Capillary electrophoretic separation of poly(ethylene glycol)-modified granulocyte-colony stimulating factor

Avs valuated the utility of capillary electrophoretic methods for analyzing poly(ethylene glycol)(PEG)-modified granulocyte-colony stimulating factor (G-CSF), a long-acting form of GCSFfor the treatment of cancer therapy-induced neutropenia. Low- and high-molecularweightPEG-G-CSF conjugates prepared with aldehyde-activated PEG-5K and PEG-20K wereseparated by high-performance size-exclusion chromatography (HP-SEC), capillary zone electrophoresis(CZE), and sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE). HPSECshowed low resolution for separating mono- and di-PEG-G-CSFs. SDS-CGE had higherresolution, but required a long analysis and had low peak efficiency. CZE could successfullyseparate both PEG-5K- and PEG-20K-conjugated G-CSFs with a running time of 20 min andhigh peak efficiency. In conclusion, CZE was better than SDS-CGE for separating PEG-G-CSFconjugates and will be useful for PEGylation studies, such as reaction monitoring for optimizationof the PEGylation reaction, and purity and stability tests of PEG-G-CSF.