title: Quantitative determination of the urinary excretion of ketobemidone and four of its metabolites after intravenous and oral administration in man.
abstract: 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.
mesh_terms: D000284:Administration, Oral; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000378:metabolism*; D001711:Biotransformation; D002849:Chromatography, Gas; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D013058:Mass Spectrometry; D008614:Meperidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000701:Analgesics, Opioid; D008614:Meperidine; C012394:ketobemidone