what is Freeze drying?

　Freeze drying, also known as lyophilization. It is a low temperature dehydration process which involves freezing the product, lowering pressure, then removing the ice by sublimation. The freeze-dried products are easy to store for a long time, and can be restored to the state before lyophilization and maintain the original characteristics after adding water. The original shape of the product is maintained and quality of the rehydrated product is excellent. Primary applications of freeze drying include biological (e.g. bacteria and yeasts), biomedical (e.g. surgical transplants), and food processing (e.g. fruits,vegetable,meat,etc.)
　　Freeze drying of drugs: 1. The medicine is dispensed before freezing, and the dosage is accurate. 2. Dry at low temperature to retain the heat sensitive substance in the dried drug. 3. Drying under low pressure, the dried drugs are not easy to oxidize and deteriorate, and at the same time can sterilize or inhibit the vitality of certain bacteria due to lack of oxygen. 4. The dried drug can form a "skeleton" when frozen, and can maintain its original shape after drying, forming a porous structure and the color is basically unchanged. 5, Good rehydration, freeze-dried drugs can quickly absorb water to reduce the state before lyophilization. 6. Dehydrated thoroughly, suitable for long-distance transportation and long-term storage.
　　Lyophilizer is also called freeze dryer. Lyophilizer is the equipment for dehydration. Originated in the 19th century, lyophilizer made considerable progress in the last 20 years. Nowadays lyophilizer is widely used in medicine, biological products, food, blood products, active substances field.
　　Working principle of lyophilizer:
　　Under vacuum condition, material is freeze dried via principle of sublimation. The moisture in the pre-frozen material is directly sublimed from solid state (ice) to gaseous state (vapor), without melting. Freeze dried products is formed as sponginess, no shrinkage, rehydration excellent, very little water containing. The appropriate packaging can be stored and transported at room temperature for a long time.
　　Advantage of lyophilizer:
　　There are variety of drying methods, such as sunshine bask drying, boiled drying, parch drying, spray drying and vacuum drying. But the ordinary drying methods are usually above 0 ° C or higher temperatures, so the dried products are small in size, texture harden, and some heat-sensitive material nature changed, inactivation, and some substances even oxidation. But our lyophilizer worked below 0 ° C, so the freeze dried products can keep its original color, smell, taste, shape, bioactive molecule and prevents the lost of nutrition, and also easily regain water.
　　Lyophilizer needs to be worked in low temperature and vacuum condition, so refrigeration system and vacuum system must be adopted on lyophilizer. High quality Germany Bitzer or Italy Refcomp refrigerator and Germany Leybold or England Edwards vacuum pump, and also Siemens control systems are configured in our lyophilizer system to ensure stable performance.