title: Bioavailability and bioequivalence of etonogestrel from two oral formulations of desogestrel: Cerazette and Liseta.
abstract: In a three-period cross-over study with 24 healthy young females (study part 1), the bioavailability of etonogestrel (3-ketodesogestrel) was determined after a single oral dose of two Cerazette tablets (each containing 75 microg desogestrel), one Liseta tablet (containing 150 microg desogestrel and 1.5 mg 17beta-estradiol), and an intravenous dose of 150 microg etonogestrel. Etonogestrel serum levels from 23 subjects could be analysed by radio-immunoassay. The geometric mean bioavailability of etonogestrel from Cerazette and Liseta tablets was 0.79 and 0.82, with 95% confidence intervals of 0.73-0.86 and 0.76-0.88, respectively. Also, the oral formulations were found to be bioequivalent. Subsequently, the single-dose pharmacokinetic parameters of etonogestrel from Cerazette tablets were compared with those after multiple dosing of one Cerazette tablet once daily for 7 days, in a subgroup of 12 subjects (study part 2). A steady state was observed from the fourth day of daily dosing onwards, with time-invariant parameters except for a 14% lower dose-normalised AUC. The least-squares geometric means of the elimination half-life of etonogestrel were approximately 30 h for the three single-dose treatments in study part 1, as well as for the single- and multiple-dose treatments of Cerazette in study part 2, without differences between groups.
authors.affiliation: N.V. Organon, Oss, The Netherlands.
authors.forename: C J
authors.initials: CJ
authors.lastname: Timmer
authors.forename: N
authors.initials: N
authors.lastname: Srivastava
authors.forename: T O
authors.initials: TO
authors.lastname: Dieben
authors.forename: A F
authors.initials: AF
authors.lastname: Cohen
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D003271:Contraceptive Agents, Female / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D017135:Desogestrel / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D013810:Therapeutic Equivalency; D014753:Vinyl Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D003271:Contraceptive Agents, Female; D014753:Vinyl Compounds; C044815:etonogestrel; D017135:Desogestrel