Drug Testing in Blood: Validated Negative-Ion Chemical Ionization Gas Chromatographic–Mass Spectrometric Assay for Enantioselective Measurement of the Designer Drugs MDEA, MDMA, and MDA and Its Application to Samples from a Controlled Study with MDMA

An assay was developed to measure the enantiomers of the designer drugs MDA, MDMA, and MDEA in small plasma volumes (0.2 mL or less). After extraction and derivatization, the enantiomers were separated by gas chromatography and detected by mass spectrometry within 17 minutes. The method was linear for MDA at 1–50 μg/L and for MDMA and MDEA at 5–250 μg/L per enantiomer, with extraction yields of 82.1%–95.3%. Applied to samples from a controlled study after a single 75 mg dose of racemic MDMA, the assay showed that R-(−)-MDMA concentrations significantly exceeded those of S-(+)-MDMA, with ratios always above 1.0 and increasing over time. S-(+)-MDA concentrations exceeded those of R-(−)-MDA, with ratios also increasing but remaining below 1.0.

Study at a glance

Abstract

Abstract 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.