The work aims to develop mucoadhesive and thermo-responsive in situ gelling systems, using hydrophobically-modified hydroxypropyl-methyl cellulose (Sangelose, SG) and beta-cyclodextrin (β-CD) derivatives, for preventing viral respiratory infections. Eight SG/CD systems with varying CD concentrations were evaluated for rheological properties, mucoadhesiveness, spreadability and sprayability via nasal devices
cytotoxicity was in vitro investigated on reconstituted nasal epithelia. Additionally, droplet size distribution and spray deposition were assessed for the most promising systems. The addition of β-CD derivatives to SG solution was responsible for a rapid sol-gel transition within a physiological temperature range (29-34 °C). SG/CD systems were characterized by a prevalence of the elastic properties on the viscous ones at 37 °C, functional to the formation of a protective gel barrier on the mucosa. The most promising systems showed sprayability and spreadability suitable for nasal administration, while in vitro tests demonstrated their non-toxicity. All the sprays were characterized by droplets with size >
100 μm, functional to avoid droplet exhalation or lung deposition
spray deposition studies confirmed uniform distribution across nasal turbinates, crucial for trapping inhaled particles. In conclusion, a mucoadhesive and thermo-responsive in situ gelling system consisting of SG and β-CD derivatives was successfully developed as promising nasal spray for the prevention of respiratory infections.