Many drugs to treat respiratory disorders are formulated as dry powders and delivered directly into the lungs by inhalation. One of the challenges in inhalation therapy is guaranteeing the precise dose is delivered uniformly throughout the lungs. The drug particles may preferentially deposit in some locations in certain airways and not reach other locations or airways, especially in cases of obstructive disease. This project will explore ways to promote dispersal of drug particles after they have been deposited onto the liquid lining of airway surfaces. The strategy is to use surfactants, delivered as particles, with the drug particles to establish spatial variations of surface tension in the liquid along airway surfaces. Variations in surface tension induce flows called Marangoni flows that can entrain the drug particles and move them along airway surfaces. The project comprises a series of experiments to understand the dynamics of particle motion along the liquid surface and to determine how material properties influence the final extent of drug dispersal.
The project will explore factors that determine the extent of dispersal of inhaled drug particles, including properties of the surfactant, such as surface tension reduction, solubility and kinetics of dissolution as well as wettability of the surfactant particles and size of the particles. Similar properties for the drug particles will affect the motion of the particles entrained in the Marangoni flow. Collective effects related to how the deposition pattern of large numbers of co-mingled surfactant and drug model particles controls large scale powder dispersal will be determined, and a multi-variate analysis will be performed to determine the primary factors that control the extent of post-deposition dispersal. As an alternative to co-administering two kinds of particles, a composite particle that contains both the drug and a surfactant to induce the Marangoni flow will be examined.
