As a result of dissimilarity in lung morphometry and physiological conditions, therapeutic aerosol particles deposit differently in humans of various ages and body weights. These particles also deposit differently in non-human species that are often utilized in inhalation and dosing studies. The focus of this work is to determine the optimal particle size and deposition (traditional efficiency and volume-weighted) of therapeutic particles in humans of both genders ranging in age from 3 months old to 21 years old and three non-human species (B6C3F1 mouse, Long-Evans hooded rat, and Beagle dog). This study finds that in humans, both optimal particle size and volume-weighted deposition are age and weight dependent; as age and weight increase, optimal particle size and deposition increase. Also, for all ages, breathing rates that are lower than normal enhance volume-weighted deposition and shift optimal particle size. Additionally, a rigorous sensitivity analysis of breathing rate and particles diameter on deposition shows that at normal breathing rates, sensitivity to breathing rate is greater than sensitivity to particle diameter for young children, but sensitivities to both become similar as age/body weight increase. At optimal breathing rates, the sensitivity to both breathing rate and particle diameter are lowest at the optimal breathing rates for children; for healthy adults, however, there is no apparent difference in sensitivity at normal and optimal breathing rates. This study also found that the mouse represents infants and young children relatively well, the rat represents older children relatively well, and the canine likely represents adolescents well. In addition, numerous studies postulate that the use of heliox instead of air will improve deposition as a result of the differences in density and dynamic viscosity; therefore, this study evaluates the effects of heliox based upon the differences in these properties. The results indicate that based on these properties, heliox does not appear to have any significant effect on deposition.
","abstract_html":"<p>As a result of dissimilarity in lung morphometry and physiological conditions, therapeutic aerosol particles deposit differently in humans of various ages and body weights. These particles also deposit differently in non-human species that are often utilized in inhalation and dosing studies. The focus of this work is to determine the optimal particle size and deposition (traditional efficiency and volume-weighted) of therapeutic particles in humans of both genders ranging in age from 3 months old to 21 years old and three non-human species (<em>B6C3F<sub>1</sub></em> mouse, Long-Evans hooded rat, and Beagle dog). This study finds that in humans, both optimal particle size and volume-weighted deposition are age and weight dependent; as age and weight increase, optimal particle size and deposition increase. Also, for all ages, breathing rates that are lower than normal enhance volume-weighted deposition and shift optimal particle size. Additionally, a rigorous sensitivity analysis of breathing rate and particles diameter on deposition shows that at normal breathing rates, sensitivity to breathing rate is greater than sensitivity to particle diameter for young children, but sensitivities to both become similar as age/body weight increase. At optimal breathing rates, the sensitivity to both breathing rate and particle diameter are lowest at the optimal breathing rates for children; for healthy adults, however, there is no apparent difference in sensitivity at normal and optimal breathing rates. This study also found that the mouse represents infants and young children relatively well, the rat represents older children relatively well, and the canine likely represents adolescents well. In addition, numerous studies postulate that the use of heliox instead of air will improve deposition as a result of the differences in density and dynamic viscosity; therefore, this study evaluates the effects of heliox based upon the differences in these properties. The results indicate that based on these properties, heliox does not appear to have any significant effect on deposition.</p>","abstract_has_math":false,"creators":["Weber, Lisa M."],"institution":null,"degree_name":"M.S.","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Corinne Lengsfeld, Ph.D.","Peter Laz","Bradley Davidson"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-01-01T08:00:00Z","date_published":"2011-01-01T08:00:00Z","updated_at":"2026-07-24T02:02:53Z","subjects":["Animals","Deposition","Breathing rate","Lung","Particle","Alveolar","Particle size","Biomedical Engineering and Bioengineering","Engineering"],"languages":["en"],"rights":["Copyright is held by the author. User is responsible for all copyright compliance.
"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.du.edu/etd/694","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Corinne Lengsfeld, Ph.D.","Peter Laz","Bradley Davidson"]},{"key":"dc:creator","label":"Author","values":["Weber, Lisa M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2001-01-01T08:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Animals","Deposition","Breathing rate","Lung","Particle","Alveolar","Particle size","Biomedical Engineering and Bioengineering","Engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright is held by the author. User is responsible for all copyright compliance.
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"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Pulmonary Particle Deposition in Relation to Age, Body Weight, and Species"]}]}],"canonical_facts":{"dc:contributor":["Corinne Lengsfeld, Ph.D.","Peter Laz","Bradley Davidson"],"dc:creator":["Weber, Lisa M."],"dc:date.available":["2001-01-01T08:00:00Z"],"dc:description.abstract":["As a result of dissimilarity in lung morphometry and physiological conditions, therapeutic aerosol particles deposit differently in humans of various ages and body weights. These particles also deposit differently in non-human species that are often utilized in inhalation and dosing studies. The focus of this work is to determine the optimal particle size and deposition (traditional efficiency and volume-weighted) of therapeutic particles in humans of both genders ranging in age from 3 months old to 21 years old and three non-human species (B6C3F1 mouse, Long-Evans hooded rat, and Beagle dog). This study finds that in humans, both optimal particle size and volume-weighted deposition are age and weight dependent; as age and weight increase, optimal particle size and deposition increase. Also, for all ages, breathing rates that are lower than normal enhance volume-weighted deposition and shift optimal particle size. Additionally, a rigorous sensitivity analysis of breathing rate and particles diameter on deposition shows that at normal breathing rates, sensitivity to breathing rate is greater than sensitivity to particle diameter for young children, but sensitivities to both become similar as age/body weight increase. At optimal breathing rates, the sensitivity to both breathing rate and particle diameter are lowest at the optimal breathing rates for children; for healthy adults, however, there is no apparent difference in sensitivity at normal and optimal breathing rates. This study also found that the mouse represents infants and young children relatively well, the rat represents older children relatively well, and the canine likely represents adolescents well. In addition, numerous studies postulate that the use of heliox instead of air will improve deposition as a result of the differences in density and dynamic viscosity; therefore, this study evaluates the effects of heliox based upon the differences in these properties. The results indicate that based on these properties, heliox does not appear to have any significant effect on deposition.
"],"dc:format":["application/pdf"],"dc:identifier":["https://digitalcommons.du.edu/etd/694"],"dc:language":["en"],"dc:rights":["Copyright is held by the author. User is responsible for all copyright compliance.
"],"dc:subject":["Animals","Deposition","Breathing rate","Lung","Particle","Alveolar","Particle size","Biomedical Engineering and Bioengineering","Engineering"],"dc:title":["Pulmonary Particle Deposition in Relation to Age, Body Weight, and Species"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["M.S."]},"updated_at":"2026-07-24T02:02:53Z"}