Synthesizing industrial-scale quantities of biologicals, especially antibodies, can introduce unwanted changes into these fragile molecules. The main sources of damage result from sheer stress due to drag as the liquid flows through pipes and tubing, cavitation or vapor bubbles formation, and grinding, when solid parts of the instrumentation impinge against one another.
At the meeting, James Colandene, Ph.D., associate director of drug production at Human Genome Sciences, talked about physical and chemical stresses that occur during the filtration process. “We perform small-scale studies to determine Vmax and flow rate through a given surface area of the filter, taking into account a greater than 50% safety margin. These studies ensure maximum batch capacity and maximum fill speed.”
At filtration pressures of up to 50 psi, Dr. Colandene’s team observed no adverse effects on product quality. Given the wide range of parameters under which they can perform their operations, Dr. Colandene and his colleagues do not consider filtration pressure to be a key parameter. He did, however, warn against extensive foaming, which denatures biological molecules.
“In our small-scale characterizations we determined that the only significant physical stress on our product was cavitation, which can be avoided with the right equipment.”