A small molecule tetravalent platinum prodrug self-assembled nanoparticle and a preparation method and application thereof

Abstract

The present application relates to a kind of small molecule tetravalent platinum prodrug self-assembly nanoparticles and its preparation method and application, the self-assembly nanoparticles are made by small molecule tetravalent platinum prodrug with perfluorocarbon chain as axial ligand Self-assembly is made without the aid of other adjuvant or nanocarrier.The self-assembly nanoparticles not only can reduce the systemic toxicity of divalent platinum drugs and improve the solubility problem of tetravalent platinum prodrug, but also have the advantages of simple structure, extremely high drug loading and avoid the toxicity of high molecular adjuvant.In addition, the present application also provides a kind of nano ozone delivery system, which can promote the generation of reactive oxygen species and alleviate the radiotherapy resistance caused by intratumoral hypoxia by delivering ozone to tumor when combined with X-ray irradiation, so as to achieve radiotherapy sensitization.The self-assembly nanoparticles and nano ozone delivery system described in the present application all have the ability to enhance the killing effect on tumor cells, reduce the toxicity of divalent platinum drugs on normal cells, tumor tissue targeting and accumulation, enhance the antitumor effect in vivo, etc., and have good clinical application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological medicine, and particularly relates to a small-molecule tetravalent platinum prodrug self-assembled nanoparticle as well as a preparation method and application thereof. BACKGROUND

[0002] Cisplatin is an effective chemotherapeutic drug and has been widely used as a standard-of-care drug for the treatment of various cancers. However, the clinical application of cisplatin is largely limited by its dose-limiting toxicities (such as nephrotoxicity and myelosuppression). In addition, cisplatin has poor pharmacokinetic properties, and off-target effects can lead to its interaction with nucleophiles such as human serum albumin and glutathione, thereby inactivating it and reducing its effective concentration for acting on tumors and exerting an anti-tumor effect.

[0003] In order to alleviate the toxic side effects of cisplatin, it has become a promising strategy to construct cisplatin into a tetravalent platinum prodrug with tumor selectivity. Cisplatin has a tetrahedral structure and can generate an octahedral Pt(IV) prodrug with two axial ligands after oxidation. This Pt(IV) prodrug is more biologically inert than cisplatin, and when in the reducing environment of tumor cells, the Pt(IV) prodrug can be converted into cisplatin by releasing the ligands to exert biological functions.

[0004] Since tetravalent platinum prodrugs generally have poor water solubility and are difficult to be administered intravenously, many studies have been devoted to improving the water dispersibility and pharmacokinetic properties of tetravalent platinum prodrugs by means of nanomedicine delivery systems. Delivery of prodrugs by nanocarriers is also beneficial to reducing the degradation of prodrugs in the circulatory system and overcoming the problem of systemic toxicity caused by the premature release of Pt(IV) prodrugs. So far, a large number of nanocarriers encapsulating tetravalent platinum prodrugs have been reported, such as liposomes, polymer micelles, and albumin, but few platinum nanomedicines have entered clinical trials. This is because these nanocarrier-based platinum preparations have problems such as low drug loading capacity and auxiliary material toxicity, and the preparation process is too complex to be mass-produced and quality-controlled. SUMMARY

[0005] To solve the above problems, the application provides a small-molecule tetravalent platinum prodrug self-assembled nanoparticle, a preparation method and application thereof. The self-assembled nanoparticle is prepared by a small-molecule tetravalent platinum prodrug with a perfluorocarbon chain as an axial ligand without the aid of other adjuvants or nanocarriers. The nanoparticle has the advantages of simple structure, ultra-high drug loading capacity and avoidance of high-molecular-weight adjuvant toxicity while reducing the systemic toxicity of divalent platinum drugs and solving the problem of poor solubility of tetravalent platinum prodrugs. Further, the application also provides a small-molecule tetravalent platinum prodrug nano-ozone delivery system, which is composed of the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug loaded with perfluorocarbon. The nano-ozone delivery system can promote the generation of reactive oxygen species and relieve the radiotherapy resistance caused by hypoxia in tumors by delivering ozone to the tumors, thereby achieving radiotherapy sensitization in combination with X-ray irradiation.

[0006] The technical scheme of the application is as follows:

[0007] A preparation method of a small-molecule tetravalent platinum prodrug self-assembled nanoparticle, comprising the following steps:

[0008] Under ultrasonic conditions, a dimethyl sulfoxide solution of the small-molecule tetravalent platinum prodrug is added dropwise into pure water, and after removing the dimethyl sulfoxide in the system, the nanoparticle is obtained.

[0009] The structure of the small-molecule tetravalent platinum prodrug is shown in formula I:

[0010]

[0011] wherein X and Y are single ligands or complex ligands, R1 and R2 are leaving groups, and n is an integer selected from 5-18.

[0012] cisplatin, carboplatin or oxaliplatin; and n is an integer selected from 5-18.

[0013] Further preferably, the structure of the small-molecule tetravalent platinum prodrug is shown in formula II:

[0014]

[0015] wherein n is an integer selected from 5-18.

[0016] The concentration of the dimethyl sulfoxide solution of the small-molecule tetravalent platinum prodrug is 5-15 mg / mL, preferably 15 mg / mL;

[0017] The volume ratio of the dimethyl sulfoxide solution of the small-molecule tetravalent platinum prodrug to pure water is 1:2-1:100, preferably 1:20.

[0018] The ultrasonic wave is a 20-75 W probe ultrasonic wave, preferably 35 W.

[0019] The method for removing dimethyl sulfoxide in the system is dialysis or centrifugation followed by resuspension after replacing the supernatant.

[0020] The method produces small-molecule tetravalent platinum prodrug self-assembled nanoparticles. The small-molecule tetravalent platinum prodrug self-assembled nanoparticles have a particle size of 100-250 nm, preferably 100-150 nm.

[0021] A nano-ozone delivery system is formed by encapsulating perfluorocarbon in the small-molecule tetravalent platinum prodrug self-assembled nanoparticles. The nano-ozone delivery system has a particle size of 130-300 nm, preferably 150-200 nm.

[0022] The perfluorocarbon is selected from perfluorodecalin and / or perfluorohexane.

[0023] The method for preparing the nano-ozone delivery system comprises the following steps:

[0024] After the organic solution of the small-molecule tetravalent platinum prodrug is mixed with the perfluorocarbon, it is ultrasonicated to emulsify; then it is transferred to pure water and ultrasonicated to form a uniform emulsion; then the organic solvent in the nanoparticles is removed to obtain the small-molecule tetravalent platinum prodrug self-assembled nanoparticles loaded with perfluorocarbon, which is the nano-ozone delivery system.

[0025] In addition to ozone, the gas loaded in the nano-ozone delivery system can also be other perfluorocarbon-soluble gases, such as oxygen, nitric oxide, carbon monoxide, etc.

[0026] The mass ratio of the small-molecule tetravalent platinum prodrug to the perfluorocarbon is 1:4-1:95.

[0027] The organic solution of the small-molecule tetravalent platinum prodrug is a dimethyl sulfoxide solution with a concentration of 5 mg / mL-15 mg / mL or an acetone solution with a concentration of 1 mg / mL-5 mg / mL. Preferably, it is a dimethyl sulfoxide solution with a concentration of 15 mg / mL or an acetone solution with a concentration of 2 mg / mL.

[0028] The volume ratio of the perfluorocarbon to the organic solution of the small-molecule tetravalent platinum prodrug is 1:1-1:5 when the solvent is DMSO, preferably 1:1; and 1:5-1:50 when the solvent is acetone, preferably 1:20.

[0029] The ultrasonication is water bath ultrasonication or probe ultrasonication, wherein the probe ultrasonication power is 20-75 W, preferably 35 W.

[0030] The volume ratio of the organic solution of the small-molecule tetravalent platinum prodrug to the pure water is 1:2-1:50, preferably 1:20, when the solvent is dimethyl sulfoxide; and the volume ratio is 1:2-1:5, preferably 1:2, when the solvent is acetone.

[0031] The method for removing the organic solvent in the nanoparticle comprises: removing dimethyl sulfoxide by dialysis or centrifugal replacement and resuspension, or removing acetone by rotary evaporation.

[0032] The small-molecule tetravalent platinum prodrug self-assembled nanoparticle and the nanoparticle ozone delivery system are used for preparing a cancer treatment drug.

[0033] The drug or drug nanocarrier comprises: loading other drugs into the small-molecule tetravalent platinum prodrug self-assembled nanoparticle, doping the small-molecule tetravalent platinum prodrug with other nanoparticle materials to self-assemble into a nanoparticle, and using the small-molecule tetravalent platinum prodrug nanoparticle ozone delivery system to deliver other gases.

[0034] The small-molecule tetravalent platinum prodrug self-assembled nanoparticle and the nanoparticle ozone delivery system have the advantages of simple structure, high drug loading capacity, and avoidance of high-molecular-weight auxiliary material toxicity.

[0035] The small-molecule tetravalent platinum prodrug self-assembled nanoparticle and the nanoparticle ozone delivery system have the advantages of simple structure, high drug loading capacity, and avoidance of high-molecular-weight auxiliary material toxicity. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0037] Figure 1 Structure identification of the small-molecule tetravalent platinum prodrug with perfluorocarbon chain as axial ligand; Oxoplatin in the figure is tetravalent cisplatin, and Pt(IV)-PFOA is a small-molecule tetravalent platinum prodrug with perfluorocarbon chain as axial ligand;

[0038] Figure 2 Schematic diagram of physicochemical property characterization of small-molecule tetravalent platinum prodrug self-assembled nanoparticles and small-molecule tetravalent platinum prodrug nano-ozone delivery system; PtF in the figure is a small-molecule tetravalent platinum prodrug self-assembled nanoparticle, PFD is perfluorodecalin, PFD@PtF is a small-molecule tetravalent platinum prodrug self-assembled nanoparticle loaded with perfluorodecalin, O3 is ozone, and O3_PFD@PtF is a small-molecule tetravalent platinum prodrug nano-ozone delivery system; TBS is Tris-hydrochloric acid buffer; sodium citrate is a reducing substance, which provides a reducing environment required for the release of tetravalent platinum prodrug; PFD@Tween80 is a Tween80 emulsion of perfluorodecalin, which is used as a positive control for loading ozone.

[0039] Figure 3 Cell killing effect diagram of small-molecule tetravalent platinum prodrug self-assembled nanoparticles and small-molecule tetravalent platinum prodrug nano-ozone delivery system under X-ray irradiation. SUM149 is a human triple-negative breast cancer cell line, 4T1 is a mouse triple-negative breast cancer cell line, and MCF-10A is a human normal breast cell line; IC50 is the half inhibitory concentration; Blank is a blank control group, PtF is a small-molecule tetravalent platinum prodrug self-assembled nanoparticle group, Cisplatin is a cisplatin group, O3_PFD@PtF small-molecule tetravalent platinum prodrug nano-ozone delivery system group, Irradiation is an X-ray irradiation group, R+PtF small-molecule tetravalent platinum prodrug self-assembled nanoparticle combined with X-ray irradiation group, R+cisplatin cisplatin combined with X-ray irradiation group, and R+O3_PFD@PtF small-molecule tetravalent platinum prodrug nano-ozone delivery system combined with X-ray irradiation group;

[0040] Figure 4 In vivo biodistribution diagram of small-molecule tetravalent platinum prodrug self-assembled nanoparticles.

[0041] Figure 5Schematic diagram of the effect of small molecule tetravalent platinum prodrug self-assembled nanoparticles and small molecule tetravalent platinum prodrug nano-ozone delivery system on a mouse subcutaneous tumor model; Blank is a blank control group, PtF is a small molecule tetravalent platinum prodrug self-assembled nanoparticle group, Cisplatin is a cisplatin group, O3_PFD@PtF small molecule tetravalent platinum prodrug nano-ozone delivery system group, Irradiation is an X-ray irradiation group, R+PtF small molecule tetravalent platinum prodrug self-assembled nanoparticles combined with X-ray irradiation group, R+cisplatin cisplatin combined with X-ray irradiation group, R+O3_PFD@PtF small molecule tetravalent platinum prodrug nano-ozone delivery system combined with X-ray irradiation group. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0043] The above technical solutions will be described in detail below in combination with specific embodiments.

[0044] Unless otherwise specified, all the reagents mentioned in this paper are commercially available high-purity reagents that meet the experimental requirements.

[0045] Example 1: Synthesis of small molecule tetravalent platinum prodrug Pt(IV)-PFOA

[0046] Step 1: Preparation of tetravalent platinum prodrug Oxoplatin: 100 mg of cisplatin was uniformly suspended in 2.5 mL of pure water, and stirred and placed in a 55°C oil bath. 3.5 mL of 30% hydrogen peroxide was added, and the stirring was continued in a 55°C oil bath for 1.5 h in the dark. The reaction solution was placed at 4°C overnight, and the product was fully crystallized and filtered to obtain the precipitate. The precipitate was washed with 240 μL of pre-cooled pure water, 240 μL of anhydrous ethanol, and 600 μL of anhydrous ether in sequence to obtain a yellowish powder product Oxoplatin;

[0047] Step 2: Preparation of perfluorooctanoyl chloride: 1 g of perfluorooctanoic acid, 104 μL of dichlorosulfide, and 50 μL of DMF were stirred at 75°C under nitrogen protection for 4 h. The remaining dichlorosulfide and DMF in the system were removed by rotary evaporation to obtain a yellowish liquid perfluorooctanoyl chloride;

[0048] Step 3: Preparation of small molecule tetravalent platinum prodrug Pt(IV)-PFOA: Oxoplatin was thoroughly mixed with excess perfluorooctanoyl chloride under nitrogen protection and reacted at 75°C for 12 h with stirring; the resulting precipitate was washed three times with saturated sodium bicarbonate and then thoroughly washed with pure water. After drying the precipitate, a white powdery solid Pt(IV)-PFOA was obtained.

[0049] Figure 1 The structure of the small molecule tetravalent platinum prodrug obtained according to the above steps was identified. Figure 1 A represents the synthetic route for a small molecule tetravalent platinum prodrug; Figure 1 B represents the appearance of perfluorooctanoic acid, perfluorooctanoyl chloride, cisplatin, Oxoplatin, and Pt(IV)-PFOA. Figure 1 C represents the Fourier transform infrared spectra of perfluorooctanoic acid, perfluorooctanoyl chloride, and Pt(IV)-PFOA; Figure 1 D is the 1H NMR spectrum of Pt(IV)-PFOA ( 1 H-NMR and nuclear magnetic fluorine spectroscopy (H-NMR) 9 F-NMR image.

[0050] Example 2: Preparation of PtF nanoparticles self-assembled from small molecule tetravalent platinum prodrugs

[0051] Pt(IV)-PFOA was prepared as a 15 mg / mL dimethyl sulfoxide solution. Under 35 W sonication, 100 μL of the Pt(IV)-PFOA dimethyl sulfoxide solution was slowly added dropwise to 2 mL of pure water to form PtF nanoparticles. The PtF nanoparticles were then subjected to further sonication at 35 W for 10 min to ensure uniform particle size. The final PtF nanoparticles were then dialyzed through a 3500D dialysis membrane to remove dimethyl sulfoxide from the system.

[0052] The small molecule tetravalent platinum prodrug self-assembled nanoparticles PtF are spherical with a diameter of 100-150 nm.

[0053] Example 3: Preparation of a small molecule tetravalent platinum prodrug nano-ozone delivery system

[0054] Step 1: Prepare a 2 mg / mL acetone solution of Pt(IV)-PFOA. Add 50 μL of perfluoronaphthane to 1 mL of the Pt(IV)-PFOA acetone solution. Mix the system thoroughly and sonicate until emulsified. Then add 2 mL of pure water and sonicate until a homogeneous emulsion PFD@PtF is formed. Remove the acetone from the obtained PFD@PtF nanoparticles by rotary evaporation to obtain self-assembled nanoparticles loaded with perfluoronaphthane small molecule tetravalent platinum prodrug. The self-assembled nanoparticles loaded with perfluoronaphthane small molecule tetravalent platinum prodrug have a core-shell structure, with perfluorinated carbon as the core and small molecule tetravalent platinum prodrug as the outer shell. The nanoparticle diameter is 150-250 nm.

[0055] Step 2: ozone was bubbled into the tumor-targeting nano-aerosol delivery system emulsion obtained in step 1 to obtain ozone-enriched nanoparticles.

[0056] Figure 2 A schematic diagram of the characterization of the physicochemical properties of the obtained small-molecule tetravalent platinum prodrug self-assembled nanoparticles and small-molecule tetravalent platinum prodrug nano-ozone delivery system; Figure 2 A is a schematic diagram of the preparation process of the small-molecule tetravalent platinum prodrug nano-ozone delivery system; Figure 2 B is a particle size result diagram of the small-molecule tetravalent platinum prodrug self-assembled nanoparticles and the small-molecule tetravalent platinum prodrug nano-ozone delivery system; Figure 2 C is a transmission electron microscope image of the small-molecule tetravalent platinum prodrug self-assembled nanoparticles; Figure 2 D is a release curve diagram of the small-molecule tetravalent platinum prodrug self-assembled nanoparticles in a reducing medium, which shows that the tetravalent platinum prodrug can release cisplatin in response to reducing conditions; Figure 2 E is an ozone release curve diagram of the nano-ozone delivery system, which shows that the nano-ozone delivery system can efficiently and stably load ozone.

[0057] Experimental Example 1

[0058] In this experimental example, the in vitro cell killing effect of the small-molecule tetravalent platinum prodrug self-assembled nanoparticles and the small-molecule tetravalent platinum prodrug nano-ozone delivery system was detected, as follows:

[0059] Step 1: logarithmically growing murine and human triple-negative breast cancer cells 4T1 and SUM149 normal breast cells were seeded in a 96-well plate at a density of 2000 cells / well;

[0060] Step 2: after culturing the cells overnight until they adhered, the blank control group, the small-molecule tetravalent platinum prodrug self-assembled nanoparticle group, the cisplatin group, the small-molecule tetravalent platinum prodrug nano-ozone delivery system group, the X-ray irradiation group, the small-molecule tetravalent platinum prodrug self-assembled nanoparticle combined with X-ray irradiation group, the cisplatin combined with X-ray irradiation group, and the small-molecule tetravalent platinum prodrug nano-ozone delivery system combined with X-ray irradiation group were each provided with 6 replicate wells. The nanoparticle and cisplatin dosing concentration was equivalent to cisplatin at 2 μM, and the X-ray irradiation dose was 20 Gy;

[0061] Step 3: after culturing for 96 h after treatment, the drug-containing medium was replaced with 100 μL / well of complete medium, and thiazolyl blue (MTT, 2.5 mg / mL) was added at a volume of 20 μL / well; the cells were incubated in the dark for 4 h;

[0062] Step 4: 10% SDS solution was added in a volume of 100 μL / well, and the absorbance value was detected in the cell incubator overnight, the cell survival rate was calculated, and the comparison between groups was made.

[0063] Figure 3 Figure 1 shows the cell killing effect of the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug and the nano-ozone delivery system of the small-molecule tetravalent platinum prodrug under X-ray irradiation. It can be seen from the figure that the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug and the nano-ozone delivery system of the small-molecule tetravalent platinum prodrug can effectively inhibit the proliferation of SUM149 and 4T1 cells. Figure 3 A and Figure 3 It can be seen from the figures that the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug and the nano-ozone delivery system of the small-molecule tetravalent platinum prodrug can effectively inhibit the proliferation of SUM149 and 4T1 cells. Figure 3 C and Figure 3 It can be seen from the figures that the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug has weaker cytotoxicity on normal cells MCF-10A than cisplatin.

[0064] Experimental Example 2

[0065] In this experimental example, the in vivo distribution of the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug was detected, and the specific steps were as follows:

[0066] Step 1: TNBC tumor transplantation models were constructed in female BALB / c mice; 4T1 cell suspension was subcutaneously injected into the right back of BALB / c mice; 100 μL of 4T1 cell suspension was injected into each mouse, i.e. 5 × 10 5 4T1 cells;

[0067] Step 2: when the tumor volume reached 200 mm 3 , the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug loaded with fluorescent dye Nile Red was injected into the tail vein, and the distribution of the nanoparticle was observed at different time points with excitation light of 500 nm and emission light of 600 nm.

[0068] Figure 4 Figure 2 shows the in vivo biodistribution of the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug obtained by the above method. It can be seen that the nanoparticle of the application can be effectively enriched in the tumor site and can last for more than 24 hours.

[0069] The in vivo tumor inhibition effect of the self-assembled nanoparticle of the small-molecule tetravalent platinum prodrug and the nano-ozone delivery system of the small-molecule tetravalent platinum prodrug was further detected, including the following steps:

[0070] Step 1: TNBC tumor transplantation models were constructed in female BALB / c mice; 4T1 cell suspension was subcutaneously injected into the right back of BALB / c mice. 100 μL of 4T1 cell suspension was injected into each mouse, i.e. 5 × 10 5 4T1 cells;

[0071] Step 2: Measure the tumor volume with vernier caliper every 3 days; when the tumor grows to about 100mm 3 When the tumor grows to about 100mm

[0072] Step 3: Measure the tumor volume and body weight of each group of mice every 2 days, and draw the tumor growth curve according to the tumor volume and time, and draw the body weight change curve according to the body weight and time; on the 26th day after inoculation of tumor, the mice were sacrificed, the tumor was dissected and photographed, the ex vivo tumor was weighed and counted.

[0073] Figure 5 The schematic diagram of the effect of the small-molecule tetravalent platinum prodrug self-assembled nanoparticles and the small-molecule tetravalent platinum prodrug nano-ozone delivery system obtained according to the above steps on the mouse subcutaneous tumor model. Figure 5 A is a treatment flow chart. From Figure 5 B-5D, the mouse tumor dissection diagram, tumor growth curve, tumor volume and tumor mass diagram can be seen that the small-molecule tetravalent platinum prodrug self-assembled nanoparticles and the small-molecule tetravalent platinum prodrug nano-ozone delivery system can effectively inhibit the growth of tumor tissue. From Figure 5 E-5F, the experimental endpoint mouse weight and mouse weight change curve can be seen that the small-molecule tetravalent platinum prodrug self-assembled nanoparticles and the small-molecule tetravalent platinum prodrug nano-ozone delivery system reduce the systemic toxicity of cisplatin to mice.

[0074] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a nano-ozone delivery system, characterized in that, Includes the following steps: (1) Synthesis of small molecule tetravalent platinum prodrug Pt(IV)-PFOA Step 1: Preparation of the tetravalent platinum prodrug Oxoplatin: 100 mg of cisplatin was uniformly suspended in 2.5 mL of pure water and placed in a 55°C oil bath with stirring. 3.5 mL of 30% hydrogen peroxide was added, and the mixture was stirred in the oil bath at 55°C in the dark for 1.5 h. The reaction solution was placed at 4°C overnight. After the product had fully crystallized, the precipitate was filtered off. The precipitate was washed successively with 240 μL of pre-cooled pure water, 240 μL of anhydrous ethanol, and 600 μL of anhydrous diethyl ether to obtain a pale yellow powder product, Oxoplatin. Step 2: Preparation of perfluorooctanoic acid: 1 g of perfluorooctanoic acid, 104 μL of thionyl chloride and 50 μL of DMF were stirred at 75 °C for 4 h under nitrogen protection; the remaining thionyl chloride and DMF in the system were removed by rotary evaporation to obtain a pale yellow liquid perfluorooctanoic acid. Step 3: Preparation of small molecule tetravalent platinum prodrug Pt(IV)-PFOA: Oxoplatin was thoroughly mixed with excess perfluorooctanoyl chloride under nitrogen protection and reacted at 75°C for 12 h with stirring; the resulting precipitate was washed three times with saturated sodium bicarbonate and then thoroughly washed with pure water. After drying the precipitate, a white powdery solid Pt(IV)-PFOA was obtained. (2) Preparation of PtF nanoparticles self-assembled from small molecule tetravalent platinum prodrugs Pt(IV)-PFOA was prepared as a 15 mg / mL dimethyl sulfoxide solution. Under 35 W sonication, 100 μL of the Pt(IV)-PFOA dimethyl sulfoxide solution was slowly added dropwise to 2 mL of pure water to form PtF nanoparticles. The PtF nanoparticles were further subjected to 35 W sonication to achieve uniform particle size, with a total sonication time of 10 min. The final PtF nanoparticles were then dialyzed through a 3500 D dialysis membrane to remove dimethyl sulfoxide from the system. (3) Preparation of a small molecule tetravalent platinum prodrug nano-ozone delivery system Step 1: Prepare a 2 mg / mL acetone solution of Pt(IV)-PFOA. Add 50 μL of perfluoronaphthane to 1 mL of the Pt(IV)-PFOA acetone solution. Mix the system thoroughly and sonicate until emulsified. Then add 2 mL of pure water and sonicate until a homogeneous emulsion PFD@PtF is formed. Remove the acetone from the obtained PFD@PtF nanoparticles by rotary evaporation to obtain self-assembled nanoparticles of small molecule tetravalent platinum prodrug loaded with perfluoronaphthane. The self-assembled nanoparticles of small molecule tetravalent platinum prodrug loaded with perfluoronaphthane have a core-shell structure, with perfluorinated carbon as the core and small molecule tetravalent platinum prodrug as the outer shell. The nanoparticle diameter is 150-250 nm. Step 2: Introduce ozone into the tumor-targeting nano-gas delivery system emulsion obtained in Step 1 to obtain an ozone-rich nano-ozone delivery system.

2. The use of the nano-ozone delivery system prepared by the method of claim 1 in the preparation of drugs for treating triple-negative breast cancer.

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