Connected flow-through chromatography processes as continuous downstream processing of proteins

Continuous manufacturing is expected to increase the productivity of protein drug production. However, it is not easy to build the continuous process especially for downstream processing as many unit operations (chromatography and membrane filtration) are involved. An operation method known as flow-through chromatography (FTC) is considered to be an efficient method for separating two components as the flow is continuous. In FTC, a target protein is eluted from the chromatography column without adsorption whereas contaminants are strongly bound. Since at least two different modes of chromatography are needed in order to remove contaminants, two FTC columns have to be connected in order to build the continuous process. This is not an easy task since the mobile phase properties (pH, salt, buffer ions) are different for the two columns. In this paper, we investigated how connected FTC columns can remove impurities efficiently from the cell culture broth containing monoclonal antibody. It was found that the sequence (activated carbon - anion exchange chromatography - cation exchange chromatography) is most efficient when the mobile phase pH and conductivity were properly chosen