Feasibility study of pollen-shape drug carriers in dry powder inhalation.

The feasibility of using pollen-shape carriers in dry powder inhalation is studied. Pollen-shape hydroxyapatite (HA) particles are synthesized with a geometric diameter range from 21.1 to 48.6 microm and effective density range from 0.21 to 0.41 g/cm(3). The flowability of the particles is characterized by the Carr's compressibility index (CI) and angle of slide (theta). The HA carriers are found to have better flowability than commonly used lactose (LA) carrier with similar size range. The HA carriers are also found to be capable of high drug attachment. The aerosolization and deposition properties of a model drug are compared using HA and LA as carriers. Results indicate that pollen-shape HA carriers have good potential to be used as drug carrier in dry powder inhalation. It can give higher drug emission and respirable fraction than traditional LA carriers.