Effect of mixing of fine carrier particles on dry powder inhalation property of salbutamol sulfate (SS)

The most commonly used formulations for dry powder inhalations are binary o rdered mixes composed of micronized drugs and coarse carriers. An optimal d ry powder aerosol formulation should possess an optimal inhalation property and a good flow property. These characteristics are especially important f or a multidose dry powder inheler (DPI). In the present study, model powder blend were prepared consisting of synthesized sugar (different particle si zed isomalt; IM-PF, IM-FS, IM-F) as a carrier and micronized salbutamol sul fate (SS). These ordered mixtures were aerosolized by the multidose JAGO DP I (SkyePharma AG) and in vitro deposition properties (fine particle fractio n, FPF) were evaluated by a twin impinger (TI) at a flow rate of 60 l/min. The separation property between SS and carrier particles was investigated b y the centrifuge method and air jet sieve (AJS) method. It was found that F PF decreased with increasing carrier particle size. However, a large carrie r particle possesses a good flow property. Therefore, the effect of mixing of fine carrier particles (IM-PF) into the large carrier particles (IM-FS) on dry powder inhalation property was investigated. When the proportion of IM-PF (fine carrier) increase from 0% to 25% of the total carrier powder bl end, the FPF also increases from 16.7% to 38.9%. It is concluded that the e ffect of mixing of fine carrier particles might be a suitable method for im proving the dry powder inhalation properties.