Polymeric microparticles have been developed which encapsulate therapeutic compounds such as drugs, cellular materials or components, and antigens, and can have targeting ligands directly bound to the microparticle surface. Preferred applications include use in tissue engineering matrices, wound dressings, bone repair or regeneration materials, and other applications where the microparticles are retained at the site of application or implantation. Another preferred application is in the use of microparticles to deliver anti-proliferative agents to the lining of blood vessels following angioplasty, transplantation or bypass surgery to prevent or decrease restenosis, and in cancer therapy. In still another application, the microparticles are used to treat or prevent macular degeneration when administered to the eye, where agents such as complement inhibitors are administered.