Isolation of monoclonal antibody from a Chinese hamster ovary supernatant. I: assessment of different separation concepts.

The performance of different non-affinity purification techniques commonly used for isolating CHO derived monoclonal antibodies has been investigated. Ion exchange chromatography (IEC), hydrophobic interaction chromatography (HIC), aqueous-two-phase extraction (ATPE) and their integration has been evaluated in terms of yield and purity of the product obtained. The integration of chromatographic techniques comprised two steps, in which the CHO supernatant was directly injected into the IEC column to capture monoclonal IgG1 and then the isolated fraction was processed using the HIC column. To reduce the influence of the feed media on retention of the target protein, the feed mixture was on-column diluted by use of the multi-injection technique. In the coupled process of extraction and chromatography the ATPE operation was used for the pre-purification of the supernatant as well as for buffer exchange. The bottom ATPE phase containing the target protein was further purified on the HIC column without feed dilution. The influence of operating conditions on the effectiveness of different purification processes has been evaluated. The best performance with respect to the product purity was achieved for the coupled process of IEC and HIC. The experimental data acquired were exploited in subsequent investigations for determining underlying kinetic parameters and for the process prediction and optimization.