title: Delivery of inhalation drugs to children for asthma and other respiratory diseases.
abstract: Infants and children constitute a patient group that has unique requirements in pulmonary drug delivery. Since their lungs develop continuously until they reach adulthood, the airways undergo changes in dimensions and number. Computational models have been devised on the growth dynamics of the airways during childhood, as well as the particle deposition mechanisms in these growing lungs. The models indicate that total aerosol deposition in the body decreases with age, while deposition in the lungs increases with age. This has been observed on paediatric subjects in in vivo studies. Issues unique to children in pulmonary drug delivery include their lower tidal volume, highly variable breathing patterns, air leaks from facemasks, and the off-label or unlicensed use of pharmaceutical products due to lack of clinical data for this age group. The aerosol devices used are essentially those developed for adult patients that have been adapted to paediatric use. Facemasks should be used with nebulisers and spacers for infants and young children. An idealised throat that mimic the average particle deposition in paediatric throats has been designed to obtain more clinically relevant aerosol dispersion data in vitro. More effort should be spent on studying particle deposition in the paediatric lung and developing products specific for this subpopulation to meet their needs.
authors.affiliation: Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region. Electronic address: pclkwok@hku.hk.
authors.forename: Philip Chi Lip
authors.initials: PC
authors.lastname: Kwok
authors.affiliation: Faculty of Pharmacy, The University of Sydney, Camperdown, New South Wales 2006, Australia.
authors.forename: Hak-Kim
authors.initials: HK
authors.lastname: Chan
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D002648:Child; D006801:Humans; D009330:Nebulizers and Vaporizers; D010372:Pediatrics; D012137:Respiratory System / Q000378:metabolism; D019141:Respiratory System Agents / Q000008:administration & dosage*; D012140:Respiratory Tract Diseases / Q000188:drug therapy* / Q000378:metabolism
chemical_list: D000336:Aerosols; D019141:Respiratory System Agents
keywords: Aerosol; Airways; Deposition; Dry powder inhaler; Lungs; Metered dose inhaler; Nebuliser; Paediatric; Spacer; Throat