It is very important to control the pre-freezing process of Sihuan freeze-drying pharmaceutical freeze-drying machine

Sihuan freeze-drying pharmaceutical freeze-drying machine is based on the principle of vacuum drying, with compact and reasonable structure, convenient maintenance, automatic control and easy operation
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Freeze-drying is a method of freezing water-containing materials in advance and then subliming them in a vacuum state to obtain dry items
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Generally, the original biological and chemical properties of the product after being freeze-dried by a freeze-drying machine are basically unchanged, and it is easy to store for a long time
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Therefore, it can be widely used in chemical industry, biological products and other fields
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The pre-freezing of the four-ring freeze-drying pharmaceutical freeze dryer is an important stage in the freeze-drying process
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The control of the pre-freezing process is very important
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When the temperature of the aqueous solution drops to a certain level, according to the eutectic concentration of the solution, the solution with low concentration begins to freeze, and this temperature is called the freezing point
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In general the freezing point is dominated by the concentration and decreases with the concentration
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When the temperature of the solution is lower than the freezing point, a part of the solution will crystallize out, and the concentration of the remaining solution will increase, so the freezing point will drop, and then continue to cool, the ice crystals will increase with cooling, and the concentration of the remaining solution will be followed by an increase
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However, when the temperature drops to a certain point, the remaining solution is completely frozen.
At this time, the frozen material is mixed with ice crystals, and the temperature at this time is the eutectic point
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Pre-freezing will have a certain destructive effect on cells and life, and the mechanism is very complicated.
It is generally believed that the mechanical and solute effects of water freezing during the pre-freezing process are the cause of the inactivation of biochemical drugs during the freeze-drying process.
important factor in degeneration
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Mechanical effect means that the volume of water increases when it freezes, resulting in the destruction of some weak molecular bonds in the active site of the active substance, resulting in loss of activity; Inconsistent changes in solubility under such temperature conditions lead to changes in pH value, resulting in changes in the environment in which the active substances are located, resulting in inactivation or denaturation
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The following measures can be used to solve this phenomenon: ① Pre-freezing adopts the quick-freezing method.
First, the temperature of the shelf is lowered to -45 °C, and then the product is put into the product for rapid freezing to form fine ice crystals, making it too late to produce mechanical effects
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② When choosing a buffer, choose a buffer paired salt with equivalent solubility
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③ Add product protective agent
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