Urinary excretion profiles of N-hydroxy-3,4-methylenedioxymethamphetamine in rats

N-hydroxy-3,4-methylenedioxymethamphetamine (N-OH-MDMA) is a psychedelic illicit drug that has recently been circulating in Japan. The aims of this study were (i) to optimise enzymatic hydrolysis conditions of the conjugated forms of N-OH-MDMA and its demethylated metabolite N-hydroxy-3,4-methylenedioxyamphetamine (N-OH-MDA), (ii) to investigate the urinary excretion profiles of N-OH-MDMA in rats, and (iii) to compare urinary excretion profiles of N-OH-MDMA and 3,4-methylenedioxymethamphetamine (MDMA). Conjugated forms of the N-hydroxylated compounds (N-OH-MDMA and N-OH-MDA) were almost successfully hydrolysed to their nonconjugated forms under anaerobic conditions after helium purging of the solution. The sum of N-OH-MDMA and N-OH-MDA was used to evaluate the amount of excreted N-hydroxylated metabolites because of degradation of N-OH-MDMA to N-OH-MDA during hydrolysis. Up to 24 h after oral administration of N-OH-MDMA oxalate, the main urinary metabolites were MDMA (14.3% of dose) and 3,4-MDA (7.7% of dose). Most of the N-hydroxylated forms were excreted as glucuronide conjugates. The total amount of N-hydroxylated metabolites after hydrolysis was 1.1% of dose. Urinary excretion profiles of MDMA were similar to that of N-OH-MDMA. It may be difficult to differentiate between abuse of MDMA and N-OH-MDMA by urine analysis.