Liposome suitable for water-soluble polysaccharide protection and preparation method thereof

Abstract

The invention discloses a liposome suitable for water-soluble polysaccharide protection and a preparation method thereof, and relates to the technical field of pharmaceutical preparations, and each 100mL of solvent comprises the following components in parts by weight: 1-10 parts of lycium barbarum polysaccharide, 15-25 parts of phospholipid and 3-5 parts of cholesterol. Polysaccharide is prepared into lipidosome through reverse evaporation, and the high-stability polysaccharide lipidosome is prepared by controlling parameters such as the mass ratio of polysaccharide, lecithin and cholesterol, film forming time, stirring and ultrasonic time and the like. The preparation process is simple and easy to operate, bioaccessibility is improved, popularization and application are facilitated, steps are simple, operation is easy, the prepared liposome has the advantages of being high in encapsulation efficiency, capable of overcoming polysaccharide instability, free of additional surfactants and the like, no harmful waste is discharged, and the comprehensive utilization rate of resources is high.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical preparations, and in particular to a liposome suitable for water-soluble polysaccharide protection and a preparation method thereof. Background Art

[0002] As a nanoscale microcapsule that artificially simulates the cell membrane structure, liposomes have shown great potential in drug delivery, nutritional fortification, cosmetics and other industrial fields in recent years. Its core structure is composed of an aqueous core wrapped by a phospholipid bilayer, which can simultaneously encapsulate hydrophilic and hydrophobic active substances, and is therefore widely used to improve the stability, solubility and bioavailability of bioactive substances. In the prior art, the application of liposomes is becoming more and more extensive, but there are still many problems in its preparation method and formulation composition, which limits its in-depth application in a wider range of fields. Existing liposomes are usually composed of auxiliary materials such as phospholipids, cholesterol and surfactants. Among them, phospholipids are the main components of the lipid bilayer membrane, and cholesterol regulates the fluidity and stability of the membrane by embedding in the phospholipid bilayer, thereby enhancing the mechanical strength and antioxidant capacity of the liposome. Surfactants are used as stabilizers or structural modifiers to improve the stability of liposomes during storage and in vitro and in vivo environments, while improving the dispersibility of liposomes. However, the addition of surfactants also brings certain side effects, such as potential toxicity and structural effects on encapsulated substances, especially in the field of food and medicine, where their safety is strictly restricted. There are many methods for preparing liposomes, including thin film dispersion, injection, reverse phase evaporation, ultrasound and microemulsion. These methods are used in both laboratory research and industrial production, but they generally have some defects that are difficult to overcome. For example: Complex preparation process: The existing liposome preparation process usually involves multiple steps, including dissolution, film formation, ultrasound, homogenization and solvent removal, which increases time and labor costs and is not conducive to large-scale production. Surfactant dependence: In order to improve the stability or control the release performance of liposomes, it is often necessary to add a variety of surfactants. These chemical additives may bring toxicity risks, especially in drug delivery and food applications, their safety becomes a limiting factor. Solvent residue problem: In some preparation methods, organic solvents (such as chloroform and methanol) are required to dissolve lipids. Although the solvent can be removed in subsequent steps, there will inevitably be trace residues, which will affect the safety of the product. Insufficient stability: Traditional liposomes are prone to structural instability or leakage of active substances in complex environments (such as high temperature, oxidative environment or gastrointestinal conditions), affecting the use effect.

[0003] Although liposome technology has made significant progress, the core problems in its preparation methods and applications have not been fundamentally solved. 1) Formula complexity: Traditional liposome preparation relies on the combination of multiple ingredients, including phospholipids, cholesterol and various surfactants, which increases the complexity of the process and places higher requirements on the safety of raw materials. In particular, the selection and dosage of surfactants need to be repeatedly optimized, which often consumes a lot of resources. 2) Potential safety issues: Surfactants such as polysorbate, Tween or deoxycholate may cause cytotoxicity or allergic reactions at certain concentrations and are not suitable for fields such as food and medicine that have extremely high safety requirements. In addition, the use of organic solvents increases the risk of solvent residues, especially for sensitive populations or special uses (such as children's food or medicine). These potential risks must be avoided. 3) Difficulty in process scale-up: Many laboratory preparation methods are difficult to directly apply to industrial production. In particular, the solvent removal and homogenization processes will significantly increase energy consumption and costs when scaled up, and may also affect the uniformity and encapsulation rate of liposomes. 4) Storage and stability limitations: Traditional liposomes are prone to problems such as lipid oxidation, leakage of active substances or disintegration of the bilayer membrane during storage. Especially under liquid storage conditions, insufficient stability becomes a major bottleneck. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a liposome suitable for water-soluble polysaccharide protection and a preparation method thereof, which is composed only of phospholipids and cholesterol. By optimizing their ratio and preparation conditions, the high stability and efficient active substance encapsulation ability of the liposome are achieved without the need for additional addition of surfactants.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing liposomes protected by water-soluble polysaccharides, the specific steps are as follows: Phospholipids and cholesterol are added to a solvent to prepare an oil phase mixture, and a lipid film is obtained by distillation; The wolfberry polysaccharide solution is mixed with the lipid film, and the lipid film is dissolved and then emulsified to obtain a mixed solution; The mixed solution was filtered through microporous filter membranes with pore sizes of 0.45 μm, 0.22 μm and 0.1 μm in sequence to obtain a polysaccharide liposome suspension, namely, wolfberry polysaccharide liposome.

[0006] Furthermore, in terms of weight, every 100 mL of the solvent includes 1 to 10 parts of wolfberry polysaccharide, 15 to 25 parts of phospholipids, and 3 to 5 parts of cholesterol.

[0007] Furthermore, the concentration of the Lycium barbarum polysaccharide solution is 1 mg / mL to 10 mg / mL.

[0008] Furthermore, the phospholipid is lecithin, and the lecithin is selected from soybean lecithin or egg yolk lecithin.

[0009] Furthermore, the solvent is an organic solvent, and the organic solvent includes any one of methanol, anhydrous ethanol, ether, acetone or acetonitrile, or a combination of at least two thereof.

[0010] Furthermore, in the step of adding phospholipids and cholesterol into a solvent to prepare an oil phase mixture and distilling to obtain a lipid film, specifically: Phospholipids and cholesterol are added to a solvent to prepare an oil phase mixture, and a lipid film is obtained by vacuum distillation. The evaporation rate of the organic solvent is 50 mL to 100 mL of organic solvent every 20 min to 30 min.

[0011] Furthermore, in the step of adding phospholipids and cholesterol into a solvent to prepare an oil phase mixture and distilling to obtain a lipid film, specifically: The ratio of the total mass of the phospholipid and cholesterol after mixing to the volume of the solvent is 0.9~0.72:50~100.

[0012] Furthermore, in the step of mixing the Lycium barbarum polysaccharide solution with the lipid film, and dissolving the lipid film and emulsifying it to obtain a mixed solution, specifically: The wolfberry polysaccharide solution was injected into a container containing a lipid film, and the container was rotated at 50 r / min~70 r / min for 50 min~70 min at 50°C to completely remove and dissolve the lipid film, and then ultrasonic emulsification was performed for 10 min~20 min to obtain a mixed solution.

[0013] Further, the mixed solution is filtered through microporous membranes with pore sizes of 0.45 μm, 0.22 μm and 0.1 μm in sequence to obtain a polysaccharide liposome suspension, i.e., a step of preparing wolfberry polysaccharide liposomes, specifically: The mixed solution was sequentially passed through a microporous filter membrane with a pore size of 0.45 μm for 3 times, a microporous filter membrane with a pore size of 0.22 μm for 3 times, and a microporous filter membrane with a pore size of 0.1 μm for 3 times to obtain a polysaccharide liposome suspension.

[0014] The present invention also provides a liposome suitable for water-soluble polysaccharide protection, which is prepared by the above preparation method and has a particle size of 100nm-200nm. The wolfberry polysaccharide liposome is stored in the form of a suspension for 28 days, and the particle size is 130nm-230nm; the absolute value of the Zeta potential is 32mV-42mV.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides a method for preparing liposomes suitable for water-soluble polysaccharide protection, which does not require a surfactant and significantly simplifies the formulation design and preparation process. The liposome formulation of the present invention is composed only of phospholipids and cholesterol. By optimizing their ratio and preparation conditions, the high stability and efficient active substance encapsulation capacity of the liposome are achieved without the need for additional surfactant. This simplified design not only improves safety and process feasibility, but also has the following technical advantages. 1) The formula is pure and safer: the liposomes of the present invention only use phospholipids and cholesterol, and do not involve surfactants or other chemical additives, which fundamentally avoids the toxic risks and safety hazards that may be caused by surfactants. This pure formula is particularly suitable for food, medicine and other fields with strict safety requirements. In addition, phospholipids and cholesterol are both natural ingredients with a wide range of sources and good biocompatibility. 2) The preparation process is simplified and suitable for industrial production: by optimizing the ratio and preparation conditions of phospholipids and cholesterol, the present invention does not require complicated homogenization and solvent removal steps, and only requires simple dissolution and emulsification to complete the liposome preparation, which greatly reduces energy consumption and time costs. This method is simple in process and can be directly scaled up for industrial production. 3) Enhanced stability and relaxed storage conditions: By precisely controlling the ratio of phospholipids and cholesterol, the liposomes of the present invention exhibit excellent structural stability under high temperature, oxidative environment and gastrointestinal conditions. Compared with traditional liposomes, the leakage rate of active substances in the product of the present invention is significantly reduced, and it is suitable for a variety of storage conditions, providing technical support for extending the shelf life of the product. At the same time, stable existence can be achieved in a short period of time without freeze-drying. 4) Efficient active substance encapsulation ability: The present invention significantly improves the encapsulation efficiency of liposomes for hydrophilic and hydrophobic active substances through reasonable molecular design in the preparation of liposomes. At the same time, the density of the lipid bilayer is optimized, providing better control for the stability and release of active substances.

[0016] The liposome formula of the present invention is composed of only phospholipids and cholesterol, and does not involve surfactants or other chemical additives, which fundamentally avoids potential toxic risks and safety hazards. Both phospholipids and cholesterol are natural ingredients with good biocompatibility, and are suitable for fields with strict safety requirements. The prepared liposomes provide a protective microenvironment for water-soluble polysaccharides, which can significantly improve their stability, especially under high temperature, oxidative environment and gastrointestinal conditions. By optimizing the ratio of phospholipids and cholesterol, liposomes show excellent structural stability, reduce the leakage rate of active substances, and extend the shelf life of products. Liposomes can improve the bioavailability of water-soluble polysaccharides, and through encapsulation, make them more easily absorbed and utilized by cells. The bilayer structure of liposomes provides a sustained release effect for polysaccharides, which helps to maintain their effective concentration in the body. Water-soluble polysaccharides encapsulated by liposomes have wider application prospects in the fields of pharmaceutical preparations, health products, etc. This technology is not only applicable to Lycium barbarum polysaccharides, but can also be extended to the encapsulation and protection of other water-soluble polysaccharides. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Transmission electron microscopy images of liposomes; Figure 2 Particle size changes of liposomes during 28 days of storage; Figure 3 Zeta changes of liposomes during 28 days of storage; Figure 4 In vitro recovery and bioaccessibility of polysaccharides from liposomes were determined at 0 and 28 days of storage. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] The invention provides a liposome suitable for water-soluble polysaccharide protection. According to weight parts, each 100 mL of solvent comprises 1 to 10 parts of wolfberry polysaccharide, 15 to 25 parts of phospholipids and 3 to 5 parts of cholesterol.

[0020] Optionally, the phospholipid is lecithin, and the lecithin is selected from soybean lecithin or egg yolk lecithin.

[0021] Optionally, the solvent is an organic solvent, and the organic solvent includes any one of methanol, anhydrous ethanol, ether, acetone or acetonitrile, or a combination of at least two thereof.

[0022] The present invention also provides a method for preparing the above-mentioned liposome suitable for water-soluble polysaccharide protection, comprising the following steps: (1) Drying Lycium barbarum polysaccharide at a constant temperature of 40°C for 22 h to 26 h; (2) dissolving phospholipids and cholesterol in a solvent to form an oil phase mixture, and then rapidly removing the solvent by rotary evaporation under reduced pressure to form a uniform lipid film; (3) Dissolve the Lycium barbarum polysaccharide powder in ultrapure water to a final concentration of 1 mg / mL to 10 mg / mL; (4) Inject 100 mL of Lycium barbarum polysaccharide solution into a container containing a lipid film, rotate at 50° C. for 50 min to 70 min until the lipid film prepared in step (2) is completely detached and dissolved, perform ultrasonic emulsification for 10 min to 20 min, and then filter through a microporous filter membrane with a pore size of 0.45 μm for 3 times, a microporous filter membrane with a pore size of 0.22 μm for 3 times, and a microporous filter membrane with a pore size of 0.1 μm for 3 times to obtain a polysaccharide liposome suspension; pass through the filter membrane to physically remove the macromolecular phospholipids and polysaccharide conjugates, and reduce the size of the liposomes by extrusion, so that the liposomes can be highly stable in the suspension without freeze-drying.

[0023] Preferably, the vacuum distillation speed in step (2) is 20 min to 30 min to achieve a rate of evaporation of 50 mL to 100 mL of organic solvent. Too slow a rate may result in a decrease in the subsequent stability of the liposomes.

[0024] Preferably, in step (2), the ratio of the total mass of the phospholipid and cholesterol after mixing to the volume of the solvent is 0.9-0.72:50-100.

[0025] Preferably, the rotation speed in step (4) is 50 r / min to 70 r / min. Too high a rotation speed will reduce the liposome yield.

[0026] The liposome preparation formula designed by the present invention can achieve the stable existence of liposomes without surfactant. The prepared liposomes do not need to be filtered or extruded, and the particle size is less than 300nm; the particle size after extrusion is less than 200nm; it meets the requirements of medicinal use and in vivo absorption. The material of the present invention is easy to identify and has a wide range of applications. At the same time, the stability of the liposomes is basically equivalent to that of the liposomes currently using surfactants.

[0027] The invention utilizes a reverse evaporation method, controls the mass ratio of wolfberry polysaccharides, lecithin and cholesterol, fully stirs, ultrasonic time and other parameters, and uses wolfberry as a raw material to prepare wolfberry polysaccharide liposomes. The preparation process is simple and easy to operate, does not contain potential unsafe factors such as additional surfactants, is convenient for promotion and application, has simple steps and is easy to operate. The prepared wolfberry polysaccharide liposomes have the advantages of high encapsulation rate, overcoming polysaccharide instability, certain sustained-release effect and the like, does not discharge harmful wastes, and has a high comprehensive resource utilization rate.

[0028] The wolfberry polysaccharide liposome obtained by the present invention has the characteristics of high encapsulation rate, good reproducibility, and can overcome the poor stability of polysaccharides, low bioavailability and easy degradation. After the wolfberry polysaccharide is prepared into liposomes, the wolfberry polysaccharide can be effectively exerted, so that the wolfberry polysaccharide has a wider application in medical preparations and health care products.

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0030] Example 1 A liposome suitable for water-soluble polysaccharide protection comprises, by weight, 1 part of wolfberry polysaccharide, 15 parts of soybean lecithin and 3 parts of cholesterol in every 100 mL of methanol solvent.

[0031] A method for preparing liposomes protected by water-soluble polysaccharides is as follows: Drying the Lycium barbarum polysaccharide at 40° C. for 22 hours to obtain Lycium barbarum polysaccharide powder; Dissolve the wolfberry polysaccharide powder in ultrapure water at a final concentration of 1 mg / mL to obtain a wolfberry polysaccharide solution; Accurately weigh the above amount of lecithin and cholesterol, place them in a dry and clean eggplant-shaped flask, and add an appropriate amount of methanol to dissolve them. Evaporate them under reduced pressure in a 55°C water bath to quickly remove the methanol, so that the phospholipid membrane material forms a uniform lipid film on the wall of the eggplant-shaped flask.

[0032] 100 mL of Lycium barbarum polysaccharide solution was injected into a container containing a lipid film, rotated at 50° C. for 50 min until the lipid film was completely detached and dissolved, then ultrasonic emulsified for 10 min, and then filtered through a microporous filter membrane with a pore size of 0.45 μm for 3 times, a microporous filter membrane with a pore size of 0.22 μm for 3 times, and a microporous filter membrane with a pore size of 0.1 μm for 3 times to obtain a polysaccharide liposome suspension; the macromolecular phospholipids and polysaccharide conjugates were physically removed through the filter membrane, and the size of the liposomes was reduced by extrusion, so that the liposomes can exist in the suspension with high stability without freeze-drying.

[0033] The morphology of liposomes was observed using a JEM-2800 transmission electron microscope. Figure 1 It can be seen that the prepared liposomes are single-layer membrane structures with uniform sizes and a particle size of about 200 nm, which meets the liposome standards.

[0034] Example 2 A liposome suitable for water-soluble polysaccharide protection comprises 10 parts of wolfberry polysaccharide, 25 parts of soybean lecithin and 5 parts of cholesterol in every 100 mL of anhydrous ethanol solvent in parts by weight.

[0035] Preferably, the phospholipid is soy lecithin.

[0036] A method for preparing liposomes protected by water-soluble polysaccharides is as follows: Drying the Lycium barbarum polysaccharide at a constant temperature of 40° C. for 26 hours to obtain Lycium barbarum polysaccharide powder; Dissolve the wolfberry polysaccharide powder in ultrapure water at a final concentration of 10 mg / mL to obtain a wolfberry polysaccharide solution; Accurately weigh the above amount of lecithin and cholesterol, place them in a dry and clean eggplant-shaped flask, and add an appropriate amount of anhydrous ethanol to dissolve them. Evaporate the anhydrous ethanol quickly under reduced pressure in a 55°C water bath to form a uniform lipid film on the wall of the eggplant-shaped flask.

[0037] 100 mL of Lycium barbarum polysaccharide solution was injected into a container containing a lipid film, and the solution was rotated at 50°C for 70 min until the lipid film was completely detached and dissolved, and then ultrasonic emulsification was performed for 20 min, and then the solution was filtered through a microporous filter membrane with a pore size of 0.45 μm for 3 times, a microporous filter membrane with a pore size of 0.22 μm for 3 times, and a microporous filter membrane with a pore size of 0.1 μm for 3 times to obtain a polysaccharide liposome suspension; NanoBrook 90 Plus PALS laser particle size Zeta potential analyzer was used to analyze the changes in liposome particle size and potential during the 28-day storage period. The liposomes were stored in suspension form for 28 days, and the particle size remained at about 200 nm, without significant swelling ( Figure 2 ). Although the absolute value of Zeta potential decreased, it was not significant. At the same time, the absolute value of Zeta potential was always higher than 20, indicating that the liposomes were extremely stable ( Figure 3 ).

[0038] Example 3 A liposome suitable for water-soluble polysaccharide protection comprises 5 parts of wolfberry polysaccharide, 20 parts of egg yolk lecithin and 4 parts of cholesterol in every 100 mL of acetonitrile solvent in parts by weight.

[0039] A method for preparing liposomes suitable for water-soluble polysaccharide protection is as follows: Drying the Lycium barbarum polysaccharide at a constant temperature of 40° C. for 26 hours to obtain Lycium barbarum polysaccharide powder; Dissolve the wolfberry polysaccharide powder in ultrapure water at a final concentration of 5 mg / mL to obtain a wolfberry polysaccharide solution; Accurately weigh the above amount of lecithin and cholesterol, place them in a dry and clean eggplant-shaped flask, add an appropriate amount of acetonitrile to dissolve them, and evaporate the acetonitrile under reduced pressure in a 55°C water bath to quickly remove the acetonitrile, so that the phospholipid membrane material forms a uniform lipid film on the wall of the eggplant-shaped flask.

[0040] 100 mL of Lycium barbarum polysaccharide solution was injected into a container containing a lipid film, and the solution was rotated at 50°C for 70 min until the lipid film was completely detached and dissolved, and then ultrasonic emulsification was performed for 15 min, and then the solution was filtered through a microporous filter membrane with a pore size of 0.45 μm for 3 times, a microporous filter membrane with a pore size of 0.22 μm for 3 times, and a microporous filter membrane with a pore size of 0.1 μm for 3 times to obtain a polysaccharide liposome suspension; The liposomes stored for 0 and 28 days were digested in vitro by an in vitro digestion method, and the recovery rate and bioaccessibility of the polysaccharides were determined. The specific method was as follows: 1 mL of the sample was placed in 3 mL of simulated gastric fluid with a pH of 3 and placed in a dialysis bag with a molecular weight cutoff of 2 kDa; the dialysis bag was placed in a beaker containing 150 mL of release medium and oscillated at 37°C and 100 r / min for 2 h; then, the pH of the solution was adjusted to 7.5 and 3 mL of simulated intestinal fluid was added; then the dialysis bag was placed in a beaker containing 150 mL of release medium and oscillated at 37°C and 100 r / min for 24 h. The simulated gastric fluid consisted of 2 g / L NaCl, 7 mL HCl, 3.2 g / L pepsin, and 5 g / L lipase, and the release medium consisted of 75 mL ethanol and 75 mL enzyme-free simulated gastric fluid; the simulated intestinal fluid consisted of 6.8 g / L potassium dihydrogen phosphate, 10 g / L trypsin, 5 g / L lipase, and 12 g / L porcine bile salt, with a pH of 7.5. 3 mL of dialysate was collected at a specific time point, and an equal volume of fresh medium was added, and the dialysate absorbance was determined by the phenol-sulfuric acid method. As can be seen from the figure, the liposomes had good oral and gastric digestion stability and intestinal digestibility at both 0 and 28 days ( Figure 4 ).

[0041] In summary, the present invention discloses a liposome suitable for water-soluble polysaccharide protection and a preparation method thereof, which relates to the technical field of pharmaceutical preparations. According to the weight percentage, each 100 mL of solvent includes 1 to 10 parts of Lycium barbarum polysaccharide, 15 to 25 parts of phospholipids, and 3 to 5 parts of cholesterol. The present invention prepares liposomes by reverse evaporation of polysaccharides, and prepares highly stable polysaccharide liposomes by controlling the mass ratio, film-forming time, stirring and ultrasonic time between polysaccharides, lecithin and cholesterol. The preparation process is simple and easy to operate, the bioaccessibility is improved, it is easy to promote and apply, the steps are simple, and it is easy to operate. The prepared liposomes have the advantages of high encapsulation rate, overcoming the instability of polysaccharides and not requiring additional surfactants, no harmful waste discharge, and high comprehensive resource utilization.

Claims

1. A method for preparing liposomes protected by water-soluble polysaccharides, characterized in that: The specific steps are as follows: Phospholipids and cholesterol are added to a solvent to prepare an oil phase mixture, and a lipid film is obtained by distillation; The wolfberry polysaccharide solution is mixed with the lipid film, and the lipid film is dissolved and then emulsified to obtain a mixed solution; The mixed solution was filtered through microporous filter membranes with pore sizes of 0.45 μm, 0.22 μm and 0.1 μm in sequence to obtain a polysaccharide liposome suspension, namely, wolfberry polysaccharide liposome.

2. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: In terms of weight, every 100 mL of the solvent includes 1 to 10 parts of wolfberry polysaccharide, 15 to 25 parts of phospholipids, and 3 to 5 parts of cholesterol.

3. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: The concentration of Lycium barbarum polysaccharide solution is 1mg / mL~10mg / mL.

4. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: The phospholipid is lecithin, and the lecithin can be soybean lecithin or egg yolk lecithin.

5. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: The solvent is an organic solvent, and the organic solvent includes any one of methanol, anhydrous ethanol, ether, acetone or acetonitrile, or a combination of at least two thereof.

6. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: In the step of adding phospholipids and cholesterol to a solvent to prepare an oil phase mixture and distilling to obtain a lipid film, specifically: Phospholipids and cholesterol are added to a solvent to prepare an oil phase mixture, and a lipid film is obtained by vacuum distillation. The evaporation rate of the organic solvent is 50 mL to 100 mL of organic solvent every 20 min to 30 min.

7. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: In the step of adding phospholipids and cholesterol to a solvent to prepare an oil phase mixture and distilling to obtain a lipid film, specifically: The ratio of the total mass of the phospholipid and cholesterol after mixing to the volume of the solvent is 0.9~0.72:50~100.

8. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: In the step of mixing the Lycium barbarum polysaccharide solution with the lipid film, and emulsifying the lipid film after dissolving to obtain a mixed solution, specifically: The wolfberry polysaccharide solution was injected into a container containing a lipid film, and the container was rotated at 50 r / min~70 r / min for 50 min~70 min at 50°C to completely remove and dissolve the lipid film, and then ultrasonic emulsification was performed for 10 min~20 min to obtain a mixed solution.

9. The method for preparing liposomes suitable for protection by water-soluble polysaccharides according to claim 1, characterized in that: The mixed solution is filtered through microporous membranes with pore sizes of 0.45 μm, 0.22 μm and 0.1 μm in sequence to obtain a polysaccharide liposome suspension, i.e., a step of preparing wolfberry polysaccharide liposomes, specifically: The mixed solution was sequentially passed through a microporous filter membrane with a pore size of 0.45 μm for 3 times, a microporous filter membrane with a pore size of 0.22 μm for 3 times, and a microporous filter membrane with a pore size of 0.1 μm for 3 times to obtain a polysaccharide liposome suspension.

10. A liposome suitable for protection of water-soluble polysaccharides, characterized in that: The preparation method according to any one of claims 1 to 9 is used to prepare the lycium barbarum polysaccharide liposomes with a particle size of 100nm to 200nm. The lycium barbarum polysaccharide liposomes are stored in the form of a suspension for 28 days, and the particle size is 130nm to 230nm; the absolute value of the Zeta potential is 32mV to 42mV.

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