title: Liquid chromatography-quadrupole time-of-flight mass spectrometry for screening in vitro drug metabolites in humans: investigation on seven phenethylamine-based designer drugs.
abstract: 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.
authors.affiliation: The University of Queensland, The National Research Centre for Environmental Toxicology, 39 Kessels Road, Coopers Plains, QLD 4108, Australia. Electronic address: foon.lai@uqconnect.edu.au.
authors.forename: Foon Yin
authors.initials: FY
authors.lastname: Lai
authors.affiliation: Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.
authors.forename: Claudio
authors.initials: C
authors.lastname: Erratico
authors.affiliation: Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.
authors.forename: Juliet
authors.initials: J
authors.lastname: Kinyua
authors.affiliation: The University of Queensland, The National Research Centre for Environmental Toxicology, 39 Kessels Road, Coopers Plains, QLD 4108, Australia.
authors.forename: Jochen F
authors.initials: JF
authors.lastname: Mueller
authors.affiliation: Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium. Electronic address: adrian.covaci@uantwerpen.be.
authors.forename: Adrian
authors.initials: A
authors.lastname: Covaci
authors.affiliation: Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.
authors.forename: Alexander L N
authors.initials: AL
authors.lastname: van Nuijs
mesh_terms: D015104:3,4-Methylenedioxyamphetamine / Q000031:analogs & derivatives / Q000032:analysis; D000588:Amines / Q000032:analysis; D000662:Amphetamines / Q000032:analysis; D052117:Benzodioxoles / Q000032:analysis; D001572:Benzofurans / Q000032:analysis; D002082:Butylamines / Q000032:analysis; D002384:Catalysis; D002853:Chromatography, Liquid / Q000379:methods*; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry; D003600:Cytosol / Q000378:metabolism; D015198:Designer Drugs / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008099:Liver / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008694:Methamphetamine / Q000031:analogs & derivatives / Q000032:analysis; D008862:Microsomes, Liver / Q000378:metabolism; D008956:Models, Chemical; D010627:Phenethylamines / Q000737:chemistry*; D011437:Propylamines / Q000032:analysis; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000379:methods; D062065:Wastewater / Q000737:chemistry; D018508:Water Purification / Q000379:methods
chemical_list: D015104:3,4-Methylenedioxyamphetamine; D000588:Amines; D000662:Amphetamines; D052117:Benzodioxoles; D001572:Benzofurans; D002082:Butylamines; D003577:Cytochrome P-450 Enzyme System; D015198:Designer Drugs; D008694:Methamphetamine; D010627:Phenethylamines; D011437:Propylamines; D062065:Wastewater; C060169:4-methoxymethamphetamine; C051570:N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine; C587038:6-(2-aminopropyl)benzofuran; C000608250:5-(2-aminopropyl)benzofuran; C029261:phenethylamine; C078956:4-methylthioamphetamine; C000608249:1-(benzo(d)(1,3)dioxol-5-yl)butan-2-amine; C105430:benzofuran; C100230:4-methoxyamphetamine
keywords: High-resolution mass spectrometry; LC-QTOF-MS analysis; Metabolite characterisation; New psychoactive substances; Wastewater-based epidemiology