DETERMINING SOLUTION CONCENTRATION WITHIN AEROSOL DROPLETS OUTPUT BY JET NEBULIZERS

The concentration of the solution within aerosol droplets exiting a je t nebulizer is determined by applying a control volume analysis to the air, water, and solute transport through the nebulizer. Measurements and calculations are made for the DeVilbiss Pulmo-Neb(R) disposable ne bulizer delivering two unit dose nebules of Ventolin(R) (2.5 ml, 1 mgm l(-1) salbutamol sulphate, 0.9% saline), and it is shown that the drop let solution concentration is closely approximated by the concentratio n of the solution remaining in the nebulizer's reservoir. By increasin g the time the aerosol droplets have before contacting the ambient env ironment, it is shown that the droplets are in equilibrium as they exi t the nebulizer, and therefore the concentration of the solution in th e droplets is independent of droplet size.