US Patent 7385040 Antibody purification

The present invention relates to a method of separating antibodies from contaminants in a solution, which method comprises contacting the solution with a chromatography resin comprised of a support to which multi-modal ligands have been immobilised, wherein a multi-modal ligand comprises at least one cation-exchanging group and at least one aromatic or heteroaromatic ring system. In one embodiment, the ring-forming atoms of the aromatic or hereoaromatic entity are selected among C, S or O, and the cation exchanging group is a weak cation exchanger. The present method may be used as a single step procedure or as a polishing step following a capture on a Protein A column.