Devices for the delivery of drugs having antiprogestinic properties

A device for the controlled release over a prolonged period of time of a drug having antiprogestinic properties, said device comprising a core comprising said drug and optionally a membrane encasing said core, said core and/or membrane being made of a siloxane-based elastomer composition comprising at least one elastomer and optionally a non-crosslinked polymer, wherein said elastomer composition comprises poly(alkylene oxide) groups and the poly(alkylene oxide) groups are present in the elastomer or polymer as alkoxy-terminated grafts of polysiloxane units, or as blocks, the said grafts or blocks being linked to the polysiloxane units by silicon-carbon bonds, or as a mixture of these forms, said poly(alkylene oxide) groups having the formula

• —R3—O—(CHR—CH2—O)m—
• where R is hydrogen or lower alkyl, R3 is a linear or branched C2-C6 alkylene group and m is from 1 to 3.