METABOLISM OF ISOPRENALINE AFTER AEROSOL AND DIRECT INTRABRONCHIAL ADMINISTRATION IN MAN AND DOG

Abstract

1 Administration of isoprenaline by aerosol inhalation to man results in over 80% being metabolized to the sulphate conjugate. 2 The majority of an inhaled dose is probably swallowed since the metabolic pattern resembles that after an oral dose. 3 Isoprenaline, administered in aqueous solution directly into the bronchial tree in both man and dog, is rapidly O-methylated to 3-O-methyl isoprenaline, which is subsequently conjugated with sulphate. 4 3-O-Methylation is the main metabolic pathway for the small part of an inhaled dose which does enter the bronchial tree.