Lyophilization/freeze drying is a method of extracting the water from Biological samples, foods and other products so that foods or products remain stable and are easier to store and preserved at room temperature. Biological materials should be dried to stabilize them for storage, preservation and shipping. In many cases this drying can cause damage and some loss of cellular or protein activity. Lyophilization significantly reduces damage to biological samples.
Lyophilized/freeze dried products retain their original properties. By adding water or other solvents they can be reconstituted easily and very quickly to a usable solution. For example the Proteins and many other products are presented as a freeze-dried powder in vials for reconstitution by the administering doctor or pharmacy.
Commonly, water is used as solvent, but in some pharmaceutical applications alcohol is used to dissolve or disperse the product. The freeze dryer itself is a sterile environment, protected by air-sterilizing vent filters.Vent filters also protect the exhaust, and prevent droplets or particles of active ingredients from being carried into the environment.
There is a wide range of substances for which freeze drying/Lyophilization is used as conservation/preservation method without changing their composition. In the aseptic pharmaceutical and biotechnology production, freeze drying/Lyophilization are often applied to the following products:
- antibiotics,
- bacteria,
- vaccines,
- hormones,
- vitamins, enzymes, and peptides,
- liposome and collagen,
- plants and liver extracts,
- radio-immuno essays,
- Blood plasma, plasma fractions, and antibodies.
Process of Lyophilization/freeze drying is recommended for the products whose composition changes on the preservation such as proteins, but in the process of Lyophilization, there is no change in the composition of any substance. Some of applications of this process are;
- This process provides an efficient technique for preservation of temperature sensitive products, mainly those of biological origin such as proteins, enzymes, blood plasma, vaccines, etc.
- Lyophilization helps in achieving the chemical balance, such as for biological reagents.
- Lyophilization is very efficient for the packaging of constituents that cannot be mixed in the liquid state.
- It helps in improving the storage life and improved marketing of the end product.
It helps in resolving certain filling problems. It may be difficult, for instance, to divide several milligrams of powder into precise vial dosages, due to the difficulty of measuring tiny amounts, homogeneity, granulation, static electricity etc. The distribution of the product from the liquid state eliminates such production problems.