Possibilities and advantages of additive manufacturing in dry powder formulations for inhalation

In dry powder formulations for inhalation, coarse carrier particles are often used to improve handling, dosing and dispersion of the active pharmaceutical ingredient (API). Carrier particles, mostly alpha-lactose monohydrate crystals, always show a certain size distribution and are never exactly uniform in their geometry. This might be one factor of the rather high invivo variability in fine particle dose from dry powder inhalers. To address the inhomogeneity of carrier particles, additive manufacturing has come to mind. The parametric design of the perfect carrier geometry could further improve the efficiency of dry powder formulations. In this study, a numerical simulation setup using the discrete element method as well as an experimental approach with 3D printed particles were used to determine the loading capacity of a model API onto two different carrier geometries. The difference between the two geometries was reduced solely to their surface's topology to assess the impact of that. The results indicate differences in the loading capacity for the two geometries, depending on the loading process. This study highlights the importance of the carrier geometry for the efficiency of dry powder formulations and thus, strengthens the idea of artificially designed and printed carrier particles.