%0 Journal Article %A U Bondesson %A P Hartvig %A B Danielsson %T Quantitative determination of the urinary excretion of ketobemidone and four of its metabolites after intravenous and oral administration in man. %D 1981 %J Drug Metabolism and Disposition %P 376-380 %V 9 %N 4 %X The urinary excretion of ketobemidone and its metabolites has been quantified in man after intravenous and oral administration. The metabolism of ketobemidone was found to proceed via 4 metabolic pathways: N-demethylation, ring-hydroxylation, O-methylation, and conjugation. The metabolites were isolated and identified after hydrolysis of the corresponding conjugates. A mean total recovery of about 80% of the dose was found in urine as ketobemidone and metabolites after oral and iv administration, conjugated metabolites amounted to 34-68% of the dose. After iv administration the recovery of unchanged ketobemidone in urine was 13-24%, and after oral administration it was 3-10%. Norketobemidone constituted 10-37% of the dose irrespective of route of administration. 4'-Hydroxyketobemidone amounted to 3-12% of the dose. Neither ketobemidone N-oxide nor metabolites formed after reduction of ketobemidone could be detected in the urine. Less than 2% of the dose was found in feces after iv administration. %U https://dmd.aspetjournals.org/content/dmd/9/4/376.full.pdf