Development and validation of an optimized and horizontal imaged capillary isoelectric focusing method for mAbs charge heterogeneity analysis

Charge heterogeneity is widely recognized as a Critical Quality Attribute for mAbs, and imaged capillary isoelectric focusing has become the high-throughput gold standard technique for both manufacturers and regulatory agencies. Considering the exponential spread of mAbs across a wide range of medical applications​, the current lack of analytical procedure harmonization renders the feasibility of charge variants evaluation increasingly challenging, particularly in the context of large-scale control activities by supervisory authorities. This issue is highlighted by relevant EDQM's activities within the Biological Standardisation Programme, as well as by a recent publication in Ph. Eur. of a special general chapter on mAbs charge variant analysis by (i)ciEF. To satisfactorily address this urgent demand, the present article describes the development and validation of a mAbs cross-applicable icIEF method fully aligned with the Ph. Eur. Concept. The optimized method provides a further improvement in terms of accuracy, precision and linearity with respect to the general method published in Ph. Eur., as validated according ICH Q2(R2) requirements and elevating the isoelectric point as a valuable identity parameter for mAbs. These results represent a significant advance in the standardization of icIEF technique, thereby streamlining its utilisation in routine quality control activities and reinforcing its relevance in the anti-counterfeiting domain.