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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of High Resolution Mass Spectrometry for the Screening and Confirmation of Novel Psychoactive Substances

Seither, Joshua Zolton 25 April 2018 (has links)
There has been an emergence of novel psychoactive substances (NPS) in forensic casework globally. Although the reported prevalence of these compounds has been relatively low in comparison to traditional drugs of abuse, published case studies suggest that some NPS have significant pharmacological effects that may cause severe impairment and/or death. Because of these effects, it is important that toxicology laboratories have the capability of identifying these compounds to complete a comprehensive toxicological analysis for human performance and post-mortem investigations. Recently, mass spectrometry has gained favor over traditional screening assays such as immunoassays for the identification of NPS in biological specimens. This trend is mainly a result of the fact that mass spectrometry provides the required sensitivity and selectivity for a broader range of analytes. High resolution tandem mass spectrometry has been suggested for analysis of NPS, as this technique further increases selectivity by increasing mass accuracy and providing MS/MS spectral data. The main goal of the present study was to investigate the applicability of using high resolution mass spectrometry to screen for and confirm a large number of novel psychoactive substances. The present study consisted of three main tasks, which included 1) the creation of a large high resolution MS/MS spectral library and database, 2) the development of a solid phase extraction (SPE) method and acquisition methods, and 3) a collision induced dissociation (CID) study of regioisomeric NPS compounds. The MS/MS spectral library created contains spectral data for 252 NPS. In addition, 875 NPS entities were included in the compound database. The library and database can be used by toxicology laboratories to aid in the identification of NPS in casework using MS/MS spectral data and full scan MS data, respectively. The analytical method developed used SPE and high resolution mass spectrometry (HRMS). The HRMS method demonstrated limits of detection ranging from 0.5- 5 ng/mL for NPS from various structural drug classes. The CID experiments demonstrated that relative ion abundance alone could be used to differentiate some sets of regioisomers. The present work can aid toxicology laboratories in the identification of NPS and demonstrates the applicability of HRMS for their screening and confirmation.
2

Young people's perceptions of novel psychoactive substances

Freeman, Jodie January 2018 (has links)
Novel Psychoactive Substances (NPS) also known as "legal highs" replicate the effects of illegal substances such as ecstasy and cocaine. The most common NPS reported are stimulants and synthetic cannabinoids. Despite the Psychoactive Ban (2016) recent reports identified the UK as having the largest market of NPS use anywhere in Europe. These substances have a short history of consumption and consequently little is known about their effects and health implications. Despite this, the sale of NPS is easily achieved through the internet and street dealers. Increased reports of negative health consequences from NPS consumption and research findings highlighting the willingness of young people to consume drugs without knowing what they are, mean it is vital that we investigate young people's understandings and perceptions of them. At present there are very few in-depth qualitative studies on NPS. A series of 7 focus groups with a range of young people (40=N: aged 16- 24 years) across the Merseyside area were carried out. Research sites included colleges, youth groups, supported living accommodations, and youth drug and alcohol services. Focus group interviews explored participants' perceptions of NPS and were followed up with a few semi structured interviews with selected participants. The direction of the study focused on mainly on synthetic cannabinoids which may reflect the age of the study's population. Using thematic analysis informed by a social constructionist perspective, three main themes were identified around stigma and identity, attractive features of NPS and risk. Findings showed that young people's perceptions of these substances were dependent on their level of experience with illegal substances and NPS. A novel finding was that synthetic cannabinoid use is employed in the normalisation of cannabis use. Local, national and policy recommendations are made on how youth and health services in both educational and specialised services could work more closely and effectively with young people NPS. They also identify a need among young people for specific guidelines on how to use the Internet and Print media in relation to previous knowledge and experience.
3

Forensic Toxicological Screening and Confirmation of 800+ Novel Psychoactive Substances by LC-QTOF-MS and 2D-LC Analysis

Eckberg, Melanie N 24 August 2018 (has links)
Novel psychoactive substances (NPS) represent a great challenge to toxicologists due to the ability of illicit drug manufacturers to alter NPS chemical structures quickly and with ease to circumvent legislation regulating their use. Each time a new structure is introduced, there is a possibility that it has not been previously recorded in law enforcement or scientific databases. Many toxicology laboratories use targeted analytical methods that rely on libraries of known compounds to identify drugs in samples. However, these libraries do not include large numbers of NPS which could result in non-identification or detection. High-resolution mass spectrometry (HRMS) has been suggested as a method for screening a wide variety of analytes due to its higher sensitivity and mass accuracy as compared to some other forms of mass spectrometry. This technique can generate characteristic MS/MS spectral data for use in compound identification. The main goal of this research was to create a high-resolution mass spectrometry (HRMS) library of NPS and metabolites, as well as validate a method for screening and confirmation of these substances. The study consisted of three main tasks which included; the development of a large high-resolution MS/MS spectral library and database, validation of a method for screening and confirmation of over 800 NPS and metabolites, and screening of blind-spiked and authentic urine specimens to determine real-world applicability of the HRMS library and method. During validation, several isomeric and structurally related NPS were observed which could not be adequately separated using traditional LC methods. A fourth task was therefore added to investigate improved separation using two-dimensional liquid chromatography (2D-LC). Increased resolving power is achieved in 2D-LC through the coupling of multiple orthogonal separation systems. Ultimately, an on-line, comprehensive method was developed using orthogonal reversed-phase columns in each dimension (RP x RP) for improved separation of co-eluting and isomeric synthetic cannabinoids. This work can aid laboratories in the identification of NPS through the use of a validated LC-QTOF-MS method for screening and confirmation and HRMS spectral library. In instances where isomeric and structurally related NPS are not sufficiently separated, RP x RP methods can be explored.
4

Evaluation of the long-term stability of select phenylacetylindole, cycloalkylindole, quinolinyl, and carboxamide synthetic cannabinoids using LC-MS/MS

Phung, Erika Dang 11 October 2019 (has links)
Despite efforts to control synthetic cannabinoids, clandestine manufacturers continue to modify their structures to avoid legal consequences, creating an ever-changing analytical target for forensic laboratories (1). Forensic toxicology laboratories often lack the needed resources or do not have the capabilities to test for these compounds and metabolites, requiring specimens to be submitted to reference laboratories (2). Drug stability can be affected by long storage times, temperature and preservatives (3). Although these factors can be controlled, systematic research is necessary to identify their impacts on the stability of these new synthetic cannabinoids that are continually emerging. The purpose of this research is to assess the stability of 17 synthetic cannabinoids in human whole blood and 10 synthetic cannabinoid metabolites in human urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) over thirty-five weeks. The analysis methods were validated in accordance to the Academy Standards Board (ASB) method validation guidelines for quantitative analysis and stability evaluation of the following analytes in blood: 4-cyano CUMYL-BUTINACA, ADB-PINACA, EMB-FUBINACA, JWH-250, MO-CHMINACA, 5-fluoro-3,5-ABPFUPPYCA, 5-fluoro ADB-PINACA, APP-PICA, CUMYL-THPINACA, PB-22, XLR11, 5-fluoro PY-PINACA, MDMB-FUBICA, MEP-CHMICA, NM2201, RCS-8, and UR144. The stability analysis in urine includes the following metabolites: 5-fluoro MDMB-PICA metabolite 7, 5-fluoro PB-22 3-carboxyindole, AB-FUBINACA metabolite 3, ADB-PINACA N-(4-hydroxypentyl), ADB-PINACA pentanoic acid, UR-144 Degradant N-pentanoic acid, PB-22 N-(5-hydroxypentyl), MDMB-FUBICA metabolite 3, UR-144 N-(5-hydroxypentyl), and JWH-250 N-pentanoic acid. Research samples were prepared by spiking with certified reference standards (Cayman Chemical, Ann Arbor, MI, USA) of each select synthetic cannabinoid in certified drug-free human whole blood (Boston Medical Center, Boston, MA, USA; Biological Specialty Corporation, Colmar, PA) and drug-free urine that was received as donations following the approved Institutional Review Board guidelines (Boston University School of Medicine, Boston, MA, USA). Blood samples were aliquoted into 6 mL BD Vacutainer Plastic Collection Tubes (Fisher Scientific, Waltham, MA, USA) and urine samples were stored in 15 mL Falcon Conical Centrifuge Tubes (Fisher Scientific, Waltham, MA, USA). Stability under room temperature (20ºC), refrigerator (4ºC), and freezer (-20ºC) at low and high concentrations were evaluated at select time points. A 5% solution of potassium oxalate and sodium fluoride or ethylenediaminetetraacetic acid (EDTA) was added to the preserved blood samples by the manufacturer prior to storage. The anticoagulant, potassium oxalate, was only added in solution to the preserved samples whereas none was added to the nonpreserved samples. Short-term urine samples were preserved with 1% of sodium fluoride prior to storage. Extraction of analytes was conducted using supported-liquid extraction (SLE) ISOLUTE 1 mL cartridges (Biotage, Charlotte, NC, USA) and reconstituted in 100 μL of 50:50 mixture of 0.1% formic acid in millipore deionized water and 0.1% formic acid in acetonitrile (Fisher Scientific, Waltham, MA, USA). Analysis was performed in triplicate using a reverse-phase C18 column (Waters XBridge C18 3.5 μM, 2.1 x 50 mm, Milford, MA, USA) on the Shimadzu Prominence Ultra-Fast Liquid Chromatography (UFLC, Kyoto, Japan) with SCIEX 4000 Q-Trap Electrospray Ionization Tandem Mass Spectrometry (ESI/MS/MS, Waltham, MA, USA) in positive ionization mode. The total run time was 8 minutes with a flow rate of 0.6 mL/min and injection volume of 10 μL. Linear calibration curves for each analyte with the exception of a quadratic regression for PB-22, all had acceptable R2 values > 0.99 using a weighting factor of 1/x. A linear dynamic range of 0.5 – 25 ng/mL was used for all analytes in blood except for NM2201 and APP-PICA with a limit of quantitation (LOQ) of 0.1 ng/mL and MO-CHMINACA with a working range of 0.5 – 15 ng/mL. A linear working range of 5 – 40 ng/mL was utilized for all metabolites in urine. No signs of carryover were observed. In general, analytes were considered stable if the average area ratio between the analyte and internal standard at the time point was within ± 20% of the average area ratio response at time point zero. In some cases, it was necessary to evaluate the complete picture of the stability data by reviewing analyte area, concentration, and overall stability data trend between timepoints at the low and high concentrations. In certain situations, an analyte was considered stable even if specific timepoints for a concentration were outside the ±20% range. For example, in cases where one concentration at a timepoint was within the ±20% range and the other concentration fell within ±30% range the analyte was considered stable overall. Long-term stability results revealed that all synthetic cannabinoids were stable at 21 to 35 weeks in frozen blood preserved with sodium fluoride except for APP-PICA. The preservatives are recommended to be added to blood to reduce the possibility of matrix inferences and minimize detrimental impacts on the stability of synthetic cannabinoids. Analytes experienced lower degradation in the order of samples that were kept frozen, refrigerated, and then at room temperature. Blood analytes that were stable up to 35 weeks in freezer generally had a core structure of a carbonyl substituent on a pyrazole or pyrrole with surrounding nonpolar groups; whereas compounds with two polar carbonyl functional groups present were found to experience degradation much earlier at 1 week or less in room temperature and refrigerator storage conditions. 5-fluoropentyl analogs, like XLR11 and 5-fluoro ADB-PINACA, in comparison to their counterpart analyte, UR144 and ADB-PINACA, were unstable at earlier time points under all storage conditions. Instability in the majority of the urine metabolites was not observed until after 9 weeks and was generally consistent across all storage conditions. The validated methods demonstrate a sensitive and reliable way to positively identify 17 different synthetic cannabinoids in human whole blood and 10 synthetic cannabinoid metabolites in urine for rapid time stability analysis at various storage conditions. The use of SLE improved sample preparation efficiency by decreasing the extraction time from 1 hour to 30 minutes compared to traditional extraction methods, such as solid-phase extraction (SPE) and liquid-liquid extraction (LLE). Further studies into additional matrices, such as oral fluid, longer storage times, and other emerging synthetic cannabinoid analytes would expand the scope of this research.
5

Neurochemical and neuropharmacological studies on a range of novel psychoactive substances

Loi, Barbara January 2018 (has links)
Introduction: Over recent decades, there has been an increase in the availability and use of Novel Psychoactive Substances (NPS) all over the world. They include several classes of chemicals that mimic the effects of illicit drugs and have been purposefully introduced into the market to circumvent or undermine the purpose of legal regulation. Currently, there is information lacking on the pharmacology of these substances; however, the increasing number of cases and outbreaks of intoxications/deaths is becoming a cause for deepening concern. Multi-disciplinary research in the fields of biology, chemistry, clinical medicine and web analysis is needed to develop responses against this tidal wave. Aim: The overall aim of this project is to gain insights into pharmacological, neurochemical and molecular properties of selected NPS to provide a reliable background needed for detection, assessment, and management of NPS-related harms. A range of approaches and methodologies was employed and a spectrum of different fields of knowledge has been engaged to gain some understanding into the complex multi-faceted phenomenon of NPS. Methods: Different substances have been selected as targets for the present project according to the clinical pattern of toxicity raised by their worldwide use and the lack of scientific knowledge available about them. The methods employed were: in vitro quantitative autoradiography (to evaluate the binding properties of the novel SCs BB-22, 5F-PB-22, 5F-AKB-48 and STS-135 at the cannabinoid receptor type 1 and N-methyl-D-aspartate receptor; and the binding properties of the synthetic stimulants 5-IT and 2-DPMP at the dopamine transporter in rat brain slices); in vitro Fast Scan Cyclic Voltammetry (to assess the effects of BB-22 on evoked dopamine efflux and dopamine re-uptake half-life in nucleus accumbens brain slices); in vivo microdialysis (to monitor dopamine release in terminal areas of the reward system after acute administration of the synthetic cannabinoids BB-22, 5F-PB-22, 5F-AKB-48 and STS-135; the dieting aid compound 2,4-DNP; the synthetic stimulants 2-DPMP and D2PM in freely moving animals); in silico molecular docking (to investigate the intermolecular interactions of the SCs BB-22, 5F-PB-22, 5F-AKB-48 and STS-135, and other referent compounds, with a homology model of the rodent cannabinoid receptor type 1 (CB1R) and the crystal structure of the human CB1R); and a web-based analysis approach (to analyse the information provided by a range of fora communities on 4,4'-DMAR use, additionally critical reviewing the available evidence-based literature on this topic). Results: Our in vitro quantitative autoradiography studies, confirmed that the index compounds BB-22, 5F-PB-22, 5F-AKB-48 and STS-135, behave as highly potent CB1R ligands able to compete with the radioligand [3H]CP-55,940 in cortical and striatal brain slices. On the other hand, all synthetic cannabinoids tested were unable to compete with the radioligand [3H]MK-801 in the same cerebral areas, rejecting the hypothesis of their potential binding to the N-methyl-D-aspartate receptor (NMDAR) at all concentrations investigated. Consistent with previous in vitro studies, 5-IT and 2-DPMP behaved as highly potent dopamine transporter (DAT) ligands able to compete with the radioligand [125 I]RTI-121 in a concentration-dependent way in the Caudate Putamen (CPu) and Nucleus Accumbens (NAc) brain slices. Notably, 2-DPMP was able to displace the radioligand in both cerebral regions, starting from lower concentrations compared to 5-IT. In vitro Fast Scan Cyclic Voltammetry findings demonstrated that local application of the synthetic cannabinoid BB-22 in brain slices, was unable to change evoked dopamine efflux and dopamine reuptake time-constant in the NAc shell at any doses tested. The results obtained would suggest the relative contributions of complex neuronal circuits, either within or outside the NAc, whose modulation would interfere with the interactions between BB-22 and dopaminergic neurons and represent critical pathways accounting for some of the rewarding properties of BB-22 exposure. In vivo microdialysis outcomes suggested that all SCs tested could increase dopamine release in the NAc shell at specific doses, while no changes in dopamine output were observed in other areas of the reward system, namely NAc core and medial prefrontal cortex (mPFCx) after BB-22 administration. These outcomes provided a circumstantial pre-clinical evidence for a greater putative abuse liability of SCs compared to the natural compound found in cannabis (Δ9‐THC). Furthermore, the acute treatment with 2,4-DNP did not cause any change in dopamine release in the NAc shell and CPu rejecting the hypothesis of psychoactivity of this substance at the dose tested. On the other hand, the synthetic stimulant 2-DPMP elicited a comparable increase of dopamine (DA) release in the NAc shell and CPu at the higher doses tested, while D2PM caused a selective increase of DA release in the NAc shell, providing a circumstantial preclinical evidence for a putative abuse liability of this compound at the highest dose assessed. The in silico molecular docking studies demonstrated that the SCs BB-22, 5F-PB-22, 5F-AKB-48 and STS-135 interact with CB1 receptor residues that, according to previous mutation and computational studies, are considered crucial for synthetic cannabinoid binding recognition. Additionally, they share some interacting residues with other aminoalkylindole derivatives (e.g. WIN-55,212-2). The web-based analysis focused on 4,4'-DMAR, suggested that fora members co-operate in exchanging an extensive body of knowledge about this drug, and the recurring topics of discussion include: routes of administration and dosages; desired and undesired effects; comparison and association with other drugs and medications; overall impression; provision of harm reduction advice. This approach has been useful to better understand some of the clinical and psychopharmacological issues pertaining to 4,4'-DMAR. Conclusions: Overall, these studies provided new pharmacological, neurochemical and molecular knowledge on a range of Novel Psychoactive Substances essential for identifying potential therapeutical approaches against their use/abuse. The novelty of this project lies in the adoption of a multi-disciplinary approach involving a range of methodologies from different areas of expertise (neurobiology, pharmacology, chemistry, netnography) all integrated to clarify some aspects of the index NPS, which were not yet available in the current literature. Additional studies are needed to better explain short and long-term effects of the index NPS, their abuse potential, and their interactions with other drugs of abuse.
6

Akutní účinky nové psychoaktivní látky ze skupiny derivátů fenyletylaminu - animální studie / Acute effects of new psychoactive substance from the group of phenethylamine derivatives - an animal study

Syrová, Kateřina January 2019 (has links)
Synthetic N-methoxybenzyl ("NBOMe") phenylethylamine derivatives were developed as highly potent agonists for the research of 5-hydroxytryptamine receptors, however they have become available on the black market in the past few years. They are sought by recreational users as "legal LSD", in worse cases the replacement is unsuspected and these substances are a cause of serious intoxication with signs of serotonin toxicity. At this moment, there is very little data available, but their low price, easy access via the internet and legal status make these substances an interesting target for recreational users and a big challenge for scientists and for the lawmakers. 2CBFly-NBOMe belongs to this group. There is no information about its recreational use for now, but thiat is probably only a matter of time. The aim of this study is to determine acute effects of 2CBFly-NBOMe in Wistar rats. Active substance significantly reduced locomotor activity of the animals and caused higher anxiety, it also disrupted sensorimotor gating and lowered body temperature of animals. Pharmacokinetic profile was measured only in the blood serum, the highest concentrations of 2CBFly-NBOMe were detected 30-60 minutes after the administration of hallucinogen. This paper provides first information on the effect of 2CBFly-NBOMe on...
7

Qualitative research of online drug misuse communities with reference to the novel psychoactive substances

Jebadurai, Jeshoor Kumar January 2013 (has links)
Objective: This research aimed at reviewing the information provided by the online drug misuse communities with reference to the available evidence-based literature on the novel psychoactive substances. Methodology: Among hundreds of novel psychoactive substances, four groups (phenethylamines, tryptamines, piperazines and miscellaneous) were selected for the study. Various website drug fora were identified by Google and Yahoo search engines using a set of specific key words. The methods consisted of extracting and analysing qualitative data from the identified website fora. This was also supplemented by critical reviewing the existing evidence-based literature search for each of the selected psychoactive compounds. Results: The combined search results identified 84 unique website fora from which qualitative data were extracted for thirty novel psychoactive substances and organised into technical folders. This data extracted from online communities has thrown some light on factors such as the mode of purchase, subjective experiences, reasons for use, combinations, legislation, mechanisms of action in the CNS, side effects, toxicity and its management. This would enable the clinicians to be obtain full history when assessing and would inform better treatment choices. Conclusions: A range of novel psychoactive substances have been made recently available across the globe. The sale is easily achieved through the Internet. New legislations are made to control some recreational substances whilst newer substances appear. Furthermore, the distributors sell the backlog of products even after controlling of the substance has occured and hence are liable to potentiating criminal investigations. It is here suggested as well that the 'genuinity' of each onlince susbtance is questionable. Evidence-based literature is scant for the vast majority of these substances. Accidental overdoses are common occurences and some of the potential life-threatening clinical situations include sympathomimetic toxidrome and serotonin syndrome. Benzodiazepines appear to help with agitation and neuropsychiatric manifestations. Better levels of international cooperation and rapid share of available information may be needed to tackle the emerging problem of the novel psychoactive substances.

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