Abstract

The novel dry powder nebulizer works based on magnetic responsive elements that can rotate and collide with each other in chaotic motion. An external magnet below the dosing chamber generates powder disaggregation by the magnetic field that forces the collision of the magnetic responsive elements (MRE) during the inhalation maneuver. The following study is a step further in the optimization of the device by evaluating the use of an external single-phase coil that generates a magnetic field from the top of the dosing chamber. The goal is to promote the vertical motion of the MRE and force them to collide into the mesh. We hypothesized that increasing the collision of the MRE on the mesh can disaggregate the micronized drug and increase the efficiency. The study followed a DOE Box-Behnken approach to determine the effect of how frequently a magnetic field is applied and the strength of that magnetic field. Additionally, as a third variable, the size of the mesh used to prevent the large aggregates from coming out of the dosing chamber was evaluated as well. The results demonstrate a strong correlation from the model, being able to predict the most efficient combination of power, frequency of cycling, and mesh size that should be used to obtain a higher fine particle fraction (FPF) from this new version of the dry powder nebulizer. The results suggested that the testing limits of the DOE should be expanded. Overall, shorter magnetic field cycles seem to benefit the quality of the aerosol.