OPTIMIZATION OF PREPARATIVE ION-EXCHANGE CHROMATOGRAPHY OF PROTEINS -LINEAR GRADIENT SEPARATIONS

In this study, the Steric Mass Action (SMA) model of ion exchange is e mployed in concert with appropriate mass balance equations to predict the separation performance of preparative ion-exchange chromatography. The model is able to accurately predict linear gradient separations o f the proteins alpha-chymotrypsinogen A, cytochrome c, and lysozyme un der overloaded conditions. The optimization behavior of preparative io n-exchange chromatography is examined under conditions of baseline res olution and induced sample displacement. This work demonstrates that a simple iterative procedure can be employed to establish optimal gradi ent conditions for preparative ion-exchange chromatography of proteins . The results also indicate that under appropriate conditions, sample displacement can be employed to dramatically improve the production ra te with minor losses in product yield or purity. Linear gradient separ ations with sample displacement are also less sensitive to the adsorpt ion properties of the feed stream than baseline resolved separations, resulting in simplified methods development.