Effect of electrostatic charge and size distributions on respirable aerosol deposition in lung model

Nebulizers, metered dose inhalers (MDIs), and dry powdered inhalers (DPIs) are frequently used to deliver drugs through inhalation drug delivery. These devices generate aerosol in the 0.5-5 /spl mu/m size range that deposits into the various regions of the lung. These inhaled particles may deposit in the various generations of the respiratory system by the complex action of the five deposition mechanisms: interception, impaction, gravitational settling, diffusion, and electrostatic forces. The last deposition mechanism is electrostatic force, which can be significantly important because the deposition of particle fraction in each generation is influenced by the electrostatic charge it carries. Particles of controlled electrostatic charge were generated and deposited in the various stages of the Anderson cascade impactor (ACI) and the effect of particle charge on their deposition in the various stages was studied. It was found that the aerosol with net neutral charge (0 /spl mu/C/g) deposited in the lower stage (fourth stage) of ACI, compared to particles with a net positive or negative charge of 3 /spl mu/C/g that deposited in the upper stage (second stage) of ACI.