Method of analysis of recombinant acidic fibroblast growth factor by capillary electrophoresis

Fibroblast growth factors are a series of well characterized proteins that have intriguing pharmacological properties. Acidic fibroblast growth factor (aFGF) recently appeared in the literature for its efficacy in spinal cord repair in rats. The protein has proven difficult to analyze by capillary electrophoresis, because it has a tendency to unfold, aggregate and precipitate, especially near and above physiological temperatures. By studying the turbidity of capillary electrophoresis running buffers and aFGF at 50 degrees C, conditions were found that stabilize the aFGF solution, thereby allowing the capillary electrophoretic separation of the protein from its recombinant production impurities. The buffer system employs 50 mM phosphate buffer at pH 2.5 with 0.25% hydroxypropylmethylcellulose (HPMC) additive. This system provided the best efficiency and selectivity of the systems studied and was developed for pharmaceutical purity analysis.