Method for improving drug encapsulation efficiency of magnetic liposome

Abstract

The invention discloses a method for improving the drug encapsulation efficiency of a magnetic liposome. The method specifically comprises the following steps: placing a prepared drug-loaded magnetic liposome suspension in an alternating magnetic field; wherein the intensity of the alternating magnetic field is 100-400 A / m, and the action time of the magnetic field is 2-15 min. The method provided by the invention not only can effectively improve the hydrophilic drug encapsulation efficiency of the magnetic liposome, but also can effectively improve the structural stability of the drug-loaded magnetic liposome, thereby effectively solving the problem of drug burst release of the drug-loaded magnetic liposome in a physiological environment caused by non-uniform coating of magnetic nanoparticles outside the liposome.

Description

Technical Field

[0001] The invention relates to a method for improving the encapsulation efficiency of magnetic liposome drugs. Background Art

[0002] Liposomes are closed vesicles composed of a lipid bilayer with a unique amphiphilic structure that can encapsulate drugs within their internal aqueous phase or bilayer, thereby achieving efficient drug delivery. Magnetic liposomes, based on traditional liposomes, incorporate magnetic nanoparticles. They combine the biocompatibility of liposomes with the magnetic targeting properties of magnetic nanoparticles. Guided by an external magnetic field, they can achieve precise drug delivery, significantly increasing drug concentration at the site of disease and reducing toxicity to normal tissues.

[0003] Drug encapsulation efficiency is one of the key indicators for measuring liposome quality. A low encapsulation efficiency means that a large amount of drugs cannot be effectively encapsulated inside the liposomes, which not only reduces the drug delivery efficiency but may also increase the toxic side effects of drugs on normal tissues during the delivery process. Therefore, it is of great significance to improve the drug encapsulation efficiency of functional liposomes such as liposomes and magnetic liposomes.

[0004] In order to improve the encapsulation efficiency of hydrophilic drugs in liposomes, existing methods include solvent evaporation, reverse phase evaporation, and the addition of polymer excipients. Solvent evaporation and reverse phase evaporation methods increase the aqueous space within the liposome by removing the solvent, thereby achieving the effect of improving the encapsulation efficiency of hydrophilic drugs (the encapsulation efficiency of hydrophilic drugs by solvent evaporation is generally up to about 30%, the encapsulation efficiency of hydrophilic drugs by reverse phase evaporation is generally up to about 60%, and the encapsulation efficiency of polymer excipients is generally up to about 50%). However, solvent-based methods may leave residual solvents, which may cause drug degradation or damage to the lipid membrane. The incorporation of polymer excipients improves the encapsulation efficiency of hydrophilic drugs by changing the lipid composition, but this method greatly increases the complexity of the preparation process. Summary of the Invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a method for preparing drug-loaded magnetic liposomes that can not only effectively improve the encapsulation efficiency of magnetic liposomes for hydrophilic drugs, but also effectively improve the structural stability of drug-loaded magnetic liposomes.

[0006] Technical solution: The method for improving the drug encapsulation efficiency of magnetic liposomes described in the present invention is specifically: placing the prepared drug-loaded magnetic liposome suspension in an alternating magnetic field; wherein the intensity of the alternating magnetic field is 100-400 A / m, and the magnetic field action time is 2-15 minutes.

[0007] More preferably, the intensity of the alternating magnetic field is 150-300 A / m, and the magnetic field exposure time is 4-10 minutes. Excessively high magnetic field intensity (500 A / m) can generate significant heat instantaneously, potentially causing liposome membrane rupture. Excessively long exposure time (over 10 minutes) can lead to frequent contact between liposomes with high membrane fluidity, resulting in liposome fusion, thereby preventing the drug-loaded magnetic liposomes from achieving sustained release.

[0008] The drug-loaded magnetic liposome suspension is prepared by the following method: phospholipids and cholesterol are mixed, dissolved in an organic solvent, and ultrasonically treated until dissolved to obtain a phospholipid solution; the phospholipid solution is slowly injected into degassed ultrapure water, and ultrasonically treated to obtain a uniform liposome dispersion; drugs and magnetic nanoparticles are added to the liposome dispersion, and ultrasonically treated to obtain a drug-loaded magnetic liposome suspension.

[0009] The phospholipid layer of the drug-loaded magnetic liposome suspension is composed of phospholipids and cholesterol, with magnetic nanoparticles attached to its surface and hydrophilic drugs wrapped inside. In degassed ultrapure water, the concentration of the added phospholipids is 10-1000 μg / mL, the concentration of the added magnetic nanoparticles is 10-50 μg / mL, and the concentration of the added drugs is 50-1000 μg / mL.

[0010] The organic solvent is chloroform, diethylene glycol monoethyl ether, ethanol or a mixture thereof; the phospholipid is soybean lecithin, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, 1-palmitoyl-2-myristoylphosphatidylcholine, dipalmitoylphosphatidylglycerol, distearoylphosphatidylglycerol, dimyristoylphosphatidylglycerol, dipalmitoylphosphatidylethanolamine, dilauroylphosphatidylethanolamine, dimyristoylphosphatidylethanolamine, 1-stearoyl-2-oleoylphosphatidylcholine, 1-palmitoyl-2-myristoylphosphatidylcholine, 1-stearoyl-2-palmitoylphosphatidyl One of choline, dimyristoylphosphatidylserine, distearoylphosphatidylserine or 1-palmitoyl-2-oleoylphosphatidylethanolamine or a mixture thereof; the mass ratio of cholesterol to phospholipid is 1:2 to 1:4; the drug is a mixture of one or more of doxorubicin hydrochloride, cytarabine, doxorubicin (DOX) base, beclomethasone dipropionate, magnesium ascorbyl phosphate, resveratrol or gemcitabine; the magnetic nanoparticles are superparamagnetic iron oxide nanoparticles, the surface of which is modified with oleic acid, citric acid, chitosan, polyethylene glycol, polyethyleneimine or polylysine, and the particle size is 5 to 120 nm.

[0011] The temperature of the ultrasonic treatment is 20-60° C., the ultrasonic power is 10-30 W, and the ultrasonic time is 10-60 min.

[0012] Under an alternating magnetic field, the magnetic nanoparticles on the surface of drug-loaded magnetic liposomes can convert magnetic energy into thermal energy, generating a magnetocaloric effect, inducing a phase change of phospholipid molecules from a glassy state to a fluid state. In this process, drug molecules attached to the outside of the phospholipid layer enter the interior of the magnetic liposomes, promoting the encapsulation of drug molecules, resulting in an increase in the drug content in the water core / lipid bilayer of the magnetic liposomes, thereby achieving an increase in the drug encapsulation rate; at the same time, the self-assembled magnetic nanoparticles can be more evenly coated outside the liposomes, increasing the density of the liposome structure, thereby effectively inhibiting the problem of drug burst release from liposomes under physiological conditions during drug delivery, thereby effectively improving the structural stability of drug-loaded magnetic liposomes under physiological conditions.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the method of the present invention can not only effectively improve the encapsulation rate of hydrophilic drugs in magnetic liposomes, but also effectively improve the structural stability of drug-loaded magnetic liposomes, and effectively solve the problem of drug burst release from drug-loaded magnetic liposomes under physiological conditions due to uneven coating of magnetic nanoparticles outside the liposomes; therefore, the method of the present invention can improve the drug encapsulation rate of magnetic liposomes while effectively suppressing the burst release effect, thereby obtaining drug-loaded magnetic liposomes with good drug delivery effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 These are transmission electron micrographs of the magnesium ascorbyl phosphate magnetic liposomes in Example 1 before and after the action of an alternating magnetic field; (a) is the magnetic liposome before the action of an alternating magnetic field; (b) is the magnetic liposome after the action of an alternating magnetic field. DETAILED DESCRIPTION

[0015] Example 1

[0016] The method for improving the drug encapsulation efficiency of magnetic liposomes of the present invention comprises the following steps:

[0017] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and ultrasonically treated until dissolved to obtain a mixed solution (mixed solution of soybean lecithin and cholesterol); the mixed solution was slowly injected into degassed ultrapure water, and ultrasonically treated at 50°C and 30W for 30 minutes to obtain a uniform liposome dispersion, and the added concentration of soybean lecithin was 500 μg / mL relative to the degassed ultrapure water; magnesium ascorbyl phosphate and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and ultrasonically treated at 50°C and 30W for 60 minutes to form a magnesium ascorbyl phosphate magnetic liposome suspension (the added concentration of magnesium ascorbyl phosphate was 300 μg / mL and the added concentration of magnetic nanoparticles was 30 μg / mL relative to the degassed ultrapure water); Figure 1 (a)

[0018] (2) Add 2 mL of magnesium ascorbyl phosphate magnetic liposome suspension to a vial, place it in a magnetic field strength of 150 A / m and apply an alternating magnetic field for 4 minutes. The temperature is changed from 24°C to 26°C. After cooling, drug-loaded magnetic liposomes are obtained, such as Figure 1 (b) shows that the unencapsulated free magnesium ascorbyl phosphate was removed by centrifugation.

[0019] The absorbance was measured using a UV-visible spectrophotometer and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of magnesium ascorbyl phosphate. The result was an increase from 62.8% (step (1)) to 83.5% (step (2)). The in vitro drug release curve (Table 1) showed that the magnesium ascorbyl phosphate magnetic liposomes had better sustained-release properties after the alternating magnetic field, that is, the structure was more stable under physiological conditions.

[0020] Table 1 shows the in vitro drug release curve of magnesium ascorbyl phosphate magnetic liposomes before and after the alternating magnetic field

[0021]

[0022] Example 2

[0023] The method for improving the drug encapsulation efficiency of magnetic liposomes of the present invention comprises the following steps:

[0024] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution; the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C, 30W for 30 min to obtain a uniform liposome dispersion, wherein the concentration of soybean lecithin added was 500 μg / mL relative to the degassed ultrapure water; doxorubicin (DOX) base and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C, 30W for 60 min to form a doxorubicin (DOX) base magnetic liposome suspension (the concentration of doxorubicin (DOX) base added was 300 μg / mL, and the concentration of magnetic nanoparticles added was 30 μg / mL relative to the degassed ultrapure water);

[0025] (2) Add 2 mL of doxorubicin (DOX) base magnetic liposome suspension to a vial, place it in a magnetic field strength of 150 A / m and apply an alternating magnetic field for 4 minutes. The temperature is changed from 24°C to 26°C. After cooling, the drug-loaded magnetic liposomes are obtained, and the unencapsulated free doxorubicin (DOX) base is removed by centrifugation.

[0026] The absorbance was measured using a UV-visible spectrophotometer, and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of doxorubicin (DOX) base. The results showed that the drug encapsulation efficiency increased from 82.8% to 98.9%. The in vitro drug release curve (Table 2) showed that the doxorubicin (DOX) base magnetic liposomes exhibited better sustained-release properties after the alternating magnetic field, indicating that the structure was more stable under physiological conditions.

[0027] Table 2 shows the in vitro drug release curve of doxorubicin (DOX) base magnetic liposomes before and after the alternating magnetic field

[0028]

[0029] Example 3

[0030] The method for improving the drug encapsulation efficiency of magnetic liposomes of the present invention comprises the following steps:

[0031] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution (mixed solution of soybean lecithin and cholesterol); the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C and 30W for 30 min to obtain a uniform liposome dispersion, and the added concentration of soybean lecithin was 500 μg / mL relative to the degassed ultrapure water; gemcitabine and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C and 30W for 60 min to form a gemcitabine magnetic liposome suspension (the added concentration of gemcitabine was 300 μg / mL and the added concentration of magnetic nanoparticles was 30 μg / mL relative to the degassed ultrapure water);

[0032] (2) Add 2 mL of gemcitabine magnetic liposome suspension to a vial, place it in a magnetic field strength of 150 A / m and apply an alternating magnetic field for 4 minutes. The temperature is changed from 24°C to 26°C. After cooling, drug-loaded magnetic liposomes are obtained, and the unencapsulated free gemcitabine is removed by centrifugation.

[0033] The absorbance was measured using a UV-visible spectrophotometer and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the gemcitabine concentration-absorbance standard curve. The result showed that the drug encapsulation efficiency increased from 46.6% (step (1)) to 68.4%. The in vitro drug release curve (Table 3) showed that the sustained-release properties of the gemcitabine magnetic liposomes after the alternating magnetic field were better, that is, the structure was more stable under physiological conditions.

[0034] Table 3 shows the in vitro drug release curve of gemcitabine magnetic liposomes before and after the alternating magnetic field

[0035]

[0036] Comparative Example 1

[0037] The only difference between Comparative Example 1 and Example 1 is that the time for applying the alternating magnetic field in step (2) is 2 minutes, specifically:

[0038] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution; the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C and 30W for 30 min to obtain a uniform liposome dispersion, wherein the concentration of soybean lecithin added was 500 μg / mL relative to the degassed ultrapure water; magnesium ascorbyl phosphate and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C and 30W for 60 min to form a magnesium ascorbyl phosphate magnetic liposome suspension (the concentration of magnesium ascorbyl phosphate added was 300 μg / mL, and the concentration of magnetic nanoparticles added was 30 μg / mL relative to the degassed ultrapure water);

[0039] (2) Add 2 mL of magnesium ascorbyl phosphate magnetic liposome suspension to a vial, place it in a magnetic field strength of 150 A / m and apply an alternating magnetic field for 2 minutes. The temperature is changed from 24°C to 25°C. After cooling, the drug-loaded magnetic liposomes are obtained, and the unencapsulated free magnesium ascorbyl phosphate is removed by centrifugation.

[0040] The absorbance was measured using a UV-visible spectrophotometer, and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of magnesium ascorbyl phosphate. The result showed that the drug encapsulation efficiency increased from 62.8% to 75.2%. The in vitro drug release curve (Table 4) demonstrated the sustained-release properties of magnesium ascorbyl phosphate magnetic liposomes after the alternating magnetic field.

[0041] Table 4 is the in vitro drug release curve of magnesium ascorbyl phosphate magnetic liposomes before and after the alternating magnetic field action in Comparative Example 1

[0042]

[0043]

[0044] Comparative Example 2

[0045] The only difference between Comparative Example 2 and Example 1 is that the time for applying the alternating magnetic field in step (2) is 10 minutes, specifically:

[0046] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution; the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C and 30W for 30 min to obtain a uniform liposome dispersion, wherein the concentration of soybean lecithin added was 500 μg / mL relative to the degassed ultrapure water; magnesium ascorbyl phosphate and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C and 30W for 60 min to form a magnesium ascorbyl phosphate magnetic liposome suspension (the concentration of magnesium ascorbyl phosphate added was 300 μg / mL, and the concentration of magnetic nanoparticles added was 30 μg / mL relative to the degassed ultrapure water);

[0047] (2) Add 2 mL of magnesium ascorbyl phosphate magnetic liposome suspension to a vial, place it in a magnetic field strength of 150 A / m and apply an alternating magnetic field for 10 minutes. The temperature is changed from 24°C to 28°C. After cooling, the drug-loaded magnetic liposomes are obtained, and the unencapsulated free magnesium ascorbyl phosphate is removed by centrifugation.

[0048] The absorbance was measured using a UV-visible spectrophotometer and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of magnesium ascorbyl phosphate. The result was changed from 62.8% to 78.1%. The in vitro drug release curve is shown in Table 5.

[0049] Table 5 is the in vitro drug release curve of magnesium ascorbyl phosphate magnetic liposomes before and after the alternating magnetic field action of Comparative Example 2

[0050]

[0051]

[0052] Comparative Example 3

[0053] Comparative Example 3 is different from Example 1 only in that the alternating magnetic field strength in step (2) is 500 A / m, specifically:

[0054] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution; the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C and 30W for 30 min to obtain a uniform liposome dispersion, wherein the concentration of soybean lecithin added was 500 μg / mL relative to the degassed ultrapure water; magnesium ascorbyl phosphate and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C and 30W for 60 min to form a magnesium ascorbyl phosphate magnetic liposome suspension (the concentration of magnesium ascorbyl phosphate added was 300 μg / mL, and the concentration of magnetic nanoparticles added was 30 μg / mL relative to the degassed ultrapure water);

[0055] (2) Add 2 mL of magnesium ascorbyl phosphate magnetic liposome suspension to a vial, place it in a magnetic field strength of 500 A / m and apply an alternating magnetic field for 4 minutes. The temperature is changed from 24°C to 26°C. After cooling, the drug-loaded magnetic liposomes are obtained, and the unencapsulated free magnesium ascorbyl phosphate is removed by centrifugation.

[0056] The absorbance was measured using a UV-visible spectrophotometer and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of magnesium ascorbyl phosphate. The result was changed from 62.8% to 68.5%. The in vitro drug release curve is shown in Table 6.

[0057] Table 6 is the in vitro drug release curve of magnesium ascorbyl phosphate magnetic liposomes before and after the alternating magnetic field action of Comparative Example 3

[0058]

[0059] Comparative Example 4

[0060] Comparative Example 4 is different from Example 1 only in that the alternating magnetic field strength in step (2) is 50 A / m, specifically:

[0061] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution; the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C and 30W for 30 min to obtain a uniform liposome dispersion, wherein the concentration of soybean lecithin added was 500 μg / mL relative to the degassed ultrapure water; magnesium ascorbyl phosphate and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C and 30W for 60 min to form a magnesium ascorbyl phosphate magnetic liposome suspension (the concentration of magnesium ascorbyl phosphate added was 300 μg / mL, and the concentration of magnetic nanoparticles added was 30 μg / mL relative to the degassed ultrapure water);

[0062] (2) Add 2 mL of magnesium ascorbyl phosphate magnetic liposome suspension to a vial, place it in a magnetic field strength of 50 A / m and apply an alternating magnetic field for 4 minutes. The temperature is changed from 24°C to 26°C. After cooling, the drug-loaded magnetic liposomes are obtained, and the unencapsulated free magnesium ascorbyl phosphate is removed by centrifugation.

[0063] The absorbance was measured using a UV-visible spectrophotometer and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of magnesium ascorbyl phosphate. The result was changed from 62.8% to 65.6%. The in vitro drug release curve is shown in Table 7.

[0064] Table 7 is the in vitro drug release curve of magnesium ascorbyl phosphate magnetic liposomes before and after the alternating magnetic field action of Comparative Example 4

[0065]

[0066] Comparative Example 5

[0067] Comparative Example 5 is different from Example 1 only in that the concentration of magnetic nanoparticles added in step (1) is 60 μg / mL, specifically:

[0068] (1) Soy lecithin and cholesterol were mixed in a mass ratio of 3:1, dissolved in diethylene glycol monoethyl ether and sonicated until dissolved to obtain a mixed solution; the mixed solution was slowly injected into degassed ultrapure water, and sonicated at 50°C and 30W for 30 min to obtain a uniform liposome dispersion, wherein the concentration of soybean lecithin added was 500 μg / mL relative to the degassed ultrapure water; magnesium ascorbyl phosphate and citric acid-modified superparamagnetic iron oxide nanoparticles (particle size of 7 nm) were added to the liposome dispersion, and sonicated at 50°C and 30W for 60 min to form a magnesium ascorbyl phosphate magnetic liposome suspension (the concentration of magnesium ascorbyl phosphate added was 300 μg / mL and the concentration of magnetic nanoparticles added was 60 μg / mL relative to the degassed ultrapure water);

[0069] (2) Add 2 mL of magnesium ascorbyl phosphate magnetic liposome suspension to a vial, place it in a magnetic field strength of 150 A / m and apply an alternating magnetic field for 4 minutes. The temperature is changed from 24°C to 27°C. After cooling, the drug-loaded magnetic liposomes are obtained, and the unencapsulated free magnesium ascorbyl phosphate is removed by centrifugation.

[0070] The absorbance was measured using a UV-visible spectrophotometer and the drug encapsulation efficiency of the drug-loaded magnetic liposomes before and after the alternating magnetic field was calculated based on the concentration-absorbance standard curve of magnesium ascorbyl phosphate. The result was changed from 62.8% to 80.3%. The in vitro drug release curve is shown in Table 8.

[0071] Table 8 is the in vitro drug release curve of magnesium ascorbyl phosphate magnetic liposomes in comparative example 5 before and after the alternating magnetic field

[0072]

Claims

1. A method for improving the drug encapsulation efficiency of magnetic liposomes, characterized in that: Specifically, the prepared drug-loaded magnetic liposome suspension is placed in an alternating magnetic field; wherein the intensity of the alternating magnetic field is 100-400 A / m, and the magnetic field action time is 2-15 minutes.

2. The method according to claim 1, wherein: The intensity of the alternating magnetic field is 150-300 A / m, and the magnetic field action time is 4-10 minutes.

3. The method according to claim 1, wherein: The drug-loaded magnetic liposome suspension is prepared by the following method: phospholipids and cholesterol are mixed, dissolved in an organic solvent, and ultrasonically treated until dissolved to obtain a phospholipid solution; the phospholipid solution is slowly injected into degassed ultrapure water, and ultrasonically treated to obtain a uniform liposome dispersion; drugs and magnetic nanoparticles are added to the liposome dispersion, and ultrasonically treated to obtain a drug-loaded magnetic liposome suspension.

4. The method according to claim 3, wherein: In the degassed ultrapure water, the concentration of the added phospholipid is 10-1000 μg / mL, the concentration of the added magnetic nanoparticles is 10-50 μg / mL, and the concentration of the added drug is 50-1000 μg / mL.

5. The method according to claim 3, wherein: The added mass ratio of cholesterol to phospholipid is 1:2 to 1:

4.

6. The method according to claim 3, wherein: The organic solvent is chloroform, diethylene glycol monoethyl ether, ethanol or a mixture thereof.

7. The method according to claim 3, wherein: The phospholipid is one of soybean lecithin, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine, distearoylphosphatidylcholine, 1-palmitoyl-2-myristoylphosphatidylcholine, dipalmitoylphosphatidylglycerol, distearoylphosphatidylglycerol, dimyristoylphosphatidylglycerol, dipalmitoylphosphatidylethanolamine, dilauroylphosphatidylethanolamine, dimyristoylphosphatidylethanolamine, 1-stearoyl-2-oleoylphosphatidylcholine, 1-palmitoyl-2-myristoylphosphatidylcholine, 1-stearoyl-2-palmitoylphosphatidylcholine, dimyristoylphosphatidylserine, distearoylphosphatidylserine or 1-palmitoyl-2-oleoylphosphatidylethanolamine, or a mixture thereof.

8. The method according to claim 3, wherein: The drug is a mixture of one or more of doxorubicin hydrochloride, cytarabine, doxorubicin base, beclomethasone dipropionate, magnesium ascorbyl phosphate, resveratrol or gemcitabine.

9. The method according to claim 3, wherein: The magnetic nanoparticles are superparamagnetic iron oxide nanoparticles, the surface of which is modified with oleic acid, citric acid, chitosan, polyethylene glycol, polyethyleneimine or polylysine, and the particle size is 5 to 120 nm.

10. The method according to claim 3, wherein: The temperature of the ultrasonic treatment is 20-60° C., the ultrasonic power is 10-30 W, and the ultrasonic time is 10-60 min.

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