Absorption, excretion and disposition of cyclindole in laboratory animals and human volunteers

Radioactivity from orally administered single doses of cyclindole-14C was excreted primarily in the urine of the rat (99%/48 hr), monkey (80%/120 hr), and dog (70%/144 hr). Approximately 38-58% of a daily dose of cyclindole was recovered from 24-hr human urine, as determined by gas chromatography. Substantial amounts of unchanged drug were voided by dogs. Cyclindole was metabolized primarily by N-demethylation and/or hydroxylation in the 7-position. Hydroxylation at the 6-carbon atom was of minor importance in humans only; none of the animal species excreted the 6-hydroxy metabolite. Dogs were capable of N-demethylation, but no metabolites oxidized at the 6- or 7-carbon atoms were detected in dog urine.