Selection of adsorbents for recombinant human erythropoietin purification

Abstract In this work, screening of adsorbents for the capture step of recombinant human erythropoietin (rhEPO) purification from human embryonic kidney cells supernatant was done. Anion-exchange, cation-exchange and multimodal adsorbents were first examined in batch equilibrium measurements at different pH and NaCl concentrations. Binding capacity of rhEPO and impurity proteins and rhEPO selectivity factor were determined. The best performance characteristics were exhibited by cation exchangers and multimodal adsorbents with cation-exchange ligands at pH 6–7. Binding capacity of impurity proteins was typically below 10 mg/g and the selectivity factor was close to 8. Preferential binding of rhEPO was confirmed in chromatographic column experiments for two selected adsorbents – Fractogel EMD SE HiCap and Capto MMC. Most impurity proteins were removed in the breakthrough during the loading phase. rhEPO was then eluted with the concentration factor of about 4–5.