Improving nasal spray deposition: advances and strategies to overcome anatomical and physiological barriers.

Introduction: Nasal sprays offer a versatile, noninvasive delivery route for topical, systemic, immunological, and nose-to-brain therapies, yet effective targeting is limited by nasal anatomical complexity and physiological constraints.

Areas covered: The literature related suboptimal intranasal spray deposition to nasal valve constriction, convoluted nasal passages, mucociliary clearance, and vast geometrical variability. This review examined recent strategies that enhanced dosimetry realism and improved target delivery: (1) including mucus coating and nasal cycle effects, (2) optimizing delivery protocols such as the spray angle, head position, and dosing regimen, (3) engineering device features to improve targeting, and (4) tailoring formulation properties like the viscosity and surface tension to support liquid film translocation. Experimental findings highlighting protocol-driven improvements in spray targeting to the nasopharynx and olfactory region are also discussed.

Expert opinion: The effectiveness of nasal sprays hinges on their ability to deliver medication beyond the anterior nasal cavity to the intended target sites. Achieving this requires not only optimized spray dynamics and device design, but also the strategic use of liquid film translocation following initial deposition. Advances in physiologically realistic models and anatomically guided protocols will be key to unlocking the full therapeutic potential of nasal spray technologies.