Metabolism of amrinone in animals

The biotransformation of 14C-amrinone was studied in rats, dogs, and monkeys by automated gradient high-performance liquid chromatography. The major pathways of metabolism elucidated are: A) glucuronidation at the primary amino nitrogen atom and/or the enolized oxygen atom of the pyridone ring; B) addition of glutathione at the pyridone 2-position and ultimate hydrolysis of this compound to the 2-S-cysteinyl metabolite; C) formation of the primary amino N-acetyl derivative and subsequent oxidation of this to the corresponding N-glycolate. In each species studied, urine was the primary route of elimination and unchanged amrinone was the major urinary excretion product, the other known pathways being: rat, A and C; dog, A and B; monkey, A.