Categories Of Substances Research Articles

A Review on N-nitrosamine Impurity

Abstract: Nitrosamines are a category of substances that have a nitroso group linked to an amino group in their molecular structure. They are a category of carcinogens developed as a by-product of drug synthesis and also constituted in the presence of sodium nitrite or nitric acid and secondary amines (like dimethyl amines and diethyl amine) that must be monitored in drug production. In mid-June 2018, the Food and Drug Administration and the European Medicines Agency became aware of the existence of an impurity called N-nitrosamine in some frequently used medications, such as those for blood pressure, antacids, and diabetes. N-nitrosamines are of major concern because the ICH M7 (R1)2 guideline categorizes them as Class 1 impurities or mutagenic carcinogens, and the International Agency for Cancer Research categorizes them as potential carcinogens. The existence of N-nitrosamines in pharmaceutical drugs must be minimized to the greatest extent possible and must be at or below the threshold based on ICH M7(R1)2 fundamentals for materials in the "cohort of concern" described in this guideline and measured based on lifetime constant exposure.

The value of toxicological analysis in acute poisoning patients with uncertain exposure histories: a retrospective and descriptive study from an institute of poisoning.

In clinical practice, some patients might not be able or unwilling to provide a thorough history of medication and poison exposure. The aim of this study was to use toxicological analysis to examine the clinical characteristics of patients with acute poisoning whose exposure history was uncertain from a toxicological analysis perspective. This was a retrospective and descriptive study from an institute of poisoning. Patient registration information and test reports spanning the period from April 1, 2020 to March 31, 2022, were obtained. Patients with uncertain exposure histories and who underwent toxicological analysis were included. Clinical manifestations and categories of toxics were analyzed. Among the 195 patients with positive toxicological analysis results, the main causes of uncertain exposure history was disturbance of consciousness (62.6%), unawareness (23.6%) and unwillingness or lack of cooperation (13.8%). The predominant clinical manifestations were disturbed consciousness (62.6%), followed by vomiting and nausea (14.4%) and liver function abnormalities (8.7%). A comparison of clinical manifestations between patients with positive and negative (n=99) toxicological analyses results revealed significantly different proportions of disturbances in consciousness (63% vs. 21%), dizziness (1.5% vs. 5.1%), multi-organ failure (1.5% vs. 7.1%), and local pain (0 vs 4%). The main categories of substances involved were psychiatric medications (23.1%), sedatives (20.5%), insecticides (13.8%), and herbicides (12.8%). The clinical manifestations of acute poisoning in patients with an uncertain exposure history are diverse and nonspecific, and toxicological analysis plays a pivotal role in the diagnosis and differential diagnosis of such patients.

Predictors of Substance Use Risk in Nurse Anesthetists.

Certified registered nurse anesthetists (CRNAs) are exposed daily to highly addictive substances and stressful work environments, placing them at risk for substance use disorders (SUDs). Previous research, which is scarce, indicated that drugs of choice were opioids and propofol. Therefore, the purpose of this study was to investigate predictors of SUD risk using the World Health Organization Alcohol, Smoking and Substance Involvement Screening Test. From June to July 2020, an online survey was sent via the American Association of Nurse Anesthesiology Research Survey Service to 3,000 CRNAs with a response of approximately 225 members. CRNAs were found to be at a moderate risk for SUDs in the following categories: 10.27% for tobacco, 23.56% for alcohol, and 6.28% for cannabis. Regression analysis by substance category includes robust, differing models in this homogeneous sample. Predictors for all three models include a collection of demographic variables, religiosity, anxiety, difficulties due to anxiety, depression, substance use history, contact with the American Association of Nurse Anesthesiology Peer Assistance Program, and organizational support. Over 10% of CRNAs are at risk for developing tobacco use disorder, and almost one quarter of those surveyed are at a moderate risk for developing alcohol use disorder. These data are of concern and may indicate a shift of preferred substances used by CRNAs from controlled substances to alcohol.

Development of QSAR model based on Monte Carlo optimization for predicting GABAA receptor binding of newly emerging benzodiazepines.

Benzodiazepines and their derivatives belong to a category of new psychoactive substances that have been introduced into the continually expanding illicit market. However, there is a notable absence of available pharmacological data for these substances. To gain a deeper understanding of their pharmacology, we employed the Monte Carlo optimization conformation-independent method as a tool for developing QSAR models. These models were built using optimal molecular descriptors derived from both SMILES notation and molecular graph representations. The resulting QSAR model demonstrated robustness and a high degree of predictability, proving to be very reliable. Moreover, we were able to identify specific molecular fragments that exerted both positive and negative effects on binding activity. This discovery paves the way for the swift prediction of binding activity for emerging benzodiazepines, offering a faster and more cost-effective alternative to traditional in vitro/in vivo analyses.

SUBSTANCE-RELATED AND ADDICTIVE DISORDERS: SUICIDE RISK ASSESSMENT

With the publication of the DSM-5 manual, gambling is placed in the category of behavioral addictions and renamed Gambling Disorder, along with substance addictions, in the substance and addictive disorders category. A change is made, compared to the DSM-IV that we could consider fundamental that is the shift of gambling from the impulse control chapter to the addiction chapter, in line with scientific research in recent years that has placed gambling closer to the addictive disorder. The hypothesis of this paper is to test whether between the relevancies and risk factors involved in substance use disorders and addiction disorders, of which gambling disorder is currently the only categorized disorder, there may be an analogy for what concerns suicide risk. KEYWORDS:Gambling disorder; addictions; suicide risk

Is God a Substance? Avicenna on Essence, Being, and the Categories

Avicenna scholars unanimously agree that Avicenna takes the position that God is not classifiable according to the Aristotelian scheme of the ten categories. However, Avicenna scholars are in little agreement about precisely why God evades categorial classification. Scholars report numerous and, at times, mutually inconsistent arguments purportedly made by Avicenna. In this study, I argue that Avicenna has only one argument as to why God is not in the category of substance—the Essence-Being Distinction Argument—and that he makes this argument consistently throughout his major philosophical encyclopediae. Having clarified this argument, two consequences follow. First, we can study this argument to learn not only about God in Avicenna’s philosophical theology but also about the nature and structure of the categories in Avicenna’s metaphysics. I argue that Avicenna’s Essence-Being Distinction Argument reveals a route by which one may arrive at a real distinction between essence and being from a philosophical, rather than a theological premise. Second, Avicenna’s Essence-Being Distinction Argument, along with the prevalence and consistency thereof, suggests that God has an essence for Avicenna and that texts, wherein Avicenna denies that God has an essence, are exceptional and should not govern our broader interpretation of Avicenna’s philosophical theology.

Postbiotics in the medical field under the perspective of the ISAPP definition: scientific, regulatory, and marketing considerations.

Diverse terms have been used in the literature to refer to the health benefits obtained from the administration of non-viable microorganisms or their cell fragments and metabolites. In an effort to provide continuity to this emerging field, the International Scientific Association of Probiotics and Prebiotics (ISAPP) convened a panel of experts to consider this category of substances and adopted the term postbiotic, which they defined as a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host." This definition does not stipulate any specific health benefit, finished product, target population or regulatory status. In this perspective article, we focused on postbiotics developed for pharmaceutical uses, including medicinal products and medical devices. We address how this field is regulated for products based on inanimate microorganisms, marketing considerations and existing examples of postbiotics products developed as cosmetics for the skin, for vaginal health, and as orally consumed products. We focus on the European Union for regulatory aspects, but also give examples from other geographical areas.

Substance Use and Mental Health Screening Within an Emergency Department-Based HIV Screening Program: Outcomes From 1 Year of Implementation.

The emergency department (ED) may be an optimal setting to screen for substance use disorders (SUDs) and co-occurring psychiatric disorders (CODs). We report on the frequency of problematic substance use and comorbid elevated mental health symptoms detected during a 1-year implementation period of an ED-based SUD/COD screening approach within an established ED HIV screening program. Patients (N = 1,924) were approached by dedicated HIV screening staff in an urban, Midwestern ED. Patients first completed measures assessing problematic alcohol (Alcohol Use Disorder Identification Test-Concise [AUDIT-C]) and substance use across 10 categories of substances (National Institute on Drug Abuse-Modified Alcohol, Smoking, and Substance Involvement Screening Test [NIDA-Modified ASSIST]). Patients with positive alcohol and/or substance use screens completed measures assessing symptoms of depression (Patient Health Questionnaire-9 [PHQ-9]), anxiety (Generalized Anxiety Disorder-7 [GAD-7]), and post-traumatic stress disorder (PTSD) (PTSD Checklist-Civilian [PCL-C]). Patients were predominantly male (60.3%) with a mean age of 38.1 years (SD = 13.0); most identified as White (50.8%) or Black (44.8%). A majority (58.5%) had a positive screen for problematic alcohol and/or other substance use. Of those with a positive substance use screen (n = 1,126), 47.0% had a positive screen on one or more of the mental health measures with 32.1% endorsing elevated depressive symptoms, 29.6% endorsing elevated PTSD-related symptoms, and 28.5% endorsing elevated anxiety symptoms. Among those receiving ED HIV screening, a majority endorsed problematic alcohol and/or other substance use and co-occurring elevated mental health symptoms. Substance use and mental health screening programs that can be integrated within other ED preventive services may enhance the identification of individuals in need of further assessment, referral, or linkage to substance use treatment services.

Fluorescent-Nanoparticle-Impregnated Nanocomposite Polymeric Gels for Biosensing and Drug Delivery Applications.

Nanocomposite polymeric gels infused with fluorescent nanoparticles have surfaced as a propitious category of substances for biomedical purposes owing to their exceptional characteristics. The aforementioned materials possess a blend of desirable characteristics, including biocompatibility, biodegradability, drug encapsulation, controlled release capabilities, and optical properties that are conducive to imaging and tracking. This paper presents a comprehensive analysis of the synthesis and characterization of fluorescent-nanoparticle-impregnated nanocomposite polymeric gels, as well as their biomedical applications, such as drug delivery, imaging, and tissue engineering. In this discourse, we deliberate upon the merits and obstacles linked to these substances, encompassing biocompatibility, drug encapsulation, optical characteristics, and scalability. The present study aims to provide an overall evaluation of the potential of fluorescent-nanoparticle-impregnated nanocomposite polymeric gels for biomedical applications. Additionally, emerging trends and future directions for research in this area are highlighted.

From Enzymatic Dopamine Biosensors to OECT Biosensors of Dopamine.

Neurotransmitters are an important category of substances used inside the nervous system, whose detection with biosensors has been seriously addressed in the last decades. Dopamine, a neurotransmitter from the catecholamine family, was recently discovered to have implications for cardiac arrest or muscle contractions. In addition to having many other neuro-psychiatric implications, dopamine can be detected in blood, urine, and sweat. This review highlights the importance of biosensors as influential tools for dopamine recognition. The first part of this article is related to an introduction to biosensors for neurotransmitters, with a focus on dopamine. The regular methods in their detection are expensive and require high expertise personnel. A major direction of evolution of these biosensors has expanded with the integration of active biological materials suitable for molecular recognition near electronic devices. Secondly, for dopamine in particular, the miniaturized biosensors offer excellent sensitivity and specificity and offer cheaper detection than conventional spectrometry, while their linear detection ranges from the last years fall exactly on the clinical intervals. Thirdly, the applications of novel nanomaterials and biomaterials to these biosensors are discussed. Older generations, metabolism-based or enzymatic biosensors, could not detect concentrations below the micro-molar range. But new generations of biosensors combine aptamer receptors and organic electrochemical transistors, OECTs, as transducers. They have pushed the detection limit to the pico-molar and even femto-molar ranges, which fully correspond to the usual ranges of clinical detection of human dopamine in body humors that cover 0.1 ÷ 10 nM. In addition, if ten years ago the use of natural dopamine receptors on cell membranes seemed impossible for biosensors, the actual technology allows co-integrate transistors and vesicles with natural receptors of dopamine, like G protein-coupled receptors. The technology is still complicated, but the uni-molecular detection selectivity is promising.

In vitro metabolism of cathinone positional isomers: does sex matter?

Synthetic cathinones, one of the most prevalent categories of new psychoactive substances, have been posing a serious threat to public health. Methylmethcathinones (MMCs), notably 3-MMC, have seen an alarming increase in their use in the last decade. The metabolism and toxicology of a large majority of synthetic cathinones, including 3-MMC and 2-MMC, remain unknown. Traditionally, male-derived liver materials have been used as in vitro metabolic incubations to investigate the metabolism of xenobiotics, including MMCs. Therefore, little is known about the metabolism in female-derived in vitro models and the potential sex-specific differences in biotransformation. In this study, the metabolism of 2-MMC, 3-MMC, and 4-MMC was investigated using female rat and human liver microsomal incubations, as well as male rat and human liver microsomal incubations. A total of 25 phase I metabolites of MMCs were detected and tentatively identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Seven sex-specific metabolites were detected exclusively using pooled male rat liver microsomal incubations. In addition, the metabolites generated from the sex-dependent in vitro metabolic incubations that were present in both male and female rat liver microsomal incubations showed differences in relative abundance. Yet, neither sex-specific metabolites nor significant differences in relative abundance were observed from pooled human liver microsomal incubations. This is the first study to report the phase I metabolic pathways of MMCs using in vitro metabolic incubations for both male and female liver microsomes, and the relative abundance of the metabolites observed from each sex.Graphical abstract

Fentanyl and other New Psychoactive Synthetic Opioids. Challenges to Prevention and Treatment.

Synthetic opioids have played a significant role in the current opioid crisis in the United States (U.S.) and Canada and are a matter of concern worldwide. New psychoactive opioids (NPOs) are classified in the internationally recognized new psychoactive substances (NPSs) category. This group comprises compounds that may have been synthesized decades ago but appeared only recently in the illicit drug market. Such is the case of fentanyl, fentanyl analogs, and non-fentanyl opioids. Most NPOs have effects similar to morphine, including euphoria and analgesia, and can produce fatal respiratory depression. Here, we present an overview of the systemic and molecular effects of main NPOs, their classification, and their pharmacological properties. We first review the fentanyl group of NPOs, including the four compounds of clinical use (fentanyl, alfentanil, sufentanil, and remifentanil) and the veterinary drug carfentanil. We also provide essential information on non-medical fentanyl analogs and other synthetic opioids such as brorphine, etonitazene, and MT-45, used as adulterants in commonly misused drugs. This paper also summarizes the scarce literature on the use of NPOs in Mexico. It concludes with a brief review of the challenges to prevention and treatment posed by NPOs and some recommendations to face them.

Микросателлитные локусы в генетической оценке плюсовых деревьев Pinus sylvestris L.

In this study, a comparative analysis was performed to estimate the genetic diversity levels of Pinus sylvestris L. in 49 seed orchards of I generation and progeny test plantings using 4-nucleus microsatellite loci. The seed orchards are located in the Petrozavodsk and Zaonezhye regions of the Republic of Karelia. The progeny trials were created by half-sibling seed progenies of the clones in the Petrozavodsk seed orchard. Micro-Checker software was used to identify null alleles and exclude genotyping errors. Coefficients of genetic originality were determined by examining the genetic structure of breeding objects in relation to the proportion between the rare and the dominant alleles for each selected tree. A major part of the rarest alleles (27.3–37.0 %) and a small fraction of the most common alleles (3.3–14.8 %) were detected for the distinct range of the pine trees in both seed orchards and test cultures. The largest number (40) of all identified alleles (51) was found in the Petrozavodsk seed orchard. The Hardy-Weinberg test comparing allele rates to expectational values showed a lack of heterozygotes in each category of the empirical substances. The selected material also had high levels of allelic and genetic diversity. The average number of alleles per locus ranged from 7.75 to 10.50. The average effective number was from 5.00 to 6.54. The observed heterozygosity varied from 0.60 to 0.70. The expected heterozygosity was 0.63–0.71. The numerical deviations were statistically insignificant. The AMOVA molecular dispersion result was 5 %, indicating the absence of significant genetic differentiation between the breeding objects. The heterozygote deficiency was caused not only by the presence of null alleles, but also by the selection. Namely, the set of alleles in the experimental material, randomly selected from a limited number of genotypes (clones), may differ from the natural population. The high level of the rarest alleles in the given range of the pine trees can also be explained as a selection effect. The results obtained in this study are important for creating breeding objects with higher genetic value. For citation: Ilinov A.A., Raevsky B.V. Genetic Evaluation by Microsatellite Loci of Pinus sylvestris L. Plus Trees. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 48–68. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-48-68

The qualification of nuclear substances and nuclear liability

Organising transport of nuclear substances presents a number of challenges, including how to properly qualify the substances from a nuclear liability perspective. The nuclear liability conventions provide a generic definition of “nuclear substances” (referred to as “nuclear material” under certain conventions), which gives wide discretion to national legislation in its interpretation. Moreover, the nuclear liability conventions also exclude certain categories of nuclear substances, subject to specific conditions being met, to ensure that the risk associated with their transport may be dealt with under general tort law. The implementation or application of these exclusions is carried out by each concerned country in accordance with its domestic legislation, which may lead to discrepancies in the qualification of substances to be transported by different stakeholders.

Assessing the impact of a major electronic music festival on the consumption patterns of illicit and licit psychoactive substances in a Mediterranean city using wastewater analysis

The consumption patterns of five categories of psychoactive substances (PS), including “conventional” illicit drugs, new psychoactive substances (NPS), therapeutic opioids, alcohol and nicotine, were studied in the city of Split, Croatia, using wastewater-based epidemiology (WBE), with an emphasis on the impact of a large electronic music festival. The study involved the analysis of 57 urinary biomarkers of PS in raw municipal wastewater samples collected in three characteristic periods, including the festival week in the peak-tourist season (July) and reference weeks in the peak-tourist season (August) and the off-tourist season (November). Such a large number of biomarkers allowed the recognition of distinct patterns of PS use associated with the festival, but also revealed some subtle differences between summer and autumn seasons. The festival week was characterized by markedly increased use of illicit stimulants (MDMA: 30-fold increase; cocaine and amphetamine: 1.7-fold increase) and alcohol (1.7-fold increase), while consumption of other common illicit drugs (cannabis and heroin), major therapeutic opioids (morphine, codeine and tramadol) and nicotine remained rather constant. Interestingly, NPS and methamphetamine clearly contributed to the festival PS signature in wastewater, but their prevalence was rather low compared to that of common illicit drugs. Estimates of cocaine and cannabis use were largely consistent with prevalence data from national surveys, whereas differences were found for typical amphetamine-type recreational drugs, particularly MDMA, and for heroin. The WBE data suggest that the largest proportion of morphine came from heroin consumption and that the percentage of heroin users seeking treatment in Split is probably rather low. The prevalence of smoking calculated in this study (30.6 %) was consistent with national survey data for 2015 (27.5–31.5 %), while the average alcohol consumption per capita >15 years (5.2 L) was lower than sales statistics suggest (8.9 L).

A REVIEW _SOIL IMPROVEMENT USING THE MULTI TYPE OF POLYPROPYLENE MATERIAL

The increasing recognition among individuals of the detrimental impact of humanmade substances on the natural world has resulted in the development of more ecologically sound substitutes for ensuring the durability of diverse polymers. Researchers have demonstrated a notable propensity towards a methodology for producing substances that possess the ability to serve as an alternative to artificial compounds. In recent years, there has been a notable surge in demand for composite materials comprising both natural and synthetic fibers for commercial purposes, which has had a significant impact on multiple industrial sectors. Natural fibers are a category of substances that are environmentally degradable and abundantly present in their native ecosystems. The aforementioned materials exhibit characteristics such as economical viability, low mass density, inherent ability to regenerate, biodegradability, and distinctive attributes. The primary aim was to evaluate cost-effective methods for soil stabilization. The study investigates a range of materials that have the potential to enhance soil characteristics, such as polypropylene, fiber glass, and fiber plastic. The text examines the potential of said materials to augment shear strength and ameliorate soil quality through the reduction of plasticity, permeability, and compressibility, as well as the enhancement of soil strength

QSAR-QSIIR-based prediction of bioconcentration factor using machine learning and preliminary application

Bioconcentration factor (BCF) is one of the important parameters for developing human health ambient water quality criteria (HHAWQC) for chemical pollutants. Traditional experimental method to obtain BCF is time-consuming and costly. Therefore, prediction of BCF by modeling has attracted much attention. QSAR (Quantitative Structure-Activity Relationship) model based on molecular descriptor is often used to predict BCF, however, in order to improve the accuracy of prediction, previous models are only applicable for prediction for a single category of substance and a single species, and cannot meet the needs of BCF prediction of pollutants lacing toxicity data. In this study, optimized 17 traditional molecular descriptor and five kinds of bioactivity descriptor were selected from more than 200 molecular descriptor and 25 kinds of biological activity descriptors. A QSAR-QSIIR (Quantitative Structure In vitro-In vivo Relationship) model suitable for multiple chemical substances and whole species is constructed by using optimized 4-MLP machine learning algorithm with selected molecular and bioactivity descriptors. The constructed model significantly improves the prediction accuracy of BCF. The R2 of verification set and test set are 0.8575 and 0.7924, respectively, and the difference between predicted BCF and measured BCF is mostly less than 1.5 times. Then, BCF of BTEX in Chinese common aquatic products is predicted using the constructed QSAR-QSIIR model, and the HHAWQC of BTEX in China are derived using the predicted BCF, which provides a valuable reference for establishment of China’s BTEX water quality standards.

Genotoxic effects of polycyclic aromatic hydrocarbons (PAHs) present in vehicle-wash wastewater on grass carp (Ctenopharyngodon idella) and freshwater mussels (Anodonta cygnea)

Vehicle-wash wastewater (VWW) contains high levels of various petrochemicals such as polycyclic aromatic hydrocarbons (PAHs), a carcinogenic category of organic substances. However, the genotoxic effects of PAHs present in VWW remain largely unknown. We explored the genotoxic effects of PAHs present in VWW on fish grass carp (Ctenopharyngodon idella) and freshwater mussels (Anodonta cygnea). Fish and freshwater mussels were divided into control and exposed groups, the prior groups were treated at weekly intervals with clean water, and the latter with Σ16PAHs contaminated VWW for up to four weeks. The samples of blood from fish and haemolymph from freshwater mussels were collected and analyzed using the comet assay technique. Results exhibited that in control fish and freshwater mussel groups the genotoxicity decreased with every week passing following the order of W1 > W2 > W3 > W4, ranging from 8.33 ± 3.06 to 25.3 ± 4.62 and from 46.0 ± 6.93 to 7.67 ± 3.79, respectively. The exposed fish and freshwater mussel groups indicated an increase in genotoxicity with increasing week intervals with an order of W4 > W3 > W2 > W1, ranging from 55.7 ± 11.9 to 128.3 ± 10.0 and from 112.7 ± 8.50 to 183.3 ± 10.1, respectively. The genotoxic effect of Σ16PAHs on fish was comparatively lower than on freshwater mussels. This study elucidates that VWW is highly genotoxic and should be treated before discharging into aquatic ecosystems.

Categories in Topics I 9: A New Plea For a Traditional Interpretation

Abstract The list of katēgoriai presented at the start of Top. I 9 was traditionally interpreted as a version of the canonical Aristotelian list of categories, and as largely equivalent to the list we find in Categories 4. Accordingly, its first item, the ‘what it is’, was identified with the category of substance. This interpretation has been challenged by several scholars, all sharing the view that the ‘what it is’ in Top. I 9 cannot be substance, since it collects items belonging to all Aristotelian categories (e. g. human being, colour, length). Rather, they say, it is a manner of predication – i. e. essential predication – and can only determine an ontologically miscellaneous class of items. Against this family of proposals, I argue afresh that the traditional interpretation is almost entirely correct. To this purpose, I take advantage of the distinction between kinds of predicate and kinds of predication.

Challenges in Drug Surveillance: Strengthening the Analysis of New Psychoactive Substances by Harmonizing Drug Checking Services in Proficiency Testing.

Drug checking is a proven harm reduction strategy and provides real-time information on the market of new psychoactive substances (NPS). It combines chemical analysis of samples with direct engagement with people who use drugs (PWUD), giving the ability to increase preparedness and responsiveness towards NPS. Next to that, it supports rapid identification of potential unwitting consumption. However, NPS cause a toxicological battle for the researchers, as factors such as the unpredictability and quick shift of the market complicate the detection. To evaluate challenges posed towards drug checking services, proficiency testing was set up to evaluate existing analytical techniques and investigate the capability to correctly identify circulating NPS. Twenty blind substances, covering the most common categories of substances, were analyzed according to the existing protocols of the existing drug checking services, including several analytical methods such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography with diode array detector (LC-DAD). The proficiency test scores range from 80 to 97.5% accuracy. The most common issues and errors are mainly unidentified compounds, presumably due to no up-to-date libraries, and/ or confusion between structural isomers, such as 3- and 4-chloroethcathinone, or structural analogs, such as MIPLA (N-methyl-N-isopropyl lysergamide) and LSD (D-lysergic acid diethylamide). The participating drug checking services have access to adequate analytical tools to provide feedback to drug users and provide up-to-date information on NPS.