Publications by authors named "Evelyn Goh"

High-quality draft genomes of six subspecies strains from Cambodian poultry marketplaces were sequenced. The strains were identified as Corvallis-, Monschaui-, and Kentucky-serovars. The fluoroquinolone resistance gene, was found in three strains in different Cambodian provinces.

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Psilocin is a well-studied controlled substance with potential psychotherapeutic applications. However, research gaps remain regarding its metabolism. Our objective was to elucidate a comprehensive Phase I metabolic profile of psilocin to support its forensic management and clinical development.

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Urinalysis of lysergic acid diethylamide (LSD) poses a challenge due to its rapid metabolism, resulting in little to no LSD detectable in urine. Instead, its primary metabolite, 2-oxo-3-hydroxy-LSD, is predominantly detected. In this study, we observed several urine profiles with iso-LSD detected together with 2-oxo-3-hydroxy-LSD.

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The COVID-19 pandemic has demonstrated the detrimental effects of a lack of understanding of public health measures. During the pandemic, lockdowns, social distancing, and mask mandates introduced by governments were met with skepticism, doubt, and an unwillingness to comply, increasing the extent of negative outcomes as a result. Albeit devastating, the pandemic has offered an invaluable opportunity to observe the correlation between the prevalence of public health education and compliance with public health measures during critical times.

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Numerous methods and techniques have been published for the identification of new psychoactive substances (NPS) and their metabolites in urine. However, there lacks a holistic approach to analyze different groups of NPS and their metabolites with decision points for reporting their use. In this study, data-dependent acquisition workflow using liquid chromatography--quadrupole time-of-flight mass spectrometry was developed and validated for the identification of a total of 94 NPS and metabolites in urine using the established decision points.

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Background: The continuous introduction of new synthetic cannabinoid (SC) subtypes and analogues remains a major problem worldwide. Recently, a new "OXIZID" generation of SCs surfaced in seized materials across various countries. Hence, there is an impetus to identify urinary biomarkers of the OXIZIDs to detect their abuse.

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Concurrent use of alcohol with synthetic cannabinoids (SCs) has been widely recorded among drug abusers. The susceptibilities of three indazole-3-carboxamide type SCs with methyl ester moiety, 5F-MDMB-PINACA, 5F-MMB-PINACA, and MMB-FUBINACA, to transesterification in the presence of ethanol warranted further investigation in view of probable augmented toxicity. In vitro metabolite identification experiments were first performed using human liver microsomes (HLMs) to characterize the novel metabolites of the three parent SCs in the presence of ethanol.

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Background: (S)-N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-butyl-1H-indazole-3carboxamide (ADB-BUTINACA) is an emerging synthetic cannabinoid that was first identified in Europe in 2019 and entered Singapore's drug scene in January 2020. Due to the unavailable toxicological and metabolic data, there is a need to establish urinary metabolite biomarkers for detection of ADB-BUTINACA consumption and elucidate its biotransformation pathways for rationalizing its toxicological implications.

Methods: We characterized the metabolites of ADB-BUTINACA in human liver microsomes using liquid chromatography Orbitrap mass spectrometry analysis.

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5F-MDMB-PINACA and 4F-MDMB-BINACA are synthetic cannabinoids (SCs) that elicit cannabinoid psychoactive effects. Defining pharmacokinetic-pharmacodynamic (PK-PD) relationships governing SCs and their metabolites are paramount to investigating their in vivo toxicological outcomes. However, the disposition kinetics and cannabinoid receptor (CB) activities of the primary metabolites of SCs are largely unknown.

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An SPE-based cleanup protocol was developed for ultra-performance LC (UPLC)/MS/MS determination of residues of the common aminoglycoside antibiotics streptomycin, dihydrostreptomycin, neomycin, and gentamicin in bovine milk, kidney, and muscle. Recoveries for all compounds except neomycin ranged from 80 to 104% for all matrixes studied; recoveries for neomycin ranged from 71 to 84%. Intraday and interday precision data were under 15% for all sample matrixes.

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SB1317 (TG02) is a novel small molecule potent CDK/JAK2/FLT3 inhibitor. To evaluate full potential of this development candidate, we conducted drug metabolism and pharmacokinetic studies of this novel anti-cancer agent. SB1317 was soluble, highly permeable in Caco-2 cells, and showed > 99% binding to plasma from mice, dog and humans.

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The preclinical absorption, distribution, metabolism, and excretion (ADME) properties of Pracinostat [(2E)-3-[2-butyl-1-[2-(diethylamino) ethyl]-1H-benzimidazol-5-yl]-N-hydroxyarylamide hydrochloride; SB939], an orally active histone deacetylase inhibitor, were characterized and its human pharmacokinetics (PK) was predicted using Simcyp and allometric scaling. SB939 showed high aqueous solubility with high Caco-2 permeability. Metabolic stability was relatively higher in dog and human liver microsomes than in mouse and rat.

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In vitro liver microsomal stability, permeability, pharmacokinetics (PK) and oral bioavailability of SB639, a novel HDACi (Histone Deacetylase inhibitor), were determined. The in vitro metabolism was examined in mouse, rat, dog and human liver microsomes. The permeability and efflux potential of SB639 were determined using Caco-2 cell monolayers.

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A liquid chromatography/tandem mass spectrometric method for the quantification of 6-(3-benzoyl-ureido)-hexanoic acid hydroxyamide (EX-2), a novel histone deacetylase (HDAC) inhibitor, in mouse plasma was developed to support in-house pharmacokinetic (PK) studies in the lead optimization stage. In order to determine the PK parameters for EX-2 in comparison to other HDAC inhibitors such as suberoylanilide hydroxamic acid (SAHA), PXD-101 and LBH-589, which are currently in different stages of clinical trials, research-grade bio-analytical method validations were carried out for EX-2 and these reference HDAC inhibitors, which were synthesized by in-house medicinal chemists. The components of validation consisted of specificity, extraction efficiency, signal-response of calibration standards, lower limit of quantification, autosampler stability and accuracy and precision of quality control samples.

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