Quantitative analysis and design of a spray aerosol inhaler. Part 1: effects of dilution air inlets and flow paths.
BACKGROUND
The objective of this study was to evaluate the effects of modifying inhaler design variables on aerosol drug deposition within the mouthpiece for a representative spray system using a quantitative analysis and design approach.


METHODS
Capillary aerosol generation (CAG) was selected as a model spray aerosol system in conjunction with four prototype inhaler body and mouthpiece combinations. In vitro experiments were used to determine drug deposition in the mouthpiece and induction port. Validated computational fluid dynamics (CFD) simulations were implemented to establish relationships between design variables, transport characteristics, and aerosol drug deposition.


RESULTS
Results of this study indicated that both the size of the upstream dilution air inlets and the flow pathway configuration near the spray nozzle significantly influenced aerosol transport and deposition. CFD results showed that the primary transport characteristics associated with drug deposition were turbulence intensity and the effective diameter of the mouthpiece. Strong quantitative correlations were developed between the identified transport characteristics and mouthpiece drug deposition.


CONCLUSIONS
Based on quantitative analysis and design, turbulence intensity and effective mouthpiece diameter were identified as key transport characteristics within the design space that directly influenced aerosol deposition and may be used to predict and optimize drug delivery to the patient.
Longest
P Worth
PW
Department of Mechanical Engineering, Virginia Commonwealth University, Richmond, Virginia., Department of Pharmaceutics, Virginia Commonwealth University, Richmond, Virginia. pwlongest@vcu.edu
Hindle
Michael
M
D000336:Aerosols; D004867:Equipment Design; D009330:Nebulizers and Vaporizers
D000336:Aerosols