Quality assurance of monoclonal antibody pharmaceuticals based on their charge variants using microchip isoelectric focusing method

•The imaged microchip isoelectric focusing (mIEF) was developed for the analysis of monoclonal antibody (mAb) pharmaceuticals.•mIEF technique makes it possible to assure the heterogeneities of mAb pharmaceuticals in more easy and rapid manner.•mIEF shows much higher performance in operations, and its resolving powers are comparable with those obtained by cIEF.

Monoclonal antibody (mAb) pharmaceuticals are much more complex than small-molecule drugs. Such complex characteristics raise challenging questions for regulatory evaluation. Although heterogeneity in mAbs based on their charge variants has been mainly evaluated using gel-based isoelectric focusing (IEF) method, recent development in capillary electrophoresis and microchip electrophoresis has made it possible to assure their heterogeneities in more easy and rapid manner. In the present paper, we customized the imaged microchip isoelectric focusing (mIEF) for the analysis of mAbs, and compared the customized version with the conventional capillary isoelectric focusing (cIEF) method, and found that mIEF has much higher performance in operations, and its resolving powers are comparable with those obtained by cIEF.