Imaged Capillary Isoelectric Focusing analysis of charge heterogeneity of recombinant protein drugs

OBJECTIVE To analyze the charge heterogeneity of insulin degludec, sujinzumab, aflibercept and recombinant human growth hormone, and to provide a reliable and rapid analysis method for quality control of four recombinant protein drugs. METHODS The recombinant protein drugs to be tested were detected with imaged capillary isoelectric focusing(iCIEF). The samples were mixed with carrier amphoteric electrolyte in a certain proportion and detected under the focusing conditions of 1 500~3 000 V. RESULTS The isoelectric focal electrophoresis of insulin degludec showed a single peak with an average isoelectric point of 5.25. Four isoelectric points were detected of secukinumab, which 8.66 was the main peak, accounting for 67.78% of the total peak area. A total of 12 isoelectric points were detected for aflibercept fusion protein, and the peak area of 6 isoelectric points accounted for >10% of the total peak area, and the RSD was <0.10%. rhGH had 3 isoelectric points, of which 5.45 was the main peak, accounting for 87.60% of the total peak area. CONCLUSION iCIEF technique is useful to detect the charge heterogeneity of insulin degludec, sujinzumab, aflibercept and rhGH. It is of great significance for quality control for four protein drugs.