(569l) Evaluation of the Flow Properties of Pollen Shape Hydroxyapatite Particles for Dry Powder Inhalation

The use of pollen shape (spiked sphere) particles for dry powder inhalation is studied. Pollen shape hydroxyapatite (HA) particles are synthesized to cover both size ranges of typical drug and carrier particles for pulmonary drug delivery. The HA particles produced have geometric diameter range from 5-50 µm and effective density range from 0.2-0.72 g/cm3. The flow properties of the powders are characterized by the Carr's compressibility index (CI). The aerodynamic properties of the particles have been studied in vitro by using an eight-staged Anderson Cascade Impactor with a Rotahaler®. HA powder samples of different sizes have been used as single formulation in the experiment. The HA particles are found to have lower CI values than commonly used lactose carrier particles with similar size range. The pollen shape particles also show high emitted dose and fine particle fraction and correlates well with the corresponding mean aerodynamic diameter.