Polymeric nanocarriers for nose-to-brain drug delivery in neurodegenerative diseases and neurodevelopmental disorders

Neurodegenerative diseases are progressive conditions that affect the neurons of the central nervous system (CNS) and result in their damage and death. Neurodevelopmental disorders include in-tellectual disability, autism spectrum disorder, and attention-deficit/hyperactivity disorder and stem from the disruption of essential neurodevelopmental processes. The treatment of neurodegenerative and neu-rodevelopmental conditions, together affecting w120 million people worldwide, is challenged by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier that prevent the crossing of drugs from the systemic circulation into the CNS. The nose-to-brain pathway that bypasses the BBB and in-creases the brain bioavailability of intranasally administered drugs is promising to improve the treatment of CNS conditions. This pathway is more efficient for nanoparticles than for solutions, hence, the research on intranasal nano-drug delivery systems has grown exponentially over the last decade. Polymeric nano -particles have become key players in the field owing to the high design and synthetic flexibility. This re-view describes the challenges faced for the treatment of neurodegenerative and neurodevelopmental conditions, the molecular and cellular features of the nasal mucosa and the contribution of intranasal nano-drug delivery to overcome them. Then, a comprehensive overview of polymeric nanocarriers inves-tigated to increase drug bioavailability in the brain is introduced.(c) 2023 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).