The nasal cavity is ideal for drug delivery for local action and systemic action, due to the relatively large surface area, mucosal surface and blood supply.
Following the Montreal Protocol, as aqueous nasal products were available, CFC nasal products were phased out immediately despite having approximately 50% of the market. Since then, the aqueous nasal spray has dominated the marketplace, but FDA approvals in 2012 for HFA nasal aerosols (e.g. Zetonna™, QNASL®) provide alternatives for the 7.8% of US population aged 18 and over, and potentially the estimated 400 million people worldwide, suffering from allergic rhinitis.
Relative benefits of HFA nasal aerosols compared to aqueous nasal sprays are demonstrated via clinical studies quantifying initial deposition by gamma scintigraphy of 2 different nasal devices/formulations containing the same active ingredient: ciclesonide HFA nasal aerosol (74μg/actuation) and ciclesonide aqueous nasal spray (50μg/actuation, Omnaris®) in an open label, single dose, single site, non-randomised study. Delivery via HFA nasal aerosol resulted in deposition of almost the entire delivered dose within the nasal cavity (mean 98.4% vs. 76.4% for aqueous), negligible external nasal drip (0.0% vs. 22.7% for aqueous), negligible lung deposition (1.4%) and minimal deposition in the nasopharynx (0.2%).
The improved deposition and retention of the HFA nasal aerosol compared to the aqueous nasal spray (from this and other published studies), with less dripping down the nose and less drainage down the throat (meaning no aftertaste or odour) are advantageous, in line with preferences desired by patients.