Lyophilization: From Space to Pharma

Lyophilization (also abbreviated as “lyo”), the technical word for freeze drying, is a slow, low temperature dehydration process via sublimation (transition of water directly from ice to vapor) that maintains the chemical structure of the original material.

Modern day, commercial freeze drying first gained notoriety during World War II for its use creating shelf stable blood plasma and penicillin that could be used in field hospitals. It wasn’t until the 1950s and 60s that the process started being used in the pharmaceutical and food-processing industries. Among the early applications in food were freezedried meals that could be rehydrated with water and served hot to astronauts in space.

Reconstitution

Freeze-dried products are powders in their final form. Before administering the drug to the patient, the powder is reconstituted by adding a specific volume of diluent (e.g. water, saline) to the vial and inverting it as pictured below. The powder dissolves and the solution is drawn into a syringe or IV bag to dose to the patient.

Basics of Freeze Drying

Q:  Why would you spend 48-96 hours drying the water off a product at low temperature and pressure? Wouldn’t it be way easier to simply boil the water off instead?

A:  While it would be much more cost-effective to remove the water by boiling, the high temperatures harm the active ingredient (the protein) and make the product ineffective. As for the time, the process needs to happen slowly in order to preserve the crystal structure so that the product can be rehydrated.

Benefits of Freeze Drying

Lyophilization Equipment

Equipment like the lyophilizers pictured below are used to perform the freeze-drying cycle depicted on the first slide. Vials are loaded onto shelves within the lyo chamber. First, the door is tightly sealed and the condenser is activated to cool the chamber. The equipment also has a strong pump that pulls air out of the chamber to create the vacuum. Lastly, during drying, the pump removes the vapor from the chamber and sends it to the condenser where it freezes.