High‐capacity multimodal anion‐exchange membranes for polishing of therapeutic proteins
Joshua Osuofa, Daniel Henn, Jinxiang Zhou, Anna Forsyth, Scott M. Husson
Abstract
Abstract This contribution reports on a study using Purexa™‐MQ multimodal anion‐exchange (AEX) membranes for protein polishing at elevated solution conductivities. Dynamic binding capacities (DBC 10 ) of bovine serum albumin (BSA), human immunoglobulins, and salmon sperm DNA (ss‐DNA) are reported for various salt types, salt concentrations, flowrates, and pH. Using 1 mg/ml BSA, DBC 10 values for Purexa™‐MQ were >90 mg/ml at conductivities up to 15 mS/cm. The membranes maintained a high, salt‐tolerant BSA DBC 10 of 89.8 ± 2.7 (SD) over the course of 100 bind‐elute cycles. Polishing studies with acidic and basic monoclonal antibodies at >2 kg/L loads showed that Purexa™‐MQ had higher clearance of host cell proteins and aggregate species at high conductivity (13 mS/cm) and in the presence of phosphate than other commercial AEX media. Purexa™‐MQ also had a high ss‐DNA DBC 10 of 50 mg/ml at conductivities up to 15 mS/cm, markedly outperforming other commercial products. In addition to the effectiveness of Purexa™‐MQ for protein polishing at elevated solution conductivities, its unusually high binding capacity for ss‐DNA indicates potential applications for plasmid DNA purification.