title: Adsorption equilibrium and kinetics of monomer-dimer monoclonal antibody mixtures on a cation exchange resin.
abstract: Adsorption equilibrium and kinetics are determined for a monoclonal antibody (mAb) monomer and dimer species, individually and in mixtures, on a macroporous cation exchange resin both under the dilute limit of salt gradient elution chromatography and at high protein loads and low salt based on batch adsorption equilibrium and confocal laser scanning microscopy (CLSM) experiments. In the dilute limit and weak binding conditions, the dimer/monomer selectivity in 10mM phosphate at pH 7 varies between 8.7 and 2.3 decreasing with salt concentration in the range of 170-230mM NaCl. At high protein loads and strong binding conditions (0-60mM NaCl), the selectivity in the same buffer is near unity with no NaCl added, but increases gradually with salt concentration reaching high values between 2 and 15 with 60mM added NaCl. For these conditions, the two-component adsorption kinetics is controlled by pore diffusion and is predicted approximately by a dual shrinking core model using parameters based on single component equilibrium and kinetics measurements.
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA, United States.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Reck
authors.affiliation: MedImmune, Gaithersburg, MD, United States.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pabst
authors.affiliation: MedImmune, Gaithersburg, MD, United States.
authors.forename: Alan K
authors.initials: AK
authors.lastname: Hunter
authors.affiliation: MedImmune, Gaithersburg, MD, United States.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Chemical Engineering, University of Virginia, Charlottesville, VA, United States. Electronic address: gc@virginia.edu.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Carta
mesh_terms: D000327:Adsorption; D000911:Antibodies, Monoclonal / Q000737:chemistry; D002021:Buffers; D002411:Cation Exchange Resins / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical; D002852:Chromatography, Ion Exchange; D004058:Diffusion; D007700:Kinetics; D011108:Polymers / Q000737:chemistry; D011506:Proteins / Q000032:analysis
chemical_list: D000911:Antibodies, Monoclonal; D002021:Buffers; D002411:Cation Exchange Resins; D011108:Polymers; D011506:Proteins
keywords: Ion exchange; Monoclonal antibodies; Monomer/dimer separation; Protein adsorption equilibrium and kinetics