Mitoxantrone-cholesterol prodrug and self-assembled nanoparticles thereof and preparation method thereof

Abstract

The application relates to a mitoxantrone-cholesterol prodrug and self-assembled nanoparticles and a preparation method thereof, and belongs to the technical field of medicines, and particularly relates to a redox-sensitive mitoxantrone-cholesterol prodrug and construction of self-assembled nanoparticles containing the prodrug, and application of the self-assembled nanoparticles in the field of drug delivery. A 2,2'-dithiodiglycolic acid bridged mitoxantrone-cholesterol prodrug is synthesized, and a prodrug self-assembled nanoparticle is prepared. The mitoxantrone-cholesterol prodrug self-assembled nanoparticle of the application significantly reduces the systemic toxicity of mitoxantrone on the basis of ensuring the curative effect, and has better tolerance and a higher tolerance dose.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to a mitoxantrone-cholesterol prodrug, its self-assembled nanoparticles, and its preparation method. Background Technology

[0002] Cancer poses a serious threat to human health. Chemotherapy is currently one of the most commonly used strategies for cancer treatment, especially for advanced tumors, tumors that cannot be surgically removed, and tumors that have metastasized. Mitoxantrone (MTO) is a non-specific drug that affects the cell cycle. It acts on the nucleic acid sites of cells, causing abnormal nucleic acid synthesis in tumor cells, thereby exerting an anti-tumor effect. It is used to treat advanced breast cancer, chronic lymphocytic leukemia, and adult acute lymphoblastic leukemia. However, mitoxantrone is not selective for tumor cells and has serious side effects such as myelosuppression and cardiotoxicity. In addition, mitoxantrone is composed of an anthraquinone core and side chains containing amino and hydroxyl groups. This unique structure makes it neither strongly hydrophilic nor lipophilic, and its solubility in water and organic solvents is poor, which seriously hinders the clinical application of its conventional formulations.

[0003] Prodrug strategies and nanotechnology are widely used to improve the delivery of chemotherapy drugs. Prodrugs themselves have little or no biological activity, but they can be metabolized in vivo to become active parent drugs and exert their effects. Prodrug strategies can improve problems such as low drug solubility, poor stability, and significant side effects. However, small molecule prodrugs lack tumor targeting and are rapidly cleared or prematurely degraded in vivo, leading to low therapeutic efficiency. Loading drugs into nanoparticles can improve drug pharmacokinetics and in vivo distribution, thereby helping to improve the drug's tumor targeting and reduce its toxic side effects on normal tissues. However, traditional nanoformulations often load drugs through physical encapsulation, which has drawbacks such as low drug loading (generally less than 10%) and poor safety of carrier materials. In contrast, small molecule prodrug self-assembled nanoparticles combine the advantages of prodrugs and nanotechnology, resulting in high drug loading, avoiding adverse reactions caused by carrier materials, simple preparation processes, good reproducibility, and good application transformation potential.

[0004] Studies have shown that hydrophobic interactions are the driving force behind the self-assembly of small molecule prodrugs. Therefore, to construct prodrugs with self-assembly capabilities, it is usually necessary to link the drug with a lipophilic side chain to enhance its hydrophobicity. Lipophilic side chains do not possess pharmacological activity; their primary function is to enhance the flexibility of the drug molecule, balance intermolecular forces, and promote prodrug self-assembly. Most existing prodrugs use fatty acids or fatty alcohols as side chains. Compared to fatty acids or fatty alcohols, cholesterol is more hydrophobic and exhibits better biocompatibility and biodegradability. Modifying the structure of mitoxantrone with cholesterol holds promise for constructing self-assembly-capable prodrugs, enabling efficient delivery of mitoxantrone. Any form of antitumor drug delivery system requires the release of active drug at the tumor site, which is crucial for the efficacy and safety of antitumor drugs. The high redox state at the tumor site can trigger drug release, making redox-responsive nanomedicines a promising candidate for cancer treatment. Introducing disulfide bonds, diselenyl bonds, monosulfide bonds, or monoselenide bonds with dual redox responsiveness into the structure of prodrugs holds promise for achieving intelligent activation and drug release at the tumor site. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a mitoxantrone-cholesterol prodrug, its self-assembled nanoparticles, and a preparation method thereof. Specifically, it involves the construction of a redox-sensitive mitoxantrone-cholesterol prodrug and self-assembled nanoparticles containing the prodrug. The self-assembled nanoparticles formed from this mitoxantrone-cholesterol prodrug possess advantages such as uniform particle size, high drug loading, good stability, and good safety. Furthermore, the mitoxantrone-cholesterol prodrug more effectively disrupts the aggregation forces of drug molecules, further enhancing the prodrug's self-assembly ability. The mitoxantrone-cholesterol prodrug and self-assembled nanoparticles of this invention significantly reduce the toxic side effects of mitoxantrone, increase the tolerable dose of mitoxantrone, and provide more options and approaches for mitoxantrone delivery, meeting the urgent clinical need for highly effective and low-toxicity chemotherapy drugs.

[0006] To achieve the above objectives, the present invention provides a method for synthesizing mitoxantrone-cholesterol prodrug, comprising the following steps:

[0007] (1) Dissolve the dicarboxylic acid in acetic anhydride (AC2O), stir at room temperature for 1-3 h to obtain the dicarboxylic acid anhydride, add toluene, and remove toluene and acetic anhydride by rotary evaporation under reduced pressure;

[0008] (2) Dissolve cholesterol and the dicarboxylic acid anhydride obtained in step (1) above in dichloromethane, and then add the 4-dimethylaminopyridine (DMAP) dissolved in dichloromethane dropwise to the above reaction system. Stir at room temperature for 6-24 hours, and separate the cholesterol-dicarboxylic acid monoester by chromatography column.

[0009] (3) Dissolve the cholesterol-diacid monoester obtained in step (2) in anhydrous dichloromethane, and then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), 1-hydroxybenzotriazole (HOBT) and 4-dimethylaminopyridine (DMAP) dissolved in dichloromethane dropwise under ice bath conditions. Stir in an ice-salt bath for 2-5 h under nitrogen protection. After the reaction is completed, add mitoxantrone raw material dissolved in anhydrous dichloromethane. React at room temperature for 24-32 h under nitrogen protection. Then, mitoxantrone-cholesterol prodrug is obtained by preparative liquid phase separation and purification.

[0010] The molar ratio of the dicarboxylic acid to acetic anhydride (AC2O) in step (1) above is 1:1-100;

[0011] The volume ratio of acetic anhydride (AC2O) to toluene in step (1) above is 1:3-10;

[0012] The dicarboxylic acid mentioned in step (1) above includes one of dithiodicarboxylic acid, diselenodicarboxylic acid, monothiodicarboxylic acid, or monoselenodicarboxylic acid, wherein the dithiodicarboxylic acid is 2,2'-dithiodiacetic acid, 3,3'-dithiodipropionic acid, or 4,4'-dithiodibutyric acid; the diselenodicarboxylic acid is 2,2'-diselenodicarboxylic acid, 3,3'-diselenodipropionic acid, or 4,4'-diselenodibutyric acid; the monothiodicarboxylic acid is monothiodicarboxylic acid, monothiodipropionic acid, or monothiodibutyric acid; and the monoselenodicarboxylic acid is monoselenodicarboxylic acid, monoselenodipropionic acid, or monoselenodibutyric acid.

[0013] The molar ratio of dicarboxylic anhydride, 4-dimethylaminopyridine (DMAP), and cholesterol in step (2) above is 1:0.05-2:1-10;

[0014] The molar ratio of mitoxantrone, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), 1-hydroxybenzotriazole (HOBT), 4-dimethylaminopyridine (DMAP), and cholesterol-dicarboxylic acid monoester in step (3) above is 1:1-5:1-5:1-5;

[0015] The purity of the final product mitoxantrone-cholesterol prodrug described in step (3) above is greater than 95%;

[0016] The general formula of the mitoxantrone-cholesterol prodrug described in step (3) above is as follows:

[0017]

[0018] Where n = 1 to 3;

[0019] R is one of a disulfide bond, a monosulfide bond, a diselenide bond, or a monoselenide bond;

[0020] The mitoxantrone-cholesterol prodrug self-assembled nanoparticles proposed in this invention can be non-PEGylated prodrug self-assembled nanoparticles or PEG-modified prodrug self-assembled nanoparticles.

[0021] Specifically, the preparation method of mitoxantrone-cholesterol prodrug self-assembled nanoparticles provided by the present invention is as follows:

[0022] a. Dissolve the mitoxantrone-cholesterol prodrug and the modifier in an organic solvent;

[0023] b. Under stirring conditions, slowly add the solution obtained in step a to the aqueous solution;

[0024] c. Distillation is used to remove the organic solvent from the solution obtained in step b, yielding mitoxantrone-cholesterol prodrug self-assembled nanoparticles.

[0025] The PEG modifiers mentioned in step a above include TPGS, DSPE-PEG, PLGA-PEG and PE-PEG, and the molecular weight of the PEG modifiers is 1000-5000;

[0026] The mass ratio of mitoxantrone-cholesterol prodrug to PEG modifier in step a above is 1:0.1-5;

[0027] The organic solvent mentioned in step a above is one of methanol, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide or acetone; the volume ratio of the organic solvent to the aqueous solution is 1:4-20, preferably 1:4-10;

[0028] The distillation described in step c above is specifically carried out under reduced pressure at 25-35°C.

[0029] The present invention has the following beneficial effects:

[0030] (1) The present invention designs and synthesizes mitoxantrone-cholesterol prodrug, and the synthesis method is simple and easy to perform;

[0031] (2) Self-assembled nanoparticles of mitoxantrone-cholesterol prodrug with small particle size and uniform particle size distribution were prepared by a simple and easy method.

[0032] (3) The formulation properties, cytotoxicity, pharmacokinetics, antitumor effects and safety of the prodrug self-assembled nanoparticles were investigated. The results showed that the mitoxantrone-cholesterol prodrug self-assembled nanoparticles had good antitumor effects and could effectively reduce the toxic side effects of mitoxantrone.

[0033] (4) This invention provides more options for developing new prodrugs and their self-assembled nanoparticles as nanomedicine delivery systems, meeting the urgent clinical need for highly effective and low-toxicity chemotherapy agents. Attached Figure Description

[0034] Figure 1 This is the mass spectrum of the 2,2'-dithiodiacetic acid-bridged mitoxanone-cholesterol prodrug of Example 1 of the present invention;

[0035] Figure 2 This is a blood drug concentration-time curve of the mitoxantrone-cholesterol prodrug self-assembled nanoparticles of Example 3 of the present invention;

[0036] Figure 3 This is a blood drug concentration-time curve of the parent drug of the mitoxantrone-cholesterol prodrug self-assembled nanoparticles in Example 3 of the present invention;

[0037] Figure 4 This is a graph showing the concentration-time of the prodrug parent drug and the blood drug concentration of the mitoxantrone-cholesterol prodrug self-assembled nanoparticles in Example 3 of the present invention.

[0038] Figure 5 This is a 4T1 cytotoxicity diagram of the mitoxantrone-cholesterol prodrug self-assembled nanoparticles of Example 4 of the present invention.

[0039] Figure 6 This is a graph showing the change in mouse tumor volume during the in vivo antitumor experiment of mitoxantrone-cholesterol prodrug self-assembled nanoparticles in Example 5 of the present invention.

[0040] *: P<0.05; ***: P<0.001.

[0041] Figure 7 This is a tumor load diagram from the in vivo antitumor experiment of mitoxantrone-cholesterol prodrug self-assembled nanoparticles in Example 5 of the present invention.

[0042] *: P<0.05; ***: P<0.001; ns: No significant difference.

[0043] Figure 8 This is a graph showing the change in mouse body weight during the in vivo antitumor experiment of mitoxantrone-cholesterol prodrug self-assembled nanoparticles in Example 5 of the present invention.

[0044] ****:P<0.0001.

[0045] Figure 9 This is a comparison of leukocytes, lymphocytes, monocytes, and neutrophils in the in vivo antitumor experiment of mitoxantrone-cholesterol prodrug self-assembled nanoparticles of Example 5 of the present invention.

[0046] Figure 10This is a comparison of the percentages of lymphocytes, monocytes, and neutrophils in the in vivo antitumor experiment of the mitoxantrone-cholesterol prodrug self-assembled nanoparticles of Example 5 of the present invention. Detailed Implementation

[0047] The present invention will be further illustrated by way of embodiments below, but the invention is not limited to the scope of the embodiments described herein.

[0048] The mitoxantrone-cholesterol prodrug provided by this invention, wherein the mitoxantrone-cholesterol prodrug (MTO-SS-CLS) is a 2,2'-dithiodiacetic acid-bridged linker or a pharmaceutically acceptable salt thereof, has the following structural formula:

[0049]

[0050] This invention provides the application of mitoxantrone-cholesterol prodrug or mitoxantrone-cholesterol prodrug self-assembled nanoparticles in drug delivery, injection administration, oral administration or topical administration, and antitumor drugs.

[0051] Example 1

[0052] Synthesis of mitoxantrone-cholesterol prodrug bridged by 2,2'-dithiodiacetic acid

[0053] 2,2'-Dithiodiacetic acid was dissolved in acetic anhydride in a 25 mL round-bottom flask. After complete dissolution, the mixture was magnetically stirred at 25 °C for 2 hours under nitrogen protection. The solution was then transferred to a 100 mL round-bottom flask, and three times the volume of toluene was added. The toluene and acetic anhydride were removed by rotary evaporation under reduced pressure to obtain dithiodiacetic anhydride. In the reaction, the molar ratio of 2,2'-dithiodiacetic acid to acetic anhydride was 1:10.

[0054] Dithiodiacetic anhydride, formed by dissolving in dichloromethane, was added, followed by a dichloromethane solution containing cholesterol. A solution of 4-dimethylaminopyridine (DMAP) dissolved in dichloromethane was then slowly added dropwise. The mixture was magnetically stirred at 25°C for 12 hours under nitrogen protection to obtain the intermediate product, cholesterol-dithiodiacetic anhydride monoester. The purified cholesterol-dithiodiacetic anhydride monoester was obtained by column chromatography using a cyclohexane-ethyl acetate elution system. The molar ratio of DMAP:cholesterol:dithiodiacetic anhydride was 0.1:1.5:1.

[0055] The purified cholesterol-dithiodiacetic acid monoester was dissolved in anhydrous dichloromethane solution. Then, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), 1-hydroxybenzotriazole (HOBT), and 4-dimethylaminopyridine (DMAP) dissolved in dichloromethane were added dropwise under ice bath conditions. The reaction was activated at 0°C for 2 hours under nitrogen protection. Mitoxantrone dissolved in dichloromethane solution was then added, and the mixture was stirred at 25°C for 24 hours under nitrogen protection. After the reaction was complete, the product was separated from the preparation solution to obtain the 2,2'-dithiodiacetic acid-bridged mitoxantrone-cholesterol prodrug. The molar ratio of mitoxantrone:EDCI:HOBT:DMAP:cholesterol-dicarboxylic acid monoester was 1:0.6:0.3:1.

[0056] The structure of the product was confirmed by mass spectrometry, and the mass spectrum is shown below. Figure 1 As shown.

[0057] Example 2

[0058] Preparation of self-assembled nanoparticles of mitoxantrone prodrug without PEGylation / PEG modification

[0059] Non-PEGylated mitoxantrone-cholesterol prodrug self-assembled nanoparticles: 2 mg of mitoxantrone-cholesterol prodrug was accurately weighed and dissolved in 0.2 mL of methanol. While stirring, the solution was slowly added dropwise to 1.8 mL of aqueous solution, where the prodrug spontaneously formed uniform self-assembled nanoparticles. The organic solvent in the formulation was removed by rotary evaporation at 30 °C to obtain non-PEGylated MTO-SS-CLS nanoparticles.

[0060] PEGylated mitoxantrone-cholesterol prodrug self-assembled nanoparticles: Accurately weigh 4 mg of mitoxantrone-cholesterol prodrug and DSPE-PEG 2k 1 mg of the prodrug was dissolved in 0.4 mL of methanol. While stirring, the solution was slowly added dropwise to 3.6 mL of aqueous solution, causing the prodrug to spontaneously form uniform self-assembled nanoparticles. The organic solvent in the formulation was removed by rotary evaporation at 30 °C to obtain PEGylated MTO-SS-CLS nanoparticles.

[0061] The results are shown in Table 1. The particle size of the unPEGylated / PEG-modified MTO-SS-CLS nanoparticles was around 130 nm, while the particle size distribution of the PEGylated MTO-SS-CLS nanoparticles was more uniform. Therefore, the PEGylated MTO-SS-CLS nanoparticles are preferred.

[0062] Table 1. Particle size and particle size distribution of mitoxantrone-cholesterol prodrug self-assembled nanoparticles

[0063]

[0064] Example 3

[0065] Pharmacokinetic Study of Self-Assembled Nanoparticles of Mitoxantrone-Cholesterol Prodrug

[0066] Pharmacokinetic studies were conducted using SD rats (180-220g). Rats were randomly assigned to groups and fasted for 12 hours before administration, with free access to water. Mitoxantrone solution and PEGylated mitoxantrone-cholesterol prodrug self-assembled nanoparticles prepared in Example 2 were administered intravenously at a dose of 2.5 mg / kg (equivalent to 2.5 mg / kg of mitoxantrone). Blood was collected from the orbital sinus at specified time points, and plasma was obtained. The drug concentration in the plasma was determined by liquid chromatography-mass spectrometry. The experimental results are as follows: Figure 2-4 As shown, compared with the mitoxantrone solution group, the prodrug self-assembled nanoparticles had a prolonged residence time in the blood and significantly increased the area under the drug-time curve (AUC) of mitoxantrone. 0-24h This ensures the tumor-targeted accumulation of mitoxantrone. Only a small amount of mitoxantrone was detected released from the prodrug nanoparticles, indicating that the prodrug nanoparticles have good safety (Table 2).

[0067] Table 2 Pharmacokinetic parameters of mitoxantrone-cholesterol prodrug self-assembled nanoparticles

[0068]

[0069] Example 4

[0070] Cytotoxicity assay of mitoxantrone-cholesterol prodrug self-assembled nanoparticles

[0071] The cytotoxicity of mitoxantrone-cholesterol prodrug self-assembled nanoparticles to mouse breast cancer (4T1) cells was investigated using the MTT assay. Healthy cells were digested, diluted to 10,000 cells / mL with culture medium, and after homogenization, 200 μL of cell suspension was added to each well of a 96-well plate. The plates were incubated for 12 hours to allow cell attachment. After cell attachment, either mitoxantrone solution or the PEGylated mitoxantrone-cholesterol prodrug self-assembled nanoparticles prepared in Example 2 were added, and the plates were incubated for another 48 hours. Untreated cells served as a control. At the end of incubation, 35 μL of MTT (5 mg / mL) was added to each well, and the plates were incubated at 37°C for 4 hours. The culture medium was discarded, and 200 μL of LDMSO was added to each well, followed by shaking for 10 min. The absorbance was measured at 490 nm using a microplate reader.

[0072] Cytotoxicity results such as Figure 5 As shown, the cytotoxicity of the prodrug self-assembled nanoparticles was reduced compared to the mitoxantrone solution. This is because mitoxantrone requires release from the prodrug self-assembled nanoparticles, and the drug release process limits the cytotoxicity of mitoxantrone.

[0073] Example 5

[0074] Antitumor experiment of self-assembled nanoparticles of mitoxantrone-cholesterol prodrug

[0075] To establish a 4T1 cell-bearing mouse model, 4T1 cells (75 μL containing 10...) were used. 7 (1 cell) was subcutaneously injected into BALB / c mice. When the tumor volume reached 100-150 mm... 3 At approximately 10:00 AM, the mice were randomly divided into 5 groups (5 mice per group). The PEGylated mitoxantrone-cholesterol prodrug self-assembled nanoparticles prepared in Example 2 were administered via tail vein every other day. Mitoxantrone solution and saline were used as control groups. A total of 5 injections were administered. The doses of mitoxantrone solution were 1 mg / kg and 5 mg / kg, and the doses of the prodrug self-assembled nanoparticles were equivalent to mitoxantrone at 10 mg / kg and 15 mg / kg. Tumor volume and mouse weight were measured daily.

[0076] The results are as follows Figure 6-10 As shown, at a dose of 5 mg / kg, all mice experienced a weight loss exceeding 20% ​​of their initial body weight on day four, indicating severe toxicity. At a dose of 1 mg / kg, mouse weight showed a continuous downward trend after the third administration of mitoxantrone solution. At doses of 10 mg / kg and 15 mg / kg, the prodrug self-assembly demonstrated significant antitumor effects. No weight loss was observed in the mice in this group, showing no significant difference compared to the saline group, indicating better safety and lower toxicity. Blood routine test results for each group are shown below. Figure 9-10 As shown, the mitoxantrone solution resulted in a significant decrease in white blood cells and lymphocytes, indicating myelosuppression. Therefore, the mitoxantrone-cholesterol prodrug self-assembled nanoparticles not only possess significant antitumor effects but also exhibit low toxicity and high safety.

Claims

1. A mitoxantrone-cholesterol prodrug, characterized in that, The structural formula is as follows: ； Where n = 1 to 3; R is one of a disulfide bond, a monosulfide bond, a diselenide bond, or a monoselenide bond.

2. The method for preparing a mitoxantrone-cholesterol prodrug according to claim 1, characterized in that, Includes the following steps: (1) Dissolve the diacid in acetic anhydride (AC2O) and stir to obtain the diacid anhydride. Add toluene and remove toluene and acetic anhydride by rotary evaporation under reduced pressure. The diacid is one of 2,2'-dithiodiacetic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid, 2,2'-diselenodiacetic acid, 3,3'-diselenodipropionic acid, 4,4'-diselenodibutyric acid, monothiodiacetic acid, monothiodipropionic acid, monothiodibutyric acid, monoselenodiacetic acid, monoselenodipropionic acid, or monoselenodibutyric acid. (2) Dissolve cholesterol and the dicarboxylic acid anhydride obtained in step (1) above in dichloromethane, and then add the 4-dimethylaminopyridine (DMAP) dissolved in dichloromethane dropwise to the above reaction system and stir. Separate the cholesterol-dicarboxylic acid monoester by chromatography column. (3) Dissolve the cholesterol-diacid monoester obtained in step (2) in anhydrous dichloromethane, and then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), 1-hydroxybenzotriazole (HOBT) and 4-dimethylaminopyridine (DMAP) dissolved in dichloromethane dropwise under ice bath conditions and stir. After the reaction is completed, add mitoxantrone raw material dissolved in anhydrous dichloromethane and react. Then, mitoxantrone-cholesterol prodrug is obtained by preparative liquid phase separation and purification.

3. The method for preparing a mitoxantrone-cholesterol prodrug according to claim 2, characterized in that, The molar ratio of the dicarboxylic acid to acetic anhydride (AC2O) in step (1) is 1:1-100; the stirring is specifically carried out at room temperature for 1-3 hours; the volume ratio of acetic anhydride (AC2O) to toluene is 1:3-10.

4. The method for preparing a mitoxantrone-cholesterol prodrug according to claim 2, characterized in that, In step (2), the molar ratio of dicarboxylic anhydride, 4-dimethylaminopyridine (DMAP), and cholesterol is 1:0.05-2:1-10; the stirring is specifically carried out at room temperature for 6-24 hours; in step (3), the molar ratio of mitoxanone, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), 1-hydroxybenzotriazole (HOBT), 4-dimethylaminopyridine (DMAP), and cholesterol-dicarboxylic acid monoester is 1:1-5:1-5:1-5; the stirring is specifically carried out under nitrogen protection in an ice-salt bath for 2-5 hours; the reaction is specifically carried out under nitrogen protection at room temperature for 24-32 hours.

5. The method for preparing a mitoxantrone-cholesterol prodrug according to claim 2, characterized in that, The purity of the final product mitoxantrone-cholesterol prodrug described in step (3) is greater than 95%.

6. The self-assembled nanoparticles of the mitoxantrone-cholesterol prodrug according to claim 1.

7. The method for preparing self-assembled nanoparticles of mitoxantrone-cholesterol prodrug according to claim 6, characterized in that, Includes the following steps: a. Dissolve the mitoxantrone-cholesterol prodrug and the PEG modifier in an organic solvent, wherein the mass ratio of the mitoxantrone-cholesterol prodrug to the PEG modifier is 1:0.1-5; the PEG modifier is one of TPGS, DSPE-PEG, PLGA-PEG, or PE-PEG, and the molecular weight of the PEG modifier is 1000-5000; the organic solvent is one of methanol, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, or acetone. b. Under stirring conditions, slowly add the solution obtained in step a to the aqueous solution; c. Remove the organic solvent from the solution obtained in step b by distillation to obtain mitoxantrone-cholesterol prodrug self-assembled nanoparticles.

8. The method for preparing self-assembled nanoparticles of mitoxantrone-cholesterol prodrug according to claim 7, characterized in that, The volume ratio of the organic solvent to the aqueous solution in step b is 1:4-20.

9. The method for preparing self-assembled nanoparticles of mitoxantrone-cholesterol prodrug according to claim 7, characterized in that, The distillation described in step c is specifically carried out under reduced pressure at 25-35°C.

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