Particle sizing methods for the detection of protein aggregates in biopharmaceuticals

Protein aggregation is a common biological phenomenon which is responsible for degenerative diseases and is problematic in the pharmaceutical industry. According to the rules provided by regulatory agencies, industry is supposed to assess the product quality regarding the presence of subvisible particles. Also, they should evaluate the technologies that are used to measure these particles. Therefore, US FDA and industry have been looking for methods capable of accurately characterizing the protein products. Four sizing techniques reviewed here are good candidates to be used for characterization of protein and their aggregates: dynamic light scattering, size-exclusion chromatography, electron microscopy and Taylor dispersion analysis. The first three are more established techniques while the last one is a more recent and growing technique.