[Distribution and site of action of inhaled aerosols].

Intrapulmonary distribution of nebulized aerosols and sites of air way dilatation following metered-dose aerosol delivery were studied by radionuclide methods. Aerosols penetrate to more peripheral site in slow inhalation and deposition of aerosols in diseased area was enhanced by release at a high lung volume. Pulmonary deposition of radioaerosols released from spacers was over 50% of activity in the spacer. Predominant site of bronchodilatation (beta-stimulant) was on large airways, though action on small airways was also noted.