The Influence of the Route of Administration on Urinary Metabolites of Isoetharine

Abstract

1. The metabolites of isoetharine found in urine from man and dog are O-methylisoetharine, isoetharine sulphate, isoetharine glucuronide, O-methyl-isoetharine sulphate and O-methylisoetharine glucuronide. No sulphate conjugate is formed by the rat.

2. The route of administration in man and dog influences the relative amounts of metabolites. Following oral doses, isoetharine is first conjugated with sulphate, probably in the gut wall. After intravenous or intrabronchial dosing, isoetharine is first O-methylated and then conjugated, probably in the liver.