Multiple functions of caprylic acid-induced impurity precipitation for process intensification in monoclonal antibody purification

Abstract

New emerging technologies delivering benefits in terms of process robustness and economy are an inevitable prerequisite for monoclonal antibody purification processes intensification. Caprylic acid was proven as an effective precipitating agent enabling efficient precipitaton of product- and process-related impurities while leaving the antibody in solution. This purification step at mild acidic pH was therefore introduced in generic antibody platform approaches after Protein A capture and evaluated for its impact regarding process robustness and antibody stability. Comparison of 13 different monoclonal antibodies showed significant differences in antibody recovery between 65–95% during caprylic acid-induced impurity precipitation. Among six compared physicochemical properties, isoelectric point of the antibody domains was figured out to correlate with yield. Antibodies with mild acidic pI of the light chain were significantly susceptible to caprylic acid-induced precipitation resulting in lower yields. Virus clearance studies revealed that caprylic acid provided complete virus inactivation of an enveloped virus. Multiple process relevant factors such as pH range, caprylic acid concentration and antibody stability were investigated in this study to enable an intensified purification process including caprylic acid precipitation for HCP removal of up to 2 log10 reduction values at mAb yields >90% while also contributing to the virus safety of the process.