Browsing School, Graduate by Title "Advancing Analytical Methodologies for Classic and Novel Stimulants"
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Advancing Analytical Methodologies for Classic and Novel StimulantsDespite decreasing cocaine prevalence in the US, it remains one of the most widely used illicit stimulants worldwide. However, little is known about cocaine and metabolites' disposition in alternative matrices. Additionally, novel psychoactive stimulants, including synthetic cathinones, recently emerged on the drug market with no shortage of challenges for clinical and forensic toxicologists. The primary objective of this research was to advance analysis and interpretation of classic and novel stimulant test results. We developed and validated methods to identify classical stimulants, e.g. cocaine and its metabolites, in oral fluid (OF), breath and dried blood spots (DBS), to determine whether these alternative matrices are suitable to detect cocaine intake in forensic, clinical and workplace drug testing programs. We demonstrated that OF is a suitable matrix to identify cocaine use following intravenous cocaine. In contrast, although cocaine and metabolites were identified in breath and DBS, further research is necessary to address limitations of these analyses, such as low prevalence and variability, before routine implementation in drug testing programs. We also evaluated a new OF on-site roadside screening test for cocaine detection and found that the Draeger DrugTest 5000 was a sensitive, specific, and efficient on-site OF screening device for both cocaine and BE with proposed confirmation cutoffs of 8 and 10 μg/L. Furthermore, we developed and evaluated analytical screening and confirmation methods for novel stimulants, e.g. synthetic cathinones, and human hepatocytes and high resolution-mass spectrometry (HRMS) techniques to elucidate optimal metabolites for identification of a new synthetic cathinone, 4-methoxy-α-PVP. Immunoassays do not readily detect synthetic cathinones, and those specifically developed for cathinone detection exhibited large negative % bias and poor specificity and efficiency. Inclusion of metabolites in confirmatory methods is imperative for quantification and characterization after preclinical in vivo drug administration to expand our knowledge of these psychoactive stimulants. Metabolite profiling with human hepatocytes and HRMS identified 4-OH-α-PVP, in addition to the parent compound, as a suitable biomarker. It is critical to determine analytical targets to establish synthetic cathinone intake, link toxicity to causative agents and provide necessary preclinical safety data to support controlled drug administration studies.