Effect of particle shape on dry particle inhalation: study of flowability, aerosolization, and deposition properties.

The shape effects of dry particles on flowability, aerosolization, and deposition properties in inhalation drug delivery are studied. The properties are compared with similar size range particles of different shapes such as sphere, needle, cube, plate, and pollen. Flowability of the particles is characterized by Carr's compressibility index and angle of slide (theta) method. The aerosolization and deposition properties of the particles are studied in vitro using an eight-stage Anderson cascade impactor with a Rotahaler. Pollen-shaped particles are found to exhibit better flowability, higher emitted dose, and higher fine particle fraction than particles of other shapes in similar size range. They showed minimum theta of 35 degrees and maximum emitted dose of 87% and fine particle fraction of 16%. The use of pollen-shaped particles can be a potential improvement in dry particle inhalation.