Allergic rhinitis is treated with a variety of systemic and locally applied drugs. The effectiveness of the intranasally applied formulations is diminished by the cleaning mechanisms of the nose, rhinorrhea in particular. Slowing down of the clearance of the nasal mucosa and prolonging the contact time of locally applied drugs with the nasal mucosa would improve their efficacy. One method is creating dosage forms containing mucoadhesive polymers. We have demonstrated that a mucoadhesive solution containing HPMC enhances the clinical efficacy of oxymetazoline. However, the industrial development of fixed combinations of pharmaceutical compound and mucoadhesive carrier requires substantial investments, escalating manifold if different pharmaceutical compounds have to be rendered mucoadhesive.

NoAl is a cellulose derivative powder, which forms a gel layer on contact with the mucosal surface of the nose blocking the contact of the pollen grains with the nasal mucosa in seasonal allergic rhinitis. However, there is another potential benefit of applying NoAl (HPMC) along with other commercially available drugs for local treatment of rhinitis, as the formation of a gel layer can substantially delay their clearance from the nose and thus increase their effectiveness. This hypothesis needs to be substantiated clinically.

The main objective of the trial is to test the synergy between HPMC and oxymetazoline (both applied nasally) on the increase of peak nasal inspiratory flow in patients suffering from moderately severe / severe persistent allergic rhinitis.

The design of the trial is parallel-groups, double blind, randomized, placebo controlled, single centre study.

Forty patients are randomly assigned to receive either oxymetazoline followed by HPMC (Group A) or oxymetazoline followed by placebo (Group B).

Each patient is followed up for 15 days. Day 1 is the screening and inclusion visit. Data will then be collected on day 8 & 15. Patients will fill in diaries their everyday symptoms, adverse events and applied medications.

Inclusion Criteria:

• Male or female patients
• Age ≥ 18 and ≤ 50 years
• Moderately severe / severe persistent allergic rhinitis
• Positive skin prick test for perennial aero-allergens
• Active symptoms with prominent congestion at the time of inclusion

Exclusion Criteria:

• Subjects with pollen sensitization during the respective pollen season
• Subjects with arterial hypertension, arrhythmia or evidence of heart ischemia
• Subjects with other serious chronic comorbidities and bad therapeutic control
• Subjects with nasal polyposis
• Flu-like episode during the past 30 days
• Subjects unable to give informed consent
• Subjects with any of the contra-indications of oxymetazoline or NoAL
• Pregnant or lactating women