Characterization of Chemical and Physical Modifications of Human Serum Albumin by Capillary Zone Electrophoresis.

Therapeutic proteins can easily undergo chemical or physical changes during their manufacturing, purification, and storage. These modifications might change or reduce their biological activity. Therefore, it is important to have analytical methodologies that are able to reliably detect, characterize, and quantify degradation products in formulations. Capillary Zone Electrophoresis (CZE) is very well suited for the analysis of proteins due to its relatively easiness of implementation, separation efficiency, and resolving power. We describe here a CZE method that allows separating more than nine forms in therapeutic albumin, including oxidized, glycated, and truncated forms. This method uses a polyethylene oxide (PEO) coating and a buffer composed of HEPES and SDS at physiological pH. The method is reproducible (RSD < 0.5 and 4 % for migration times and peak areas, respectively) and allows quantitation of albumin forms in pharmaceutical preparations.