New drug candidate modalities for central nervous system (CNS) diseases with high unmet medical needs has expanded from small molecule drugs to medium and high molecular weight drugs, and expectations for therapeutic drug development are increasing. However, these drug modalities delivery into the brain via systemic blood circulation is limited by the blood-brain barrier (BBB), and the development of a drug delivery system (DDS) that overcomes the BBB is key to the development of new drugs for CNS diseases.
　In recent years, the administration routes have divaricated along with the diversification of modalities. Among above, intranasal administration has been noted as a method of non-invasive delivery of a drug modality to the brain by bypassing the BBB via the nose-to-brain direct route. This route has the potential to be novel administration route into the CNS for all drug modalities that are not expected to penetrate the BBB. However, intranasal administration of a modality alone is often insufficient in terms of its delivery efficiency and delivery deeper site into the brain, in addition, there are very few reports on drug delivery into the spinal cord. Therefore, to achieve efficient nose-to-brain drug delivery to the CNS, including the spinal cord, it is necessary to design DDS nanocarriers based on an understanding of nose-to-brain/spinal cord pharmacokinetics. In this situation, the nose-to-brain drug delivery research using nanoparticles as DDS nanocarriers (nanoDDS) has recently become more active and diversified.
In this symposium, we will review the representative mechanisms as well as the types and characteristics of typical nanoparticles in nose-to-brain delivery, and introduce our latest research on nanoDDS of nucleic acid drugs based on nose-to-brain route.