In vitro study on the aerosol emitted from the DPI inhaler under two unsteady inhalation profiles

Results presented in the paper confirm its assumption to be true. Different inhalation curves were associated with substantially different inhaler performances. The quicker and more forceful curve II produced better dispersion. Aerosol dynamics is particularly susceptible to the strong aerodynamic effects of unsteadiness acquired from relatively small values of flow rates. The initial part of inspiration may contribute to achieving higher respirable dose content before the peak inspiratory flow is attained. Deaggregation upon impactions with chamber wall and subsequent collisions with grid are assumed to produce desired fine particle fraction. The paper elucidates the relevance of considering time-varying character of inspiration.