Briefly describe the three stages of freeze drying, and the correct process flow of freeze drying is

Pre-freezing stage: The liquid material is cooled to freeze into a solid state.

Sublimation drying stage: vacuuming, and proper heating is that the moisture in the material is directly sublimated from the solid state into a gaseous state to be extracted.

Analysis of the drying stage: vacuuming, further heating so that the bound water in the material escapes and is pumped away.

The correct process flow of freeze-drying is: measuring eutectic point, pre-freezing, sublimation, drying, and sublimation.

Specific process: The process flow of freeze-drying is first to measure the eutectic silver guess point, so that the pre-freezing temperature is reduced to below the eutectic point of the product 10 20 to ensure that the pre-freezing is complete, and then sublimation drying to basically remove the water in the liquid medicine. Finally, it is dried to remove the sublimated water vapor or residual moisture.

Freeze drying is also known as sublimation drying. A drying method in which an aqueous material is frozen below freezing point, the water is turned into ice, and then the ice is converted into vapor under a higher vacuum. The material can be frozen in a refrigeration unit and then dried.

However, it can also be frozen directly in the drying chamber by rapidly pumping into a front-impact vacuum. The water vapor generated by sublimation is removed by the condenser. The vaporization heat required in the process of sublimation is generally supplied by thermal radiation.

Freeze dryer.

Freeze drying, also known as freeze drying and freeze drying, is a process of freezing liquid or moist substances (usually food, drugs, biological products, etc.) and directly sublimating ice crystals into water vapor at low pressure, so that the substance retains its original shape and activity, and at the same time prolongs its shelf life. Here's the right process for freeze drying:

Freezing: The substance to be processed is placed in a low-temperature environment, usually in a freezer or freezer, so that it can be quickly frozen into a solid state. The purpose of freezing is to form ice crystals during the drying process, thus reducing the destruction of the substance upon evaporation.

Main drying: The frozen material is placed in a vacuum dryer (or freeze dryer) and the temperature is raised so that the ice crystals are directly sublimated from a solid state to water vapor without going through a liquid transition. In the process of main drying, the moisture in the substance evaporates and is pumped out, thus reducing the moisture in the substance to a lower level.

Auxiliary drying (optional): For some special substances, auxiliary drying may be required to ensure that they are completely dry. Assisted drying is generally carried out at a higher temperature to remove more residual moisture. Slim lift and.

Pre-cooling: After drying, the substance is removed from the dryer, but the surface of the substance may be damp at this time, so it is necessary to pre-cool it in a closed environment to avoid moisture absorption.

Encapsulation (optional): Substances that have been freeze-dried may be susceptible to moisture absorption, and in order to keep them dry, the substances can be sealed to prevent moisture from re-entering.

The correct execution of the freeze-drying process helps to maintain the quality and activity of the substance, prolong its shelf life, and is widely used in the food industry, pharmaceutical industry, biotechnology and other fields. Different substances may have different process parameters and drying conditions, so in practical applications they need to be adapted to the specific substances and requirements.

Answer]: Due to the high vacuum degree and low temperature in the drying process, it is suitable for hot dismantling of sensitive drugs, oxidizing materials and volatile components, which can prevent the deterioration and loss of drugs; The volume of the dried product is the same as that of the liquid state, so the dried product is loose, porous, spongy and easily soluble, so it is often used in the preparation of injections that are solid and dissolved when using biological products, antibiotics, etc. The disadvantages are high equipment investment cost, large power consumption, long drying time and low production capacity.

Due to the high vacuum degree and low temperature in the drying process, it is suitable for the drying of heat-sensitive drugs, aerobic reedification materials and volatile components, which can prevent the deterioration and loss of drugs. The volume of the dried product is the same as that of the liquid state, so the dried product is loose, porous, spongy and easily soluble, so it is often used in the preparation of injections that are solid and dissolved when using biological products, antibiotics, etc. The disadvantages are high equipment investment cost, large power consumption, long drying time and low production capacity.

The characteristics of freeze-drying do not include (d).

a.Suitable for heat-sensitive drugs BDry c. at low temperaturesDry in high vacuum conditionsThe dried finished product has a high moisture content and is not easy to store for a long timeThe dried finished product is loose and easy to dissolve.

Freeze Drying Knowledge Extension:

Freeze drying is the use of the principle of ice crystal sublimation, in a highly vacuum environment, the moisture of the frozen food materials is directly sublimated from the ice solid to steam without the melting of ice, the moisture in the general vacuum drying materials is converted into vapor in the liquid state and the food is dried, so freeze drying is also called freeze sublimation drying.

Freeze drying is different from ordinary heating drying, the moisture in the material is basically sublimated and dried on the frozen solid surface below 0, and the substance itself remains in the ice rack when frozen, so the volume of the dried product remains unchanged, loose and porous. Ice needs heat during sublimation, and the material must be properly heated, and a certain temperature gradient must be formed between the heating plate and the sublimation surface of the material, so as to facilitate the smooth progress of heat transfer.

The main advantages are:

1) The dried material retains its original chemical composition and physical properties: such as porous structure, colloidal properties, etc.; Consumes less heat than other drying methods. The disadvantage is that it is more expensive and cannot be widely adopted. It is used to dry antibiotics, vegetables and fruits, etc.

2) The water-containing biological sample is frozen and fixed, and the water in the sample is directly sublimated by ice under the condition of low temperature and high vacuum to achieve the purpose of drying.

a.The texture of the freeze-dried product is thipone, and the orange dissolves quickly after adding water.

b.Freeze-drying is carried out under vacuum conditions, and the resulting products are not conducive to long-term storage.

c.Freeze-drying should be carried out at a temperature and pressure above the triple point of water.

d.The freeze-drying process is the process in which water changes from solid to liquid and then from liquid to vapor.

e.Samples with high viscosity are susceptible to freeze-drying than samples with low viscosity.

Correct Answer: a

a.It can avoid the decomposition and deterioration of drugs due to high heat.

b.The product has low water content and is conducive to long-term storage.

c.The product has a loose texture and dissolves quickly when water is added.

d.There are fewer foreign substances in the product than if it were produced by other methods.

e.The dosage is accurate, and the silver is in good appearance.

Correct answer: Guess the beam abcde