A new method simultaneously measures the ratio of l- and d-enantiomers of amphetamine, methamphetamine, MDA, MDMA, and MDEA in urine. The assay uses liquid-liquid extraction, derivatization with l-TPC, and gas chromatography-mass spectrometry. It provides accurate results for amphetamine and methamphetamine at concentrations of 10 ng/mL or higher and for MDA, MDMA, and MDEA at 25 ng/mL or higher. In eight subjects from a controlled MDMA study, the percentage of l-MDMA was initially greater and increased over time. For the metabolite MDA, the d-enantiomer initially dominated, but the l-enantiomer proportion gradually increased, exceeding the d-enantiomer within 36 hours postdose.
Two commercial immunoassay reagents, Abbott's Amphetamine/Methamphetamine II and Amphetamine Class, were tested for their ability to detect a wide range of amphetamine-related compounds, including stereoisomers, metabolites, and illicit analogues such as MDMA, MDA, and mescaline, at concentrations from 100 to 100,000 ng/mL. The Amphetamine/Methamphetamine II reagent showed better overall performance, especially for detecting over-the-counter medications, while the Amphetamine Class reagent did not improve detection of amphetamine, methamphetamine, or illicit analogues. Some illicit analogues were reliably detected, but many others were not. The Amphetamine Class reagents are a poor choice unless detecting over-the-counter compounds is specifically needed.
After a single neurotoxic dose (20 mg/kg) of MDMA given to male Dark Agouti rats, the drug and three of its metabolites—MDA, HMMA, and HMA—appeared in urine at different peak times: MDMA at 4 hours, MDA at 8 hours, HMMA at 12 hours, and HMA at 16 hours. All four compounds remained detectable in urine for up to 168 hours (detection limit 25 ng/mL). In plasma, MDMA and MDA peaked at 2 hours, HMMA at 4 hours, and HMA at 24 hours, but with high variability at that time point. No MDMA or metabolites were detectable in plasma at 96 or 168 hours (detection limit 10 ng/mL).