Characterization of suspension-based metered dose inhaler formulations composed of spray-dried budesonide microcrystals dispersed in HFA-134a.

Purpose: To assess the physicochemical characteristics and aerosol properties of suspensions of lipid-coated budesonide microcrystals dispersed in HFA-134a.

Methods: Lipid-coated budesonide microcrystals were prepared by spray-drying an emulsion-based feedstock. Physicochemical characteristics of spray-dried particles were assessed by electron microscopy, laser diffraction, and differential scanning calorimetry.