Protein PEGylation is a great tool to improve the delivery of therapeutic proteins, but it adds a level of complexity to the product. As well as the characterisation of individual components (PEG and protein), the conjugate also has to be thoroughly characterised.

In addition to all the analytical tests proposed for proteins, Quality Assistance has developed specific methods for the analysis of PEGylated proteins using state-of-the-art analytical techniques, such as the determination of molecular mass distribution and PEG-to-protein ratio (MALDI-TOF and SEC-UV/RI/MALLS), the determination of conjugation sites by peptide mapping (UPLC-UV/MS) and the determination of free PEG (HPLC/CAD).