Abstract: Localized delivery of 1,25 D3 directly to a target area using biodegradable polymeric matrices maximizes the efficacy of this drug while minimizing systemic exposure and toxicity. Anticalcemic analogs of 1,25 D3 have also been incorporated into controlled release polymer formulations to achieve efficacious intracranial concentrations of 1,25 D3 analogs for the treatment of intracranial tumors as well as neurodegenerative disorders such as Alzheimer's disease as well as to maximize the efficacy of these analogs in the treatment of systemic malignancies. The therapeutic efficacy of these formulations was demonstrated through a variety of studies in vitro and in vivo. Hybrid analogs of 1,25 D3 were incorporated into biodegradable polymer wafers composed of a polyanhydride copolymer of 1,3-bis(p-carboxyphenoxy)propane (CPP) and sebacic acid (SA) in a 20:80 molar ratio. In addition to providing improved treatments for malignancies and neurodegenerative disorders.