Influence of Mouthpiece Geometry on the Aerosol Delivery Performance of a Dry Powder Inhaler
- 442 Downloads
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 wordscomputational 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.A. R. Clark. Medical aerosol inhalers: past, present, and future. Aerosol Sci. Technol. 22:374–391 (1995).Google Scholar
- 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
- 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
- 19.ANSYS CFX, 2003. http://www.ansys.com/cfx. (accessed 08/01/04).
- 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