The nasal cavity offers a unique physiological environment for drug administration, characterized by a highly vascularized mucosal surface and a relatively large surface area. Intranasal delivery allows for rapid absorption directly into the systemic circulation, bypassing "First-Pass Metabolism" in the liver. This results in higher bioavailability for many compounds and a faster "Onset of Action" compared to oral medications.

The efficacy of a nasal spray is governed by the "Mucociliary Clearance" (MCC) rate. To ensure the drug remains in contact with the nasal mucosa long enough for absorption, many formulations utilize "Mucoadhesive Agents" like chitosan or carbopol. For a detailed breakdown of the liquid, powder, and pressurized delivery formats, the Nasal Spray Market overview provides a technical analysis. By optimizing the pH and tonicity of the formulation, manufacturers can minimize nasal irritation while maximizing the permeability of the epithelial barrier.