Abstract
The present paper demonstrates the effectiveness of pressure swing granulation (PSG) for dry powder inhalation (DPI) . The popular formulation powders blending fine model drug powder (d50=2μm) with coarse lactose particles were successfully agglomerated into spherical soft granules with PSG. The effects of both lactose particles size and concentration on the product properties and their dispersion characteristics were investigated. In order to enhance the ability of forming PSG granules without reducing the lactose particle size, lactose particles surface morphology was modified with a ball-mill. By this modification, lactose particles of about 8.8μm in mean diameter were successfully agglomerated without binders over the full range of mixing ratio with the model drug particles. For developing a new particle design with a novel formulation of DPI that is suitable especially for very dilute drug concentration, PSG was also applied to the coating of PSG granules from surface modified lactose particles with fine model drug powder.
The PSG granules size distribution and strength as well as the dispersibility of the drug particles for DPI were found to be satisfactory for the practical use. Since the excellent dispersion property of PSG granules for inhalation was obtained by containing the surface-modified lactose, PSG method opens up fresh possibilities for producing dry powder for inhalation.
