The Delivery of active ingredients through the pulmonary pathway has received a considerable amount of attention in the past 10 years. The large amount of surface area and relatively quick uptake time make the lungs a good pathway for drug delivery. In recent years researchers have focused on delivering dry powder aerosol particles to the lungs. It is well understood that in this mode of drug delivery the particle size distribution of the active aerosol determines the success or failure of the drug delivery. This creates the need for tools to accurately and quickly test the particle size distribution being emitted from a dosation device. Currently the most commonly used device to try to determine aerosol size distribution is an Anderson Cascade Impactor.

Anderson Cascade Impactors is designed to impinge air onto a metal collection plate at increasing velocities as the air travels through the impactor. In the initial stage of the impactor, where the velocity is the lowest only larger particles with more thermal momentum impact on the collection plates. As the velocity of the air impinging on the surface increases smaller and smaller particles are collected. The plates can then be weighed for mass of impacted particle or sent for HPL analysis.

Inspite of these impactors serving a relatively important roll in dry powder delivery research little work has been done to evaluate the ability of these impactors to differentiate between different particle size distributions of similar size. The goal of this work is the creation of a model to predict the response of an Anderson Cascade Impactor to various dry powder particle size distribution.

In brief, the impactor is broken down into three area's of interest: 1. The entry where the Dry Powder is introduced referred to as the throat 2. the jet holes of each stage of the impactor where impaction is taking place and 3. the area around the edge of the impactor where the air is directed after impaction. Fluent is then used to simulate the flow of the in each area of interest as it would be during an impaction test. Finally, massed particles are tracked over the through the sections. When particles impact on the impaction surface they are counted as being stuck to the plate. After running many particles over all of the separated geometries a statistical model is generated for impaction in the real world ACI. The results of this model match well to data from the literature.