Intranasal Delivery of Drugs to the Central Nervous System

Dementias and other neurologic diseases continue to increase in prevalence, and there remain few truly effective treatments available to these patients. Intranasal drug delivery is an exciting administration route that can bypass the blood–brain barrier and allow for direct access to brain tissues. The potential for this administration route ranges from novel drug treatments to curative stem cell therapies. However, preclinical data have so far proved difficult to translate to humans, largely due to formulation and administration techniques. This chapter reviews the relevant anatomy, mechanisms, and limitations of the intranasal delivery route, as well as discusses the growing number of strategies to overcome these challenges. This includes not only permeability enhancers and gelling agents but also various nanocarriers and administration devices. Optimizations of intranasal administration will be necessary to pass clinical trials and for new treatments to meet the growing demand for patients with neurological diseases.