Delivery device and method

A method of treating chronic rhinosinusitis with or without nasal polyps in a subject in need thereof by delivering doses of fluticasone into a nasal cavity of the subject, the method comprising:

• inserting a nosepiece of a delivery device into a first nostril of the subject, the nosepiece including a nozzle;
• inserting a mouthpiece of the delivery device into an oral cavity of the subject;
• establishing a first flow of exhalation breath into the mouthpiece while the nosepiece is inserted into the first nostril to cause closure of an oropharyngeal velum of the subject;
• and
• manually actuating a delivery pump of the delivery device to release a first dose of fluticasone through the nozzle and to release at least a portion of the first flow of exhalation breath out of the nosepiece;
• wherein the nosepiece extends into the first nostril and is configured to expand a first nasal valve of the subject;
• and
• wherein at least 50% of the first dose of fluticasone as initially deposited is deposited in a region of the nasal cavity which is posterior of the first nasal valve and at least 30% of the first dose of fluticasone as initially deposited is deposited in a region of the nasal cavity which is posterior of the first nasal valve and above a first inferior meatus of the subject.