Identification of some N-hydroxylated metabolites of (+/-)-3,4-methylenedioxymethamphetamine in horse urine by gas chromatography-mass spectrometry.
1. The in vivo biotransformation of (+/-)-3,4-methylenedioxymethamphetamine [(+/-)-MDMA] in the thoroughbred horse was determined after oral administration. 2. Unconjugated compounds and aglycones were isolated from enzyme-hydrolysed urine by solid-phase extraction using mixed-mode cartridges. The basic isolates were derivatized (trimethylsilylether, TMS) and analysed by positive-ion electron ionization/gas chromatography-mass spectrometry (EI+/GC-MS). MDMA and 10 Phase I metabolites containing the arylisopropylamine substructure were detected. 3. N-Hydroxy amphetamine and N-hydroxymethamphetamine were synthesized. The EI + mass spectra of their O-TMS derivatives showed characteristic alpha-cleavage ions at m/z 132 and 146, respectively, as base peaks. Based upon these data, five putative N-hydroxylated metabolites of MDMA were detected. 4. In the horse, (+/-)-MDMA is metabolized by oxidative N-demethylation to form the primary amine methylenedioxyamphetamine (MDA). Both MDMA and MDA are further metabolized by oxidative demethylenation (cleavage and O-demethylation of the benzodioxole moiety) to form the corresponding catechols, 3-O-methylation to form the guaiacols and N-oxidation of the secondary and primary amine metabolites to form the hydroxylamines. 5. Both phenolic and N-hydroxy metabolites of (+/-)-MDMA undergo Phase II conjugation before excretion in urine.
Dumasia
M C
MC
Department of Drug Metabolism, Horseracing Forensic Laboratory Ltd, Fordham, Ely, UK. mdumasia@hfl.co.uk
D015104:3,4-Methylenedioxyamphetamine / Q000652:urine*; D000284:Administration, Oral; D000818:Animals; D002855:Chromatography, Thin Layer; D015198:Designer Drugs / Q000493:pharmacokinetics; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006213:Hallucinogens / Q000652:urine; D006736:Horses; D006868:Hydrolysis; D007477:Ions; D008297:Male; D013058:Mass Spectrometry; D008956:Models, Chemical; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000652:urine*; D010100:Oxygen / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
D015198:Designer Drugs; D006213:Hallucinogens; D007477:Ions; D015104:3,4-Methylenedioxyamphetamine; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D010100:Oxygen