Nanocarriers as CNS drug delivery systems for enhanced neuroprotection

Abstract

Blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BSCFB) separate central nervous system (CNS) from blood circulation and tightly protect CNS by hindering the passage of harmful substances across the barriers and allowing the transport of essential compounds for brain function. These selectively permeable barriers have become a major challenge in delivering drugs into the nervous system for the treatment of CNS diseases and complications such as Alzheimer's disease, Multiple sclerosis, and encephalitis. Due to the advancements in nanotechnology and medicine, nanocarrier-based drug delivery has emerged as a new and potential strategy for neurological treatment and protection. Depending on the techniques in preparation and functionalization, nanocarriers may be developed with different properties for cell-/tissue-/organ-specific targeted delivery and for sustained and controlled release of neurotherapeutic agents. Even though several attempts have shown successful results in effective drug delivery to the central nervous system, the lack of information about long-term nanocarrier toxicity, accumulation, and excretion restrict their use in current clinical practice. This chapter highlights recent developments in nanocarriers specifically designed to protect CNS. The interactions between nanocarriers including liposomes, micelles, organic and inorganic nanoparticles, nanofibers, and carbon-based materials with various neuroprotective agents, and their capabilities of delivering the encapsulated or conjugated drugs to the CNS are reviewed. The review also includes our investigations on the development of titanate nanospheres and nanowires and their potential use as drug delivery tools in neuroprotection. Finally, future prospects of drug delivery systems in the treatment of neurodegenerative pathologies for clinical translation are described.