Modelling oligomer formation in chromatographic separations

Oligomer forms of proteins are formed by self and cross association or complex formation with ligands. Modelling studies using an ion-exchange adsorbent have demonstrated that the formation of an oligomer form of a target protein can improve a chromatographic separation because the oligomer form displaces the impurities. The results of the investigation show that the process is very robust, that the purity, the yield, and the productivity increase with increasing load and increasing salt concentration in the eluant. An impurity level less than 1 ppm is easy to achieve having a yield of 98%. A universal model for the adsorption equilibria of mono and oligomer forms of proteins on ion-exchange, hydrophobic, and bimodal adsorbents has been developed.