TAILORING DRY POWDER INHALER PERFORMANCE BY MODIFYING CARRIER SURFACE TOPOGRAPHY BY SPRAY DRYING

In order to provide adequate performance of dry powder inhalates with respect to dosing and fine particle fraction, interparticle adhesion between drug and carrier has to be well balanced. It has to be large enough to ensure attachment of the active ingredient during powder handling and dosing, but small enough to ensure detachment of the drug from the carrier on inhalation. In this study, interparticle interactions have been modified by targeting the surface topography of the carrier or rather the contact area between drug and carrier using spray drying. Because lactose is susceptible to spray drying, resulting in partial or full amorphicity, mannitol was used here. The spray drying outlet temperature turned out to be an appropriate parameter to affect surface topography, spray drying at low temperature leading to smooth particles, and spray drying at high temperature leading to rough particle surfaces. Dosing of the inhalate was found not to be affected by surface roughness of the carrier. However, the fine particle fraction decreases with increasing surface roughness. Consequently, the use of mannitol carrier particles exhibiting different surface topographies allows for modifying interparticle interactions, thereby providing an effective tool for tailoring the performance of an inluzlate.