Distribution and excretion of methamphetamine and its metabolites in rats III. Time-course of concentrations in blood and bile, and distribution after intravenous administration

Abstract

1. The time-course of blood total radioactivity after i.v. administration of ³H-methamphetamine to rats showed a biphasic curve.

2. The biological half-life of the α phase (t^α_1/2) was 6.8 ± 2.0 min, and that of the β phase (t^β_1/2) was 11.3±0.8 h.

3. The major metabolite in the blood was unconjugated p-hydroxymethamphetamine.

4. The total radioactivity in bile peaked at 1.5 h after i.v. administration. The major metabolite in the bile was p-hydroxymethamphetamine glucuronide.

5. The major compound excreted in urine was unchanged methamphetamine.

6. Whole-body autoradiography was performed using ¹⁴C-methamphetamine, and tissue ³H concn. was determined after i.v. administration of ³H-methamphetamine to rats.