By Aryo Nikopour, Senior Vice President, Scientific & Technical Services, Nitto Avecia Pharma Services and Ming Li, Ph.D., Principle Scientist and Team Lead in Biopharmaceutical Development, Nitto Avecia Pharma Services
Unlike small molecule therapeutics, which are chemically synthesized, stable, and easily characterized, the biotherapeutics must be produced in in a living cell and present a number of challenges. Biotherapeutics are high molecular weight products with complex secondary and tertiary structure and post-translational modifications. All of which are critical to the molecule’s function and desired therapeutic effect.
Following the ICH Q6B guideline, when extensive physico-chemical information is insufficient to confirm the higher order structure for these complex molecules, the biological activity needs to be determined. Biological activity is measured by potency assays.
According to 21 CFR 600.3(s), potency is defined as the specific ability or capacity of the product to affect a given result. Described in 21 CFR 610.10, potency tests are in vitro or in vivo tests specifically designed for each product to indicate its potency. Typical potency assays include the in vivo animal model study and in vitro cell-based assays, as well as chemical assays such as ligand binding or enzymatic reactions.
Will it be animal models, cells, or chemical assays? The decision can make or break product success.