Figure 4. . Dynamic behavior of pharmaceutical aerosol prior to, and during, inhalation.

(A) A simulation of the time-dependence of the size of particles of varying composition during condensation following a step change in relative humidity. (B) A comparison of the kinetics of particle size change during initial equilibration of an aqueous sodium chloride solution droplet following injection into a gas phase of lower RH than the starting water activity in the droplet, followed by condensation of water once the relative humidity is increased. The measurements were made with an EDB detailed in our previous work [10,34]. The model parameterization includes a quasi-steady analytical treatment of the coupling of heat and mass transport during water evaporation or condensation [34,39,41].

EDB: Electrodynamic balance; RH: Relative humidity.