With ever-increasing cell culture titers, the most common challenge for biopharmaceutical manufacturers is to continuously find new tools to debottleneck and, therefore, speed up the downstream process. Also, growing pressure from health authorities and the emergence of biosimilars is pushing the biopharmaceutical industry to lower the cost of production through greater productivity and/or increased yields.
The capture step in the downstream processing of antibodies is often the bottleneck and also the most expensive step due to the use of protein A media, an essential element in mAb purification.
Several generations of protein A media have been developed through the years in order to improve the mAb capture step. The improvements have typically addressed dynamic binding capacity (DBC), cleaning and sanitization resistance, and productivity with the same selectivity for the target molecule.
Agarose-based protein A media dominates the market. Although it has been improved over the years, agarose-based media continues to be limited in terms of operating at high velocities and pressures.
Novasep recently introduced AbSolute™ protein A media. AbSolute is a modified silica-based protein A media that maintains high DBC at higher velocities and provides improved productivity, thus reducing operating costs.
Dynamic Binding Capacity
AbSolute offers better DBC than third-generation agarose-based media. In fact, breakthrough with AbSolute occurs later than with agarose-based media. The breakthrough curve for AbSolute is steep—the result of uniform particles and homogenous pore size.
Breakthrough curves at 300 and 600 cm/h are shown in the Figure. The curves were generated with industrial mAb broth to determine DBC at 10% breakthrough.
Both types of media were packed in columns of 5 mm I.D. and 50 mm bed height; the bed volume was 0.98 mL. The concentration of IgG in industrial broth was 1.5 g/L. During the loading, fractions were collected and analyzed by HPLC to determine IgG content.
AbSolute provides much higher DBC at 10% breakthrough than the agarose-based protein A media. At 200, 300, and 600 cm/h, the DBC of AbSolute was, respectively, 38%, 76%, and 100% higher than the DBC of agarose-based protein A media. High dynamic capacity is reached at high linear velocities and low-residence time (Figure).