Basic Principles Of Freeze-Drying

By John Barley, Portfolio Manager, SP VirTis, SP Industries, Inc.

Freeze-drying is the removal of ice or other frozen solvents from a material through the process of sublimation and the removal of bound water molecules through the process of desorption.

Lyophilization and freeze-drying are terms that are used interchangeably depending on the industry and location where the drying is taking place. Controlled freeze-drying keeps the product temperature low enough during the process to avoid changes in the dried product appearance and characteristics. It is an excellent method for preserving a wide variety of heatsensitive materials such as proteins, microbes, pharmaceuticals, tissues & plasma.

In this paper we provide a lyophilization process overview, dive deeper into the subject of freeze-drying including the equipment and recipe, and review drying pressure, temperatures, cycle optimization, scale-up considerations and storage of the dried product.