Host cell protein (HCP) levels in drug products are critical to product quality since HCPs may pose a serious risk to patient safety. The challenge is to accurately quantify the complex mixture of HCP impurities, which vary in properties and abundance depending on the cell line, media, and process parameters. Generic immunoassays commonly used to measure HCP impurities are based on polyclonal antibodies raised against HCPs from non-transfected cell lines. How well a particular HCP assay recognizes all proteins depends…

Recombinant therapeutic proteins derived from E. coli require robust endotoxin removal, ideally performed using multiple process steps providing orthogonal and robust clearance. Typical recovery processes for E. coli expressed proteins consist of cell harvest by centrifugation, homogenization, collection of inclusion bodies by centrifugation, solubilization, refold, and clarification by depth filtration. Endotoxin clearance across the recovery operations is usually on the order of one log. Here, we demonstrate that endotoxin clearance can be enhanced to five logs by using 16% polyethylene…

Many biotechnological products are obtained by the help of native or recombinant microbial cells in fermentation processes. In order to get intracellular target molecules, like proteins or enzymes, the cells have to be destructed. This is done with cell rupture techniques (e.g. high-pressure homogenization) which generate a suspension containing cell debris and cell contents (proteins, DNA, mRNA, etc.). The first step in the following purification sequence is the removal of the cell debris. One possibility to do this is the…