After a low oral dose of MDMA (1.0 mg/kg), average maximum plasma concentrations were 162.9 ng/mL for MDMA and 171.9 ng/mL for its metabolite HMMA. After a high dose (1.6 mg/kg), MDMA's average maximum concentration rose significantly to 291.8 ng/mL, while HMMA's remained unchanged at 173.5 ng/mL, indicating nonlinear pharmacokinetics. The half-lives of MDMA, MDA, and HMMA ranged from roughly 7 to 13.5 hours. This study provides the first MDMA plasma pharmacokinetic data from Black participants and female participants, with more frequent and extended sampling than prior work.
In a controlled study, 15 healthy volunteers with prior MDMA use received placebo, low (1.0 mg/kg), and high (1.6 mg/kg) oral doses of MDMA in random order while wearing sweat patches for up to 7 days. MDMA was the main substance found in 59.7% of patches, with concentrations up to 3007 ng/patch; its metabolite MDA appeared in 29.4% of patches at lower levels, while other metabolites were undetected. At the 25-ng/patch threshold, 35% of patches were positive for MDMA. Sweat testing reliably detects MDMA use, but high variability in excretion means results should be interpreted qualitatively, not quantitatively.
A two-dimensional gas chromatography–mass spectrometry method with cryofocusing simultaneously quantifies MDMA, its metabolites MDA, HMMA, and HMA, and MDEA in human plasma. Limits of quantification were 1.0 μg/L for MDA and 2.5 μg/L for the other four compounds. Calibration curves were linear up to 100 μg/L for MDA and HMA and up to 400 μg/L for MDEA, MDMA, and HMMA, with correlation coefficients above 0.997. Extraction efficiencies from plasma were at least 85%, recoveries ranged from 85.6% to 107.2% of target, and intra- and interassay imprecision was below 8.5% at three concentrations. None of 66 tested exogenous compounds interfered. The assay achieves low quantification limits suitable for pharmacokinetic studies and may apply to other analytes and complex matrices.