TY - JOUR

T1 - Liquid chromatography-quadrupole time-of-flight mass spectrometry for screening in vitro drug metabolites in humans

T2 - Investigation on seven phenethylamine-based designer drugs

AU - Lai, Foon Yin

AU - Erratico, Claudio

AU - Kinyua, Juliet

AU - Mueller, Jochen F.

AU - Covaci, Adrian

AU - van Nuijs, Alexander L.N.

N1 - Funding Information: The National Research Centre for Environmental Toxicology (Entox) is a joint venture of The University of Queensland (UQ) and Queensland Health Forensic Scientific Services (QHFSS). The authors sincerely thank Nele Van den Eede (University of Antwerp (UA)) and Walid Maho (UA) for advising on the operation of the LC-QTOF-MS instrument. We also would like to acknowledge Xiaobo Zheng (UA) for assistance with the sample preparation and Maria Jose Gomez Ramos (Entox, UQ) and Nele Van den Eede for the discussion on fragmentation in mass spectrometry. We sincerely thank Dr. Raimondo Bruno (University of Tasmania, Australia) for his valuable input on discussions and language revisions. Foon Yin Lai is funded through UQ Collaboration and Industry Engagement Fund (UQCIEF #608290) and Collaborative Research Seeding Grants of the Faculty of Health and Behavioural Sciences (UQHABS #608670). Alexander L.N. van Nuijs acknowledges FWO Flanders for his scholarship. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement #295138 (INTERFLAME project), #316665 (A-TEAM project) and #317205 (SEWPROF project). Publisher Copyright: © 2015 Elsevier B.V.

PY - 2015

Y1 - 2015

N2 - Phenethylamine-based designer drugs are prevalent within the new psychoactive substance market. Characterisation of their metabolites is important in order to identify suitable biomarkers which can be used for better monitoring their consumption. Careful design of in vitro metabolism experiments using subcellular liver fractions will assist in obtaining reliable outcomes for such purposes. The objective of this study was to stepwise investigate the in vitro human metabolism of seven phenethylamine-based designer drugs using individual families of enzymes. This included para-methoxyamphetamine, para-methoxymethamphetamine, 4-methylthioamphetamine, N-methyl-benzodioxolylbutanamine, benzodioxolylbutanamine, 5-(2-aminopropyl) benzofuran and 6-(2-aminopropyl) benzofuran. Identification and structural elucidation of the metabolites was performed using liquid chromatography-quadrupole-time-of-flight mass spectrometry. The targeted drugs were mainly metabolised by cytochrome P450 enzymes via O-dealkylation as the major pathway, followed by N-dealkylation, oxidation of unsubstituted C atoms and deamination (to a small extent). These drugs were largely free from Phase II metabolism. Only a limited number of metabolites were found which was consistent with the existing literature for other phenethylamine-based drugs. Also, the metabolism of most of the targeted drugs progressed at slow rate. The reproducibility of the identified metabolites was assessed through examining formation patterns using different incubation times, substrate and enzyme concentrations. Completion of the work has led to a set of metabolites which are representative for specific detection of these drugs in intoxicated individuals and also for meaningful evaluation of their use in communities by wastewater-based drug epidemiology.

AB - Phenethylamine-based designer drugs are prevalent within the new psychoactive substance market. Characterisation of their metabolites is important in order to identify suitable biomarkers which can be used for better monitoring their consumption. Careful design of in vitro metabolism experiments using subcellular liver fractions will assist in obtaining reliable outcomes for such purposes. The objective of this study was to stepwise investigate the in vitro human metabolism of seven phenethylamine-based designer drugs using individual families of enzymes. This included para-methoxyamphetamine, para-methoxymethamphetamine, 4-methylthioamphetamine, N-methyl-benzodioxolylbutanamine, benzodioxolylbutanamine, 5-(2-aminopropyl) benzofuran and 6-(2-aminopropyl) benzofuran. Identification and structural elucidation of the metabolites was performed using liquid chromatography-quadrupole-time-of-flight mass spectrometry. The targeted drugs were mainly metabolised by cytochrome P450 enzymes via O-dealkylation as the major pathway, followed by N-dealkylation, oxidation of unsubstituted C atoms and deamination (to a small extent). These drugs were largely free from Phase II metabolism. Only a limited number of metabolites were found which was consistent with the existing literature for other phenethylamine-based drugs. Also, the metabolism of most of the targeted drugs progressed at slow rate. The reproducibility of the identified metabolites was assessed through examining formation patterns using different incubation times, substrate and enzyme concentrations. Completion of the work has led to a set of metabolites which are representative for specific detection of these drugs in intoxicated individuals and also for meaningful evaluation of their use in communities by wastewater-based drug epidemiology.

KW - High-resolution mass spectrometry

KW - LC-QTOF-MS analysis

KW - Metabolite characterisation

KW - New psychoactive substances

KW - Wastewater-based epidemiology

U2 - 10.1016/j.jpba.2015.06.016

DO - 10.1016/j.jpba.2015.06.016

M3 - Journal article

C2 - 26112925

AN - SCOPUS:84936763691

VL - 114

SP - 355

EP - 375

JO - Journal of Pharmaceutical and Biomedical Analysis

JF - Journal of Pharmaceutical and Biomedical Analysis

SN - 0731-7085

ER -