CQAs

Critical quality attributes (CQAs) are the properties or characteristics of a drug product that must be within predefined limits to ensure the product’s quality, safety, and efficacy. CQAs can be physical, chemical, biological, or microbiological properties that have a direct impact on the intended use of the product.

CQAs are identified and managed through quality by design (QbD) practices. Key concepts include the quality target product profile (QTPP), risk assessment, and the development of a robust design space. Techniques such as design of experiments (DoE) and multivariate analysis support the characterization of how material attributes and process parameters influence CQAs. A control strategy is then established to monitor and maintain CQAs within specification throughout manufacturing.

Common examples of CQAs include potency or biological activity, chemical purity and impurity profiles, identity and integrity, dissolution or release characteristics, sterility and endotoxin levels, particle size distribution for parenterals, stability under storage conditions, and residual solvents. The specific CQAs vary by product type (small molecules, biologics, vaccines) and route of administration, but all are focused on ensuring product quality throughout shelf life.

CQAs are distinct from critical process parameters (CPPs), which are variables in the manufacturing process that can affect CQAs. Controls, in-process testing, and release specifications are designed to keep CQAs within acceptable ranges. Regulatory agencies expect CQAs to be defined, justified, and maintained across the product lifecycle, with documentation in regulatory submissions and post-approval changes.