Received on April 19, 2005
Accepted on July 5, 2005

Drug Monitoring and Toxicology

Drug Testing in Blood: Validated Negative-Ion Chemical Ionization Gas Chromatographic-Mass Spectrometric Assay for Enantioselective Measurement of the Designer Drugs 3,4-Methylenedioxyamphetamine, 3,4-Methylenedioxymethamphetamine (MDMA), and 3,4-Methylenedioxyethylamphetamine and Its Application to Samples from a Controlled Study with MDMA

¹ Department of Experimental and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, University of Saarland, Homburg, Germany
² National Institute of Criminalistics and Criminology, Brussels, Belgium
³ Experimental Psychopharmacology Unit, Brain & Behaviour Institute, Maastricht University, Maastricht, The Netherlands

^* To whom correspondence should be addressed. E-mail: hans.maurer{at}uniklinikum-saarland.de.

Background: The enantiomers of the designer drugs 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) differ in their pharmacologic and toxicologic potency. The aim of this study was to develop an assay for measuring these enantiomers in small plasma volumes and to analyze samples from a controlled study with MDMA.

Methods: The analytes were extracted from 0.2 mL of plasma by mixed-mode solid-phase extraction. After derivatization with S-(-)-heptafluorobutyrylprolyl chloride, the resulting diastereomers were separated by gas chromatography (HP-5MS) within 17 min and detected by mass spectrometry in the negative-ion chemical ionization mode. The method was fully validated and applied to samples from a controlled study in which a single dose of racemic MDMA (75 mg) was administered.

Results: The derivatized enantiomers were well separated and detected with good sensitivity. The assay was linear (per enantiomer) at 1-50 µg/L for MDA and 5-250 µg/L for MDMA and MDEA. Analytical recovery, accuracy, repeatability, and intermediate precision data were within required limits. Extraction yields were 82.1%-95.3%. In the study samples, concentrations of R-(-)-MDMA significantly exceeded those of S-(+)-MDMA. Their ratios (R vs S) were always >1.0 and increased over time. Concentrations of S-(+)-MDA exceeded those of R-(-)-MDA, their ratios (R vs S) also increasing over time but remaining <1.0.

Conclusions: This assay enables sensitive, reliable, and fast enantioselective measurement of MDA, MDMA, and MDEA in small volumes of plasma. The controlled study data confirm previous findings of MDMA and MDA enantiomer ratios (R vs S) increasing over time after ingestion of racemic MDMA.