Systems for local, sustained release of zoledronic acid as a potential treatment for metastatic bone disease

Bone pain is the leading cause of morbidity in patients with metastatic cancer. Systemic administration of zoledronic acid (ZA) decreases skeletally-related events in bone cancer patients but is associated with major side effects. This project investigated two biomaterials, poly(methyl methacrylate) (PMMA) bone cement and poly(lactic-co-glycolic acid) (PLGA), for local ZA delivery. Compressive properties of PMMA samples were tested with increased drug loading, and in vitro ZA release profiles from PMMA cylinders and PLGA films were measured over 8 weeks. The activity of ZA eluted from both materials was evaluated on the RAW 264.7 macrophage cell line. PMMA samples released up to only 17% of incorporated drug, whereas PLGA films released over 95%. A burst profile was observed for PMMA, while ZA release from PLGA exhibited a typical triphasic profile. Drug bioactivity remained above 50% for both materials. Local ZA delivery from these materials may be useful in the treatment of metastatic bone cancer.