Non-size-based membrane chromatographic separation and analysis of monoclonal antibody aggregates

Humanized monoclonal antibody produced by mammalian cell culture may contain significant amounts of antibody dimers and smaller amounts of higher order aggregates. These are undesirable in therapeutic formulations, and their content should be lower than specific allowable limits. Quantitative analysis of aggregate content is usually carried out by size exclusion chromatography (SEC), which is slow and often gives poorly resolved peaks. We describe a novel hydrophobic interaction membrane chromatography-based technique for rapid, non-size-based separation and analysis of the aggregate content in monoclonal antibody samples. The typical sample analysis time using this technique is less than 3 min, this being significantly faster than SEC. The technique gives excellent resolution of the antibody, its dimer, and higher order aggregates and could potentially be scaled up for large-scale manufacture of aggregate-free monoclonal antibody. This work also clearly shows that monoclonal antibody aggregates are more hydrophobic than the monomer form, a fact that could have significant theoretical and practical implications.