“Intranasal Delivery”

In this chapter, we describe the applicability of cell-penetrating peptides (CPPs) to enhance nasal absorption to the systemic circulation and the nose-to-brain delivery of biologics. The intranasal coadministration with amphipathic CPP, penetratin, can significantly increase the systemic absorption of peptides and proteins such as insulin and interferon, and interestingly it has also the potential to deliver drugs to the brain, which is the most difficult therapeutic target in the body. Importantly, noninvasive intranasal administration can be a patient-friendly route compared to invasive administration routes such as intravenous and subcutaneous injections. Thus, CPPs can be useful tools for enhancing the nasal permeation of various therapeutic modalities, thereby increasing their clinical value.