Plasma concentrations of 3-keto-desogestrel after oral administration of desogestrel and intravenous administration of 3-keto-desogestrel

The plasma concentrations of 3-keto-desogestrel have been measured by radioimmunoassay in a crossover study in nine healthy feamle volunteers given oral desogestrel (150 μg) and ethinyloestradiol (30 μg) and intravenous (i.v.) 3-keto-desogestrel (150 μg) and ethinyloestradiol (30 μg).

Bioavailability ranged between 40.0 and 113% with a mean value (± SD) of 76.1 ± 22.5%. Only 3 subjects had a bioavailability of less than 70%. There was no significant difference in the elimination half life of 3-keto-desogestrel which was 12.6 ± 4.1h following i.v. administration and 11.9 ± 4.1h after oral administration of desogestrel.