Albumin binding type adriamycin prodrug as well as self-assembled nanoparticles and application thereof

Abstract

The invention belongs to the field of new auxiliary materials and new dosage forms of pharmaceutical preparations, and particularly relates to construction of albumin-bound adriamycin prodrugs and prodrug self-assembled nanoparticles and application of the albumin-bound adriamycin prodrugs and the prodrug self-assembled nanoparticles in preparation of antitumor drugs. The invention provides a novel albumin binding type adriamycin prodrug, self-assembled nanoparticles containing the prodrug are constructed, and the in-vivo circulation time of the drug is remarkably prolonged through specific binding of maleimide or acryloyl chloride and in-vivo albumin, so that tumor targeting of the drug is realized; meanwhile, the drug can be intelligently released in tumor cells due to the reduction-sensitive disulfide bond, the toxic and side effects on normal cells are reduced, and the drug has a wide clinical transformation prospect.

Description

Technical Field

[0001] The invention belongs to the field of new adjuvants and new dosage forms of pharmaceutical preparations, and specifically relates to the construction of albumin-bound doxorubicin prodrugs and prodrug self-assembly nanoparticles, and their application in the preparation of anti-tumor drugs. Background Art

[0002] Cancer still poses a serious threat to human health, and chemotherapy is still one of the most effective ways to treat cancer. Doxorubicin is an anthracycline antitumor drug that can inhibit the synthesis of DNA and RNA. It is mainly suitable for acute leukemia and is effective for acute lymphocytic leukemia and granulocytic leukemia. However, doxorubicin has strong side effects, the most serious of which is cardiac toxicity, which limits its clinical application. In addition, doxorubicin also inhibits bone marrow hematopoiesis, manifested as thrombocytopenia and leukopenia. Doxil is the world's first antitumor nanoformulation, which significantly improves the pharmacokinetic data of doxorubicin and reduces the cardiac toxicity of doxorubicin, but its shortcomings limit its widespread clinical application: 1) complex preparation process and low drug loading (less than 11%); 2) hand-foot syndrome caused by long circulation time; 3) too little cellular uptake of drugs caused by too high PEG content; 4) slow drug release due to drug crystallization in the internal water phase. Therefore, it is urgent to construct a new type of doxorubicin nanoformulation to overcome the above shortcomings.

[0003] Prodrugs refer to chemical derivatives that are inactive or less active in vitro after chemical structure modification, and are activated in vivo to release active drugs to exert their efficacy. Prodrug strategy is one of the effective ways to improve the delivery efficiency of anthracyclines. DOXO-EMCH, also known as INNO-206, is the first albumin-binding prodrug to enter clinical trials. It is a prodrug covalently linked by acid-sensitive hydrazone bonds between doxorubicin and maleimide, which can quickly and selectively bind to endogenous or exogenous albumin. In the blood circulation, the compound will not release free parent drugs. After being internalized by lysosomes, it can be hydrolyzed under acidic conditions to release doxorubicin. Phase I clinical trials have shown that the maximum tolerated dose of DOXO-EMCH in humans is 2 to 5 times that of doxorubicin solution. At the same time, phase I and phase II clinical results have shown that DOXO-EMCH can significantly reduce cardiac toxicity compared with doxorubicin. However, the Phase III clinical trial failed due to safety issues, which may be due to the lack of tumor cell selectivity of the acid-sensitive hydrazone bond, resulting in drug leakage in normal cells.

[0004] Tumor tissue has a unique microenvironment characterized by uncontrolled cell growth and abnormal protein expression. Tumor cells typically have 7-10 times higher glutathione concentrations than normal cells. This difference makes reduction-sensitive monosulfide bonds, disulfide bonds, monoselenium bonds, and diselenium bonds useful strategies for prodrug design, which can achieve bio-intelligent activation at the tumor site and minimize toxicity to normal tissues. On this basis, the self-assembled nanoparticle delivery system of the prodrug strategy combines the advantages of nanotechnology and prodrug strategies, including high drug loading, good stability, and low toxic side effects, and has become a hot topic in chemotherapy drug delivery research in recent years. Summary of the invention

[0005] The present invention designs a series of new albumin-bound doxorubicin prodrugs, using acryloyl chloride and maleimide as the target head for covalently linking albumin in vivo, using carbamate bonds and carbamate bond-bridged disulfide bonds as the connecting chains between doxorubicin and acryloyl chloride or maleimide groups, and synthesizing prodrugs with propionic acid and succinimide as side chains. At the same time, reduction-sensitive disulfide bond-linked maleimide nanoparticles (DSSMNPs) and reduction-sensitive disulfide bond-linked acryloyl chloride nanoparticles (DSSA NPs) prepared by self-assembly nanotechnology have the advantages of simple preparation process, high drug loading, good stability, etc.

[0006] The first objective of the present invention is to provide a series of albumin-bound doxorubicin prodrugs connected by different connecting bonds and connecting groups, so that the prodrug can quickly bind to albumin in the blood, enhance drug stability, significantly prolong drug circulation time, quickly release chemotherapy drugs in tumor cells, and have strong anti-tumor activity.

[0007] The second object of the present invention is to provide a method for synthesizing the above-mentioned prodrugs connected by different connecting bonds and connecting groups. And to provide and compare the effects of the above-mentioned prodrugs with different connecting bonds on cytotoxicity. Among them, the connecting chain formed by disulfide bridged carbamate bonds can form self-assembled nanoparticles, which have the advantages of small particle size and uniform distribution, high drug loading, good stability, good anti-tumor effect and good safety.

[0008] The present invention achieves the above object through the following technical solutions:

[0009] The albumin-bound doxorubicin prodrug of the present invention is doxorubicin and maleimide or acryloyl chloride directly connected by a carbamate bond and a tumor environment sensitive bond, wherein the tumor environment sensitive bond is a monosulfide bond, a disulfide bond, a diselenide bond or a monoselenide bond. After the drug is injected intravenously into the body, it quickly binds to albumin in plasma to form an albumin-drug complex, which targets tumor tissues to exert anti-tumor effects.

[0010] The albumin-bound doxorubicin prodrug or a pharmaceutically acceptable salt thereof has the following general structural formula:

[0011]

[0012] Where R is a, b, c, d or e:

[0013]

[0014] Where n = 1, 2, 3; m = 0, 1, 2

[0015] X is one of a disulfide bond, a monosulfide bond, a diselenide bond or a monoselenide bond.

[0016] In the above technical solution, further, when n=2, m=1, and X is a disulfide bond, the preferred structure is:

[0017]

[0018] In the above technical scheme, further, the prodrug of the present invention uses maleimide ring or acryloyl chloride as the target head for binding to plasma albumin, and respectively designs and synthesizes albumin-bound doxorubicin prodrugs connected by different connecting chains. The specific synthesis route and method are as follows:

[0019] (a) Prodrug of maleimide linked to a carbamate bond (abbreviated as DCM): Hydroxyethylmaleimide and p-nitrophenyl chloroformate were reacted at room temperature under the catalysis of N,N-diisopropylethylamine (DIPEA) and 4-dimethylaminopyridine (DMAP), and then separated and purified by column chromatography to obtain a yellow oily intermediate 1. Then, a solution of desalted doxorubicin in N,N-dimethylformamide (DMF) and triethylamine were added, and the reaction was stirred at room temperature for 24 hours. The obtained product was separated and purified by preparative liquid phase to obtain DCM;

[0020]

[0021] The synthesis method of the prodrug of maleimide connected to a carbamate bond is carried out under nitrogen protection throughout the reaction;

[0022] In the steps, in molar ratio, hydroxyethylmaleimide: p-nitrophenyl chloroformate: DMAP:DIPEA=1:(1-10):(0.1-1):(4-10), preferably 1:(2-5):(0.1-2):(2-5); intermediate product 1: doxorubicin: triethylamine=1:(1-10):(1-3):(4-10), preferably 1:(1-2):(5-10);

[0023] In the steps, the mass purity of the prepared prodrug connected to maleimide by carbamate bond is ≥99%;

[0024] (b) Reduction-sensitive disulfide-linked maleimide prodrug (abbreviated as DSSM): Maleimidopropionic acid and 2,2'-dithiodiethanol react at room temperature under the catalysis of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and DMAP, and then separate and purify by column chromatography to obtain a yellow oily intermediate 1. Then, the intermediate 1 and p-nitrochloroformate react at room temperature under the catalysis of DIPEA and DMAP, and then separate and purify by column chromatography to obtain a yellow oily intermediate 2. Subsequently, a DMF solution of desalted doxorubicin and triethylamine are added, and the reaction is stirred at room temperature for 24 hours. The resulting product is separated and purified by preparative liquid phase separation to obtain DSSM.

[0025]

[0026] The synthesis method of the reduction-sensitive disulfide bond-linked maleimide prodrug is carried out under nitrogen protection throughout the reaction process.

[0027] In the steps, the molar ratio of maleimidopropionic acid: 2,2'-dithiodiethanol: EDCI: DMAP is 1: (1-3): (1-5): (0.1-1), preferably 1: (1-2): (1-2): (0.1-5);

[0028] Intermediate 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5);

[0029] Intermediate 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10). In the above steps, the mass purity of the prepared reduction-sensitive disulfide-bonded maleimide prodrug is ≥ 97%;

[0030] (c) Reduction-sensitive disulfide-bonded succinimide prodrug (abbreviated as DSSU): Succinimidyl propionic acid and 2,2'-dithiodiethanol react at room temperature under the catalysis of EDCI and DMAP, and then separate and purify by column chromatography to obtain a yellow oily intermediate 1. Then, the intermediate 1 and p-nitrochloroformate react at room temperature under the catalysis of DIPEA and DMAP, and then separate and purify by column chromatography to obtain a yellow oily intermediate 2. Then, a DMF solution of desalted doxorubicin and triethylamine are added, and the reaction is stirred at room temperature for 24 hours. The resulting product is separated and purified by preparative liquid phase to obtain DSSU;

[0031]

[0032] The synthesis method of the reduction-sensitive disulfide-bond-linked succinimide prodrug is carried out under nitrogen protection throughout the reaction;

[0033] In the steps, the molar ratio of succinimidyl propionic acid: 2,2'-dithiodiethanol: EDCI: DMAP is 1: (1-3): (1-5): (0.1-1), preferably 1: (1-2): (1-2): (0.1-5);

[0034] Intermediate 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5);

[0035] Intermediate 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10). In the above steps, the mass purity of the prepared reduction-sensitive disulfide-bonded succinimide prodrug is ≥ 97%;

[0036] (d) Reduction-sensitive disulfide bond-linked acryloyl chloride prodrug (abbreviated as DSSA): Acryloyl chloride and 2,2'-dithiodiethanol were reacted in an ice bath with the addition of triethylamine as catalyst, and the reaction was carried out for 12 h. The reaction was carried out at room temperature and purified by column chromatography to obtain a yellow oily intermediate 1. The intermediate 1 and p-nitrochloroformic acid phenyl ester were then reacted at room temperature under the catalysis of DIPEA and DMAP and purified by column chromatography to obtain a yellow oily intermediate 2. Subsequently, a DMF solution of desalted doxorubicin and triethylamine were added, and the reaction was stirred at room temperature for 24 h. The obtained product was separated and purified by preparative liquid phase separation to obtain DSSA.

[0037]

[0038] The synthesis method of the reduction-sensitive disulfide bond-linked acryloyl chloride prodrug is carried out under nitrogen protection throughout the reaction;

[0039] In the steps, the molar ratio of acryloyl chloride: 2,2'-dithiodiethanol: triethylamine is 1: (1-3): (1-5): (1-5), preferably 1: (1-2): (1-2);

[0040] Intermediate 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5);

[0041] Intermediate product 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10). In the above steps, the mass purity of the prepared reduction-sensitive disulfide bond-linked acryloyl chloride prodrug is ≥ 97%;

[0042] (e) Reduction-sensitive disulfide-bonded propionic acid prodrug (abbreviated as DSSC): Propionic acid and 2,2'-dithiodiethanol were added with EDCI and DMAP for catalysis in an ice bath, and the reaction was carried out for 12 hours. The reaction was carried out at room temperature and purified by column chromatography to obtain a yellow oily intermediate 1. The intermediate 1 and p-nitrochloroformic acid phenyl ester were then reacted at room temperature under the catalysis of DIPEA and DMAP, and purified by column chromatography to obtain a yellow oily intermediate 2. Subsequently, a DMF solution of desalted doxorubicin and triethylamine were added, and the reaction was stirred at room temperature for 24 hours. The obtained product was separated and purified by preparative liquid phase separation to obtain DSSC;

[0043]

[0044] The synthesis method of the reduction-sensitive disulfide-bond-linked propionic acid prodrug is carried out under nitrogen protection throughout the reaction;

[0045] In the steps, the molar ratio of propionic acid: 2,2'-dithiodiethanol: EDCI: DMAP is 1: (1-3): (1-5): (0.1-1), preferably 1: (1-2): (1-2): (0.1-5);

[0046] Intermediate 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5);

[0047] Intermediate product 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10). In the above steps, the mass purity of the prepared reduction-sensitive disulfide-bonded propionic acid prodrug is ≥ 97%.

[0048] The present invention also provides an albumin-bound doxorubicin prodrug self-assembly nanoparticle, wherein the nanoparticle is formed by self-assembly of the reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug in the doxorubicin.

[0049] In the above technical scheme, further, it is a non-PEG modified reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles or a PEG modified reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles; the mass ratio of the reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug to the PEG modifier is 1: (0.05-1); the PEG modifier is an amphiphilic polymer or a targeting group, DSPE-PEG, TPGS, PEG-PLGA, PEG-PE or DSPE-PEG-FA.

[0050] In the above technical solution, further, the preparation method of the self-assembled nanoparticles of the PEG-modified reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug comprises the following steps:

[0051] The PEG modifier and the reduction-sensitive disulfide-linked maleimide or acryloyl chloride prodrug are dissolved in an organic solvent, and then added dropwise to water under stirring, and the reduction-sensitive disulfide-linked maleimide or acryloyl chloride prodrug self-assembles into nanoparticles with uniform particle size; the organic solvent in the preparation is removed to obtain a nanocolloid solution without any organic solvent, which is the PEG-modified reduction-sensitive disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles; the solvent is selected from dimethyl sulfoxide, N,N'-dimethylformamide, tetrahydrofuran, and acetone. The preparation method of the non-PEG-modified reduction-sensitive disulfide-linked maleimide or acryloyl chloride prodrug nanoparticles is different in that the PEG modifier is not added during the preparation process.

[0052] The self-assembled nanoparticles of the PEG-modified disulfide-bond-connected maleimide or acryloyl chloride prodrug provided by the invention have a particle size of 150-250nm, a particle size distribution of less than 0.2, and a drug loading of 50-70%.

[0053] The present invention also provides the use of the self-assembled nanoparticles of the aforementioned albumin-bound doxorubicin prodrug or its pharmaceutically acceptable salt or the aforementioned PEG-modified reduction-sensitive disulfide-bond-linked maleimide or acryloyl chloride prodrug; for use in the preparation of anti-tumor drugs; for use in the preparation of injection, oral or local administration systems; for use in the preparation of drug delivery systems with improved efficacy and reduced toxicity.

[0054] Beneficial effects of the present invention:

[0055] The invention designs and synthesizes albumin-bound doxorubicin prodrugs, and the synthesis method is simple and easy. In addition, self-assembled nanoparticles of reduction-sensitive disulfide-bond-linked maleimide or acryloyl chloride prodrugs with small particle size and uniform particle size distribution are prepared. The preparation method is simple and easy, and the toxic side effects caused by adding organic reagents or surfactants due to poor solubility of prodrug solutions are avoided. After the synthesized self-assembled nanoparticles of reduction-sensitive disulfide-bond-linked maleimide or acryloyl chloride prodrugs are injected into the body through intravenous injection, they can quickly combine with albumin in plasma to form albumin-drug conjugates, thereby increasing the stability of the drug in plasma, thereby significantly prolonging the circulation time of the drug in the body, and then targeting tumor tissues to exert their effects. The efficacy test proves that the albumin-bound doxorubicin prodrug nanoparticles have not only excellent anti-tumor effects compared with commercially available preparations of doxorubicin and doxorubicin liposomes, but also have no significant difference in mouse body weight compared with a normal saline group, have excellent safety, and achieve the purpose of increasing efficacy and reducing toxicity. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the mass spectrum of the prodrug (DCM) of maleimide linked to a carbamate bond in Example 1 of the present invention.

[0057] Figure 2 This is the mass spectrum of the reduction-sensitive disulfide-bond-linked maleimide prodrug (DSSM) of Example 1 of the present invention.

[0058] Figure 3 This is the mass spectrum of the reduction-sensitive disulfide-bond-linked maleimide prodrug (DSSU) of Example 1 of the present invention.

[0059] Figure 4 This is the mass spectrum of the reduction-sensitive disulfide-bond-linked acryloyl chloride prodrug (DSSA) of Example 1 of the present invention.

[0060] Figure 5 This is the mass spectrum (DSSC) of the reduction-sensitive disulfide-bond-linked propionic acid prodrug of Example 1 of the present invention.

[0061] Figure 6 This is an in vitro albumin binding test of the albumin-bound doxorubicin prodrug of Example 2 of the present invention.

[0062] Figure 7 This is an in vitro release test of the disulfide bond-linked maleimide or acryloyl chloride prodrug nanoparticles in Example 5 of the present invention.

[0063] Figure 8 This is a graph showing the change in tumor volume of the disulfide bond-linked maleimide or acryloyl chloride prodrug nanoparticles of Example 6 of the present invention in an in vivo anti-tumor test;

[0064] ns: P≥0.05**: P<0.01****: P<0.0001 (all two-sided t test).

[0065] Fig. 9 This is a graph showing the weight change of the disulfide bond-linked maleimide or acryloyl chloride prodrug nanoparticles of Example 6 of the present invention in an in vivo anti-tumor test;

[0066] ns: P≥0.05**: P<0.01****: P<0.0001 (all two-sided t test).

[0067] Fig.10 This is a graph of tumor load in an in vivo anti-tumor test of the disulfide bond-linked maleimide or acryloyl chloride prodrug nanoparticles of Example 6 of the present invention;

[0068] ns: P≥0.05**: P<0.01****: P<0.0001 (all two-sided t test).

[0069] Fig.11 The following are blood routine index diagrams of the disulfide bond-linked maleimide or acryloyl chloride prodrug nanoparticles in Example 6 of the present invention in an in vivo anti-tumor test; A. DSSM, B. DSSA;

[0070] ns: P≥0.05**: P<0.01****: P<0.0001 (all two-sided t test).

[0071] Fig.12 The biochemical routine index diagram of the disulfide bond-linked maleimide or acryloyl chloride prodrug nanoparticles in Example 6 of the present invention in the in vivo anti-tumor test; A. DSSM, B. DSSA;

[0072] ns: P≥0.05**: P<0.01****: P<0.0001 (all two-sided t test). DETAILED DESCRIPTION

[0073] The present invention is further described in detail below in conjunction with embodiments.

[0074] Example 1: Synthesis of three albumin-bound doxorubicin prodrugs

[0075] (a) Synthesis of carbamate-linked maleimide prodrug (DCM)

[0076] Hydroxyethyl maleimide (1 mmol) and p-nitrophenyl chloroformate (4 mmol) were dissolved in dichloromethane, and 12 mmol of DIPEA and 0.5 mmol of DMAP were added. After reacting at room temperature for 12 h, the yellow oily intermediate 1 was obtained by column chromatography separation and purification. Then 0.5 mmol of the intermediate 1, 0.3 mmol of desalted doxorubicin in DMF solution and 2.1 mmol of triethylamine were added, and the reaction was stirred at room temperature for 24 h. The above reaction was carried out under N 2 The reaction was carried out under protection, and the obtained product was separated and purified by preparative liquid phase to obtain DCM.

[0077]

[0078] 1H-NMR was used to confirm the structure of the product. The results of spectral analysis are as follows:

[0079] 1H NMR (600MHz, DMSO-d6) δ14.01 (s, 1H), 13.24 (s, 1H), 7.91–7.84 (m, 2H), 7.70 (d, J = 8.2Hz, 1H), 7.62 (dd, J = 7.0, 2.8Hz, 1H), 6 .96 (s, 2H), 5.75 (s, 1H), 5.45 (s, 1H), 5.21 (d, J=7.2Hz,, 1H), 4.91 (dd, J=5.6, 3.3Hz, 1H), 4.85 (s, 1H), 4.71 (s, 1H), 4.57 (s, 2H), 4.21–4.11(m, 1H), 3.97(s, 3H), 3.95-3.88(m, 1H), 3.53(t, J=7.2Hz, 2H), 3.00–2.88(m, 2H), 2.30(t, J=7.2Hz, 2H), 2.24 –2.16 (m, 1H), 2.10 (dd, J=14.3, 5.7Hz, 1H), 1.80 (td, J=12.9, 3.9Hz, 1H), 1.40 (dd, J=12.7, 4.7Hz, 1H), 1.12 (d, J=6.5Hz, 3H)

[0080] The product structure was confirmed by mass spectrometry. Figure 1 As shown, MS (ESI) m / z for C 34 H 34 N2NaO 15 [M+Na] + :733.18582.

[0081] (b) Synthesis of reduction-sensitive disulfide-linked maleimide prodrug (DSSM):

[0082] Maleimidopropionic acid (1 mmol) and 1.5 mmol of 2,2'-dithiodiethanol were dissolved in dichloromethane, and a dichloromethane solution of 2 mmol EDCI and 0.2 mmol DMAP was added under ice bath conditions, and then reacted at room temperature for 24 hours, and then separated and purified by column chromatography to obtain a yellow oily intermediate 1. Then, 1 mmol of the intermediate 1 and 2 mmol of p-nitrochlorophenylformate were dissolved in dichloromethane, and reacted at room temperature under the catalysis of 12 mmol DIPEA and 0.5 mmol DMAP, and separated and purified by column chromatography to obtain a yellow oily intermediate 2. Then, 0.5 mmol of the intermediate 2 and 0.3 mmol of desalted doxorubicin in DMF solution and 2.1 mmol triethylamine were added, and the reaction was stirred at room temperature for 24 hours. The above reaction was carried out in N 2 The reaction was carried out under protection, and the obtained product was separated and purified by preparative liquid phase to obtain DSSM.

[0083]

[0084] 1H-NMR was used to confirm the structure of the product. The results of spectral analysis are as follows:

[0085] 1 H NMR (600MHz, DMSO-d6) δ14.04 (s, 1H), 13.28 (s, 1H), 7.95–7.89 (m, 2H), 7.69 –7.63 (m, 1H), 6.80 (d, J = 8.3Hz, 1H), 5.46 (s, 1H), 5.22 (d, J = 4.0Hz, 1H), 4.9 8–4.92(m, 1H), 4.84(t, J=6.0Hz, 1H), 4.68(d, J=5.6Hz, 1H), 4.57(d, J=6.1H z, 2H), 4.21 (t, J=6.4Hz, 2H), 4.17–4.06 (m, 3H), 3.99 (s, 3H), 3.73–3.65 (m, 1 H), 3.56 (t, J=7.3Hz, 2H), 3.44 (dd, J=6.4, 3.0Hz, 1H), 2.98 (dd, J=16.4, 12. 4Hz, 2H), 2.93 (t, J=6.3Hz, 2H), 2.89 (t, J=6.4Hz, 2H), 2.58 (s, 4H), 2.52 (t, J =7.2Hz, 2H), 2.19 (dd, J=14.6, 4.2Hz, 1H), 2.12 (dd, J=14.3, 5.9Hz, 1H), 1.8 3(td, J=13.1, 4.0Hz, 1H), 1.47 (dd, J=12.6, 4.9Hz, 1H), 1.12 (d, J=6.5Hz, 3H)

[0086] The product structure was confirmed by mass spectrometry. Figure 2 As shown, MS (ESI) m / z for C 39 H 42 N2NaO 17 S2[M+Na] + :897.18176.

[0087] (c) Synthesis of reduction-sensitive disulfide-linked succinimide prodrug (DSSU):

[0088] Succinimidyl propionic acid (1 mmol) and 1.5 mmol of 2,2'-dithiodiethanol were dissolved in dichloromethane, and 2 mmol of EDCI and 0.2 mmol of DMAP in dichloromethane were added under ice bath conditions, and then reacted at room temperature for 24 hours, and then separated and purified by column chromatography to obtain a yellow oily intermediate 1. Then 1 mmol of the intermediate 1 and 2 mmol of p-nitrochlorophenyl formate were dissolved in dichloromethane, and reacted at room temperature under the catalysis of 12 mmol of DIPEA and 0.5 mmol of DMAP, and separated and purified by column chromatography to obtain a yellow oily intermediate 2. Then 0.5 mmol of the intermediate 2 and 0.3 mmol of desalted doxorubicin in DMF solution and 2.1 mmol of triethylamine were added, and the reaction was stirred at room temperature for 24 hours. The above reaction was carried out in N 2 The reaction was carried out under protection, and the obtained product was separated and purified by preparative liquid phase to obtain DSSU.

[0089]

[0090] 1H-NMR was used to confirm the structure of the product. The results of spectral analysis are as follows:

[0091] 1 H NMR (600MHz, DMSO-d6) δ14.03 (s, 1H), 13.27 (s, 1H), 7.96-7.86 (m, 2H), 7.43 (d, J=9.1Hz, 1H), 6.98 (s, 2H), 6.80 (d, J=8.1Hz, 1H), 5.46 (s, 1H), 5.2 1 (d, J=4.3Hz, 1H), 4.94 (t, J=4.7Hz, 1H), 4.84 (t, J=5.9Hz, 1H), 4.69 (d, J =5.6Hz, 1H), 4.57 (d, J = 5.7Hz, 2H), 4.20 (t, J = 6.3Hz, 2H), 4.16–4.07 (m, 3 H), 3.98 (s, 3H), 3.72-3.66 (m, 1H), 3.61 (t, J=7.0Hz, 2H), 3.44 (d, J=3.9 Hz, 1H), 2.98 (dd, J=16.4, 12.4Hz, 2H), 2.92-2.84 (m, 4H), 2.56 (t, J=6.9H z, 2H), 2.19 (dd, J=13.6, 2.8Hz, 1H), 2.12 (dd, J=14.1, 5.6Hz, 1H), 1.84 (td, J=13.3, 4.1Hz, 1H), 1.47 (dd, J=12.6, 4.9Hz, 1H), 1.12 (d, J=6.5Hz, 3H)

[0092] The product structure was confirmed by mass spectrometry. Figure 2As shown, MS (ESI) m / z for C 39 H 44 N2NaO 17 S2[M+Na] + :899.19678.

[0093] (d) Synthesis of reduction-sensitive disulfide-linked acryloyl chloride prodrug (DSSA):

[0094] Take 1 mmol of acryloyl chloride and 1.5 mmol of 2,2'-dithiodiethanol in dichloromethane, add triethylamine as catalyst under ice bath condition, react for 12 h, react at room temperature, separate and purify by column chromatography to obtain yellow oily intermediate 1, then dissolve 1 mmol of intermediate 1 and 2 mmol of p-nitrochlorophenyl formate in dichloromethane, react at room temperature under the catalysis of 12 mmol of DIPEA and 0.5 mmol of DMAP, separate and purify by column chromatography to obtain yellow oily intermediate 2, then add 0.5 mmol of intermediate 2 and 0.3 mmol of desalted doxorubicin in DMF solution and 2.1 mmol of triethylamine, stir and react at room temperature for 24 h, and the above reaction is carried out in N 2 The reaction was carried out under protection, and the obtained product was separated and purified by preparative liquid phase to obtain DSSA.

[0095]

[0096] 1H-NMR was used to confirm the structure of the product. The results of spectral analysis are as follows:

[0097] 1H NMR (600MHz, DMSO-d6) δ14.03 (s, 1H), 13.27 (s, 1H), 7.94–7.84 (m, 2H), 7.68–7.57 (m, 1H), 6.81 (d, J=8.1Hz, 1H), 6.31 (d, J=17.2Hz , 1H), 6.15 (dd, J=17.3, 10.4Hz, 1H), 5.94 (d, J=10.4Hz, 1H), 5.45 (s, 1H), 5.21 (d, J=4.0Hz, 1H), 4.96–4.91 (m, 1H), 4.86 (s, 1H), 4.7 1(s, 1H), 4.57(s, 2H), 4.31(t, J=6.3Hz, 2H), 4.16–4.07(m, 3H), 3.97(s, 3H), 3.69(dq, J=9.8, 4.7Hz, 1H), 3.46-3.41(m, 1H), 3.03– 2.88 (m, 6H), 2.22–2.16 (m, 1H), 2.10 (dd, J=13.8, 5.3Hz, 1H), 2.04–1.93 (m, 1H), 1.83 (td, J=12.9, 4.1Hz, 1H), 1.12 (d, J=6.5Hz, 3H)

[0098] The product structure was confirmed by mass spectrometry. Figure 3 As shown, MS (ESI) m / z for C 35 H 38 NO 15 S2[MH] - :776.16852.

[0099] (e) Synthesis of reduction-sensitive disulfide-linked propionic acid prodrug (DSSC):

[0100] Take a dichloromethane solution of 1 mmol of propionic acid and 1.5 mmol of 2,2'-dithiodiethanol, add EDCI (2 mmol) and DMAP (0.2 mmol) as catalyst under ice bath conditions, react for 12 h, react at room temperature and separate and purify by column chromatography to obtain a yellow oily intermediate 1, then dissolve 1 mmol of the intermediate 1 and 2 mmol of p-nitrochloroformic acid phenyl ester in dichloromethane, react at room temperature under the catalysis of 12 mmol of DIPEA and 0.5 mmol of DMAP and separate and purify by column chromatography to obtain a yellow oily intermediate 2, then add 0.5 mmol of the intermediate 2 and 0.3 mmol of desalted doxorubicin in DMF solution and 2.1 mmol of triethylamine, stir and react at room temperature for 24 h, and the above reaction is carried out in N 2 The reaction was carried out under protection, and the obtained product was separated and purified by preparative liquid phase to obtain DSSC.

[0101]

[0102] 1H-NMR was used to confirm the structure of the product. The results of spectral analysis are as follows:

[0103] 1 H NMR (600MHz, DMSO-d6) δ14.04 (s, 1H), 13.29 (s, 1H), 7.94–7.91 (m, 2H), 7. 66 (dd, J=5.9, 4.0Hz, 1H), 6.80 (d, J=8.1Hz, 1H), 5.46 (s, 1H), 5.21 (d, J=4. 1Hz, 1H), 4.98–4.91 (m, 1H), 4.84 (t, J=6.0Hz, 1H), 4.69 (d, J=5.7Hz, 1H), 4 .57(d, J=6.1Hz, 2H), 4.21(t, J=6.3Hz, 2H), 4.16–4.06(m, 3H), 3.99(s, 3H) , 3.72–3.66 (m, 1H), 3.44 (dd, J=6.3, 2.1Hz, 1H), 3.03–2.97 (m, 2H), 2.94 ( t, J=6.4Hz, 2H), 2.89 (t, J=6.4Hz, 2H), 2.29 (q, J=7.5Hz, 2H), 2.20 (dd, J=1 4.3, 3.5Hz, 1H), 2.12 (dd, J=14.1, 5.6Hz, 1H), 1.83 (td, J=13.0, 4.0Hz, 1H) , 1.47 (dd, J=12.6, 4.9Hz, 1H), 1.12 (d, J=6.5Hz, 3H), 0.99 (t, J=7.5Hz, 3H)

[0104] The product structure was confirmed by mass spectrometry. Figure 3 As shown, MS (ESI) m / z for C 35 H 41 NNaO 15 S2[M+Na] + :802.18098.

[0105] Example 2: In vitro albumin binding test of albumin-bound doxorubicin prodrug

[0106] The methanol solution of DCM, DSSM, DSSA, DSSU and DSSC was added to the phosphate solution of human serum albumin (HSA) at pH 7.4, so that the concentrations of prodrug and bovine serum albumin were 100 μM and 250 μM, respectively. Then, it was placed at 37 degrees Celsius for incubation at 0 min, 5 min, 30 min, and 90 min, and samples were directly taken into high performance liquid chromatography to examine the binding. The results are shown in Figure 6As shown in the figure, maleimide as the prodrug DCM and DSSM as the target head are almost completely bound to albumin within 5 minutes, while acryloyl chloride as the prodrug connected to the target head DSSA is relatively completely bound to albumin at 90 minutes. In contrast, the control group succinimide (DSSU) and propionic acid (DSSC) also hardly bind to albumin after incubation for 90 minutes.

[0107] The results showed that the prodrugs DCM, DSSA and DSSU could rapidly bind to albumin in in vitro experiments.

[0108] Example 3: Preparation of PEG-modified and non-PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles

[0109] Preparation of PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles:

[0110] Regarding disulfide-linked maleimide prodrugs: Accurately weigh 0.2105 mg DSPE-PEG 2K and 4 mg of disulfide-linked maleimide prodrug, dissolved in 1 mL of tetrahydrofuran; for disulfide-linked acryloyl chloride prodrug: accurately weigh 0.2105 mg of DSPE-PEG 2K and 4 mg of disulfide-linked acryloyl chloride prodrug were dissolved in 1 mL of acetone. The acetone solution was then slowly added dropwise to 4 mL of deionized water under stirring to spontaneously form PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles with uniform particle size. The tetrahydrofuran or acetone was removed by reduced pressure rotary evaporation to obtain a 1 mg / mL nanocolloid solution without organic reagents, as shown in Table 1.

[0111] Table 1. Particle size, size distribution and drug loading of PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles

[0112]

[0113] Preparation of non-PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles:

[0114] Regarding disulfide-linked maleimide prodrugs: accurately weigh 4 mg of disulfide-linked maleimide prodrugs and dissolve them in 1 mL of tetrahydrofuran; regarding disulfide-linked acryloyl chloride prodrugs: accurately weigh 4 mg of disulfide-linked acryloyl chloride prodrugs and dissolve them in 1 mL of acetone. Then, under stirring, the acetone solution was slowly added dropwise to 4 mL of deionized water to spontaneously form disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles with uniform particle size. The tetrahydrofuran or acetone was removed by reduced pressure rotary evaporation to obtain a 1 mg / mL nanocolloid solution without organic reagents, as shown in Table 2.

[0115] Table 2. Particle size, size distribution and drug loading of non-PEGylated disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles

[0116]

[0117]

[0118] The results showed that both PEG-modified and non-PEG-modified disulfide-linked maleimide or acryloyl chloride prodrugs can form self-assembled nanoparticles, and at a concentration of 1 mg / mL, nanoparticles with a suitable and uniform particle size can be formed. Example 4: Cytotoxicity of albumin-bound doxorubicin prodrug solution and PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles

[0119] The MTT method was used to investigate the cytotoxicity of albumin-bound doxorubicin prodrug solution and PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles on mouse breast cancer (4T1) cells and mouse melanoma cells (B16F10). First, the cells in good condition were digested and diluted to 5×10 3After cells / mL cells were blown evenly, 200 μL of cell suspension was added to each well of a 96-well plate, and the cells were placed in an incubator at 37°C and 5% CO2 for 24 hours to adhere to the wall. After the cells adhered to the wall, doxorubicin solution or albumin-bound doxorubicin prodrug solution and PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles (calculated according to the doxorubicin concentration) were added, and the dilutions were all diluted with the corresponding culture fluid and sterile filtered with a 0.22 μm filter membrane. 200 μL of the test solution was added to each well, and 3 parallel wells were added for each concentration. The control group, that is, no test solution was added, a single 200 μL culture fluid was added, and the cells were placed in an incubator and incubated together. After 48 hours of drug addition, the 96-well plate was taken out, 20 μL of 5 mg / mL MTT solution was added to each well, and the culture medium was removed after incubation in an incubator for 4 hours, and 200 μL DMSO was added to each well and oscillated on an oscillator for 10 minutes to fully dissolve the blue-purple crystals. Well A1 (containing only 200 μL DMSO) was set as the zeroing well, and the absorbance value of each well after zeroing was measured at 490 nm using an ELISA reader.

[0120] The results of the cytotoxicity experiments were analyzed and the half inhibitory concentration (IC 50 ). The results are shown in Table 2.

[0121] Table 2. Cytotoxicity of albumin-bound doxorubicin prodrug solution and PEG-modified disulfide-linked maleimide or acryloyl chloride prodrug self-assembled nanoparticles

[0122]

[0123] The results showed that the cytotoxic trend was the strongest for doxorubicin solution, DSSM NPs showed stronger cytotoxicity in 4T1 cells than DSSM solution; DSSA NPs showed stronger cytotoxicity in 4T1 cells than DSSA solution.

[0124] Example 5: In vitro release test of disulfide-linked maleimide or acryloyl chloride prodrug nanoparticles

[0125] The in vitro release of PEG-modified small molecule prodrug self-assembled nanoparticles was investigated using a pH 7.4 phosphate buffer containing 30% ethanol as the release medium. The PEG-modified small molecule prodrug self-assembled nanoparticles (prodrug content of 200 mg) prepared in Example 2 were added to 30 mL of the release medium, and samples were taken at set time points at 37°C, and the doxorubicin concentration was determined by high performance liquid chromatography. Glutathione (GSH) was added to the release medium to investigate the release of the nanoparticles under reducing conditions.

[0126] The results are as follows Figure 7As shown, the prodrug nanoparticles connected by disulfide bonds to maleimide or acryloyl chloride have extremely high stability, and the nanoparticles are hardly hydrolyzed in the blank medium, and doxorubicin is difficult to release from the prodrug. When a certain concentration of glutathione is contained in the release medium, the doxorubicin released by the prodrug nanoparticles connected by disulfide bonds to maleimide or acryloyl chloride gradually increases over time, and shows a trend of increasing doxorubicin release as the glutathione concentration increases. The experimental results show that the albumin-bound doxorubicin small molecule prodrug designed by the present invention has the characteristics of reduction-sensitive drug release, can respond to the specific reduction environment of the tumor site, and achieve tumor site-specific drug release, which is expected to improve the anti-tumor effect of doxorubicin and reduce the toxic and side effects on the body.

[0127] Example 6: In vivo antitumor test of disulfide-linked maleimide or acryloyl chloride prodrug nanoparticles

[0128] Mouse breast cancer cell suspension (4T1, 1x10 6 cells / 100 μL) were inoculated in the right axilla of BABL / C mice and the tumor volume grew to 150-200 mm 3 The tumor-bearing mice were randomly divided into 5 groups, 5 mice in each group: blank control group (PBS), DOX group, DSSM NPs group, DSSA NPs group and Doxil group. The mice were given the drug once every two days for four consecutive times. After the drug administration, the survival status of the mice was observed every day, and the body weight and tumor volume were measured. The mice were killed 13 days after the drug administration, and the organs and tumors were obtained and the tumor weight was measured.

[0129] Figure 8 The results showed that in the PBS group, the tumor volume increased rapidly and reached 1000mm on day 12. 3 Compared with the blank control group, each drug-treated group showed a certain anti-tumor effect, among which DSSA NPs and DSSM NPs had the best effect in inhibiting tumor volume when the dosage reached 20 mg / kg. Fig. 9 As shown in the figure, when the dosage was 10 mg / kg, mice in the doxorubicin solution and Doxil groups were considered dead due to weight loss of more than 20%, indicating poor safety. In contrast, DSSM NPs and DSSA NPs significantly inhibited tumor growth while showing good safety in mice, with no weight loss or death. Fig.10 As shown, at a dose of up to 20 mg / kg, the tumor burden rate of the DSSM NPs and DSSA NPs groups was the lowest among all groups, showing a significant anti-tumor effect. Fig.11 and Fig.12As shown, the blood routine and liver and kidney function indicators of mice in the DSSM NPs and DSSA NPs groups were within the normal range, while the mice in the doxorubicin and doxorubicin liposome groups showed varying degrees of liver and kidney toxicity. The above results show that the synthesized albumin-bound doxorubicin prodrug has a significant anti-tumor effect without causing significant toxicity to the body, and is a safe and effective anti-tumor drug delivery system.

Claims

1. An albumin-bound doxorubicin prodrug or a pharmaceutically acceptable salt thereof, characterized in that: The prodrug structural formula is shown in the figure; Where R is a, b, c, d or e: Where n = 1, 2, 3; m = 0, 1, 2, X is one of a disulfide bond, a monosulfide bond, a diselenide bond or a monoselenide bond.

2. The method for preparing the albumin-bound doxorubicin prodrug according to claim 1, characterized in that: The preparation method is as follows: (a) Preparation of DCM, a prodrug of maleimide connected by a carbamate bond: Hydroxyethyl maleimide and p-nitrophenyl chloroformate are reacted at room temperature under the catalysis of N,N-diisopropylethylamine (DIPEA) and 4-dimethylaminopyridine (DMAP), and then separated and purified by column chromatography to obtain an intermediate product; then doxorubicin and triethylamine are added, stirred at room temperature for reaction, and the obtained product is separated and purified by preparative liquid phase to obtain DCM; (b) Preparation of reduction-sensitive disulfide-bond-linked maleimide prodrug DSSM: maleimidopropionic acid and 2,2'-dithiodiethanol are reacted at room temperature under the catalysis of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and 4-dimethylaminopyridine (DMAP), and then separated and purified by column chromatography to obtain intermediate 1; then intermediate 1 and p-nitrochloroformate are reacted at room temperature under the catalysis of N,N-diisopropylethylamine (DIPEA) and 4-dimethylaminopyridine (DMAP), and then separated and purified by column chromatography to obtain intermediate 2; then doxorubicin and triethylamine are added, the reaction is stirred at room temperature, and the resulting product is separated and purified by preparative liquid phase to obtain DSSM; (c) Preparation of reduction-sensitive disulfide-bond-linked succinimide prodrug DSSU: Succinimidyl propionic acid and 2,2'-dithiodiethanol are reacted at room temperature under the catalysis of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and 4-dimethylaminopyridine (DMAP), and then separated and purified by column chromatography to obtain intermediate 1; then intermediate 1 and p-nitrochloroformic acid phenyl ester are reacted at room temperature under the catalysis of N,N-diisopropylethylamine (DIPEA) and 4-dimethylaminopyridine (DMAP), and then separated and purified by column chromatography to obtain intermediate 2; then doxorubicin and triethylamine are added, the reaction is stirred at room temperature, and the resulting product is separated and purified by preparative liquid phase to obtain DSSU; (d) Preparation of reduction-sensitive disulfide bond-linked acryloyl chloride prodrug DSSA: acryloyl chloride and 2,2'-thiodiethanol were reacted with triethylamine in an ice bath, and the reaction was separated and purified by column chromatography to obtain intermediate 1 at room temperature; then intermediate 1 and p-nitrochloroformic acid phenyl ester were reacted with N,N-diisopropylethylamine (DIPEA) and 4-dimethylaminopyridine (DMAP) as catalysts at room temperature, and the reaction was separated and purified by column chromatography to obtain intermediate 2; then doxorubicin and triethylamine were added, and the reaction was stirred at room temperature, and the obtained product was separated and purified by preparative liquid phase to obtain DSSA; (e) Preparation of reduction-sensitive disulfide-bond-linked propionic acid prodrug DSSC: propionic acid and 2,2'-thiodiethanol were reacted in an ice bath with the addition of EDCI and DMAP for catalysis, and the reaction was separated and purified by column chromatography at room temperature to obtain intermediate 1; then intermediate 1 and p-nitrochloroformate were reacted at room temperature with the catalysis of N,N-diisopropylethylamine (DIPEA) and 4-dimethylaminopyridine (DMAP), and separated and purified by column chromatography to obtain intermediate 2; then doxorubicin and triethylamine were added, and the reaction was stirred at room temperature for 24 hours. The resulting product was separated and purified by preparative liquid phase to obtain DSSC.

3. The preparation method according to claim 2, characterized in that: In the step of preparing DCM, in molar ratio, hydroxyethylmaleimide: p-nitrophenyl chloroformate: DMAP:DIPEA=1:(1-10):(0.1-1):(4-10), preferably 1:(2-5):(0.1-2):(2-5); intermediate product 1: doxorubicin: triethylamine=1:(1-10):(1-3):(4-10), more preferably 1:(1-2):(5-10); In the step of preparing DSSM, in molar ratio, maleimidopropionic acid: 2,2'-dithiodiethanol: EDCI: DMAP = 1: (1-3): (1-5): (0.1-1), preferably 1: (1-2): (1-2): (0.1-5); intermediate product 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5); intermediate product 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10); In the step of preparing DSSU, in molar ratio, succinimidyl propionic acid: 2,2'-dithiodiethanol: EDCI: DMAP = 1: (1-3): (1-5): (0.1-1), preferably 1: (1-2): (1-2): (0.1-5); intermediate product 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5); intermediate product 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10); In the step of preparing DSSA, in molar ratio, acryloyl chloride: 2,2'-dithiodiethanol: triethylamine = 1: (1-3): (1-5): (1-5), preferably 1: (1-2): (1-2); intermediate product 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5); intermediate product 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10); In the steps of the DSSC, in molar ratio, propionic acid: 2,2'-dithiodiethanol: EDCI: DMAP = 1: (1-3): (1-5): (0.1-1), preferably 1: (1-2): (1-2): (0.1-5); intermediate product 1: p-nitrophenyl chloroformate: DMAP: DIPEA = 1: (1-10): (0.1-1): (4-10), preferably 1: (2-5): (0.1-2): (2-5); intermediate product 2: doxorubicin: triethylamine = 1: (1-10): (1-3): (4-10), preferably 1: (1-2): (5-10).

4. An albumin-bound doxorubicin prodrug self-assembled nanoparticle, characterized in that: The nanoparticles are self-assembled from the reduction-sensitive disulfide-bond-linked maleimide or acryloyl chloride prodrug according to claim 1.

5. The self-assembled nanoparticles according to claim 4, characterized in that: The invention relates to a non-PEG-modified reduction-sensitive disulfide bond-linked self-assembled nanoparticle of a maleimide or acryloyl chloride prodrug or a PEG-modified reduction-sensitive disulfide bond-linked self-assembled nanoparticle of a maleimide or acryloyl chloride prodrug; the mass ratio of the reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug to the PEG modifier is 1:(0.05-1); and the PEG modifier is DSPE-PEG, TPGS, PEG-PLGA, PEG-PE or DSPE-PEG-FA.

6. The self-assembled nanoparticles according to claim 5, characterized in that: The preparation method of the self-assembled nanoparticles of PEG-modified reduction-sensitive disulfide-bond-linked maleimide or acryloyl chloride prodrug comprises: dissolving non-reduction-sensitive disulfide-bond-linked maleimide or acryloyl chloride prodrug and PEG modifier in an organic solvent, slowly dropping the solution into water under stirring, the prodrug spontaneously forms uniform nanoparticles, removing the organic solvent, and obtaining a nano-colloid solution without organic solvent; the solvent is selected from dimethyl sulfoxide, N,N'-dimethylformamide, tetrahydrofuran, and acetone.

7. Use of the doxorubicin prodrug or its pharmaceutically acceptable salt according to any one of claims 1 to 3 or the self-assembled nanoparticles of the reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug according to claim 4, characterized in that: Application in the preparation of anti-tumor drugs.

8. Use of the self-assembled nanoparticles of the doxorubicin prodrug or its pharmaceutically acceptable salt according to any one of claims 1 to 3 or the reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug according to claim 4, characterized in that: Application in the preparation of injection, oral administration or local administration system.

9. Use of the doxorubicin prodrug or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 3 or the self-assembled nanoparticles of the reduction-sensitive disulfide bond-linked maleimide or acryloyl chloride prodrug according to any one of claim 4, characterized in that: Application in the preparation of drug delivery systems with improved efficacy and reduced toxicity.

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