Freeze-drying, also known as lyophilization, is a dehydration process in which a biological product or drug substance is first frozen and then subjected to reduced pressure to allow the ice to sublimate directly from solid to vapor, removing water without exposing the product to damaging high temperatures. It is widely used in biopharmaceutical manufacturing to improve the long-term stability, shelf life, and transportability of biologics, vaccines, viral vectors, and cell-based products that are sensitive to liquid-state degradation. The resulting lyophilized cake is typically reconstituted with sterile water or buffer prior to administration.
