In this second article, we continue defining the path to necessary and sufficient impactor quality specifications. We introduce the need for a careful definition of sufficiency. This definition, in turn, necessarily introduces the concept of acceptable risk. We have therefore set out the philosophy of establishing impactor quality specifications that are sufficient for meeting the batch release criteria for an OIP, although, in general terms, this same philosophy could potentially apply to the development of a control strategy for all new drug products based on measures of their critical quality attributes (CQAs). Ideally, the methodology will guide the developers of new OIPs so they can make sound proposals regarding impactor quality specifications to the appropriate regulators. In turn, regulators need to assure that the specifications for many instruments, of which cascade impactors are only one, are both necessary and sufficient for batch release testing in quality control.
See Part I: A grassroots look
See Part III: Implications of Type II error probability