title: Systematic interpolation method predicts protein chromatographic elution with salt gradients, pH gradients and combined salt/pH gradients.
abstract: A methodology is presented to predict protein elution behavior from an ion exchange column using both individual or combined pH and salt gradients based on high-throughput batch isotherm data. The buffer compositions are first optimized to generate linear pH gradients from pH 5.5 to 7 with defined concentrations of sodium chloride. Next, high-throughput batch isotherm data are collected for a monoclonal antibody on the cation exchange resin POROS XS over a range of protein concentrations, salt concentrations, and solution pH. Finally, a previously developed empirical interpolation (EI) method is extended to describe protein binding as a function of the protein and salt concentration and solution pH without using an explicit isotherm model. The interpolated isotherm data are then used with a lumped kinetic model to predict the protein elution behavior. Experimental results obtained for laboratory scale columns show excellent agreement with the predicted elution curves for both individual or combined pH and salt gradients at protein loads up to 45 mg/mL of column. Numerical studies show that the model predictions are robust as long as the isotherm data cover the range of mobile phase compositions where the protein actually elutes from the column.
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA, USA.
authors.forename: Arch
authors.initials: A
authors.lastname: Creasy
authors.affiliation: Biologics Process Development, Bristol-Myers Squibb, Hopewell, NJ, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Barker
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA, USA.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Carta
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D002021:Buffers; D002411:Cation Exchange Resins; D002852:Chromatography, Ion Exchange; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification; D018892:Proton-Motive Force / Q000502:physiology*; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D002021:Buffers; D002411:Cation Exchange Resins; D011506:Proteins; D012965:Sodium Chloride
keywords: Ion exchange chromatography; Linear pH gradients; Linear salt gradients; Predictive modeling; Proteins