ABSTRACT
INTRODUCTION The choice of administration route is critical for successful drug development. A judicious selection should take into consideration the properties of the drug as well as its intended use and the targeted patient population. For example, highmolecular-weight drugs such as peptides and proteins are typically developed as injection products since their relative fragility makes oral administration problematic. Even so, injection may not be preferred when considering other important factors such as patient comfort, convenience, and compliance. An alternative in this regard is noninvasive drug delivery via the intranasal (IN) route, the topic of the current chapter. Although the nasal mucosa provides a barrier to permeation of high-molecular-weight therapeutics such as peptides and proteins, the tight junctions within this tissue can be reversibly and safely opened; thus, IN delivery of peptides and proteins provides a feasible and advantageous option to injections. The rapid absorption achieved by the IN route may provide pharmacodynamic and safety advantages over the subcutaneous route of administration. Applications for IN delivery are presented, followed by discussion of considerations related to pharmacokinetic and pharmacodynamic performance, with examples demonstrating these principles.
