Ion-pair reversed-phase high performance liquid chromatography method for the quantification of isoaspartic acid in a monoclonal antibody.

Isomerization of aspartic acid residues is one of the major causes of chemical degradation during the shelf life of biological pharmaceuticals. Monoclonal antibody biopharmaceuticals are typically stored at mildly acidic pH conditions, which can lead to the isomerization reaction. The mechanism of this non-enzymatic chemical reaction has been studied in great detail.