Nanomedicine for Treating Major Brain Diseases: Advances and Future Directions.

Traditional drug delivery systems lack target specificity. Various macromolecules, which are useful to treat central nervous system (CNS) diseases, have failed in clinical trials. This is because the molecules fail to cross the blood-brain barrier (BBB) effectively. The diseases of the brain are a major cause of disability and death. Various brain diseases affect 3.4 billion people worldwide. Nanomedicine, the medical application of nanotechnology for the diagnosis and treatment of diseases, improves drugs' solubility, stability, bioavailability, safety, and therapeutic efficacy. Site-specific ligand conjugated nanomedicine increases the target-specificity of nanomedicine toward specific receptors or determinants and delivers the drugs to the target organ. Nanomedicine provides better patient care while minimizing side effects and treatment cost. Further, it has the ability to change the traditional way of diagnosing and treating diseases. This review discusses recent advances in the usefulness of nanomedicine to treat major brain diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The article also addresses the challenges in the development of nanoformulation and associated nanotoxicity.