Characterization of nasal spray pumps and deposition pattern in a replica of the human nasal airway

Deposition patterns are described of a nasal spray formulation for a novel rhinovirus protease inhibitor. These patterns, which were generated from di fferent nasal spray pumps, were characterized using a multisectional nasal airway model. A human nasal replica was made from an in vivo magnetic reson ance imaging (MRI) scan of an adult male human. The nasal replica consisted of 77 acrylic plastic sections, 1.5-mm thick. Our data showed that the aer osols were deposited mainly in the anterior and turbinate regions with litt le passing beyond the nasopharyngeal region. Detailed deposition informatio n from the turbinate region indicated that deposition was high toward the a nterior portion where most deposition was concentrated on the inferior meat us. Spray droplets were also deposited in spots of the middle and posterior portions of the turbinate region, and this nonuniform deposition pattern m ay be correlated with the flow pattern. The spray angle and droplet size of the nasal spray were found to be important in influencing the deposition p attern:in the nasal airway. The droplet size was determined by a laser-diff raction technique and the spray angle by high-speed photography. Larger dro plets and a wider spray angle increased deposition in, the anterior region of the nasal airway, which prevented more material from depositing in the t urbinate region.