Trends on Analytical Characterization of Polysorbates and Their Degradation Products in Biopharmaceutical Formulations.

Among many other applications, polysorbates (PSs) are used as the most common surfactants in biopharmaceutical products in particular to protect proteins against interfacial stress. Structural heterogeneity, presence of degradants and other impurities, and tendency for degradation are interrelated features found in commercial PSs with a direct impact on their functional properties in biopharmaceutical products. These pose a challenge for the analytical characterization of PSs at different stages of product development. This review article focuses on methods and strategies reported in the recent years for the analytical characterization of PSs, their degradants and other impurities within neat PS (i.e., PS raw materials), diluted PS solutions, as well as in biopharmaceutical formulations. The use of versatile and complementary methods applied in a systematic approach is crucial to understand the impact of the concentration, composition, and degradation of PSs on the quality of biopharmaceutical products.