EFFECT OF PARTICLE SIZE ON SLOW PARTICLE CLEARANCE FROM THE BRONCHIAL TREE

• Published in: Experimental lung research Vol. 34; no. 6; pp. 287 - 312
• Main Authors: Smith, J. R. H., Bailey, M. R., Etherington, G., Shutt, A. L., Youngman, M. J.
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01-01-2008; Taylor & Francis
• Subjects: Administration, Inhalation; Adult; Aerosols; bolus inhalation; Bronchi - metabolism; Female; Gold - administration & dosage; Gold - pharmacokinetics; Gold Radioisotopes; Humans; Indium Radioisotopes; Lung - metabolism; lung retention; Male; Middle Aged; Models, Biological; mucociliary clearance; Mucociliary Clearance - physiology; particle deposition; Particle Size; Polystyrenes - administration & dosage; Polystyrenes - pharmacokinetics
• ISSN: 0190-2148; 1521-0499
• DOI: 10.1080/01902140802093196

The Human Respiratory Tract Model of the International Commission on Radiological Protection assumes that a fraction of particles deposited in the bronchial tree clears slowly, this fraction decreasing with increasing particle geometric diameter. To test this assumption, volunteers inhaled 5-μ m aerodynamic diameter 111In-polystyrene and 198Au-gold particles simultaneously, as a 'bolus' at the end of each breath to minimize alveolar deposition. Because of the different densities (1.05 versus 19.3 g cm3), geometric diameters were about 5 and 1.2 μ m, respectively, and corresponding predicted slowly cleared fractions were about 10% and 50%. However, lung retention of the 2 particles was similar in each subject. Retention at 24 hours, as a percentage of initial lung deposit (mean ± SD) was 34 ± 12 for polystyrene and 31 ± 11 for the gold particles.