Biopharmaceutical Characterization Techniques for Early Phase Development of Proteins
Characterization of biopharmaceuticals (proteins) during early development is done for several reasons. The most important reason is the need to have supporting data that demonstrates the comparability of material used throughout development. This is particularly important as the production process is optimized and small changes in the process may affect the structure of the product. Demonstration of comparability of proteins produced throughout product development is more complicated, due to the inherently heterogeneous nature of many biologicals. This may be the result of many possible causes, such as micro-heterogeneity of glycosylation, differential proteolytic processing during cellular production, or variations in post-translational modifications. The methods used in the early phase development of these proteins must provide a meaningful way to characterize the proteins produced. This article focuses on the many analytical methods available to characterize biotherapeutics, and discusses the nature and use of the information obtained. While no single article can fully discuss all the analytical methods available, this one covers the most commonly used spectrophotometric, chromatographic, and electrophoretic methods. Mass spectroscopy is discussed separately, even though it is frequently used as a hyphenated method, i.e., liquid chromatography -mass spectroscopy (LC-MS or LC-MS/MS).