Chronic Rhinosinusitis Without Polyps

This study tests a new nasal spray for adults (18-65 years) with chronic sinusitis experiencing an acute phase. The spray contains a temperature-sensitive gel that turns into a soft gel inside the nose to slowly release three active ingredients: stem cell exosomes (to repair nasal lining), azelastine (an antihistamine and anti-inflammatory drug), and interferon alpha-2b (an antiviral agent). The study aims to evaluate safety and see if the spray can reduce symptoms, fight viruses, and improve quality of life. Participants will be randomly assigned to one of three groups: triple spray, dual spray (without exosomes), or placebo (gel only). Treatment is twice daily for 4 weeks, with follow-up visits up to day 90.