MAb Quantitation: Protein A HPLC vs. Protein A Bio-Layer Interferometry

Rapid, accurate and cost-effective quantitation of monoclonal antibodies (MAbs) is essential for bioprocessing. High Pressure Liquid Chromatography (HPLC) and the Octet® are some of the commonly used techniques for MAbs titer determination. To ensure MAbs purification column efficiency, the dynamic binding capacity (DBC) of Protein A for Mab can be determined by loading feedstock onto the column until binding sites for the MAb become saturated and MAb begins to break through.

An assessment of the relative merits of Protein A (HPLC) and the Sartorius Octet® R8 System to determine MAb concentration in a complex feedstock was performed using MAbs breakthrough as the analyte while monitoring method accuracy, precision, dynamic range, LoQ and cost per sample. The evaluation found that the Sartorius Octet® R8 system can be used to accurately quantitate 5%, 10% and 20% MAb breakthrough values in the presence of contaminant host cell proteins. Compared to HPLC analysis, the Octet® system had a slightly larger dynamic range and performed best at low concentrations with an almost 30-fold lower LoQ. The Octet® was further shown to provide a fast, accurate and economical means of quantifying MAbs, and decreases process development plate of samples.