Nasal drug delivery has emerged as a major focus in pharmaceutical development because it combines convenience, rapid absorption, high bioavailability, and the potential for both local and systemic effects. Recent approvals and pipeline candidates for conditions including Alzheimer’s disease, depression, migraines, diabetes, seizures, and opioid overdoses illustrate the expanding therapeutic scope of nasal delivery.

The nasal cavity is especially attractive because it provides a direct pathway to systemic circulation and, in some cases, to the central nervous system. This has opened opportunities for innovative nose-to-brain therapies. Similarly, nasal vaccines target the nasal-associated lymphoid tissue (NALT), stimulating mucosal immunity as a needle-free alternative to injections.¹^,²^,³

A key challenge in nasal drug delivery is ensuring accurate and consistent deposition within targeted regions of the nasal cavity. This is complicated by natural anatomical variability and the many factors that influence spray performance, including device design and formulation properties.⁴ Nasal cast testing has emerged as a valuable tool, providing developers with a rapid, cost effective, and reproducible method to evaluate deposition and guide optimisation early in development.⁵^,⁶