title: Enantioselective quantitation of the ecstasy compound (R)- and (S)-N-ethyl-3,4-methylenedioxyamphetamine and its major metabolites in human plasma and urine.
abstract: An enantioselective HPLC method has been developed and validated for the stereospecific analysis of N-ethyl-3,4-methylenedioxyamphetamine (MDE) and its major metabolites N-ethyl-4-hydroxy-3-methoxyamphetamine (HME) and 3,4-methylenedioxyamphetamine (MDA). These compounds have been analyzed both from human plasma and urine after administration of 70 mg pure MDE-hydrochloride enantiomers to four subjects. The samples were prepared by hydrolysis of the o-glucuronate and sulfate conjugates using beta-glucuronidase/arylsulfatase and solid-phase extraction with a cation-exchange phase. A chiral stationary protein phase (chiral-CBH) was used for the stereoselective determination of MDE, HME and MDA in a single HPLC run using sodium dihydrogenphosphate, ethylendiaminetetraacetic acid disodium salt and isopropanol as the mobile phase (pH 6.44) and fluorimetric detection (lambda(ex) 286 nm, lambda(em) 322 nm). Moreover, a suitable internal standard (N-ethyl-3,4-methylenedioxybenzylamine) was synthesized and qualified for quantitation purposes. The method showed high recovery rates (>95%) and limits of quantitation for MDE and MDA of 5 ng/ml and for HME of 10 ng/ml. The RSDs for all working ranges of MDE, MDA and HME in plasma and urine, respectively, were less than 1.5%. After validation of the analytical methods in plasma and urine samples pharmacokinetic parameters were calculated. The plasma concentrations of (R)-MDE exceeded those of the S-enantiomer (ratio R:S of the area under the curve, 3.1) and the plasma half time of (R)-MDE was longer than that of (S)-MDE (7.9 vs. 4.0 h). In contrast, the stereochemical disposition of the MDE metabolites HME and MDA was reversed. Concentrations of the (S)-metabolites in plasma of volunteers were much higher than those of the (R)-enantiomers.
authors.affiliation: Department of Pharmaceutical Analysis, University of Tuebingen, Auf der Morgenstelle 8, D-72076, Tuebingen, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Buechler
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwab
authors.forename: Gerd
authors.initials: G
authors.lastname: Mikus
authors.forename: Beate
authors.initials: B
authors.lastname: Fischer
authors.forename: Leo
authors.initials: L
authors.lastname: Hermle
authors.forename: Claudia
authors.initials: C
authors.lastname: Marx
authors.forename: Georg
authors.initials: G
authors.lastname: Grön
authors.forename: Manfred
authors.initials: M
authors.lastname: Spitzer
authors.forename: Karl Artur
authors.initials: KA
authors.lastname: Kovar
mesh_terms: D015104:3,4-Methylenedioxyamphetamine / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism
chemical_list: D015104:3,4-Methylenedioxyamphetamine; C051800:3,4-methylenedioxyethamphetamine