Patent ID: 8481079

Claim:
A drug delivery system consisting of one or more compartments, said compartments comprise a progestogenic compound dissolved in a thermoplastic polyethylene vinylacetate copolymer whereby, if the delivery system consists of one compartment, the compartment comprises (i) a core of a thermoplastic polyethylene vinylacetate copolymer containing 30 to 50 wt % vinylacetate comprising the progestogenic compound, the progestogenic compound being dissolved in the polyethylene vinylacetate copolymer at a concentration below the saturation level at 25° C. between 0.1 and 1.0 wt %, based on the weight of the core, and an estrogenic compound; and (ii) a skin of a thermoplastic polyethylene vinylacetate copolymer covering the core, the copolymer containing 1 to 15 wt % vinylacetate, the skin being permeable for both compounds, and the skin having a thickness in the range of 10 to 110 μm; if the delivery system consists of more than one compartment, only one compartment comprises (iii) the progestogenic compound, the progestogenic compound being dissolved in a core of a thermoplastic polyethylene vinylacetate copolymer containing 30 to 50 wt % vinylacetate at a concentration below the saturation level at 25° C. between 0.1 and 1.0 wt %, based on the weight of the core, and an estrogenic compound; and (iv) a skin of a thermoplastic polyethylene vinylacetate copolymer covering the core, the copolymer containing 1 to 15 wt % vinylacetate, the skin being permeable for both compounds, and the skin having a thickness in the range of 10 to 110 μm, wherein the drug delivery system is physically stable when stored at or above room temperature.