Hair analysis for drugs of abuse. XVIII. 3,4-Methylenedioxymethamphetamine (MDMA) disposition in hair roots and use in identification of acute MDMA poisoning.

Disposition of 3,4-methylenedioxymethamphetamine (MDMA) in hair roots was studied using rats and the hair root samples were evaluated to prove acute MDMA poisoning. The back hair of male pigmented hairy rats (n = 6) was shaved and 5 d later the animals were intraperitoneally administered with acute poisonous doses (20, 40, 60, 80 and 100 mg/kg) of MDMA. Roots of the hairs were then plucked out with a hair nipper 5 min and, 0.5, 1, 2, 6 and 24 h after injection. The hair root samples were, directly or after being washed with detergent, extracted with methanol-5 N HCl (20:1) under ultrasonication in ice-cold water for 4 h. After filtration and evaporation, the residue was derivatized with pentafluoropropionic anhydride and analyzed by GC/MS. From all samples including the 5 min sample, MDMA was detected at high concentrations (up to 156 ng/mg) accompanied by 3,4-methylenedioxyamphetamine (MDA). Some of the animals died within 2 h after administration, but in the surviving rats the MDMA concentrations in the hair roots increased up to 6 h and then slowly decreased until 24 h. The remaining MDMA after washing apparently increased from 13-31% at 0.5 h to 51-83% at 24 h in the surviving rats. These facts show that most of drugs in the hair roots are not yet immobilized in the early stage and are thereafter gradually incorporated into the hair shaft. Increase of the MDMA concentration stopped soon after death of the animal, probably due to the cessation of hair growth. Although the ratios of MDA/MDMA steadily increased over time, those after death plateaued, probably due to the cessation of metabolism after death. It was clearly shown that MDMA is more quickly incorporated into and more firmly retained in hair than methamphetamine (MA) by comparing their disposition in hair roots.