Amphetamine-type Stimulants Research Articles

Preparation of polydopamine-functionalized mesoporous silica-coated core/shell magnetic nanocomposite for efficiently extracting five amphetamine-type stimulants from wastewater followed by UPLC-MS/MS determination

Wastewater-based epidemiology (WBE) was a near-real-time monitoring strategy for illegal drugs. However, solid-phase extraction (SPE) widely used in WBE was time-consuming and labor-intensive to extract ultra-trace target compounds from wastewater. In this study, a convenient magnetic solid-phase extraction (MSPE) approach based on newly designed and synthesized polydopamine functionalized core-shell magnetic mesoporous silica (Fe3O4@nSiO2@mSiO2@PDA) nanocomposite was synthesized and firstly utilized for simultaneously extracting five amphetamine-type stimulants (ATSs) from wastewater samples. Subsequently, ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method coupled with optimal MSPE was developed for determination of ultra-trace ATSs in wastewater. The validation results indicated a favorable linearity ranging from 1 to 200 ng L−1, low limit of detection (0.5–2.5 ng L−1), and qualified recovery (95.1–106.6%) and repeatability (0.6–6.2%). In addition, the Fe3O4@nSiO2@mSiO2@PDA nanoparticles could be reused for at least ten times without significant loss of the adsorption efficiencies of ATSs. Finally, the MSPE-UPLC-MS/MS method was successfully applied to real wastewater samples with the results that the preparation procedure was shrunk from 2 h to 30 min without obvious decline of extraction efficiency compared with the SPE. Hence, based on merits of the novel Fe3O4@nSiO2@mSiO2@PDA nanocomposite, the proposed method is convenient and reliable for determination of ATSs in wastewater.

Fast on-site screening of 3,4-methylenedioxyethylamphetamine (MDEA) in forensic samples using carbon screen-printed electrode and square wave voltammetry

The worldwide seizures of illicit synthetic drugs have been dramatically increasing over the past decade, when the quantity of seized amphetamine-type stimulants (ATS) quadrupled, while seized ecstasy (3,4–methylenedioxymethamphetamine or MDMA)-like substances doubled. In this work, a simple and fast methodology for the electrochemical screening of ecstasy analogue MDEA (3,4-methylenedioxyethylamphetamine) in forensic samples is presented, for the first time, using a carbon screen-printed electrode (C-SPE) and square wave voltammetry (SWV). The electrochemical behavior of MDEA was studied by cyclic voltammetry at different pH values (2 to 12), where an altered electrochemistry of this drug on C-SPE, with an unreported redox pair, was observed in comparison with previous works dealing with the voltammetric detection of other ATS with similar chemical structures. Based on the acquired electrochemical processes, a redox reaction mechanism for MDEA on C-SPE is proposed. The best conditions (sensitivity and selectivity) for MDEA screening were obtained by SWV (a: 40 mV, f: 30 Hz, and Estep: 4 mV) and 0.04 mol L−1 Britton Robinson buffer solution at pH 3.0 as the supporting electrolyte. The proposed method presents a wide linear range (2.5 to 30.0 µmol L−1, R2 > 0.99), high sensitivity (0.569 µA / µmol L−1), low theoretical limit of detection (0.03 µmol L−1), and good repeatability using the same C-SPE (RSD < 6%; n = 10). The inter-device reproducibility (n = 5) showed a minimal variation of peak potentials (RSD < 2.3%). The interference study was performed with some adulterants usually found in ecstasy tablets, such as paracetamol, caffeine, glucose, ketamine, cocaine, acetylsalicylic acid, amphetamine (A), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), MDMA, ethylone (bk-MDEA), n-ethylpentylone (bk-EBDP) and dibutylone (bk-DMDBD). The method was applied in real seized samples containing MDEA with addition-recovery studies close to 100%. The developed method is promising to be used as a preliminary test for the screening of MDEA in the ever-changing situation concerning seized forensic samples. The proposed sensor exhibits attractive features for application in forensic analysis, such as rapidness, simplicity, low-cost, user friendly and portability.

Amphetamine-Type Stimulant Dependence and Association with Concurrent Use of Cocaine, Alcohol, and Cannabis: A Cross-Sectional Study

Introduction: Amphetamine-type stimulants (ATSs) are the second most commonly used class of illegal substances in Europe. Although concurrent substance use has been subject to research, little is known about associations between concurrent use of cocaine, alcohol, or cannabis and ATS dependence. We expect that the concurrent use of any of the substance, especially cannabis and cocaine, is associated with ATS dependence. Methods: Cross-sectional data were gathered within the European ATTUNE study in 2018/2019. Participants (N = 721) were asked about their consumption patterns and social, psychological, and economic situation. Multivariate logistic regressions were carried out for associations between ATS dependence and use combinations of frequent cocaine, alcohol, or cannabis, with the reference group of no frequent concurrent use (model 1). Model 2 calculated associations for ATS dependence with lifetime methamphetamine use for respective use combinations. Results: The study population was on average 28.9 years old (SD = 7.7), with the majority being male (63.5%). In model 1, the adjusted odds ratio (aOR) for frequent alcohol use was 0.70 (confidence interval [CI] 0.41–1.20). Similar results were shown for model 2 (aOR 0.82, CI 0.42–1.62). Frequent cannabis use significantly reduced the chance for ATS dependence by 50% in adjusted model 1 (aOR 0.50, CI 0.28–0.89) and by 62% in model 2 (aOR 0.38, CI 0.18–0.82). For frequent cocaine use, models 1 and 2 report an aOR at 1.37 (CI 0.58–3.25) and 2.39 (CI 0.77–7.43), although not statistically significant. Frequent users of all 3 substances had a significant 3-fold chance for ATS dependence (model 1: aOR 2.98, CI 1.16–7.63; model 2: aOR 2.95, CI 1.02–8.58). Discussion: Against initial hypotheses, frequent concurrent use of alcohol or cannabis generally decreased chances for ATS dependence. An explanation could be the study population, which consists of many irregular users of ATS, who mainly consume alcohol or cannabis. Cocaine generally increased chances, although results were not significant. The frequent use of all 3 substances together with ATS in the last year was significantly associated with dependence, thus reporting important information for treatment services. Further research is needed for disentangling causal relationships underlying these associations and for pinpointing consequences for relapse prevention and retention success.

Drug Abuse Patterns of Combined Amphetamine-Type Stimulants and Opioid Dependence in Malay Male Subjects in Kota Bharu, Kelantan, Malaysia

The objective of this study was to examine the socio-demographic characteristics and drug abused patterns of combined amphetamine-type stimulants (ATS) and opioid dependence in Malay Male subjects in Kota Bharu, Kelantan, Malaysia. Seventy drug dependent subjects who were diagnosed using Diagnostic and Statistical Manual-IV (DSM-IV), and 87 control subjects who fulfilled the inclusion and exclusion criteria were interviewed using a questionnaire.The median age (IQR) for drug dependent group was 28.0 (7.68) years old while median age for control group was 24.0 (10.55). The mean (SD) initiation age for ATS was 27.39 (9.79) while the mean (SD) initiation age for opioid was 22.20 (7.19). 57.1% of the drug dependent subjects used injections as their method of opioid ingestion, while 65.7% preferred chase to ingest ATS. Most of the subjects were HIV negative (61.4%). Majority have not sought any treatment regarding their drug usage (71.4%). Most of the drug dependent subjects have been arrested and convicted for drug use (88.6%). However, majority demonstrated no history of arrest or conviction for non-drug related crime (77.1%). This study provides an update on the socio-demographic and drug abuse patterns of combined amphetamine-type stimulants and opioid dependence subjects that may help in combating the alarming increase of the drug abuse.

Illicit drug profiling: A historical perspective.

For many years following the Second World War trafficking in cocaine, heroin and methylamphetamine was on a comparatively small scale. However, by the 1970s heroin usage increased to a point where it had became a serious worldwide problem creating concern at high levels in many governments. In 1977 the United Nations International Drug Control Program convened a special meeting of experts to explore ways of 'profiling' or geo-locating heroin to aid in determining trafficking routes used to move the drug around the world. The Panel was tasked with developing a concerted research program into the chemical profiling of heroin with the express aim of using chemistry for geo-location. Eventually the scope of the program was expanded to include cocaine because it was a major problem in the United States and was being increasingly seen in European cities. The amphetamine type stimulants, methylamphetamine, amphetamine and 3, 4-methylenedioxymethamphetamine (MDMA), were also included and research into profiling techniques for these five major drugs became common. Today many countries have dedicated drug profiling programs employing large staff numbers and using sophisticated analytical technology. Drug profiling, especially the chemistry that underpins it, is an interesting field and will continue to be valuable as long as it remain relevant to the law enforcement community and its attempts to disrupt drug manufacture and trafficking.

Evaluation of substance use in Izmir during the COVID-19 pandemic

ABSTRACT Background Substance use can vary in extraordinary periods, such as natural disasters and epidemics. This study scrutinized the toxicological test results of the people who used different types of substances during the 2020 COVID-19 pandemic period in Izmir. Methods Due to the COVID-19 outbreak, extreme security measures were implemented in March, April, and May of 2020, and the lockdown was imposed at different levels. The patients who were urine tested for illegal substances were also investigated from the point of the socio-demographic characteristics and clinical data. Results Thirty-six percent of the cases (n = 32) were positive for illegal substances in urinalysis. These substances were: 60% (n = 12) amphetamine-type stimulants (ATS), 20% (n = 4) benzodiazepine, 10% (n = 2) cannabis, 5% (n = 1) buprenorphine, 5% (n = 1) cocaine. Multiple substance use observed in 12 cases. Conclusions When the pandemic period data were compared with the previous years, the drug test positive rate in the same periods of 2017 and 2018 was 25.9% and 23.9%, respectively. However, this rate increased to 36% during the pandemic period in 2020. In 2017 and 2018, cannabis was the most frequently found substance in the urine on testing with the rate of 41.5% (n = 184) and 50.8% (n = 219), respectively, it was ATS with 60% (n = 2) in 2020.

Analytical Challenges for Identification of New Psychoactive Substances: A Literature-Based Study for Seized Drugs

Correct identification of substances is essential to understand drug use and trafficking trends and guide measures for harm reduction and treatment. Two steps are needed to verify the nature of a substance properly: a presumptive test and a confirmatory test. There are presumptive tests which presents deficiencies, such as providing false-positive and false-negative results. Confirmatory tests are more reliable, but they are more expensive. With the appearance of New Psychoactive Substances (NPS), identifying and characterizing illicit substances has become more challenging. This paper focuses on presenting information about NPS characteristics and analysis. For this purpose, we have reviewed the literature to address the main aspects of five groups of NPS: amphetamine-type stimulants, synthetic cannabinoids, N-methoxybenzyl-methoxyphenylethylamine (NBOMe), synthetic opioids, and benzodiazepines. We present the main characteristics of each group and certain aspects of presumptive and confirmatory tests regarding these groups. Our findings show obstacles in developing methodologies that can correctly identify these substances, and problems can increase as new structures appear. This information can be helpful to drive research into identifying NPS and inform law enforcement and law practitioners about the main characteristics of each group and the main questions involving their identification.

Detection of amphetamine‐type stimulants using sample derivatization and SALDI‐TOF‐MS

AbstractWe have developed a gold nanoparticle‐based surface‐assisted laser desorption/ionization mass spectrometric (SALDI‐MS) method for the analysis of amphetamine‐type stimulants (ATS), including methamphetamine (MA), 3,4‐methylenedioxy‐N‐methamphetamine (MDMA), 3,4‐methylenedioxy‐N‐ethylamphetamine (MDEA), and 4‐fluoromethamphetamine (4‐FMA), by derivatization to form quaternary ammonium species. After derivatization, the ion signal intensities of the derivatives of MA, MDMA, MDEA, and 4‐FMA significantly increase as compared to that without derivatization. Moreover, there is no analyte suppression effect in our samples after derivatization. The limits of detection (LODs) for MA, MDMA, MDEA, and 4‐FMA are 0.1, 1.0, 91, and 44 ppb, respectively, with the correlation coefficients of these regressions in the calibration curves higher than 0.99. The optimal experimental conditions, including concentration of gold nanoparticles and sample preparation method, were then applied to urine samples. After a simple sample pretreatment, including extraction and derivatization, results show that the average recoveries of the SALDI‐MS method for MA and MDMA are 100.87 ± 5.8% and 98.28 ± 2.9%, respectively. In summary, we have demonstrated a method to improve the sensitivity of the SALDI method for determination of ATS by derivatization and the method has been validated in the determination of MA and MDMA in urine samples.

Behavioral Risk Factors for HIV Infection in Hospitalized Persons Who Co-use Stimulants and Opioids.

We investigated the association of 90-day opioid and stimulant co-use and HIV risk behaviors in a cross-sectional analysis of hospitalized HIV-negative people who inject drugs (PWID). We compared those injecting opioids alone to two sub-groups who co-used opioids with (1) cocaine, (2) amphetamine-type stimulants (ATS), on sex and injection drug risk behaviors assessed via the Risk Assessment Battery (RAB), where a higher score indicates a higher risk. Of 197 participants who injected opioids, 53% co-used cocaine only, 5% co-used ATS only, 18% co-used both cocaine and ATS, 24% co-used neither stimulant. PWID who injected opioids alone had a mean RAB drug risk score of 5.98 points and sex risk score of 2.16 points. Compared to PWID who injected opioids alone, PWID who co-used stimulants had higher mean drug risk RAB scores: cocaine, b = 2.84 points [95% confidence interval (CI) 1.01; 4.67]; ATS, b = 3.43 points (95% CI 1.29; 5.57). Compared to PWID who injected opioids alone, cocaine co-use was associated with higher sex RAB scores b = 1.06 points (95% CI 0.32; 1.79). Overall, we found a significant association between stimulant co-use and higher HIV sex and drug risk scores.

Factors Related to Social Disturbance Among Patients With Mental Disorders Caused by Amphetamine-Type Stimulants

Factors Related to Social Disturbance Among Patients With Mental Disorders Caused by Amphetamine-Type Stimulants

Psychoactive Substance Use Among Individuals With Chronic Spinal Cord Injury: Patterns and Characteristics

ObjectiveTo identify the patterns of nonprescription psychoactive substance (PAS) use among persons with spinal cord injury (SCI) and the relationships with demographic and injury characteristics. DesignCross-sectional, self-report assessment (SRA). SettingA medical university in the southeastern United States. ParticipantsThe participants (N=4670) were identified through a specialty hospital and 2 state-based surveillance registries. InterventionsNot applicable. Main Outcome MeasuresParticipants completed SRAs and reported the past 3 months’ use of the following substances for which they did not have a prescription: cannabis, cocaine, amphetamine-type stimulants, inhalants, sedatives/hypnotics and sleeping pills, hallucinogens, and opioids. PAS use was grouped into 4 categories: none, cannabis use only, use of cannabis and other PAS, and use of other PAS only. ResultsOf the 4577 participants who responded to the PAS use questions, 24.1% reported using at least 1 PAS without a prescription. Cannabis was the most frequently reported substance (16.4%), followed by sedatives or sleeping pills (8.0%). By PAS use group, 12.1% reported use of cannabis use only, followed by use of other PAS only (7.7%) and use of cannabis and other PAS (4.3%). There were significant differences among the groups of use by nearly all personal characteristics. ConclusionsThe use of nonprescription PASs is prevalent among adults with chronic SCI, and there are clear differences in patterns and characteristics of use.

The Relationship between Cannabis and Tobacco Co-administration and Long-Term Patterns of Cannabis Use in Young Adults Who Use Stimulants: A Prospective Population-Based Study

Background Co-administering cannabis with tobacco (i.e. co-administration of the substances mixed together) is a common practice among cannabis users, but the consequences of this practice are not well understood. This study examines the relationship between co-administering cannabis with tobacco and the long-term frequency of cannabis use in a young adult population group with high rates of cannabis and tobacco use. Methods The data are from an Australian prospective population-based study of young adults who recurrently used amphetamine-type stimulants (ATS). The mean age of participants was 20.8 years at baseline, sample size (n = 277), and 47% were female. We examined the frequency and quantity of cannabis consumption over 4 ½ years. Negative binomial regression analysis was conducted to examine the frequency of cannabis use at 12-month follow-up and at 4 ½ years, with co-administering practices as the predictor. Results At every time interval, participants who always co-administered their cannabis with tobacco used cannabis on more days in the last month than those who only sometimes co-administered, rarely co-administered, or never co-administered these substances (p < 0.001). Sometimes co-administering cannabis with tobacco at baseline predicted more frequent cannabis use at 12-month follow-up (adjusted IRR: 2.25, 95% CI: 1.05, 4.78), independently of the baseline frequency of cannabis use. However, levels of co-administering cannabis with tobacco at 12-month follow-up (rarely, sometimes, and always) did not predict high levels of cannabis use at 4 ½ years follow-up after adjusting for cannabis use at 12-month follow-up. Conclusions Among people who use ATS and cannabis, frequent cannabis use may be a marker of the practice of co-administering cannabis with tobacco, and can be used to target tobacco cessation interventions in these populations.

1220Barriers to care for people who use crystal methamphetamine

Abstract Background Crystal methamphetamine (‘ice’) causes significant societal harm in Australia and is perceived by the public to be the drug of most concern nationally. Although effective treatments exist, it is estimated that only a third of people dependent on amphetamine-type stimulants receive treatment each year. Barriers to care may for people who use ice can include psychosocial (e.g., knowledge, attitudinal) and structural barriers. This study aimed to look at the perceived and actual barriers to care for Australians, as well as help-seeking behaviours among people who use ice. Methods An online survey was conducted among 2,110 Australians including people with lived experience, health workers, affected family members/friends and community members. All participants were asked about perceived barriers to care. People with lived experience were asked additional questions about help seeking. Results Attitudinal reasons were the highest perceived barrier to care among 63.1% of participants, followed by knowledge (21.9%). People with lived experience were more likely to endorse attitudinal barriers (OR 1.35), whereas health workers were more likely to endorse knowledge related barriers (OR 0.69). Among people with lived experience who had sought help, 74.5% had visited a counsellor/psychologist and 60.6% had asked help from a family member/friend. Conclusions Understanding and reducing barriers to care is essential to reduce the harms associated with the drug. It is important to support families and friends as they are often asked to help or support a loved one using ice. Key messages It is important to understand and reduce the perceived and actual barriers to care for people who use ice. This is essential to reduce the harms associated with the drug.

A survey of amphetamine type stimulant nitrogen sources by isotope ratio mass spectrometry

The purpose of this study was to determine what variations exist in δ13C and δ15N values of nitrogen sources used in the clandestine production of amphetamine type stimulants (ATS). A survey of previously reported data revealed a lack of information on the novel nitrogen source hydroxylamine. HCl, which can be utilised in the production of MDA from helional. Samples of nitromethane, nitroethane and hydroxylamine.HCl were collected or synthesised for analysis by isotope ratio mass spectrometry (IRMS). Unlike many other nitrogen sources, nitromethane is an uncontrolled substance with legitimate applications. Nitromethane samples were collected from hobby stores around Brisbane, Australia. An investigation into the synthesis of nitromethane.HCl by the acid catalysed hydrolysis of nitromethane is also presented.The δ15N values for nitromethane (–37.21 to –0.10‰) and hydroxylamine.HCl (–97.87 to +2.19‰) expand considerably on the previously published δ15N values of nitrogen sources. The broad range of δ15N values identified should provide a useful tool in the comparison of ATS, especially when synthesised from the novel precursor helional and utilising hydroxylamine.HCl as a nitrogen source. Relatively consistent δ15N fractionation was observed for hydroxylamine.HCl synthesised from nitromethane.

Swarm Intelligence-Based Feature Selection for Amphetamine-Type Stimulants (ATS) Drug 3D Molecular Structure Classification

ABSTRACT Swarm intelligence-based feature selection techniques are implemented by this work to increase classifier performance in classifying Amphetamine-type Stimulants (ATS) drugs. A recently proposed 3D Exact Legendre Moment Invariants (3D-ELMI) molecular descriptors as 3D molecular structure representational for ATS drugs. These descriptors are utilized as the dataset in this study. However, a large number of descriptors may cause performance degradation in the classifier. To complement this issue, this research applies three swarm algorithms with k-Nearest Neighbor (k-NN) classifier in the wrapper feature selection technique to ensure only relevant descriptors are selected for the ATS drug classification task. For this purpose, the binary version of swarm algorithms facilitated with the S-shaped or sigmoid transfer function known as binary whale optimization algorithm (BWOA), binary particle swarm optimization algorithm (BPSO), and new binary manta-ray foraging optimization algorithm (BMRFO) are developed for feature selection. Their performance is evaluated and compared based on seven performance criteria. Furthermore, the optimal feature subset was then evaluated with seven different classifiers. Findings from this study have revealed the dominance of BWOA by obtaining the highest classification accuracy with the small feature size.

Polysubstance use classes and health outcomes among women attending specialist substance use treatment services.

Substance use is increasingly prevalent among women. Little research examines subgroups of women with substance use issues to identify their characteristics and thus enable treatment recommendations. The present study used latent class analysis to identify subgroups of substance use among women in substance-use treatment based on use in the 30 days prior to intake and examined changes in mental health and treatment outcomes following 60 days of treatment. Participants were women (N=493) attending specialist non-government substance use treatment services in New South Wales, Australia. Four distinct classes of substance users were identified: (i) Amphetamine Type Stimulants (ATS) Polysubstance (40.6%, n=200); (ii) Alcohol Only (33.1%, n=163); (iii) Cannabis and Alcohol (17.0%, n =84) and (iv) Other Polysubstance (9.3%, n =46). Women in the ATS Polysubstance class were the youngest and those in the Alcohol Only class were the oldest. Findings show that classes with high polysubstance use (ATS Polysubstance) differed from the single-substance use class (Alcohol Only). The ATS Polysubstance class had significantly greater improvements in health outcomes after 60 days compared to the Alcohol Only class. These findings suggest that although women with polysubstance use can benefit from substance use treatment, younger women (ATS Polysubstance) may benefit even more than older women (Alcohol Only). Future research should utilise a longitudinal design and examine additional psychosocial characteristics to extend on current findings.

Impurity profiling of methamphetamine synthesised from α-phenylacetoacetonitrile (APAAN).

The rise in popularity of 'designer' precursor compounds for the synthesis of amphetamine-type stimulants poses a significant challenge to law enforcement agencies. One such precursor is α-phenylacetoacetonitrile (APAAN). APAAN emerged in Europe in 2010 and quickly became one of the most popular precursors for amphetamine synthesis in that region. Previous literature has identified four APAAN-specific impurities formed in the synthesis of amphetamine; however, there is currently no research on the use of APAAN in the synthesis of methamphetamine, which is more likely to be employed in a non-European market. In this study methamphetamine was synthesised via three common clandestine methods: the Leuckart method and two reductive amination methods. We report the identification of five new impurities and two previously identified impurities characteristic for the use of APAAN in the synthesis of methamphetamine. The newly identified impurities were characterised by MS and NMR and determined to be (E)-3-(methylamino)-2-phenylbut-2-enenitrile, 3-(methylamino)-2-phenylbutanenitrile, 3-methyl-2,4-diphenylpentanedinitrile, 2-phenylbutyronitrile and 3-hydroxy-2-phenylbutanenitrile.

Enantioselective determination of plasma protein binding of common amphetamine-type stimulants

Amphetamine-type stimulants (ATS) like amphetamine (‘speed’), methamphetamine (‘crystal meth’) and 3,4-methylenedioxy-N-methylamphetamine (MDMA, ‘ecstasy’) represent some of the most frequently abused drugs worldwide. Another less frequently abused ATS is 4-fluoroamphetamine (4-FA). The enantiomers of these four compounds exhibit different pharmacokinetic and pharmacodynamic properties. According to the free drug theory, the pharmacological properties of a substance are dependent on its plasma protein binding (PPB). However, data on PPB of stimulant enantiomers in humans are rare or non-existent.Human plasma samples were spiked with racemic mixtures of the stimulants and subjected to ultrafiltration to extract the unbound fraction. Enantioselective liquid chromatography − tandem mass spectrometry (LC-MS/MS) methods were applied using a chiral Phenomenex® Lux3 μm AMP column. Method validation showed satisfactory selectivity, linearity (0.5 250 ng/mL), accuracy and precision. Enantiomers were quantified before and after ultracentrifugation to determine PPB.For all analytes, low to medium plasma protein binding was found. For (R)-amphetamine a slightly but significantly higher PPB was found compared to the (S)-enantiomer (31.7 % vs 29.0 %). (R)-MDMA also showed only slightly but significantly significantly higher PPB than (S)-MDMA, although the mean difference was negligible (21.6 % vs 21.3 %). For the enantiomers of methamphetamine and 4-FA, no significant differences in PPB were found.In summary, there were no or only minor differences in PBB for the enantiomers of all investigated compounds. The different pharmacological properties of the stimulant enantiomers can therefore not be explained by differences in PPB.

Amphetamine-type stimulants (ATS) drug classification using shallow one-dimensional convolutional neural network.

Amphetamine-type stimulants (ATS) drug analysis and identification are challenging and critical nowadays with the emergence production of new synthetic ATS drugs with sophisticated design compounds. In the present study, we proposed a one-dimensional convolutional neural network (1DCNN) model to perform ATS drug classification as an alternative method. We investigate as well as explore the classification behavior of 1DCNN with the utilization of the existing novel 3D molecular descriptors as ATS drugs representation to become the model input. The proposed 1DCNN model is composed of one convolutional layer to reduce the model complexity. Besides, pooling operation that is a standard part of traditional CNN is not applied in this architecture to have more features in the classification phase. The dropout regularization technique is employed to improve model generalization. Experiments were conducted to find the optimal values for three dominant hyper-parameters of the 1DCNN model which are the filter size, transfer function, and batch size. Our findings found that kernel size 11, exponential linear unit (ELU) transfer function and batch size 32 are optimal for the 1DCNN model. A comparison with several machine learning classifiers has shown that our proposed 1DCNN has achieved comparable performance with the Random Forest classifier and competitive performance with the others.

Determination of the enantiomeric composition of amphetamine, methamphetamine and 3,4-methylendioxy-N-methylamphetamine (MDMA) in seized street drug samples from southern Germany.

Amphetamine (speed), methamphetamine (crystal meth), and 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) represent the most frequently abused amphetamine-type stimulants (ATS). Differences in pharmacological potency and metabolism have been shown for the enantiomers of all three stimulants. Legal consequences in cases of drug possession may also differ according to the German law depending on the enantiomeric composition of the seized drug. Therefore, enantioselective monitoring of seized specimens is crucial for legal and forensic casework. Various kinds of samples of amphetamine (n = 143), MDMA (n = 94), and methamphetamine (n = 528) that were seized in southern Germany in 2019 and 2020 were analyzed for their chiral composition using different chromatographic methods. Whereas all samples of amphetamine and MDMA were racemic mixtures, the chiral composition of the methamphetamine specimens was diverse. Although the vast majority (n = 502) was present as (S)-methamphetamine, also specimens containing pure (R)-methamphetamine (n = 7) were found. Furthermore, few samples (n = 8) were of racemic nature or contained non-racemic mixtures of both enantiomers (n = 10). Because methamphetamine appears in varying enantiomeric compositions, any seizure should be analyzed using an enantioselective method. Amphetamine and MDMA, on the other hand, currently appear to be synthesized exclusively via racemic pathways and are not chirally purified. Nevertheless, regular monitoring of the chiral composition should be ensured.