Antibody-based drugs represent a growing segment of the pharmaceutical industry and one of the most promising classes of therapeutic drugs. The demand for protein-based drugs is expected to grow steadily for the foreseeable future. However, production of monoclonal antibody (MAb)-based drugs remains very costly, and solutions to lower production costs are needed. Downstream purification steps are becoming a target for cost reduction. The use of ion exchange chromatography to directly capture MAbs from cell culture streams or as a polishing step after an affinity separation may be a way to reduce costs.
Ion exchange chromatography is an established step in the purification of MAbs following protein A capture. In this application note, we demonstrate the utility of the combination of a cation exchange step and an anion exchange step using UNOsphere Rapid S media and UNOsphere Q media, respectively. The mirrored binding characteristics of UNOsphere Rapid S and UNOsphere Q media provide complementary purification steps for the removal of host cell proteins (HCPs), fragmented or aggregated MAbs, leached protein A ligands, DNA, and virus particles (Figure 1).
In the separation method described in this note, a protein A support was used to isolate a MAb from a cell culture feed. A large proportion of HCPs and other contaminants did not bind to the protein A support. However, along with the intact MAb, variant forms were retained by the protein A support and found in the eluted fractions. We used UNOsphere Rapid S media to separate a deamidated degradation product from the intact MAb and used UNOsphere Q media to further reduce the remaining contaminants to acceptable levels.