is a continuing problem in the world, and imply that they might have potential new psychoactive substances (NPS) activity. However, few study focus on their ecological toxicity towards fish. In the present study, the machine learning (ML) methods gcForest and random forest (RF) were employed to predict NPS activity in 30 antitussives. The potential toxic target, mode of action (MOA), acute toxicity and chronic toxicity to fish were further investigated. The results showed that both gcForest and RF achieved optimal performance when utilizing combined features of molecular fingerprint (MF) and molecular descriptor (MD), with area under the curve (AUC) = 0.99, accuracy >0.94 and f1 score > 0.94, and were applied to screen the NPS activity in antitussives. A total of 15 antitussives exhibited potential NPS activity, including frequently-used substances like codeine and dextromethorphan. The binding affinity of these antitussives with zebrafish dopamine transporter (zDAT) was high, and even surpassing that of some traditional narcotics and NPS. Some antitussives formed hydrogen bonds or salt bridges with aspartate (Asp) 95, tyrosine (Tyr) 171 of zDAT. For the ecotoxicity, the MOA of these 15 antitussives in fish was predicted as narcosis. The prenoxdiazin, pholcodine, codeine, dextromethorphan and dextrorphan exhibited very toxic/toxic to fish. It was necessary to pay close attention to the ecotoxicity of these antitussives. In this study, the integration of ML, molecular docking and ECOSAR approaches are powerful tools for understanding the toxicity profiles and ecological hazards posed by new pollutants.

Target and suspect screening of psychoactive substances in seizures and oral fluid exploiting retention time prediction and LC-MS/MS analysis

BACKGROUND

Novel psychoactive substances (NPS) are a group of substances, mainly of synthetic origin, characterized by toxicological properties extremely dangerous. The main difficulty in recognizing NPS in seizures and biological samples lies in their dynamic nature, related to the continuous synthesis and introduction on the market of new drugs, often with very similar structures to existing ones. The aim of this study was the creation of a robust and versatile method for the analysis of traditional drugs and NPS in different matrices.

RESULTS

Both target analysis and suspect screening methodologies were developed. The strategy used for suspect screening allowed to collect data through a scheduled multi reaction monitoring (sMRM) survey which triggered the collection of enhanced product ion (EPI) spectra when a compound met information dependent acquisition (IDA) criteria. The retention time of the different drugs, which was crucial to define the sMRM survey scan parameters, was predicted with a Quantitative Structure Retention (Chromatographic) Relationship (QSRR) model by Multiple Linear Regression. The model was validated through the evaluation of training set predictions, an external validation set and a leave-one out strategy; the results showed that the method fit for its purpose. The target method was validated in oral fluid as a testing matrix, with excellent results in term of recovery, accuracy, precision and matrix effect. Finally, the performances of the suspect method were evaluated by analysing a mixture containing 8 reference standards not included in the initial dataset, as well as seizures and real oral fluid samples. Four NPS were putatively identified in the analysed samples.

SIGNIFICANCE

The advantage of the proposed approach is the possibility of quantifying 65 classical drugs of abuse and NPS and, at the same time, detect and putatively identify 146 additional drugs in one single LC-MS/MS run. This is an innovative strategy for multi analyte detection and enables detection of low concentrations of drugs in complex biological matrices such as oral fluid. Considering the highly dynamic drug market, a strength of this strategy is that the analytical method can be kept up to date through the addition of new compounds based on the last drug monitoring bodies alerts without the need of authentic standards.

Tackling new psychoactive substances through metabolomics: UHPLC-HRMS study on natural and synthetic opioids in male and female murine models

Novel psychoactive substances (NPS) represent a broad class of drugs new to the illicit market that often allow passing drug-screening tests. They are characterized by a variety of structures, rapid transience on the drug scene and mostly unknown metabolic profiles, thus creating an ever-changing scenario with evolving analytical targets. The present study aims at developing an indirect screening strategy for NPS monitoring, and specifically for new synthetic opioids (NSOs), based on assessing changes in endogenous urinary metabolite levels as a consequence of the systemic response following their intake. The experimental design involved in-vivo mice models: 16 animals of both sex received a single administration of morphine or fentanyl. Urine was collected before and after administration at different time points; the samples were then analysed with an untargeted metabolomics LC-HRMS workflow. According to our results, the intake of opioids resulted in an elevated energy demand, that was more pronounced on male animals, as evidenced by the increase in medium and long chain acylcarnitines levels. It was also shown that opioid administration disrupted the pathways related to catecholamines biosynthesis. The observed alterations were common to both morphine and fentanyl: this evidence indicate that they are not related to the chemical structure of the drug, but rather on the drug class. The proposed strategy may reinforce existing NPS screening approaches, by identifying indirect markers of drug assumption.

Quantitative determination of amphetamine-type stimulants in sewage and urine by hybrid monolithic column solid-phase microextraction coupled with UPLC-QTRAP MS/MS

A needle-solid-phase microextraction (SPME) method based on hybrid monolithic column (HMC) was proposed for simultaneous separation and extraction of seven amphetamine-type stimulants (ATSs) (amphetamine, methamphetamine, cathinone, methcathinone, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyethylamphetamine), combining with ultra-performance liquid chromatography-triple quadrupole/linear ion trap mass spectrometer (UPLC-QTRAP MS/MS). Thiol functionalized HMC (T-HMC) showed high extraction efficiency and excellent elution results towards target analytes, among three kinds of single/bi-functionalized HMCs. Various parameters of SPME operation and analytical performance were investigated systematically. The adsorption mechanism of T-HMC to ATSs was also discussed and explained as a mixed mode of electrostatic and hydrophobic interactions. Under the optimum experimental conditions, the proposed T-HMC needle-SPME-UPLC-QTRAP MS/MS method was rapid and convenient with good accuracy, low sample consumption, high sensitivity and strong anti-interference ability. This method was successfully applied to quantitative determination of seven trace ATSs in complex sewage and urine samples. In view of abundant types of HMCs, the needle-SPME based on functional HMC also had the potential to selectively separating and enriching other tract new psychoactive substances in complex matrices, and could provide a reliable tool for drug monitoring, especially in applications for forensic analysis and drug abuse.

Screening for new psychoactive substances in wastewater from educational institutions

Drug (ab)use among young people is a serious issue, negatively impacting their well-being and prospects. The emergence of new psychoactive substances (NPS) further complicates the situation as they are easily accessible (e.g., online), but users are at high risk of intoxication as their chemical identity is often unknown and toxicity poorly understood. While surveys and drug testing are traditionally used in educational institutions to comprehend drug use trends and establish effective prevention programs, they are not without their limitations. Accordingly, we investigated the occurrence of NPS in educational institutions through wastewater analysis and critically evaluated the viability of the approach. The study included eight wastewater samples from primary schools (ages 6-15 years), six from secondary schools (ages 15-19 years), three from institutions for both secondary and higher education (ages 15+), and six from higher educational institutions (ages 19+). Samples were obtained mid-week and evaluated in two Slovenian municipalities; the capital Ljubljana and a smaller one (M1). Samples were screened using liquid chromatography-ion mobility-high-resolution mass spectrometry (LC-IMS-HRMS), and NPS identified at three levels of confidence (Level 1: unequivocal, Level 2: probable, Level 3: tentative) from a suspect list containing over 5600 entries. NPS were identified in all types of educational institutions. Most were synthetic stimulants, with 3-MMC, ephedrine, 4-chloro-α-PPP, and ethcathinone being unequivocally identified. Also, NPS were present in wastewater from all educational institution types revealing potential spatial but no inter-institutional trends. Although specific groups cannot be targeted, the study, as a proof-of-concept, demonstrates that a suspect screening of wastewater employing LC-IMS-HRMS can be used as a radar for NPS in educational institutions and potentially replace invasive drug testing.

Use of innovative, cross-disciplinary in vitro, in silico and in vivo approaches to characterize the metabolism of chloro-alpha-pyrrolidinovalerophenone (4-Cl-PVP)

Synthetic cathinones constitute a family of new psychoactive substances, the consumption of which is increasingly worldwide. A lack of metabolic knowledge limits the detection of these compounds in cases of intoxication. Here, we used an innovative cross-disciplinary approach to study the metabolism of the newly emerging cathinone chloro-alpha-pyrrolidinovalerophenone (4-Cl-PVP). Three complementary approaches (in silico, in vitro, and in vivo) were used to identify putative 4-Cl-PVP metabolites that could be used as additional consumption markers. The in silico approach used predictive software packages. Molecular networking was used as an innovative bioinformatics approach for re-processing high-resolution tandem mass spectrometry data acquired with both in vitro and in vivo samples. In vitro experiments were performed by incubating 4-Cl-PVP (20 µM) for four different durations with a metabolically competent human hepatic cell model (differentiated HepaRG cells). In vivo samples (blood and urine) were obtained from a patient known to have consumed 4-Cl-PVP. The in silico software predicted 17 putative metabolites, and molecular networking identified 10 metabolites in vitro. On admission to the intensive care unit, the patient's plasma and urine 4-Cl-PVP concentrations were, respectively, 34.4 and 1018.6 µg/L. An in vivo analysis identified the presence of five additional glucuronoconjugated 4-Cl-PVP derivatives in the urine. Our combination of a cross-disciplinary approach with molecular networking enabled the detection of 15 4-Cl-PVP metabolites, 10 of them had not previously been reported in the literature. Two metabolites appeared to be particular relevant candidate as 4-Cl-PVP consumption markers in cases of intoxication: hydroxy-4-Cl-PVP (m/z 282.1254) and dihydroxy-4-Cl-PVP (m/z 298.1204).

A century of research on psychedelics: A scientometric analysis on trends and knowledge maps of hallucinogens, entactogens, entheogens and dissociative drugs

A scientometric analysis was realized to outline clinical research on psychedelics over the last century. Web of Science Core Collection was searched up to March 18, 2022, for publications on psychedelics. Network analyses and bibliometrics were combined, to identify research themes and trends with Bibliometrix and CiteSpace. The primary aim was to measure research trends evolution over time, and the secondary aims were to identify bibliometric performance and influence networks of publications, authors, institutions, and countries. Sensitivity analyses were conducted for 2016-2022, and 2021 time periods. We included 31,687 documents (591,329 references), which aggregated into a well-structured network with credible clustering. Research productivity was split into an early less productive period mainly focusing on safety issues, and a "psychedelic renaissance" after the 1990s. Major trends were identified for hallucinogens/entheogens, entactogens, novel psychoactive substances (NPS), and on dissociative substances. There was a translational evolution from the bench to the bedside, with phase 2 and 3 trials and/or evidence synthesis in particular. The most recent trends concerned NPS, ketamine-associated brain changes, and ayahuasca-assisted psychotherapy. The USA and Canada were the most productive settings for the research overall, and more recently this geographical distribution became more prominent, reflecting legislative context/policy making. A translational evolution of psychedelics has been occurring, that has brought approval of esketamine for depression and will likely lead to approval of additional psychedelics across mental and physical conditions. Toxicology screening tools for NPS are urgently needed, which in turn might follow the same translational evolution of psychedelics in the future.