• Publication Date: 12/01/2020
  • Author(s):
    Mitchell, Jolyon P. Roberts, Daryl L.
  • Organization(s):
    Applied Particle Principles, LLC Jolyon Mitchell Inhaler Consulting Services, Inc.
  • Article Type: Technical Articles
  • Subjects: Instruments, Particle Characterization, Product Development/Formulation, Testing, Validation, and Regulatory Compliance
The authors conclude a three-part series describing a new approach to quality requirements for cascade impactors (CIs). Their thesis is that the inhaler testing community, both from the manufacturer and regulator perspectives, should insist that the CI quality specifications be both necessary and sufficient  for the testing of batches of drug product for release of that product to the public. Ideally, they hope such methodology would guide developers of new OIPs in making proposals for impactor quality specifications to regulators. In turn, regulators need to assure that specifications are both necessary and sufficient for batch release testing in quality control.

In Parts I and II of this series, we introduced the concept that the batch release criteria for OIPs can and should dictate the quality constraints on all cascade impactors (CIs) used for batch release testing. This logical proposition applies to the entire set of analytical equipment involved in the making and testing of a commercial drug product. However, the current approach to CI quality specifications requires only a verification of the diameter of nozzles of each stage along with a requirement that the flow rate during testing be known within ± 5% of a target value. Here, we ask two questions: Are these requirements necessary? And are these requirements sufficient? Our thesis is that the inhaler testing community, both from the manufacturer and regulator perspectives, should insist that the CI quality specifications be both necessary and sufficient for the testing of batches of drug product for release of that product to the public.

See Part I: A grassroots look
See Part II: The concept of “sufficient” as applied to impactor quality specifications

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