The in vivo human metabolism of tibolone.

In vivo metabolism of tibolone was studied in three healthy postmenopausal volunteers after daily oral administration of 2.5 mg of tibolone for 5 days and a single dose of 2.5 mg approximately equal 555 kBq of [(14)C]tibolone on day 6.

In vitro and in vivo metabolism of the progestagen Org 30659 in several species.

The metabolism of Org 30659 [(17alpha)-17-hydroxy-11-methylene-19-norpregna-4, 15-dien-20-yn-3-one], a new potent progestagen currently under clinical development by NV Organon for use in oral contraceptive and hormone replacement therapy, was studied in vivo after oral administration to rats and monkeys and in vitro using rat, rabbit, monkey, and human liver microsomes and rat and human hepatocytes. After oral administration of [7-3H]Org 30659 to rats and monkeys, Org 30659 was extensively metabolized in both species. Fecal excretion appeared to be the main route of elimination.

In vitro and in vivo metabolism of desogestrel in several species.

The metabolism of desogestrel (13-ethyl-11-methylene-18, 19-dinor-17alpha-pregn-4-en-20-yn-17-ol), an orally active progestogen, was studied in vivo after administration of single oral doses to rats and dogs and in vitro using rat, rabbit, dog, and human liver microsomes. Metabolites were isolated and identified by NMR and MS analysis. After oral administration of [3H]desogestrel to rats and dogs, desogestrel was extensively metabolized in both species.