Hair Analysis for Drugs of Abuse. IX. Comparison of Deprenyl Use and Methamphetamine Use by Hair Analysis

Abstract

Deprenyl (DPN) and its metabolites, desmethyl deprenyl (desmethyl DPN), methamphetamine (MA) and amphetamine (AP), in the hair of rats and humans dosed with DPN were analyzed by selected ion monitoring of gas chromatograph-mass spectrometry (GC-MS-SIM). After intraperitoneal administration of DPN-HCl to rats (10mg/kg/d, 10d, n=3), the area under the concentration versus time curves (AUCs) of DPN and its metabolites in the rat plasma were compared with the concentrations of drugs in rat hair newly grown for 4 weeks. The concentrations of DPN, desmethyl DPN, MA and AP in the rat hair were 0.97±0.06, 0.68±0.02, 14.04±0.54 and 13.20±1.09ng/mg, and the ratios of the concentrations in the hair to AUCs in their plasma were 0.05 : 0.02 : 0.3 : 0.2, respectively. This fact suggested that the incorporation rates of DPN and desmethyl DPN into hair from blood were relatively lower than those of MA and AP. The method was applied to determination of the metabolites in scalp hair, beard and urine of humans who orally ingested DPN (15mg/d, 5d, n=3). DPN (trace level), desmethyl DPN (0.17-0.29ng/mg), MA (1.30-2.25ng/mg) and AP (0.42-0.99ng/mg) were detected in the scalp hair collected three weeks after the first intake, while in beard or urine these drugs were detected only for a few days. It was concluded that DPN use could be distinguished from MA abuse retrospectively by the detection of DPN and/or desmethyl DPN in scalp hair. It was also shown that the ratio of AP to MA in hair or enantiomeric compositions of MA in hair would allow distinction of DPN use from MA use.