- Potency assays are essential analytical tools used to quantitatively measure the biological activity or functional capability of therapeutic products, including drugs, vaccines, and biologics.
- These assays play a critical role in drug development, manufacturing, and quality control by ensuring that each product delivers its intended therapeutic effect consistently, safely, and effectively. As a key quality attribute, potency directly reflects the strength of a product in producing its desired biological response.
- The core principle of a potency assay is to accurately represent a product’s mechanism of action: how it interacts with biological systems to achieve its therapeutic outcome.
- Because each therapeutic has a distinct mechanism of action, potency assays are highly product-specific and tailored to the drug’s biological function. Depending on the nature of the therapeutic, common types of potency assays include cell-based assays, receptor-binding assays, and enzyme inhibition assays.
- Cell-based assays evaluate the effect of a drug on living cells, measuring outcomes such as cell proliferation, apoptosis, cytokine release, or reporter gene expression.
- Receptor-binding assays assess a drug’s ability to bind to its specific cellular receptor, while enzyme inhibition assays evaluate its capacity to inhibit enzymatic activity.
- For biologics such as complex molecules derived from living organisms potency assays are particularly important. The biological activity of these products can be influenced by changes in manufacturing processes, formulation, or storage conditions. As a result, potency assays ensure that biologics maintain their intended activity and therapeutic effect throughout their lifecycle.
- Potency assays are used at multiple stages of a product’s development and manufacturing process.
- In lot release testing, they confirm that each production batch meets defined potency specifications.
- Stability testing uses potency assays to monitor biological activity over time, helping to determine the product’s shelf life and storage requirements.
- Comparability studies employ potency assays to assess the impact of manufacturing changes, ensuring product consistency and efficacy.
- Potency assays are integral to product characterization, providing detailed insights into the therapeutic’s biological activity and mechanism of action. For example, a potency assay designed for a monoclonal antibody might measure its ability to bind a target antigen or neutralize a pathogen. In the case of vaccines, potency assays may assess the immune response by measuring antibody titers or evaluating T-cell activation. The assays must be sensitive enough to detect subtle variations in biological activity and specific enough to distinguish the product from impurities or degradation products.
- Developing and validating a potency assay is a rigorous process that demands a deep understanding of the product’s mechanism of action. Assay development involves extensive optimization to ensure sensitivity, specificity, and reproducibility. Validation establishes critical performance characteristics, such as accuracy, precision, specificity, linearity, and robustness.
- These validated assays are typically performed under Good Manufacturing Practice (GMP) conditions, particularly when used for clinical trials or commercial manufacturing. Regulatory agencies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) require robust potency assays as part of the drug approval process, emphasizing their role in ensuring product quality, efficacy, and patient safety.
