The Impact of Molecular Weight on Antibody Retention on a Commercial Protein A Membrane Adsorber

We previously demonstrated that Sartobind Rapid A Protein A membrane provides better resolution than traditional resin-based Protein A column. It seems that, in comparison to the Protein A column, Sartobind Rapid A membrane can better differentiate species with different molecular weights. In the current work, we further studied Sartobind Rapid A’s molecular weight-based separation potential by using it to process eight Fc-containing molecules with distinct molecular weights. The data suggested that, except for one molecule, there is a strong correlation between a molecule’s retention time and its molecular weight. In general, larger molecules tend to have longer retention. In relevance to its application in antibody purification, Sartobind Rapid A membrane’s molecular weight-based separation potential can be translated into strong byproduct-removing capabilities. As demonstrated in the present work, under optimized conditions, Sartobind Rapid A membrane effectively removed aggregates and half-antibody, two common byproducts that are remarkably different from the product in molecular weight. Thus, Sartobind Rapid A membrane’s unique separation capability makes it a more attractive tool than resin-based Protein A columns in antibody/Fc-fusion purification, especially for molecules with complex byproduct profiles.