Studies on the Metabolism of Sympathomimetic Amines: The Metabolism of (±)-[¹⁴C] Amphetamine in the Horse

Abstract

1. The metabolism of (±)-[¹⁴C]amphetamine in horses has been studied. The biological half-life of total radioactivity in the plasma was 150–160 min.

2. In 21–28 h after rapid intravenous injection, two horses each excreted about 84% of the ¹⁴C in the urine, of which about 99% has been identified.

3. About 5% of the dose was excreted as unchanged drug and about 7% as 4-hydroxyamphetamine. The main metabolites were a precursor of 1-phenyl-propan-2-one (29%) and hippuric acid (19%). Lesser metabolites were 1-phenylpropan-2-ol and benzoyl glucuronide each of which accounted for about 12% of the dose.