Category Archives: Aerosol Penetration

Canadian HealthCare Mall: Aerosol Delivery Systems

oropharyngeal spaceWith the usual jet velocity from MDI, aerosol particle impaction theory predicts that aerosol particles 10 |xm or greater should impact on a surface 10 cm away from the actuator orifice, the distance from the MDI orifice to the posterior pharyngeal wall. Therefore, if droplets completely vaporize to their final size before reaching the oropharyngeal surface, the impaction loss should be minimal. However, a number of studies have shown that a large fraction (50 to 65 percent) of MDI aerosols delivered from the MDI is lost in the mouth, suggesting that the droplets do not have a sufficiently long residence time for complete vaporization within the oropharyngeal space.

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