Abstract: An implantable device for the controlled release of drug or diagnostic molecules in vivo which includes a substrate formed of a metal or a polyethylene, a plurality of discrete reservoirs provided in spaced positions in the substrate, and a release system disposed in the at least two reservoirs, wherein the release system comprises drug or diagnostic molecules combined with a release-controlling polymer matrix, wherein the kinetics of release of the drug or diagnostic molecules is controlled by disintegration of the polymeric matrix. The substrate and reservoirs therein may be made by a manufacturing technique which comprises compression molding, thermoforming, casting, laser cutting, etching, or a combination thereof.