LUNG DEPOSITION OF LABELLED MONODISPERSE SUBMICRONIC PARTICLES
NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CA
Pagination or Media Count:
Aerosol deposition in the rat lung has been determined as a function of particle size between 0.034 and 1.2 microns aerodynamic diameter. 22Na- Labeled aerosol was produced as monodisperse particles by a modified version of the Sinclair-LaMer glycerol generator. Particle size was determined by light scattering and was verified by light and electron microscopy. Anesthetized rats were fitted with a tracheal tube, thus avoiding oral or nasal influences on lung deposition. Respiratory minute volume as determined with this surgical preparation was about 97 mlmin. This value and the breathing pattern were practically identical to those found in nontracheotomized rats, similarly maintained at a body temperature at 37.5 C colon. For particles between 0.6 and 1.2 microns, lung deposition varied from 14 to 20. Fifteen minutes after inhalation, organ distribution of 22Na outside the lung was similar at two different particle sizes and in agreement with other studies based on intraperitoneal injection. Critical comparison of present lung deposition values in the rat with existing data on man showed close agreement with those studies in man giving low lung deposition values 20, for particles with aerodynamic diameter between 0.6 and 1.2 microns. Particles less than 0.14 micron in size showed lung deposition values of 7 to 8 this may be a particular characteristic of the rat.