Application of microchip electrophoresis sodium dodecyl sulfate for the evaluation of change of degradation species of therapeutic antibodies in stability testing.

We evaluated the performance of a commercial microchip electrophoresis instrument (LabChip(®) GXII) for the evaluation of change of degradation species of therapeutic antibodies in stability testing. This system requires a sample volume of only 5 μg, and indicates fine resolution of size variant species such as light chain, heavy chain, non-glycosylated heavy chain and various degradation species. Precision and accuracy were high; the intermediate precision of 18 determinations was only 2.1% or less as RSD and recoveries ranged from 97.8 to 103.0% for major species as heavy chain, light chain and intact molecule of a therapeutic antibody. The applicability of this method was demonstrated by applying the method for the analysis of heat-degraded products of three pharmaceutical antibodies. Though some fragment peaks commonly appeared and increased according to temperature regardless of the source of preparations, one of them indicated specific peaks implying the cleavage of the peptide chain of the heavy chain. We also compared the performance of the method with those using conventional capillary-based SDS electrophoresis. Although the absolute purity values expressed as peak area % were different for the two methods, probably due to the difference in the detection methods, similar quality profiles were obtained within 40 s by microchip-based SDS electrophoresis. In addition, the degradation manner of three marketed antibodies depending on temperature was almost the same for the two methods. At the first stage in the development of manufacturing antibody pharmaceuticals, various factors including cell selection, cell cultivation, and formulation development should be evaluated using limited sample amounts. The stability testing using microchip-based electrophoresis seems suitable for these purposes.