Location of Repository

The Interaction between the Oropharyngeal Geometry and Aerosols via Pressurised Metered Dose Inhalers

By T. Ehtezazi, I. Saleem, I. Shrubb, D. R. Allanson, I. D. Jenkinson and Christopher L. O'Callaghan


Purpose: This study investigated the effect of oropharyngeal geometry on inhaled aerosol characteristics via pressurised metered dose inhalers (pMDIs), both with or without spacers. \ud Methods: Seven adult oropharyngeal models with different centreline lengths, total volumes, and degrees of constriction were employed as induction ports for a laser diffraction particle size analyser and cascade impactor. Particle size change over time, mass median aerodynamic diameter (MMAD), average median volume diameter (DV50), inhaled doses, and oropharyngeal depositions (percentage of the nominal dose) for aerosols via suspension and ultrafine pMDIs with or without spacers at 30 l/min airflow were determined. \ud Results: Variations in oropharyngeal geometry caused significant variations in inhaled particle size distributions, doses, oropharyngeal drug depositions, and particle size change over time when pMDIs were used without spacers. However, inhaled aerosol characteristics had marginal variations for the ultrafine pMDI plus large volume spacer (MMAD range: 0.69–0.78 µm, DV50 range: 1.27–1.36 µm, inhaled dose range: 46.46–52.92%). It was found that the amounts of inhaled aerosol particles with aerodynamic size of less than 0.83 µm via pMDIs plus large volume spacer were slightly affected by the oropharyngeal geometry. \ud Conclusion: Inhaling ultrafine aerosols via spacers may reduce the effect of oropharyngeal geometry on inhaled aerosol properties

Topics: acute asthma exacerbations, inter-subject inhaled dose variability, oropharyngeal models, pressurised metered dose inhalers, ultrafine aerosols
Publisher: Springer Verlag
Year: 2009
DOI identifier: 10.1007/s11095-009-9994-z
OAI identifier: oai:lra.le.ac.uk:2381/8148

Suggested articles



  1. (1982). A Ho. Growth rate measurements and deposition modelling of hygroscopic aerosols in human tracheobronchial models. Ann Occup Hyg. doi
  2. (1995). Added external resistance reduces oropharyngeal deposition and increases lung deposition of aerosol particles in asthmatics. doi
  3. (1993). Behavior of hygroscopic pharmaceutical aerosols and the influence of hydrophobic additives.
  4. (2006). Degree of throat deposition can explain the variability in lung deposition of inhaled drugs. doi
  5. (2006). Effect of oropharyngeal length in drug lung delivery via suspension pressurized metered dose inhalers. doi
  6. (1997). Emergency treatment of acute asthma with albuterol metered-dose inhaler plus holding chamber: how often should treatments be administered? Chest doi
  7. (2003). Extra-fine particles improve lung delivery of inhaled steroids in infants: a study in an upper airway model. doi
  8. (2002). In vitro and in vivo dose delivery characteristics of large porous particles for inhalation. doi
  9. (2004). Intrasubject variability in lung dose in healthy volunteers using five conventional portable inhalers. doi
  10. Is the correct use of a dry powder inhaler (Turbohaler) age dependent? doi
  11. (2008). Lung deposition hydrofluoroalkane-philes. doi
  12. (2000). Lung deposition of inhaled drugs increases with age. doi
  13. (1996). Oropharyngeal deposition of 3.5 microns particles inhaled through an elongated mouthpiece. doi
  14. (2005). Regional lung deposition and bronchodilator response as a function of beta2-agonist particle size. doi
  15. (2008). Relative lung deposition of salbutamol following inhalation from a spacer and a Sidestream jet nebulizer following an acute exacerbation. doi
  16. (2002). Sorkness; Asthma Clinical Research Network of the National Heart Lung, and Blood Institute. Significant variability in response to inhaled corticosteroids for persistent asthma. doi
  17. (2007). Spacer inhalation technique and deposition of extrafine aerosol in asthmatic children. doi
  18. Spray pattern analysis for metered dose inhalers I: Orifice size, particle size, and droplet motion correlations. Drug Dev. doi
  19. (2007). Studies of the human oropharyngeal airspaces using magnetic resonance imaging IV--the oropharyngeal retention effect for four inhalation delivery systems. doi
  20. (2005). The Effect of Humidity on the Size of Particles Delivered from Metered-Dose Inhalers. doi
  21. (2005). The expanding role of aerosols in systemic drug delivery, gene therapy, and vaccination. doi
  22. (1636). The inhalation device influences lung deposition and bronchodilating effect of terbutaline. doi
  23. (1996). Tracheobronchial deposition and clearance in small airways in asthmatic subjects. doi
  24. (1998). Treatment of acute asthmatic exacerbations with an increased dose of inhaled steroid. doi
  25. (2000). Variability in lung deposition of inhaled drug, within and between asthmatic patients, with a pMDI and a dry powder inhaler, doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.