Improved antibody aggregate removal by hydroxyapatite chromatography in the presence of polyethylene glycol

This paper reports a method for improving the effectiveness of aggregate removal from monoclonal antibodies by the use of hydroxyapatite (HA) in the presence of polyethylene glycol (PEG). PEG preferentially enhances aggregate retention, thereby increasing the degree of separation between aggregated and non-aggregated antibodies. PEG has a similar effect on ion exchangers but only half the enhancement observed with HA. The HA method is suitable for preparation of aggregate-free IgG and IgM monoclonal antibodies for research, diagnostic, or therapeutic applications.