Direct labelling of ipratropium bromide aerosol and its deposition pattern in normal subjects and patients with chronic bronchitis

A technique for the direct labelling of ipratropium bromide with bromine-77, with reconstitution of the drug in a metered dose inhaler so as to be identical to the commercial product, was used to study drug deposition patterns in seven normal subjects and seven patients with chronic bronchitis (mean FEV1 32% (SD 12.2%) predicted normal). The gamma camera image of the thorax was divided into a middle zone--the mediastinal zone--and the lung itself into a central zone comprising its medial third and a peripheal zone, the lateral two thirds. Measurements after 10 inhalations of labelled ipratropium bromide showed similar results for the two groups of subjects. The total lung dose inhaled was 11.2% of 203 micrograms and 11.7% of 186 micrograms in the normal subjects and the patients respectively. In contrast to the deposition patterns seen in aerosol studies using steady state inhalation methods, there was no difference in deposition pattern--that is, the distribution between the central and the peripheral lung zones--between the normal subjects and the patients with airways obstruction.