The thesis presented here is that questions about accuracy and uncertainty of cascade impactor results have not been articulated by the inhaler testing community and that, consequently, producers today hold their cascade impactors to quality criteria that may be neither necessary nor sufficient for a confident batch release decision.
This first article in a three-part series takes a “fundamental” or “grassroots” look at the question of how to create both necessary and sufficient quality requirements for cascade impactors that are used for batch release testing of a specific drug product. The thought process applies to devising meaningful impactor quality requirements when testing an existing drug product or when developing a new drug product, but focuses here on batch release testing of existing drug products.
See Part II: The concept of “sufficient” as applied to impactor quality specifications
See Part III: Implications of Type II error probability