title: Comparison of in vitro deposition of pharmaceutical aerosols in an idealized child throat with in vivo deposition in the upper respiratory tract of children.
abstract: OBJECTIVE
  Deposition of drug emitted from two commercially available inhalers was measured in an in vitro child oral airway model and compared to existing in vivo data to examine the ability of the child model to replicate in vivo deposition.
  
  
  METHODS
  In vitro deposition of drug from a QVAR® pressurized metered dose inhaler (pMDI) and Pulmicort® Turbuhaler® dry powder inhaler (DPI) in an Idealized Child Throat (1) and downstream filter was measured using UV spectroscopy and simulated realistic breathing profiles. Potential effects of ambient relative humidity ranging from 10% to 90% on deposition were also considered.
  
  
  RESULTS
  In vitro QVAR pMDI deposition in the idealized mouth-throat at 50% RH (39.2 ± 2.3% of delivered dose) compared well (p>0.05) with in vivo extrathoracic deposition in asthmatic children age 8 to 14 (45.8 ± 12.3%). In vitro Turbuhaler DPI deposition in the idealized mouth-throat at 50% RH (69.0 ± 1.5%) matched in vivo extrathoracic deposition (p>0.05) in 6 to 16 year old children with cystic fibrosis (70.4 ± 21.2%). The effects of ambient humidity were found to be insignificant for Turbuhaler and minor for QVAR.
  
  
  CONCLUSIONS
  The Idealized Child Throat successfully mimics in vivo deposition data in school age children for the inhalers tested, and may provide a standard platform for optimizing pediatric treatment with inhaled pharmaceutical aerosols.
authors.affiliation: Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2G8.
authors.forename: Conor A
authors.initials: CA
authors.lastname: Ruzycki
authors.forename: Laleh
authors.initials: L
authors.lastname: Golshahi
authors.forename: Reinhard
authors.initials: R
authors.lastname: Vehring
authors.forename: Warren H
authors.initials: WH
authors.lastname: Finlay
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000493:pharmacokinetics*; D002648:Child; D004777:Environment; D006801:Humans; D006813:Humidity; D008953:Models, Anatomic; D009330:Nebulizers and Vaporizers; D010614:Pharynx / Q000033:anatomy & histology* / Q000378:metabolism*; D012137:Respiratory System / Q000378:metabolism*
chemical_list: D000336:Aerosols