Biomaterials for local drug delivery in central nervous system.

The central nervous system (CNS) is a vital part of human body which coordinate the actions by transmitting signals. Because of the existence of the blood-brain barrier and the blood-spinal cord barrier, diseases in CNS can hardly be directly intervened by non-invasive methods. While systemic delivery usually requires extravagant drug dosage and leads into toxicity in unexpected tissues, local drug delivery in CNS tissues provides a solution for the problems of physiological barriers and systematic side effects. Biomaterials are applied in local drug delivery system (LDDS) for CNS disease therapy with aims of tuning the drug release property and improving bioavailability, solubility, stability and safety of pharmaceutics. The indispensable importance and distinct physiological structure of cerebrospinal area bring about challenges to biomaterials in LDDS. Thus, properties of drug delivery systems are necessitated with prudently concern. In this review, the development of LDDS utilizing biomaterials will be presented, including sustained release, local parameter-responsible release, and regional cell-selective active targeting release. Studies on biomaterials employed as pharmaceuticals will give rise to a more efficacious method and the better understanding of LDDS design in CNS.