Abstract
Antibody pharmaceuticals are becoming more and more prevalent due to their excellent effectiveness in clinical medications, and are expected to allow tailor‐made medical treatment for rheumatic diseases, immunosuppression in cardiac transplantation, and cancer. Antibody‐type pharmaceuticals of immunoglobulin G (IgG) commonly have N‐glycosylated carbohydrate chains attached to heavy chains. The carbohydrate chains play important roles in the effectiveness of antibodies. Therefore evaluation of a glycosylated species is important in the first step of quality control of antibody pharmaceuticals. In the present work, we examined capillary electrophoresis with a newly developed, chemically modified capillary, the inner surface of which is modified with carboxyl groups, for evaluation of IgG molecular species which have carbohydrate chains; tocilizumab was used as a model. The analytical system developed in the present study is useful for determining the content of non‐glycosylated peptides. In the analysis of tocilizumab, the ratio of non‐glycosylated peptide was estimated to be 1.23% with a relative standard deviation of 3.05%. The method affords high reproducibility with simple operation, and analysis can be completed within 6 min.