Importance of Particle Size in Aerosol Therapy* (25688)

Journal/Book: Reprinted from -PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE 1960 v103 836-838. 1960;

Abstract: FRANK W. LOVEJOY JR. HERBERT CONSTANTINEÂ† AND LUCIEN DAUTREBANDEÂ‡ (Introduced by W. S. McCann) Depts. of Medicine Pharmacology and Radiation Biology University of Rochester School of Med. and Dentistry and Strong Memorial and Rochester Municipal Hospitals Rochester N. Y. *This study supported in part by grant from Heart Comm. Health Assn. of Rochester and Monroe Co. by grants from Nat. Heart Inst. and Nat. Inst. Health U.S.P.H.S. t Â† Research Fellow Am. Heart Assn. Â‡ Visiting Professor. It is known that retention of airborne particulate matter in the respiratory tract is chiefly influenced by size of particles inhaled; the large particles settle in the tracheobronchial tree and smaller ones penetrate deeper into the lungs. When smaller than 0.5 µ in diameter particles are nearly exclusively deposited upon walls of alveolar ducts and alveolar sacs (1) . To emphasize the importance of particle size in administration of medicated aerosols a small series of experiments was undertaken using 2 different sources of airborne particles: a standard nebulizer (commercially available) producing particles ranging from 0.8 to 7.4 µ averaging 3.1 µ. according to Grau (2) or from 1.6 to 14.8 µ averaging 6.2 µ according to Barach(3) as measured by optical microscopy and an aerosol generator called D-30 previously described (1) producing particles all below 0.5 µ diameter as measured by electron microscopy. Medicated aerosol was produced from a solution containing 0.1% isoproterenol 2% phenylephrine in medium composed of equal parts of USP propylene glycol and water. At 5 p.s.i. head pressure the standard nebulizer delivered 9 g of this solution in 10 minutes while the D-30 aerosol generator during same time and same pressure delivered 0.3 g only. Four normal subjects (30 32 45 and 65 years in age) breathed the medicated dispersates alternately as produced by standard nebulizer and by aerosol generator duration of inhalation varying from 5 to 20 slow deep sub-maximal breaths. Airway resistance was measured according to plethysmographic method of Du-Bois Botelho and Comroe(4) and blood pressure heart rate and electrocardiogram were recorded in serial fashion. ... ___MH

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