Electrospray-differential mobility analysis as an orthogonal tool to size-exclusion chromatography for characterization of protein aggregates.

The biopharmaceutical industry characterizes and quantifies aggregation of protein therapeutics using multiple analytical techniques to cross-validate results. Here, we demonstrate the use of electrospray–differential mobility analysis (ES–DMA), a gas-phase and atmospheric pressure ion-mobility method for characterizing protein aggregates. Two immunoglobulin Gs are systematically heat treated to induce aggregation and characterized using size-exclusion chromatography (SEC) and ES–DMA. Although ES–DMA is a gas-phase characterization method, we find that aggregation kinetic rate constants determined by ES–DMA is in good agreement with those determined by SEC. ES–DMA appears to have a higher resolution and lower limit of detection as compared with SEC. Thus, ES–DMA can potentially become an important orthogonal tool for characterization of nascent protein aggregates in the biopharmaceutical industry. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 101:1985–1994, 2012