Aggregation of recombinant human interferon alpha 2b in solution: Technical note

Sodium phosphate buffer increased the aggregation of rhIFN-α2b in the range of 1.55 to 1.810³ day⁻¹, as determined by SDS/PAGE under reduced and nonreduced conditions. In contrast, sodium citrate buffer decreased the aggregation rate of this cytokine, as compared with those samples in sodium phosphate buffer. Results from sodium citrate-phosphate buffer were very similar to those obtained with sodium citrate solutions. On the other hand, EDTA Na₂×2H₂O reduced the aggregation rate of rhIFN-α2b, showing an aggregation kinetic constant in the range of 0.52 to 0.75×10³ day⁻¹. Polysorbates 20 and 80 were less effective than the chelating agent in preventing this degradation pathway.