Optimization of monoclonal antibody (MAb) purification process

In recent years, monoclonal antibodies (mAbs) have become the most valuable products of the biopharmaceutical industry. Due to the patent expiration, biosimilar mAb production is encouraged in the world and in Turkey. However, biosimilar production is highly dependent on process variables. And also, downstream processes constitute 60 to 80% of production costs. Moreover, further purification steps should be adapted and optimized for each different product. The aim of this study is the optimization of the purification process of anti TNF-α monoclonal antibody (mAb) which is the member of therapeutic proteins. In this study, the Protein-A chromatography purification process which was carried out with Hi Trap mAb Select Sure Protein-A column was optimized. The effect of some parameters on the purification yield was determined. These parameters were determined as binding and elution buffer content, pH, incubation time and flow rate. For this purpose, buffer exchange was carried out with different binding buffers at different pH. After purification step, for small scale production, buffer exchange was found inefficient. In the new test plan, the supernatant and binding buffer were loaded onto the column with the 1:1 dilution ratio. After the determination of the appropriate binding buffer content, the experiments such as elution buffer type, flow rate and incubation time were performed without applying the buffer exchange process. At the end of the optimization study, 25 mM disodium hydrogen phosphate dihydrate, 300 mM sodium chloride at pH 7,5 was determined as an appropriate binding buffer content. And also, 10 mM glycine, 300 mM sodium chloride at pH 3,0 was determined as an appropriate elution buffer content. 1 mL/min of flow rate was determined to be suitable for mAb purification. Also there's no need to perform incubation time after loading supernatant which was diluted with binding buffer. At the end of the purification process that consisting of optimized working conditions, 53,4 % mAb recovery was achieved. After the optimization of the purification with Protein-A column, cation and anion exchange chromatographic methods were performed as further purification techniques. Dialysis procedure was applied between two chromatographic steps. Total process efficiency and impurities in purified samples were determined by performing ELISA. After affinity chromatography step, the most suitable process was determined as anion exchange chromatography.