Subdermally implantable device

摘要

Disclosed is a subdermally implantable drug-delivery device (10), which contains: a central core (11) extending in an axial direction and having an outer surface (12) and opposing ends (13 and 13'), which core includes a matrix of a pharmaceutically effective amount of a subdermally administrable drug (14) substantially uniformly dispersed in a polymeric base material (15); an intermediate polymeric layer (16) overlying the outer surface of the central core; and an outer polymeric layer (17) overlying the intermediate layer, further characterized in that the intermediate layer controls the rate of diffusion of the drug from the central core to the outer layer. In preferred embodiments, the subdermally administrable drug (14) is a contraceptive agent such as the Nestorone TM progestin; the polymeric base material (15) and the outer polymeric layer (17) each contain a polydimethylsiloxane such as Silastic TM ; the intermediate layer (16) contains a porous material such as cellulose, and the device (10) further contains sealing means such as a layer of plastic (21 and 21') and adhesive (18 and 18') cooperating with the biocompatible layer to fully encapsulate the central core and the intermediate layer. The devices provide for the substantially zero-order release of the drug for their intended lifetime without initial overdosing of the drug. Methods of treating subjects with the implantable drug-delivery devices of the invention, and methods of contraception are also disclosed.