The relative bioavailability of levonorgestrel and ethinyl estradiol administered as a low-dose combination oral contraceptive.

Author(s): Goebelsmann U, Hoffman D, Chiang S, Woutersz T

Affiliation(s): The relative bioavailability of levonorgestrel (LNG) and ethinyl estradiol (EE) administered concomitantly both as an oral tablet and as a solution was assessed in a randomized two-period crossover study in 24 healthy women. Serum concentrations were monitored for 96 h after each administration. The relative bioavailability (Fr) of LNG in the tablet with respect to the solution was 107%; thus the two formulations were bioequivalent with respect to LNG. The relative bioavailability of EE, however, was significantly lower for the tablet (Fr 83%) compared to the solution. This difference may have been due to either decreased absorption or enhanced presystemic elimination of EE from the tablet formulation.

Publication date & source: 1986-10, Contraception., 34(4):341-51.

Publication type: Clinical Trial; Randomized Controlled Trial

PIP: The relative bioavailability of levonorgestrel (LNG) and ethinyl estradiol (EE) administered concomitantly both as an oral tablet and as a solution was assessed in a randomized 2-period crossover study in 24 healthy women. Serum concentrations were monitored for 96 hours after each administration. The relative bioavailability of LNG in the tablet with respect to the solution was 107%; thus the 2 formulat6ions were bioequivalent with respect to LNG. The relative bioavailability of EE, howevedr, was significantly lower for the table compared to the solution. This difference may have been due to either decreased absorption or enhanced presystemic elimination of EE from the tablet formulation. author's modified