High-performance liquid chromatography separation of monoclonal IgG2 isoforms on a column packed with nonporous particles

The IgG2 subclass of antibodies has emerged as an attractive therapeutic framework. However, a method for sufficiently separating the three IgG2 disulfide isoforms has not been developed. Here, we report a method for efficient separation of monoclonal IgG2 isoforms by means of high-performance liquid chromatography on a column packed with 2 μm nonporous ODS silica particles. Under optimized conditions, the isoforms were separated with high resolution because mass transfer resistance in the stationary phase was reduced by the use of the small, nonporous particles. The number of separated peaks was more than twice that reported previously. The run-to-run repeatability of the IgG2 separation pattern was satisfactory, and the day-to-day repeatability of the retention time of the main peak was good (relative standard deviation 0.9%). The separation pattern can be expected to be useful for monitoring quality consistency of therapeutic antibodies.