Defoaming agent for digestive endoscopy as well as preparation method and use method of defoaming agent

Abstract

The invention provides a defoaming agent for digestive endoscopy as well as a preparation method and a use method thereof, and belongs to the technical field of medicines. The defoaming agent comprises 1%-10% of organic silicone oil and 90%-99% of polyethylene glycol; the preparation method comprises the following steps: weighing the organic silicone oil and the polyethylene glycol according to a set proportion, and respectively heating to 75-85 DEG C to form a hot melt; carrying out isothermal mixing on the two components to obtain a mixed hot melt, and carrying out intermittent shearing and stirring in a wall breaking machine to obtain an emulsified melt; flatly spreading the emulsified molten liquid in a pre-cooled container, sealing a cover, and freezing to obtain a white waxy sheet block; and crushing and sieving the white waxy sheet blocks to obtain white organic silicone oil dry milk powder, namely the defoaming agent. The method comprises the following steps: adding water into a defoaming agent and uniformly mixing to prepare a silicone oil emulsion before digestive endoscopy; the composition is orally taken or sprayed on an examined part. The dry emulsion type defoaming agent provided by the invention is simple in formula, free of additives, free of any potential safety risk, safe and reliable, good in stability and excellent in defoaming effect.

Description

Technical Field

[0001] The invention belongs to the field of pharmaceutical technology, and particularly relates to a defoaming agent for digestive endoscopy and a preparation and use method thereof. Background Art

[0002] Digestive endoscopy is an important means of diagnosing digestive tract diseases in modern times. One of the important factors that determines whether the endoscope can play an accurate and discerning diagnostic role is the quality of gastrointestinal cleaning preparation before endoscopic examination. Because the digestive tract contains various hydrophilic proteins secreted by the human body, they become foaming agents after mixing with the water in the human digestive tract, resulting in the generation of a large number of bubbles and foam, which directly affects the visual field observation under digestive endoscopy. After the gastrointestinal mucosa is cleaned, the mucosal tissue will still adhere to foam, which will affect the observation of the mucosal tissue under endoscopy; therefore, foam is the main cause of missed diagnosis and misdiagnosis during gastroscopy. For this reason, a series of operations such as diet control, laxative bowel cleansing, and the use of defoaming agents are required before digestive endoscopy observation and diagnosis.

[0003] The mechanism of action of defoamers is to destroy bubbles and inhibit the generation of bubbles by reducing surface tension. At present, defoamers are mainly divided into three categories according to their chemical structure and components: mineral oil, silicone, and polyether. Among them, silicone oil emulsions such as dimethicone are the most widely used defoamers in the pharmaceutical field. They have the advantages of fast defoaming speed and good foam suppression at room temperature, but they also have disadvantages such as low solubility and the formation of oil droplets during the preparation process; silicone oil emulsions belong to thermodynamically unstable systems, are easy to demulsify, stratify at high temperatures, have slow defoaming speed, poor foam suppression, etc., and contain water and are easy to mold and deteriorate, so they need to be combined with various additives, including but not limited to surfactants (Tween, Spam, Carbomer, etc.), preservatives (such as propylparaben), stabilizers (such as methylcellulose, hydroxymethylpropylcellulose, xanthan gum, etc.), sweeteners (aspartame, saccharin, flavoring agents, clove oil powder, menthol, etc.).

[0004] Although these additives have obtained nationally recognized safety certification, the risk of adverse reactions will overlap and increase when multiple additives are used together in one product. For example, the above-mentioned surfactants are all chemical synthetics with a numbing taste that can easily cause nausea and vomiting, and require flavor correction to cover up their bad taste; preservatives with bactericidal effects have an impact on intestinal flora and have an inhibitory effect on digestive enzymes, and their potential adverse reactions are no less than the side effects of antibiotics; sweeteners (such as saccharin) can cause thrombocytopenia, leading to the risk of acute massive bleeding, malnutrition, anorexia, etc.; thickeners (such as xanthan gum) can also be harmful to the human body.

[0005] In terms of dosage form, the current silicone oil defoamer preparations mainly include tablets, emulsions, suspensions, and soft capsules. As a new form of drug carrier, dry emulsions have received widespread attention in the pharmaceutical field in recent years. Dry emulsions are solid powders obtained by mixing drugs with suitable carriers and undergoing special processing. They are characterized by good stability, easy preparation and storage, and convenient carrying and use, which provide new ideas for the innovation and improvement of drug dosage forms. In the preparation process of dry emulsions, physical and chemical stability is an important research direction. At present, the preparation method of dry emulsions is mainly to add a certain amount of water-soluble or insoluble carriers (proppants) to liquid emulsions (raw milk), and then obtain dry milk powder through various dehydration processes such as spray drying, vacuum freeze drying, reduced pressure distillation, powder addition and drying, and other complex processes. Among the above-mentioned methods, their common advantage is that they overcome the physical instability of liquid emulsifiers and are easy to store, carry and transport. The disadvantage is that the existing dry emulsion preparation methods are relatively complicated. They all prepare liquid emulsions and then add a more cumbersome dehydration and drying process to make dry milk powder. Since the drying process mostly requires heating, there is a potential risk of adverse emulsion stability.

[0006] In view of this, the present invention proposes a defoaming agent for digestive endoscopy which has simple process, safe and reliable product, good stability and excellent defoaming effect. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a defoaming agent for digestive endoscopy and a preparation and use method thereof, aiming to solve at least one technical problem in the background technology.

[0008] The present invention is achieved in that:

[0009] The first aspect of the present invention provides a method for preparing a defoaming agent for digestive endoscopy, wherein the defoaming agent comprises the following components in weight percentage: 1%-10% of organic silicone oil and 90%-99% of polyethylene glycol;

[0010] The preparation method comprises the following steps:

[0011] Weigh the set proportion of silicone oil and polyethylene glycol, heat them to 75℃-85℃ respectively to form hot melt;

[0012] The two are mixed isothermally to obtain a mixed hot melt, which is then intermittently sheared and stirred in a wall breaking machine to obtain an emulsified melt;

[0013] The emulsified molten liquid is spread evenly in a pre-cooled container, sealed and frozen to obtain white waxy flakes;

[0014] The white waxy flakes are crushed and sieved to obtain white organic silicone oil dry milk powder, which is the defoaming agent.

[0015] Furthermore, the organic silicone oil is dimethicone or simethicone.

[0016] Furthermore, the molecular weight of the polyethylene glycol is 3000-8000.

[0017] Furthermore, the parameters of the intermittent shear stirring are: start 1min-2min, stop 1min; the total time is 15min-25min.

[0018] Furthermore, the thickness of the emulsified melt after being spread out does not exceed 0.5 mm.

[0019] Furthermore, the heating is carried out by microwave heating.

[0020] The second aspect of the present invention provides a defoaming agent for digestive endoscopy obtained by the above preparation method.

[0021] The third aspect of the present invention provides a method for using a defoaming agent for digestive endoscopy obtained by the above preparation method. 10-15 minutes before digestive endoscopy, the defoaming agent is mixed with water to form a silicone oil emulsion for oral administration or spraying on the inspection site.

[0022] The present invention simplifies and optimizes the formula composition, using only two components of a main drug (silicone oil) and a carrier (polyethylene glycol PEG); removing various additives such as emulsifiers, compound emulsifiers, thickeners, stabilizers, flavoring agents, flavoring agents, and preservatives; and providing a zero-additive emulsion product that is safe for human consumption.

[0023] The invention simplifies and optimizes the process: various forms of dehydration procedures are deleted, and after the emulsifier is prepared by the hot melt method, it does not need to be dehydrated, and the dry milk powder is directly cooled in one step.

[0024] The present invention adopts polyethylene glycol PEG as a multifunctional new emulsion carrier. Through experimental screening of physical property characteristics of existing new dry emulsion carrier materials, such as nanoparticles, liposomes, surfactants, cyclodextrins and other materials, and comparing them with the needs of medical defoamers, it is found that polyethylene glycol PEG as a defoaming dry emulsion has multifunctional properties and is a new carrier advantage material for defoamers.

[0025] Polyethylene glycol PEG has the following advantages:

[0026] (1) Polyethylene glycol PEG has an excellent coating effect. It forms a thin film on the surface of water-insoluble silicone oil particles, which wraps the silicone oil particles to prevent them from combining and aggregating. This coating effect can effectively inhibit the demulsification of silicone oil emulsions and maintain the stability of the emulsion dispersion system. When it forms a dry emulsion, its stability is more solid.

[0027] (2) Polyethylene glycol (PEG) has water-soluble hydroxyl groups at both ends of its chemical structure, which can increase the solubility of poorly soluble substances and improve bioavailability;

[0028] (3) Polyethylene glycol PEG is an inert substance in pharmacology and toxicology, has no toxic side effects, and is safe to use. It is also a similar drug to the current drugs used for digestive endoscopy, so the combined use of the two will not cause any contraindications and has good compatibility.

[0029] (4) Polyethylene glycol PEG with a molecular weight of 3000-8000 has a certain viscosity of 206cst-315cst, which is suitable for use as a lubricant when inserting the endoscope during endoscopic examination, facilitating the doctor's operation and reducing the patient's discomfort; it can also be used as an emulsifier, thickener, and stabilizer;

[0030] In addition, the melting point of polyethylene glycol PEG increases with the increase of molecular weight, and the melting point is in the range of 40℃-60℃, which is suitable for the preparation of emulsifiers by hot melt method. When making milk, when it is heated above the melting point of 60℃, it becomes a molten state and can undergo an emulsification reaction with silicone oil; when the emulsification reaction is completed and the temperature is lowered to below 40℃, it can be restored to the original solid state to form a solid dry milk powder. The present invention found that the coating effect of the two is best when the temperature of the emulsification reaction is set to 75℃~85℃, especially at 80℃. Since the emulsification reaction is carried out in a non-aqueous solution environment and no water is involved, the dehydration process can be deleted, and dry milk powder can be made in one step.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The dry emulsion defoamer provided by the present invention has a simple formula, zero additives, and no potential safety risks. The product is safe and reliable, has good stability, and has excellent defoaming effect.

[0033] 2. The dry emulsion preparation process provided by the present invention is simple and easy to implement, and does not require complicated drying and dehydration steps, and can be made into dry emulsion in one step; the equipment investment is small, the cost is low, and it saves materials, labor, energy, and the environment, and has wide application value and good economic benefits for enterprises.

[0034] 3. The dry milk powder of the present invention can form a silicone oil emulsion after being dissolved in water before use, which can be used as a supporting product before endoscopic examination. It has the functions of a lubricant and a defoaming agent, can improve the clarity of the endoscopic field of view, is conducive to the early discovery of tiny lesions, improves the diagnostic accuracy, that is, the success rate of lesion tissue biopsy, and avoids missed diagnosis and misdiagnosis.

[0035] 4. The solid dry milk powder of the present invention is stable in nature; it does not contain water, is not easy to mold or spoil, and does not require the addition of preservatives or stabilizers. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific implementation cases described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] A method for preparing a defoaming agent for digestive endoscopy comprises the following steps:

[0038] (1) Weighing 1% to 10% by weight of silicone oil and 90% to 99% of polyethylene glycol, heating them to 75° C. to 85° C. to form hot melts;

[0039] In a specific implementation, the silicone oil is dimethicone or simethicone; the molecular weight of polyethylene glycol is 3000-8000; the heating is preferably microwave heating, which heats up faster and more efficiently; the temperature after heating is 75°C to 85°C, for example, it can be 75°C, 80°C, or 85°C; the following embodiments are illustrated using 80°C as an example, but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] (2) isothermally mixing the two to obtain a mixed hot melt, and intermittently shearing and stirring the mixed hot melt in a wall breaking machine to obtain an emulsified melt;

[0041] In a specific implementation, the parameters of intermittent shear stirring are: start 1min-2min, stop 1min; the total time is 15min-25min.

[0042] (3) Spread the emulsified molten liquid evenly in a pre-cooled container with a thickness not exceeding 0.5 mm, cover it and freeze it to obtain white waxy flakes;

[0043] (4) The white waxy flakes are crushed and sieved to obtain white organic silicone oil dry milk powder, which is the defoaming agent.

[0044] Example 1

[0045] A defoaming agent for digestive endoscopy is prepared by the following method:

[0046] 1. Take 50g of dimethylsiloxane and heat it at 80℃ for 3-5min in microwave. Take 950g of polyethylene glycol 6000 and heat it at 80℃ for 3-8min in microwave to melt it into hot melt.

[0047] 2. Move the above two liquids to a wall breaking machine for intermittent stirring, shearing and emulsification for 20 minutes (stirring for 1 minute on and stopping for 1 minute). After stopping, the emulsified molten liquid is obtained;

[0048] 3. Quickly spread the emulsified molten liquid on a cooled stainless steel plate with a thickness not exceeding 0.5 mm, cover with a film, and immediately move to a refrigerator. After refrigerating for 1-3 hours, take out the white waxy flakes;

[0049] 4. Crush the waxy flakes and move them to a grinder for 1-2 minutes;

[0050] 5. After the obtained powder is sieved through a 20-mesh sieve, white dimethylsiloxane dry milk powder is obtained, which can be packaged into finished products.

[0051] Packaging specifications according to different uses:

[0052] (1) Each bottle of gastroscope defoamer is 6.0g, containing 300mg of the main drug;

[0053] (2) Each bottle of colonoscopy defoamer is 24 g, containing 1200 mg of the main drug;

[0054] The main drug is dimethylsiloxane.

[0055] Preparation and use of silicone oil emulsion: 10 minutes to 15 minutes before gastroscopy, take a bottle of dimethylsiloxane dry powder and add appropriate amount of water (about 60 ml). Shake vigorously for more than 10 times to prepare silicone oil emulsion; it can be taken orally or sprayed on the examination area.

[0056] Example 2

[0057] The formula composition ratio was modified to: dimethicone 40g, polyethylene glycol 4000, 960g. The preparation method was the same as in Example 1.

[0058] Packaging specifications: (1) Each bottle of gastroscope defoaming agent is 8g, containing 320mg of the main drug; (2) Each bottle of colonoscope defoaming agent is 32g, containing 1280mg of the main drug; the main drug is dimethicone.

[0059] The preparation and use of silicone oil emulsion are the same as in Example 1.

[0060] Example 3

[0061] The formula composition ratio was modified to: 64 g of methyl silicone oil and 936 g of polyethylene glycol 4000. The preparation method was the same as in Example 1.

[0062] Packaging specifications: (1) Each bottle of gastroscope defoaming agent is 5g, containing 320mg of the main drug; (2) Each bottle of colonoscope defoaming agent is 30g, containing 1920mg of the main drug; the main drug is methyl silicone oil.

[0063] The preparation and use of silicone oil emulsion are the same as in Example 1.

[0064] Example 4

[0065] The formula composition ratio was modified to: 80 g of methyl silicone oil and 920 g of polyethylene glycol 6000. The preparation method was the same as in Example 1.

[0066] Packaging specifications: (1) Each bottle of gastroscope defoaming agent is 4g, containing 320mg of the main drug; (2) Each bottle of colonoscope defoaming agent is 24g, containing 1920mg of the main drug; the main drug is methyl silicone oil.

[0067] The preparation and use of silicone oil emulsion are the same as in Example 1.

[0068] Comparative Example 1

[0069] The method steps are the same as the formula composition of Example 1, and the process omits the heating and melting emulsification reaction, and directly mixes the solid PEG and the silicone oil liquid and mechanically stirs them to prepare the dry emulsion defoamer.

[0070] Comparative Example 2

[0071] The defoaming agent was prepared by using the same formulation composition ratio as in Example 1, except that the hot melt heating temperature in this comparative example was reduced to 65°C, and the other reaction conditions and steps were the same as in Example 1.

[0072] Comparative Example 3

[0073] The defoaming agent was prepared by using the same formulation composition ratio as in Example 1, except that the hot melt heating temperature in this comparative example was increased to 95°C, and the other reaction conditions and steps were the same as in Example 1.

[0074] Comparative Example 4

[0075] On the basis of the formulation composition ratio of Example 1, polyethylene glycol 6000 was changed to polyethylene glycol 2000, and the other reaction conditions and steps were the same as those of Example 1 to prepare a defoaming agent.

[0076] Comparative Example 5

[0077] On the basis of the formulation composition ratio of Example 1, polyethylene glycol 6000 was changed to polyethylene glycol 9000, and the other reaction conditions and steps were the same as those of Example 1 to prepare a defoaming agent.

[0078] Comparative Example 6

[0079] The same prescription composition ratio as in Example 1, except that room temperature cooling instead of rapid freezing is adopted after the hot melt emulsification reaction in this comparative example, and other reaction conditions and steps are the same as in Example 1, to prepare a defoaming agent.

[0080] Comparative Example 7

[0081] This comparative example is the solid self-emulsifying preparation of simethicone in Example 2 of CN105878183A, and compared with Example 2 of the present application, the additives "polyoxyethylene 40 stearate, glyceryl monostearate, glycerol, and ethanol" are added.

[0082] The prescription composition ratio is: 40g of simethicone oil; 800g of PEG4000; 60g of polyoxyethylene 40 stearate; 30g of glyceryl monostearate; 20g of glycerol; 50g of 40% ethanol solution.

[0083] The preparation method comprises the following steps: keeping simethicone, polyoxyethylene 40 stearate, glyceryl monostearate and glycerin at a temperature of 65°C, stirring for 30 minutes and mixing evenly to obtain a simethicone emulsified concentrate; crushing and sieving PEG4000, mixing it with the above simethicone emulsified concentrate, spraying it with a 40% ethanol solution, making it into a soft material, sieving it, drying it at 60°C and then sieving it to obtain granules.

[0084] Example 5

[0085] The dry milk powders prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were used as samples, and static water dispersibility was measured on them in this example.

[0086] The specific determination method is: take 0.5g of the sample, put it in a beaker, add 100ml of water, shake and observe the dispersion of the sample in the water, and score it in four levels: excellent means rapid dispersion and no oil droplets appear on the liquid surface; good means fast dispersion and no oil droplets appear on the liquid surface; medium means slow dispersion and floating oil or floccules appear on the liquid surface; poor means difficult to disperse and the floccules are difficult to dissipate; observe continuously for 10 days to record the presence / absence of floating oil, precipitation, and flocculation, where "+" means presence and "-" means absence, as shown in Table 1.

[0087] Table 1

[0088]

[0089]

[0090] Example 6

[0091] The dry milk powders prepared in Examples 1 to 4, Comparative Examples 1 and 2 were used as samples, and centrifugal stability was measured in this example to determine their dynamic water dispersibility. The specific measurement method is as follows: take two 20 ml centrifugal test tubes, add 0.05 g of sample and 10 ml of water respectively, put them into a centrifuge symmetrically, centrifuge them at a speed of 3000±50 r / min for 30 min, 60 min, 120 min, 180 min, and 240 min in sequence, and visually observe the samples in the centrifugal test tubes to see if there is demulsification / stratification / oil floating in the dispersed emulsion, where "+" means yes, and "-" means no, and the results are shown in Table 2.

[0092] Table 2

[0093] sample 30min 60min 120min 180min 240min Example 1 - - - - - Example 2 - - - - - Example 3 - - - - - Example 4 - - - - - Comparative Example 1 + + + + + Comparative Example 2 - - - - - Comparative Example 3 - - - - - Comparative Example 4 - - + + + Comparative Example 5 - - - - - Comparative Example 6 + + + + + Comparative Example 7 - - - - -

[0094] Example 7

[0095] The dry milk powders obtained in Examples 1 to 4, Comparative Examples 1 and 2 were used as samples, and the defoaming power was statically measured in this example.

[0096] The specific determination method is:

[0097] Add water to the sample to prepare a sample solution with a mass concentration of 6%; take two 50ml portions of 1% octoxynol-9 solution of the foaming agent, carefully inject them into 250ml stoppered measuring cylinders respectively, take 1ml of the sample solution and put it into one of the measuring cylinders, shake it vigorously, 5 times each for 2 measuring cylinders, leave it for 1 minute, measure the foam height, and calculate the foam volume without adding the sample as 100%. The foam volume of the measuring cylinder with the sample added shall not exceed 20%. The numbers in the table are defoaming time (seconds), ≤60" (i.e. within 1 minute) is in compliance with the regulations, and >60" (i.e. more than 1 minute) is not in compliance with the regulations.

[0098] The measurement results are shown in Table 3.

[0099] Table 3

[0100]

[0101] From the data in Tables 1 to 3, it can be seen that the static stability, dynamic stability and defoaming performance of the samples of Examples 1 to 4 prepared by the hot melt method are significantly better than those of Comparative Example 1 prepared by the mechanical mixing method. In the centrifugal dynamic stability test of Example 6, if the centrifugation time exceeds 4 hours, it indicates that the shelf life of the product exceeds 1 year.

[0102] By comparing Example 1, Comparative Example 2 and Comparative Example 3, the influence of the hot melting temperature of emulsification on the properties of the obtained dry emulsion is studied. From the data in Tables 1 to 3, it can be seen that there is no obvious influence. However, there are certain difficulties in the process operation. If the melting temperature is too low, the emulsion is easy to agglomerate and affect the stirring efficiency; if the melting temperature is too high and the heat generated by high-speed stirring is easy to melt the stirrer cup and burn the stirrer. Therefore, it is appropriate to set the emulsification temperature to 75℃~85℃.

[0103] By comparing Example 1, Comparative Example 4 and Comparative Example 5, the effect of the molecular weight of the carrier PEG on the performance of the obtained dry emulsion is studied. From the data in Tables 1 to 3 combined with the process conditions, it can be seen that when the molecular weight of PEG is too large, it is not easy to have the phenomenon of oil floating and the obtained dry emulsion particles have good fluidity and are easy to pack. However, when the molecular weight is too large, the melting point is high and it is inconvenient to operate. When the molecular weight is too small, the emulsification is incomplete and the phenomenon of oil floating is easy to occur. Therefore, it is appropriate to select PEG of 3000 to 8000.

[0104] By comparing Example 1 and Comparative Example 6, the effects of normal temperature cooling and rapid freezing cooling on the properties of the obtained dry emulsion are studied. From the data in Tables 1 to 3, it can be seen that the static stability, dynamic stability and defoaming performance of the dry emulsion obtained by rapid freezing are better than those obtained by normal temperature cooling; the reason is that after the emulsification reaction is completed, the hot melt emulsion is in a liquid state and belongs to a thermodynamically unstable system. When the stirring is stopped and the emulsified particles are allowed to stand, the surface energy of the emulsified particles can easily condense with each other to form large particles. The longer the standing time, the greater the impact. Rapid cooling can quickly transform the hot melt (liquid) into a solid, fix it without condensation, and separate the oil layer.

[0105] It can be seen from the comparison between Example 2 and Comparative Example 7 that the present application simplifies the components and only uses polyethylene glycol and silicone oil, but still maintains excellent defoaming effect and stability.

[0106] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a defoaming agent for digestive endoscopy, characterized in that: The defoamer comprises the following components in weight percentage: 1%-10% of silicone oil and 90%-99% of polyethylene glycol; The preparation method comprises the following steps: Weigh the set proportion of silicone oil and polyethylene glycol, heat them to 75℃-85℃ respectively to form hot melt; The two are mixed isothermally to obtain a mixed hot melt, which is then intermittently sheared and stirred in a wall breaking machine to obtain an emulsified melt; The emulsified molten liquid is spread evenly in a pre-cooled container, sealed and frozen to obtain white waxy flakes; The white waxy flakes are crushed and sieved to obtain white organic silicone oil dry milk powder, which is the defoaming agent.

2. The method for preparing a defoaming agent for digestive endoscopy according to claim 1, characterized in that: The organic silicone oil is dimethicone or simethicone.

3. The method for preparing a defoaming agent for digestive endoscopy according to claim 1, characterized in that: The molecular weight of the polyethylene glycol is 3000-8000.

4. The method for preparing a defoaming agent for digestive endoscopy according to claim 1, characterized in that: The parameters of the intermittent shear stirring are: start 1min-2min, stop 1min; the total time is 15min-25min.

5. The method for preparing a defoaming agent for digestive endoscopy according to claim 1, characterized in that: The thickness of the emulsified melt after being spread out does not exceed 0.5 mm.

6. The method for preparing a defoaming agent for digestive endoscopy according to claim 1, characterized in that: The heating is carried out by microwave heating.

7. A defoaming agent for digestive endoscopy obtained by the preparation method according to any one of claims 1 to 6.

8. A method for using a defoaming agent for digestive endoscopy obtained by the preparation method according to any one of claims 1 to 6, characterized in that: 10-15 minutes before digestive endoscopy, the defoaming agent is mixed with water to form a silicone oil emulsion for oral administration or spraying on the inspection site.

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