Pharmaceutical Research

, Volume 24, Issue 8, pp 1450–1456 | Cite as

Influence of Mouthpiece Geometry on the Aerosol Delivery Performance of a Dry Powder Inhaler

  • Matthew S. Coates
  • Hak-Kim Chan
  • David F. Fletcher
  • Herbert Chiou
Research Paper



To investigate the influence of mouthpiece geometry on the amount of throat deposition and device retention produced using a dry powder inhaler (Aerolizer®), along with the subsequent effect on the overall inhaler performance.

Materials and Methods

Computational Fluid Dynamics analysis of the flowfield generated in the Aerolizer® with various modified mouthpiece geometries (including cylindrical, conical and oval designs) was used in conjunction with experimental dispersions of mannitol powder using a multi-stage liquid impinger to determine how the overall inhaler performance varied as the mouthpiece geometry was modified.


Geometry of the inhaler mouthpiece had no effect on device retention or the inhaler dispersion performance. In contrast, the mouthpiece geometry strongly affected the amount of throat deposition by controlling the axial component of the exit air flow velocity. The radial motion of the emitted aerosol jet was found to have little effect on throat deposition in representative mouth–throat models. Despite the reduced throat deposition, there was no difference in the overall inhaler performance.


For cases where low throat deposition is a key design parameter, this study demonstrates that the amount of throat deposition can be reduced by making minor modifications to the inhaler mouthpiece design.

Key words

computational fluid dynamics (CFD) dry powder aerosols dry powder inhaler (DPI) mouthpiece geometry pulmonary drug delivery 



This work is funded by a grant from the Australian Research Council. Matthew S. Coates was a recipient of an International Postgraduate Research Scholarship. The authors would like to thank Plastiape S.p.A. for the modification and supply of the inhalers. The authors would also like to acknowledge that the source of the Alberta geometry used in this work was kindly provided from Dr. Finlay’s Aerosol Research Laboratory of Alberta at the University of Alberta, Canada.


  1. 1.
    A. R. Clark. Medical aerosol inhalers: past, present, and future. Aerosol Sci. Technol. 22:374–391 (1995).Google Scholar
  2. 2.
    H.-K. Chan. Inhalation drug delivery devices and emerging technologies. Expert Opin. Ther. Pat. 13:1333–1343 (2003).CrossRefGoogle Scholar
  3. 3.
    C. A. Dunbar, A. J. Hickey, and P. Holzner. Dispersion and characterization of pharmaceutical dry powder aerosols. KONA 16:7–44 (1998).Google Scholar
  4. 4.
    D. Prime, P. J. Atkins, A. Slater, and B. Sumby. Review of dry powder inhalers. Adv. Drug Deliv. Rev. 26:51–58 (1997).CrossRefPubMedGoogle Scholar
  5. 5.
    A. I. Bot, T. E. Tarara, D. J. Smith, S. R. Bot, C. M. Woods, and J. G. Weers. Novel lipid-based hollow-porous microparticles as platform for immunoglobin delivery to the respiratory tract. Pharm. Res. 17:275–283 (2000).PubMedCrossRefGoogle Scholar
  6. 6.
    N. Y. K. Chew and H.-K. Chan. Use of solid corrugated particles to enhance powder aerosol performance. Pharm. Res. 18:1570–1577 (2001).PubMedCrossRefGoogle Scholar
  7. 7.
    D. A. Edwards, J. Hanes, G. Caponetti, J. Hrkach, A. Ben-Jebria, M. L. Eskew, J. Mintzes, D. Deaver, N. Lotan, and R. Langer. Large porous particles for pulmonary drug delivery. Science 276:1868–1871 (1997).PubMedCrossRefGoogle Scholar
  8. 8.
    D. L. French, D. A. Edwards, and R. W. Niven. The influence of formulation on emission, deaggregation and deposition of dry powders for inhalation. J. Aerosol Sci. 27:769–783 (1996).CrossRefGoogle Scholar
  9. 9.
    N. Y. K. Chew and H.-K. Chan. Influence of particle size, air flow, and inhaler device on the dispersion of mannitol powders. Pharm. Res. 16:1098–1103 (1999).PubMedCrossRefGoogle Scholar
  10. 10.
    M. Hindle and P. R. Byron. Dose emissions from marketed dry powder inhalers. Int. J. Pharm. 116:169–177 (1995).CrossRefGoogle Scholar
  11. 11.
    H. Steckel and B. W. Müller. In vitro evaluation of dry powder inhalers I: drug deposition of commonly used devices. Int. J. Pharm. 154:19–29 (1997).CrossRefGoogle Scholar
  12. 12.
    L. Borgström, L. Asking, B. Olsson, and L. Thorsson. Throat retention can explain the variability in lung deposition. J. Aerosol Med. 18:99 (2005).CrossRefGoogle Scholar
  13. 13.
    W. H. DeHaan and W. H. Finlay. Predicting extrathoracic deposition from dry powder inhalers. J. Aerosol Sci. 35:309–331 (2004).CrossRefGoogle Scholar
  14. 14.
    B. Grgic, W. H. Finlay, P. K. P. Burnell, and A. F. Heenen. In vitro intersubject and intrasubject deposition measurements in realistic mouth–throat geometries. J. Aerosol Sci. 35:1025–1040 (2004).CrossRefGoogle Scholar
  15. 15.
    W. Stahlhofen, G. Rudolf, and A. C. James. Intercomparison of experimental regional aerosol deposition data. J. Aerosol Med. 2:285–308 (1989).Google Scholar
  16. 16.
    M. S. Coates, D. F. Fletcher, H.-K. Chan, and J. A. Raper. Effect of design on the performance of a dry powder inhaler using computational fluid dynamics. Part 1: grid structure and mouthpiece length. J. Pharm. Sci. 93:2863–2876 (2004).PubMedCrossRefGoogle Scholar
  17. 17.
    B. Grgic, W. H. Finlay, and A. F. Heenen. Regional aerosol deposition and measurements in an idealized mouth and throat. J. Aerosol Sci. 35:21–32 (2004).CrossRefGoogle Scholar
  18. 18.
    F. R. Menter. Two-equation eddy-viscosity models for engineering applications. AIAA J. 32:269–289 (1994).CrossRefGoogle Scholar
  19. 19.
    ANSYS CFX, 2003. (accessed 08/01/04).
  20. 20.
    M. S. Coates, H.-K. Chan, D. F. Fletcher, and J. A. Raper. The role of capsule on the performance of a dry powder inhaler using computational and experimental analyses. Pharm. Res. 22:923–932 (2005).PubMedCrossRefGoogle Scholar
  21. 21.
    M. S. Coates, H.-K. Chan, D. F. Fletcher, and J. A. Raper. Influence of air flow on the performance of a dry powder inhaler using computational and experimental analyses. Pharm. Res. 22:1445–1453 (2005).PubMedCrossRefGoogle Scholar
  22. 22.
    P. G. Stecher, M. Windholz, and D. S. Leahy. The Merck Index: An encyclopedia of chemicals and drugs. 8th Edition, Merck & Co., Inc., Rahway, 1968.Google Scholar
  23. 23.
    Y. Zhang, W. H. Finlay, and E. A. Matida. Particle deposition measurements and numerical simulation in a highly idealized mouth–throat. J. Aerosol Sci. 35:789–803 (2004).CrossRefGoogle Scholar
  24. 24.
    A. F. Heenen, W. H. Finlay, B. Grgic, A. Pollard, and P. K. P. Burnell. An investigation of the relationship between the flow field and regional deposition in realistic extra-thoracic airways. J. Aerosol Sci. 35:1013–1023 (2004).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Matthew S. Coates
    • 1
    • 2
    • 3
  • Hak-Kim Chan
    • 2
  • David F. Fletcher
    • 1
  • Herbert Chiou
    • 2
  1. 1.School of Chemical and Biomolecular EngineeringThe University of SydneySydneyAustralia
  2. 2.Faculty of PharmacyThe University of SydneySydneyAustralia
  3. 3.Pfizer Global R&D, Inhalation and Device Centre of Emphasis, Cambridge Research CentreCambridgeUK

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