HAIR ANALYSIS FOR DRUG-ABUSE .14. IDENTIFICATION OF SUBSTANCES CAUSING ACUTE-POISONING USING HAIR ROOT .1. METHAMPHETAMINE

A hair root was evaluated as a specimen for proving acute methamphetam ine (MA) poisonings using an animal model and fatal cases of MA intoxi caton. First of all, male pigmented hairy rats (n = 5) were administer ed with acute poisonous doses (20, 40 and 60 mg/kg) of MA and the hair roots were plucked out with a hair nipper 5 min and 0.5, 1, 2, 6 and 24 h after i.p. injection. The hair root samples were, directly or aft er washing with detergent, extracted with methanol/5 N HCl (20:1) unde r vortex mixing at room temperature for 14 h. After evaporation, the r esidue was derivatized with pentafluoropropionic anhydride and analyze d with GC/MS. From all samples including a 5-min sample, MA was detect ed at high concentrations (similar to 150 ng/mg) with a small amount o f amphetamine (AP). Many animals died within 120 min of administration , but the concentrations in the hair roots increased up to 120 min and then slowly decreased until 24 h. Although MA was definitely detected anytime in the hair roots, almost no MA was found in 24-h plasma. In comparison of the drug levels in hair roots between the washed group a nd the unwashed group, the levels of the washed group were as a whole 4-5-fold higher than those of the unwashed group. These differences sh ow that most of the drug incorporated into hair root is still not immo bilized in the early stage. The ratios of the MA remainder in the wash ed samples increased with the elapse of time in all cases. However, th e slope of the curves definitely dropped after the death of rats, prob ably due to the stopping of the hair growth and the incorporaton of dr ug into the hair shaft. The ratios of AP/MA after death became a plate au probably due to the stoppage of the activity of metabolism after de ath, while those before death had increased over time. We analyzed the specimens of hair root of four men who died mainly due to acute poiso nings with MA. Consequently, MA in the hair roots was detected at high concentrations, 30.5-134.6 ng/mg, and its metabolite, AP, at the conc entrations of 1.2-9.0 ng/mg. Our results suggested that hair root is a good specimen for probing acute MA poisoning. (C) 1997 Elsevier Scien ce Ireland Ltd.