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Compared with conventional methods

Jul 23, 2019

Compared with conventional methods

Freeze dryer is one of the drying methods, the purpose is to store goods. The damage, decay and deterioration of articles are mainly caused by external and internal factors, such as air, water, temperature and biology. The internal factors are mainly the metabolic function of biomass itself. If the function of external and internal factors can be reduced to a lower level, the object can be kept unchanged for a certain period of time. Freeze dryer has been widely used in chemistry, pharmaceutical industry, food industry and scientific research, especially in biological drugs containing bioactive substances.

QQ图片20190114101314

Drying is a very ancient operation, but heating and drying of powders and biological products often results in irreversible agglomeration of particles, especially in the preparation of ultra-fine powders. The agglomeration of nanoparticles in liquid phase is difficult to disperse due to the fact that water in the drying process of ordinary particles is passing through the pore channels between particles. Emission, surface tension leads to extremely high additional pressure, the particles compacted together into a mass. The use of freeze dryer can avoid this problem. Freeze drying is to freeze the gel or blood to be solid, and then to sublimate the water by sublimation under reasonable conditions. Because the gasification process of ice does not affect the coalescence of solid particles, it can be well preserved. The original particles are not compacted and reunited. In addition, the freeze dryer is very suitable for processing biological products, such as blood, because it has no high temperature operation, which can prevent the deterioration of biological products.

The drying products generally have the problems of shrinking volume and hardening texture. Most of the volatile components will be lost. Some thermosensitive substances will be denatured and deactivated, and some substances will even be oxidized. Therefore, the properties of dried products are quite different from those before drying. The principle of freeze-drying is basically below 0 C, that is, under the condition of product freezing, only when the residual moisture content of the product is reduced in the later stage, can the product be raised to above 0 C, but generally not more than 40. Under vacuum conditions, when water vapor is sublimated directly, the drug remains in the freezing ice shelf, forming a spongy porous structure, so the volume of the drug is almost unchanged after drying by freeze dryer. Before reuse, as long as water for injection is added, it will dissolve immediately.

50㎡  Freeze Dryer, industrial liofilizador

There are many methods for drying the freeze dryer, such as drying, boiling, drying, spray drying and vacuum drying. However, the common drying methods are usually carried out at temperatures above 0 degrees Celsius or higher. The drying products generally have the problems of shrinking volume and hardening texture. Most of the volatile components will be lost. Some thermosensitive substances will be denatured and deactivated, and some substances will even be oxidized. Therefore, the properties of dried products are quite different from those before drying. The principle of freeze-drying is basically below 0 C, that is, under the condition of product freezing, only when the residual moisture content of the product is reduced in the later stage, can the product be raised to above 0 C, but generally not more than 40. Under vacuum conditions, when the water vapor is sublimated directly, the drug remains in the ice shelf when it is frozen, forming a porous structure similar to sponge, so its volume is almost unchanged after drying. Before reuse, as long as water for injection is added, it will dissolve immediately. Compared with conventional methods, freeze dryer has the following advantages:

1. Many thermally sensitive substances do not undergo denaturation or inactivation.

2. When drying at low temperature, the loss of some volatile components is very small.

3. During the freeze-drying process, the growth of microorganisms and the role of enzymes can not be carried out, so the original characteristics can be maintained.

4. Because of drying in the freezing state, the volume is almost unchanged, the original structure is maintained, and the phenomenon of concentration will not occur.

5. Because the water in the material exists in the form of ice crystal after pre-freezing, the inorganic salts dissolved in water are evenly distributed in the material. When the products treated by freeze dryer are sublimated, the dissolved substances dissolved in water will precipitate, thus avoiding the surface hardening caused by the precipitation of inorganic salts carried by the moisture migration from the material to the surface in general drying methods.

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