Influence of surface characteristics of modified glass beads as model carriers in dry powder inhalers (DPIs) on the aerosolization performance

Abstract

The aim of this work is to investigate the effect of surface characteristics (surface roughness and specific surface area) of surface-modified glass beads as model carriers in dry powder inhalers (DPIs) on the aerosolization, and thus, the in vitro respirable fraction often referred to as fine particle fraction (FPF). By processing glass beads in a ball mill with different grinding materials (quartz and tungsten carbide) and varying grinding time (4 h and 8 h), and by plasma etching for 1 min, glass beads with different shades of surface roughness and increased surface area were prepared. Compared with untreated glass beads, the surface-modified rough glass beads show increased FPFs. The drug detachment from the modified glass beads is also more reproducible than from untreated glass beads indicated by lower standard deviations for the FPFs of the modified glass beads. Moreover, the FPF of the modified glass beads correlates with their surface characteristics. The higher the surface roughness and the higher the specific surface area of the glass beads the higher is the FPF. Thus, surface-modified glass beads make an ideal carrier for tailoring the performance of DPIs in the therapy of asthma and chronically obstructive pulmonary diseases.

• Fine particle fraction
• glass beads
• inhalation
• surface area
• surface roughness

Acknowledgements

The authors also would like to thank the research groups of Prof. Butt and Dr. Kappl, Max Plank Institute for Polymer Research Mainz, for the provision of the AFM equipment and assisting with the AFM measurements.

Declaration of interest

The authors report no declarations of interest.

The authors acknowledge the financial support of this research project by the German Research Foundation (DFG) for financial support within the priority program SPP 1486 “Particles in Contact”.