Enantioselective determination of 3,4‐methylene‐dioxymethamphetamine and two of its metabolites in human urine by cyclodextrin‐modified capillary zone electrophoresis

A capillary electrophoresis method using a phosphate buffer with a chiral selector separates the enantiomers of MDMA (Ecstasy) and its metabolites HMMA and MDA in human urine. After enzymatic hydrolysis and solid-phase extraction, detection at 195 nm achieves detection limits of 20–50 ng/mL with 5 mL samples. Analysis of two patients' urine shows enantioselective metabolism: one patient excreted 42.28% of the racemic MDMA dose as R-(−)-MDMA and 10.16% as S-(+)-MDMA; the other excreted 28.63% and 9.34%, respectively. Metabolite enantiomer excretion varied between individuals, demonstrating interindividual differences in MDMA metabolism.

Study at a glance

Abstract

Abstract Using capillary zone electrophoresis with a phosphate buffer at pH 2.5 containing 30 m M (2‐hydroxypropyl)‐β‐cyclodextrin as chiral selector, the simultaneous separation of the enantiomers of 3,4‐methylenedioxymethamphetamine (MDMA or Ecstasy) and its two metabolites 4‐hydroxy‐3‐methoxymethamphetamine (HMMA) and 3,4‐methylenedioxyamphetamine (MDA) in human urine is reported. The assay described is based upon enzymatic hydrolysis of conjugated HMMA (major urinary metabolite) and solid‐phase extraction followed by injection of a few nL of the extract onto a 50 μm internal diameter (ID) fused‐silica capillary of 60 cm length. Solutes are detected via on‐column absorbance at 195 nm. For 375 ng/mL drug levels, intraday and interday imprecision is < 4%. With 5 mL urine samples, the detection limit is in the 20–50 ng/mL range. Via analysis of the urines of two patients, the metabolism of MDMA is demonstrated to be enantioselective, with significantly higher urinary amounts of R ‐(−)‐MDMA being excreted compared to S ‐(+)‐MDMA. Within 72h after drug administration one patient was determined to excrete 42.28 and 10.16% of the racemic MDMA dose (1.5 mg/kg body weight) as R ‐(−) and S ‐(+)‐MDMA enantiomers, respectively. Corresponding values for the second subject were found to be 28.63 and 9.34%. The metabolism of the enantiomers of the two metabolites showed interindividual differences. The first and second detected HMMA enantiomers represented 3.79 and 5.42% (first subject) and 8.51 and 4.36% (second), respectively, of the administered MDMA dose. For the MDA enantiomers, corresponding values were 2.44, 1.76, 0.75, and 0.79%, respectively.