Novel ethinyl estradiol-beta-cyclodextrin clathrate formulation does not influence the relative bioavailability of ethinyl estradiol or coadministered drospirenone

Background: A new combined oral contraceptive formulation has been developed consisting of a beta-cyclodextrin (betadex) clathrate formulation of ethinyl estradiol in combination with drospirenone (EE-betadex clathrate/drsp). In this novel EE-betadex clathrate/drsp preparation, betadex serves as an inert complexing agent to enhance stability and shelf-life. The study was conducted to investigate the relative bioavailability and pharmacokinetic parameters of EE and drsp after oral administration of EE-betadex clathrate/drsp. Methods: This was an open-label, randomized, single-dose, three-period, three-treatment, crossover study conducted in IS healthy postmenopausal women aged 45-75 years. The women received single oral doses of 40 mcg EE/6 mg drsp formulated as EE-betadex clathrate/drsp or EE/drsp (EE as a free steroid) tablets, or as a microcrystalline suspension on three separate occasions. Serum samples were collected for pharmacokinetic analyses. Results: The relative bioavailability of EE and drsp after EE-betadex clathrate/drsp tablet administration was comparable with that achieved with the EE/drsp tablet (107% and 101%, respectively). In addition, the inclusion of EE in a betadex clathrate does not affect the pharmacokinetics of either EE or drsp. There were no safety concerns with any of the medications. Conclusion: The betadex clathrate formulation of EE, when combined with DRSP, does not affect the pharmacokinetics and relative bioavailability of either EE or drsp. (c) 2008 Elsevier Inc. All rights reserved.