Powder specific active dispersion for generation of pharmaceutical aerosols
Crowder, T., & Hickey, A. (2006). Powder specific active dispersion for generation of pharmaceutical aerosols. International Journal of Pharmaceutics, 327(1-2), 65-72.
Dry powder inhalers are increasingly employed to deliver pharmaceutical aerosols. Efficient mechanisms of particle dispersion are central to their success in disease therapy. Creation of a powder aerosol requires the input of energy to transition the static powder bed into an entrained aerosol. The purpose of this study was to investigate the effects of input of vibrational energy into a powder on aerosol entrainment. Rotating drum characterization of powder flow was performed on lactose and maltodextrin excipients blended with albuterol sulfate. Dispersion experiments were conducted using an entrainment tube and a vibration actuator, vibrational energy input being derived from analysis of powder flow data from rotating drum analysis. Results of analysis of the rotating drum data showed that with increasing rotational speed powders reached a constant state of fluidization with a mean avalanche time dependent on the powder. Dispersion experiments demonstrated that the input of vibrational energy increased the dose emission while the input of frequencies specific to the powders improved the reproducibility. Frequency analysis of the vibration signals indicated that the reproducibility was determined by the bandwidth of the signal. This work suggests that an ability to tailor energy input to match the flow properties of a given powder formulation may significantly improve reproducibility of dose delivery from active dry powder inhalers