(615d) Effect of Fine Particles in the Formulation with Pollen-Shape Drug Carriers for Dry Powder Inhalation

Design and development of effective and reliable drug formulations is one of the major objectives in pharmaceutical manufacturing. Dry powder formulation in inhalation drug delivery faces different challenges to attain their target. Different factor have been studied to improve the performance of the formulations, mainly the factors related to particle?particle interactions. These formulations generally consist of large carrier particles and small active pharmaceutical ingredients (API).

Pollen-shape drug carriers are found to have good flow properties and high drug loading capacities for dry powder inhalations (DPI). However, they may have drug detachment problem and cause a reduction in drug delivery efficiency. In this study, fine particles are used as spacers to reduce the attachment of drug particles to improve drug delivery efficiencies. Model pollen-shape carrier particles (Hydroxyapatite, HA) are blended with an active ingredient (Budesonide, Bd) and fine particles (Magnesium stearate, MgSt) in HA:Bd:MgSt weight ratio of 10:1:0.2, 10:1:1 and 10:1:2.5. The blends are characterized with scanning electron microscope (SEM), blend homogeneity and sieving test. Then the inhalation properties of the formulations are studied in an Anderson cascade impactor (ACI) using a Rotahaler®. The results are also compared with conventionally used lactose (LA) carrier particles using the same blending ratios. Emitted dose (ED) and fine particle fraction (FPF) is found to increase when the MgSt fraction is increased from 0.2 to 1 for both HA and lactose carriers. However, as the MgSt fraction is further increased to 2.5, a drop in ED and FPF is observed. It is possible that when the MgSt fraction is too high, it will occupy all the active sites on the carrier surfaces and reduce the drug loading capacity of the carriers. Nonetheless, a small amount of fine particle addition is proved to be beneficial in improving the deposition performance of active ingredients from the pollen-shape carrier particles.