Freeze Drying Is the Removal of Ice or other Frozen Solvents

Freeze Drying Is the Removal of Ice or other Frozen Solvents


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.

Sublimation in the freeze drying process can be described simply as:

FREEZE - The product is completely frozen, usually in a vial, flask or tray.

VACUUM - The product is then placed under a deep vacuum, well below the triple point of water.

DRY – Heat energy is then added to the product causing the ice to sublime.

The steps required to lyophilize a product in a batch process can be summarized as follows:

Pretreatment / Formulation

Loading / Container (Bulk, Flask, Vials)

Freezing (Thermal Treatment) at atmospheric pressure

Primary Drying (Sublimation) under vacuum

Secondary Drying (Desorption) under vacuum

Backfill Stoppering (for product in vials) under partial vacuum

Removal of Dried Product from Pre Processing Equipment

In addition to providing an extended shelf-life, successful freeze-drying should yield a product that has a short reconstitution time with acceptable potency levels. The process should be repeatable with well defined temperature, pressure and time parameters for each step. Visual and functional characteristics of the dried product are also important for many applications. More information about Pre Processing Equipment , please click gf-machine or