title: Suitability of the upper airway models obtained from MRI studies in simulating drug lung deposition from inhalers.
abstract: OBJECTIVE
  In this study, the suitability of the upper airway models, obtained by applying a magnetic resonance imaging method, in simulating in vivo aerosol deposition data is determined.
  
  
  METHODS
  Depositions of salbutamol sulfate from two nebulizers in two models, one with constriction at the oropharynx (the constricted cast) and another model without that constriction (the wide cast), were determined.
  
  
  RESULTS
  For the Sidestream and Ventstream nebulizer, 76 +/- 3% (mean +/- standard deviation) and 81 +/- 2% of the emitted dose deposited in the constricted cast, whereas 51 +/- 2% and 49 +/- 3% of the emitted dose deposited in the wide cast, respectively. These values were in good agreement with in vivo data. Mostly, increasing nebulizer charge volume (by normal saline) from 2.5 ml to 5 ml increased significantly the lung dose. However, the lung doses from the Sidestream and Ventstream nebulizer with 2.5 ml charge volume via the wide cast were (1.37 +/- 0.06 and 1.38 +/- 0.05 mg) significantly larger than those for the constricted cast with 5 ml charge volume (0.87 +/- 0.15 and 0.86 +/- 0.21 mg, respectively) (p = 0.005).
  
  
  CONCLUSIONS
  The upper airway models closely simulated the in vivo deposition data. Optimizing the upper airway posture during inhalation via the nebulizers would be more efficient in increasing drug lung delivery than diluting their contents.
authors.affiliation: School of Pharmacy & Chemistry, Liverpool John Moores University, Liverpool, L3 3AF, UK. t.ehtezazi@livjm.ac.uk
authors.forename: T
authors.initials: T
authors.lastname: Ehtezazi
authors.forename: K W
authors.initials: KW
authors.lastname: Southern
authors.forename: D
authors.initials: D
authors.lastname: Allanson
authors.forename: I
authors.initials: I
authors.lastname: Jenkinson
authors.forename: C
authors.initials: C
authors.lastname: O'Callaghan
mesh_terms: D000420:Albuterol / Q000378:metabolism*; D006801:Humans; D007830:Larynx / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D036501:Metered Dose Inhalers; D008954:Models, Biological; D009330:Nebulizers and Vaporizers; D010614:Pharynx / Q000187:drug effects / Q000378:metabolism; D012137:Respiratory System / Q000187:drug effects / Q000378:metabolism*; D014132:Trachea / Q000187:drug effects / Q000378:metabolism
chemical_list: D000420:Albuterol