| 摘要 |
The present invention is dealing with a drug delivery system, preferably in a ring-shaped form suitable for vaginal administration, for the simultaneous release of a progestogenic steroid compound and an estrogenic steroid compound in a fixed physiological ratio over a prolonged period of time. The drug delivery system comprises at least one compartment comprising a thermoplastic polymer core containing the mixture of the progestogenic and estrogenic compounds and a thermoplastic polymer skin, the progestogenic compound being initially dissolved in the polymer core material in a relatively low degree of supersaturation. |
