Utilising micron scale 3D printed morphologies for particle adhesion reduction

In the pharmaceutical industry, the ability to improve the understanding of the effect of surface roughness on interparticulate interactions is critical. Dry powder inhalers often possess poor efficiency, as the powder formulations are inherently adhesive and cohesive due to their size. The complex interplay of factors that affect interparticulate interactions, means it has been difficult to isolate the effect of surface morphology. Using two photon polymerisation, this study shows the fabrication of bespoke sub-micron geometric structures, with a consistent surface chemistry. These are used to investigate the effect of surface morphologies on particle adhesion by utilising AFM force-volume mapping, to model spheres and carrier particles. This demonstrates the significant effect varying surface morphology can have on particle-surface adhesion. This approach allows for the first time an in-depth examination of the local variation effect of surface features on particle adhesion and may facilitate the design and optimisation of powder processes.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).