Oxymorphone was extensively metabolized by human, rat, dog, and guinea pig and to a lesser extent by rabbit. The most abundant metabolite in urine for all species was conjugated oxymorphone (12.7-81.7% administered dose) followed by 6β- and 6α-carbinols produced by 6-keto reduction of oxymorphone. 6β-Oxymorphol (0.2-3.1%) was found in the urine of all species, whereas 6α-oxymorphol (0.1-2.8%) was found only in human, rabbit, and guinea pig. Small amounts of free oxymorphone (≤ 10%) were excreted by all species except rabbit, which excreted 31.7%. Overall recoveries of oxymorphone and metabolites from urine ranged from 15-96% of which >80% was excreted in the first 24 hr by all species except dog. Only 35% was excreted by dog urine the first day. Stereoselectivity of 6-keto-reduction was observed for all species with the 6β-carbinol metabolite being most abundant in the urine of all but guinea pig. Considerable individual variability occurred in the excretion of free and conjugated oxymorphone by six human subjects following oral dosing. Species trends in the metabolism of 6-keto-opioids are discussed.
|Original language||English (US)|
|Number of pages||5|
|Journal||Drug Metabolism and Disposition|
|State||Published - Jan 1 1983|
ASJC Scopus subject areas
- Pharmaceutical Science