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Spray pattern analysis for metered dose inhalers: effect of actuator design
Hugh Smyth1, Geoff Brace, Tony Barbour
1College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, USA. hsmyth@salud.unm.edu
Pharmaceutical Research
|June 20, 2006
Summary
Device design significantly impacts metered dose inhaler performance. Orifice length and sump depth, alongside orifice size, influence spray patterns and particle size for better aerosol delivery.
Area of Science:
- Pharmaceutical technology
- Aerosol science
- Biomedical engineering
Background:
- Metered dose inhalers (MDIs) are crucial for drug delivery.
- Understanding device factors is key to optimizing MDI performance.
- Spray plume characteristics directly affect therapeutic efficacy.
Purpose of the Study:
- To identify device factors influencing spray pattern and particle size.
- To enhance understanding of spray plume measurements in MDIs.
- To inform the rational design of MDIs.
Main Methods:
- Utilized a statistically designed experiment to test actuator features.
- Manufactured custom actuators with varying orifice diameter, expansion chamber depth, and orifice length.
- Analyzed spray patterns using laser light sheet illumination and particle size via laser diffraction.
Main Results:
- Spray patterns were significantly affected by orifice size, orifice length, and sump depth.
- Particle size analysis confirmed all tested actuator features influenced particle size.
- Actuator design parameters are critical determinants of aerosol characteristics.
Conclusions:
- MDI aerosol performance is strongly linked to sump depth and orifice length, in addition to orifice size.
- Rational MDI design requires consideration of these geometric variables.
- Optimizing MDIs involves balancing device geometry with formulation strategies.
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