Improvement of the dispersibility of spray-dried budesonide powders using leucine in an ethanol–water cosolvent system

A new approach for enhancing the dispersibility of respirable powders containing poorly soluble pharmaceutical actives is demonstrated. Budesonide was spray-dried with leucine from an ethanol–water cosolvent feedstock. For near-azeotropic cosolvent ratios, leucine was enriched on the surface of the particles relative to the bulk composition, and the particles showed a low-density morphology. Partial encapsulation of budesonide was accomplished. The dispersibility and manufacturability of the powder were greatly improved relative to powders made from budesonide alone. Fine particle fractions from a passive dry powder inhaler exceeded 80%. The particle size was in a suitable range for respiratory drug delivery (mass mean aerodynamic diameter between 2 and 3 μm). These results demonstrate that leucine can be used in ethanol–water cosolvent systems to design respirable particles with high dispersibility and good manufacturability.