Immediately following inhalation of the radiolabeled aerosol, images of the posterior and anterior views of the chest and abdomen, a right lateral view of the oropharynx, the dosing apparatus (including wipings from the outer surface of the RESPIMAT nozzle and surrounding plastic casing, baffle, actuator, spacer, and mouthpiece), the nose plugs, and exhalation filter were recorded using a gamma camera (General Electric Maxicamera), connected to a data processing system (Bartec Micas V).
Radioactive counts from the whole lung, lung zones, oropharynx, esophagus, and stomach were corrected for background radiation, radioactive decay, and for tissue attenuation of gamma rays. The geometric mean of anterior and posterior lung counts was calculated. Oropharyngeal deposition was taken as the sum of radioactivity recorded in the mouth, pharynx, esophagus, and stomach. Data were expressed as the percentage of the metered dose deposited at each site. A posterior lung ventilation scan using the radioactive inert gas 81mKr was obtained and used to define the lung edges. The lungs were subdivided into central, intermediate, and peripheral zones as described previously. The ratio of peripheral to central lung zone deposition (ie, the lung penetration index) was calculated. flovent inhaler
Any adverse events occurring during the course of the study were recorded. Lung function tests (FEVl5 FVC, and peak expiratory flow rate) were performed before and 60 min following dosing using a spirometer (Vitalograph Compact Spirometer; Vitalograph; Buckingham, UK) to detect any bronchoconstriction associated with the study treatments.
Deposition data for inhaler devices were compared using the Wilcoxon matched-pairs signed rank test. A p value of <0.05 was considered to be significant.