| In this thesis, a rig is developed that tests the tendency of a dry powder aerosol formulation to deagglomerate, and the forces that deagglomerate it. Turbulent deaggregation using a novel powder dispersion rig was tested using the powder from the Glaxo Ventodisks and compared to the Glaxo Diskhaler. These tests showed that although the turbulence from the rig was higher, the amount of deagglomerated powder from the Diskhaler was larger. From this information it seems that turbulence is not the only force in the inhaler that is deagglomerating the powder.; Mechanical impaction deaggregation was tested by the use of an obstructing mesh. The deaggregation found when using the mesh was similar to using no mesh, leading to the conclusion that the force caused by the impaction of the powder into the grid was not large enough to deagglomerate the powder.; Ventodisks were placed in a high humidity environment (100% R.H., 25°C) and then deagglomerated with the rig and the Diskhaler. The deagglomeration achieved with the rig and the inhaler were both reduced, showing that the rig can be used to test new powder formulations. |
