Abstract: The invention provides a pharmaceutical or veterinary implant, which when parenterally administered releases a pulse of at least one biologically active material at a controllable time interval after implantation. The implant comprises the biologically active material; an excipient comprising at least one water soluble material and at least one water insoluble material; and a polymer film coating adapted to rupture at a predetermined period of time after implantation, and wherein the excipients and polymers are biocompatible. The biologically active material is selected from the group consisting of antigens, antibodies, hormones, growth promotants, antibiotics, nutrients, minerals and vitamins. Preferably the excipient comprises a combination of two or more water-soluble and water-insoluble materials.

Abstract: The present invention provides pharmaceutical or veterinary implants which, when subdermally administered releases a peptide or protein in a substantially continuous manner. The implant includes the peptide or protein and an excipient encased within a polymeric coating which is permeable, swellable and, at normal physiological pH, is non-rupturing, non-dissolving and does not degrade over the useful life the implant. The coating forms a release rate limiting barrier. All of the components used to make the implant are of a biocompatible nature. The implant is particularly useful for the sustained release of proteins or peptides for regulating the hormonally controlled reproductive cycle in sheep.