Dissolution testing can be a way of discriminating between different pharmaceutical formulations. Even though dissolution testing of oral drugs is widespread and routinely used for both quality control and R&D to identify the influence of critical manufacturing variables on dissolution profiles and for in vitro-in vivo correlations, none of the standard USP apparatus are readily adapted for investigating inhaled products. Son et al. developed a potential standardized test method, the paddle over disk apparatus, which can be conjugated with the Next Generation Impactor (NGI) allowing for a dissolution profile assessment of a respirable fraction of the aerosol. The aim of this work was to investigate the discriminatory power of the newly developed paddle over disk apparatus when analysing dry powder formulations aimed for pulmonary delivery. The obtained results show that the apparatus can be successfully employed to discriminate between different formulations of dry powders, although further research is required to optimize the parameters used.