Lyophilizer

This chapter discusses the purpose, principle of operation, specifications, and applications of lyophilizer. A lyophilizer is a device to freeze-dry a substance that means the removal of ice or other frozen solvents from a material by avoiding the liquid state through sublimation, i.e. direct conversion from ice to vapour. Freeze drying is the most gentle process for drying products. It is based on the physical phenomenon of sublimation, i.e. the direct conversion from solid to gaseous state directly without first going through a liquid (water) phase. The drying process of freeze drying is actually a two-part process consisting of primary drying and secondary drying. There are essentially three categories of freeze dryers: the manifold freeze dryer, the rotary freeze dryer, and the tray style freeze dryer. Lyophilization or freeze drying has numerous applications in pharmaceutical and diagnostic laboratories, especially for preservation of temperature sensitive products.