POLY[ALPHA-CYANOACRYLATE] HYDROLYZATE AND PREPARATION METHOD AND APPLICATION THEREOF

Abstract

The invention relates to a poly[α-cyanoacrylate] hydrolyzate, a preparation method and an application thereof, belonging to the field of pharmaceutical and chemical industry. A main technical solution is as follows: provided is a poly[α-cyanoacrylate] hydrolyzate having a chemical formula: CH.sub.2—CRCOOH.sub.n, wherein R=—CN or —COOH. Poly[2-cyanoacrylic acid] provided by the present invention is dispersed in water to prepare the negatively charged microsphere, that is, to obtain the new blank embolic microsphere, the particle size of the microsphere can be adjusted in a micron-scale range, and the microsphere have a deformation function to pass through a vascular with a specific shape, which can tightly embolize the vascular to avoid ectopic embolism caused by falling off; poly[2-carboxyacrylic acid] can be used for preparing a new nano-drug carrier, improving the curative effect of the carried drug on diseased tissues and reduce the toxic and side effects of the carried drug on normal tissues.

Claims

1. A poly[α-cyanoacrylate] hydrolyzate, having a chemical formula: CH.sub.2—CRCOOH.sub.n, wherein R=—CN or —COOH.

2. A preparation method for the poly[α-cyanoacrylate] hydrolyzate according to claim 1, comprising firstly preparing an α-cyanoacrylate polymer, and hydrolyzing the polymer to obtain the poly[α-cyanoacrylate] hydrolyzate.

3. The poly[α-cyanoacrylate] hydrolyzate according to claim 1, wherein the poly[α-cyanoacrylate] hydrolyzate is poly[2-cyanoacrylic acid] having a chemical formula: CH.sub.2—CRCOOH.sub.n.

4. The poly[α-cyanoacrylate] hydrolyzate according to claim 3, wherein a preparation method for poly[2-cyanoacrylic acid] comprises firstly preparing an α-cyanoacrylate polymer, then selectively hydrolyzing ester bonds in the polymer under alkaline conditions, and performing purification to obtain the poly[2-cyanoacrylic acid].

5. Application of the poly[α-cyanoacrylate] hydrolyzate according to claim 1, wherein poly[2-cyanoacrylic acid] is prepared as a blank embolic microsphere.

6. The application according to claim 5, wherein a preparation method for the blank embolic microsphere comprises dispersing poly[2-cyanoacrylic acid] in water to prepare a negatively charged microsphere, to obtain the blank embolic microsphere.

7. The application according to claim 5, wherein a particle size of the blank embolic microsphere ≥1 μm, and the blank embolic microsphere can be deformed.

8. The application according to claim 5, wherein the particle size of the blank embolic microsphere can be adjusted in a micron-scale range to adapt to requirements of vascular embolism targets with different diameters, and the blank embolic microsphere has a deformation function as required to pass through vascular stenosis in an embolic pathway, closely embolize vascular to avoid ectopic embolism caused by falling off.

9. The application according to claim 5, wherein the blank embolic microsphere is prepared as a drug-loaded embolic microsphere.

10. The application according to claim 9, wherein a preparation method for the drug-loaded embolic microsphere comprises combining the blank embolic microsphere with a positively charged drug to obtain the drug-loaded embolic microsphere.

11. The application according to claim 9, wherein the drug-loaded embolic microsphere actively loads and releases a drug based on a principle of charge reversal.

12. The application according to claim 9, wherein the drug-loaded embolic microsphere can directly release the drug into a local area of a diseased tissue in the diseased tissue with high vascular permeability and a low pH value.

13. The poly[α-cyanoacrylate] hydrolyzate according to claim 1, wherein the poly[α-cyanoacrylate] hydrolyzate is poly[2-carboxyacrylic acid] having a chemical formula: CH.sub.2—CRCOOH.sub.n.

14. The poly[α-cyanoacrylate] hydrolyzate according to claim 13, wherein a preparation method for the poly[2-carboxyacrylic acid] comprises firstly preparing an α-cyanoacrylate polymer, then hydrolyzing a ester bond and a cyano group of the polymer under alkaline conditions, and dialyzing to remove impurities to obtain the poly[2-carboxyacrylic acid].

15. The application of the poly[α-cyanoacrylate] hydrolyzate according to claim 13, wherein poly[2-carboxyacrylic acid] is prepared as a nano-drug carrier.

16. The application according to claim 15, wherein a preparation method for the nano-drug carrier comprises modifying a carboxy group of poly[2-carboxyacrylic acid] with an active polyethylene glycol to obtain the nano-drug carrier.

17. The application according to claim 15, wherein a preparation method for the nano-drug carrier comprises encapsulating poly[2-carboxyacrylic acid] in a liposome to obtain the nano-drug carrier.

18. The application according to claim 15, wherein the nano-drug carrier actively loads and releases a drug based on a principle of charge reversal.

19. The application according to claim 15, wherein the nano-drug carrier targetedly delivers a drug through blood, the nano-drug carrier is accumulated in a diseased tissue with high vascular permeability and a low pH value, and directly releases the drug into the diseased tissue.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0085] FIG. 1 is a diagram showing a traditional DC-Bead preparation process;

[0086] FIG. 2 shows the blank embolic microsphere (50×);

[0087] FIG. 3 is a diagram showing preparation and functioning of the drug-loaded embolic microsphere;

[0088] FIG. 4 shows the doxorubicin-loaded embolic microsphere (50×);

[0089] FIG. 5 shows an internal morphology of the doxorubicin-loaded embolic microsphere after pulverization;

[0090] FIG. 6 shows an electron microscope photograph of poly[2-carboxyacrylic acid] nano-doxorubicin;

[0091] FIG. 7 shows an electron microscopy photograph of poly[2-carboxyacrylic acid] nano-doxorubicin liposome; and

[0092] FIG. 8 is a structural schematic diagram of poly[2-carboxyacrylic acid].

DETAILED DESCRIPTION

[0093] The present invention will be further illustrated and explained below with reference to specific examples, and unless otherwise specified, raw materials and equipment used in the present invention are common raw materials and equipment.

Example 1 Preparation of poly[2-cyanoacrylic acid]

[0094] (1) Formula: n-butyl α-cyanoacrylate

[0095] Physiological Saline, Sesame Oil, Tween-80, Span-20, and Anhydrous Ethanol

[0096] n-butyl α-cyanoacrylate was dissolved in refined sesame oil without pyrogen to form 10 mL of a 30% oil solution of n-butyl α-cyanoacrylate, and the oil solution of n-butyl α-cyanoacrylate was dispersed in a 0.25% physiological saline solution of Tween-80 and span-20 with a pH value of 4.0. The pH value was adjusted to 7.8, a polymerization reaction of n-butyl α-cyanoacrylate was initiated, centrifugation was performed to separate a precipitate after 12 hours, the precipitate was washed with anhydrous ethanol, and centrifugation was repeatedly performed for 5 times. The precipitate was dispersed in 50 ml of anhydrous ethanol, and sodium hydroxide was added to selectively hydrolyze the ester bond and retain the cyano group. The anhydrous ethanol was removed by evaporation under reduced pressure, then the resulting residue was mixed with 100 mL of distilled water, the mixture was centrifuged at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain poly[2-cyanoacrylic acid].

[0097] (2) Formula: octyl α-cyanoacrylate

[0098] A 50% Dextrose Solution, Poloxamer, and Anhydrous Ethanol

[0099] Octyl α-cyanoacrylate was dissolved in a 50% dextrose solution of 0.25% poloxamer with a pH value of 4.0 to form an octyl α-cyanoacrylate emulsion, the pH value was adjusted to 7.4, polymerization was carried out at room temperature for 12 hours under stirring, centrifugation was performed to separate a precipitate, the precipitate was dispersed in 50 ml of anhydrous ethanol, sodium hydroxide was added to selectively hydrolyze ester bonds and retain cyano, the anhydrous ethanol was removed by evaporation under reduced pressure, then the resulting residue was mixed with 100 mL of distilled water, the mixture was centrifuged at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain poly[2-cyanoacrylic acid].

[0100] (3) Formula: isobutyl α-cyanoacrylate

[0101] A 10% Dextran Solution, Polyethylene Glycol 400 Monooleate, and Anhydrous Ethanol

[0102] Isobutyl α-cyanoacrylate was dissolved in a 10% dextran solution of 0.25% polyethylene glycol 400 monooleate with a pH value of 4.0 to form an isobutyl α-cyanoacrylate emulsion, the pH value was adjusted to 7.4, polymerization was carried out at room temperature for 12 hours under stirring, centrifugation was performed to separate a precipitate, then the precipitate was dispersed in 50 ml of anhydrous ethanol, sodium hydroxide was added to selectively hydrolyze ester bonds and retain cyano, the anhydrous ethanol was removed by evaporation under reduced pressure, then the resulting residue was mixed with 100 mL of distilled water, the mixture was centrifuged at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain poly[2-cyanoacrylic acid].

[0103] (4) Formula: n-butyl α-cyanoacrylate

[0104] Anhydrous Ethanol

[0105] n-butyl α-cyanoacrylate was dissolved in anhydrous ethanol to make a 50% ethanol solution, polymerization was carried out for 1 week, then sodium hydroxide was added to selectively hydrolyze ester bonds and retain cyano, the anhydrous ethanol was removed by evaporation under reduced pressure, then the resulting residue was mixed with 100 mL of distilled water, the mixture was centrifuged at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain poly[2-cyanoacrylic acid].

[0106] (5) Formula: methyl α-cyanoacrylate

[0107] Acetone, and Anhydrous Ethanol

[0108] Methyl α-cyanoacrylate was dissolved in acetone to make a 50% acetone solution, polymerization was carried out for 2 weeks, acetone was removed under reduced pressure, the resulting residue was dispersed in anhydrous ethanol, then sodium hydroxide was added to selectively hydrolyze ester bonds and retain cyano, the anhydrous ethanol was removed by evaporation under reduced pressure, the resulting residue was mixed with 100 mL of distilled water, the mixture was centrifuged at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain poly[2-cyanoacrylic acid].

[0109] (6) Formula: ethyl α-cyanoacrylate

[0110] Acetonitrile, and Anhydrous Ethanol

[0111] Ethyl α-cyanoacrylate was dissolved in acetonitrile to make a 50% acetonitrile solution, polymerization was carried out for 2 weeks, then the acetonitrile was removed under reduced pressure, the resulting residue was dispersed in anhydrous ethanol, then sodium hydroxide was added to selectively hydrolyze ester bonds and retain cyano, the anhydrous ethanol was removed by evaporation under reduced pressure, the resulting residue was mixed with 100 mL of distilled water, the mixture was centrifuged at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain poly[2-cyanoacrylic acid].

Example 2 Preparation of poly[2-cyanoacrylic acid] Blank Embolic Microsphere

[0112] (1) Formula: poly[2-cyanoacrylic acid]

[0113] Anhydrous Ethanol, and Water

[0114] 0.5 g of poly[2-cyanoacrylic acid] was prepared into 5 mL of an anhydrous ethanol solution. The solution was placed in a rotary evaporator, the ethanol was evaporated to form a film on a wall of the rotary evaporator, mixed with 50 mL of distilled water, hydration was performed for 12 h, centrifugation was performed at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain the blank embolic microsphere.

[0115] (2) Formula: poly[2-cyanoacrylic acid]

[0116] Amino Polyethylene Glycol 2000, and Water

[0117] carboxy was modified with amino polyethylene glycol 2000, an active polyethylene glycol modified catalyst:

[0118] EDC.HCl: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride;

[0119] NETS: N-hydroxysuccinimide. After polyethylene glycol modification, centrifugation was performed at 8000 rpm for 20 min, the supernatant was discarded, water washing was performed while shaking, centrifugation was performed again, and the operations were repeatedly performed for 5 times to obtain polyethylene glycol modified blank embolic microsphere.

Example 3 Preparation of poly[2-cyanoacrylic acid] Drug-Loaded Embolic Microsphere

[0120] (1) Formula: The Blank Embolic Microsphere

[0121] Doxorubicin

[0122] 1 mL of the blank embolic microsphere was mixed with an equal volume of 2 mg/mL doxorubicin 1/15 M isotonic phosphate buffer with a pH value of 7.4, the mixture was shaked for 15 min, the remaining doxorubicin solution was poured out, and then rinsing was performed with 1/15 M isotonic phosphate buffer with a pH value of 7.4 to obtain the doxorubicin-loaded embolic microsphere for tumor arterial embolization.

[0123] (2) Formula: The Blank Embolic Microsphere

[0124] Gentamicin

[0125] 1 mL of the blank embolic microsphere was mixed with an equal volume of 10 mg/mL gentamicin 1/15 M isotonic phosphate buffer solution with a pH value of 7.4, the mixture was shaked for 5 min, the remaining gentamicin solution was poured out, and then rinsing was performed with 1/15 M isotonic phosphate buffer solution with a pH value of 7.4 to obtain gentamicin-loaded embolic microsphere with anti-inflammatory treatment requirements.

[0126] Efficacy of poly[2-cyanoacrylic] embolic Microsphere

[0127] 1. New Blank Embolic Microsphere

[0128] The particle size and surface morphology of the new blank embolic microsphere were observed and measured by optical microscope and scanning electron microscope (as shown in FIG. 2). The particle size changes of the new blank embolic microsphere during long-term storage were measured at different storage temperatures. The new blank embolic microsphere can be used for embolization treatment of arterial bleeding, such as traumatic pelvic and visceral bleeding, urinary system bleeding, gastrointestinal bleeding, severe nasal and maxillofacial bleeding, massive hemoptysis, and postoperative visceral bleeding, and can also be used for embolization treatment of venous bleeding, such as gastrointestinal varices.

[0129] 2. New Drug-Loaded Embolic Microsphere

[0130] The drug loading rate, drug automatic loading rate and drug release rate of the new drug-loaded embolic microsphere were determined by a UV-Vis spectrophotometer. A rabbit model of VX2 liver cancer was established by a tumor tissue block embedding method, and the effectiveness of doxorubicin-loaded embolic microsphere in the hepatic artery was evaluated (as shown in FIG. 3). Two weeks after the embedding implantation of a tumor mass, the doxorubicin-loaded embolic microsphere were injected by open hepatic artery intubation (as shown in FIG. 4). The concentration of doxorubicin in peripheral blood of experimental rabbits was determined by high performance liquid chromatography (HPLC). The doxorubicin distribution in the tumor mass and the tumor microvessel density were observed by an immunofluorescence staining technology. The results showed that the size of the new drug-loaded embolic microsphere could effectively embolize tumor arterial vascular, and the anti-tumor effect was remarkable, and the tumor vessel density was significantly reduced. Animal experiments have shown that this new drug-loaded embolic microspheres can also be used for the treatment of renal cancer, adrenal cancer, various vascular-rich tumors in the pelvis, maxillofacial malignant tumors, and limbic, spinal and pelvic malignant tumors. The new drug-loaded embolic microsphere can also be loaded with all positively charged drugs, can be used for vascular embolization treatment with specific needs, can improve the local efficacy of drugs on diseased tissues and reduce the toxic and side effects of drugs on the whole body (as shown in FIG. 5).

Example 4 Preparation of poly[2-carboxyacrylic acid]

[0131]

TABLE-US-00001 (1) Formula: n-butyl α-cyanoacrylate 0.9 mL Tween-80 3.0 mL physiological saline (pH 2.0)  50 mL

[0132] Preparation process: Tween-80 was dissolved in physiological saline, a pH value was adjusted to 2.0 with 0.01N hydrochloric acid, n-butyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the mixture was dispersed at high speed in ice water for 45 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 7.8 with 0.01N sodium hydroxide, the resulting solution was stored overnight, centrifuged at low temperature at 8000 rpm for 20 min, and washed with 50% ethanol for 3 times, a precipitate being retained during centrifuging at 8000 rpm for 20 min each time, 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

TABLE-US-00002 (2) Formula: octyl α-cyanoacrylate 0.9 mL polyethylene glycol 400 monooleate 6.0 mL 50% dextrose (pH 2.0)  50 mL

[0133] Preparation process: polyethylene glycol 400 monooleate was added to 50% dextrose, a pH value was adjusted to 2.0 with 0.01N hydrochloric acid, octyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the mixture was dispersed in ice water for 5 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 7.8 with 0.01N sodium hydroxide, the resulting solution was continued to be dispersed overnight, centrifuged at low temperature at 8000 rpm for 40 min, and washed for three times with pure water, a precipitate being retained during centrifuging at 8000 rpm for 20 min each time, an appropriate amount of 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

TABLE-US-00003 (3) Formula: n-butyl α-cyanoacrylate 0.9 mL refined soybean oil 2.1 mL Tween-80 6.0 mL Span-20 1.2 mL 20% dextrose (pH 2.0)  50 mL

[0134] Preparation process: Tween-80 and Span-20 were added to 20% dextrose, a pH value was adjusted to 2.0 with 0.01N hydrochloric acid, n-butyl α-cyanoacrylate was added to soybean oil to prepare a solution with good flowability, the soybean oil solution of n-butyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the mixture was dispersed in ice water for 5 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 12 with 0.01N sodium hydroxide, the resulting solution was continued to be dispersed overnight, centrifuged at low temperature at 8000 rpm for 40 min, and washed with pure water for 3 times, a precipitate being retained during centrifuging at 8000 rpm for 20 min each time, an appropriate amount of 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

TABLE-US-00004 (4) Formula: isobutyl α-cyanoacrylate 0.9 mL poloxamer 6.0 mL 5% dextran (pH 2.0)  50 mL

[0135] Preparation process: poloxamer was added to 5% dextran, a pH value was adjusted to 2.0 with 0.01N hydrochloric acid, isobutyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the mixture was dispersed in ice water for 5 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 7.8 with 0.01N sodium hydroxide, the resulting solution was continued to be dispersed overnight, centrifuged at low temperature at 8000 rpm for 40 min, and washed with pure water for 3 times, a precipitate being retained during centrifuging at 8000 rpm for 20 min each time, an appropriate amount of 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

TABLE-US-00005 (5) Formula: n-butyl α-cyanoacrylate 0.9 mL anhydrous ethanol 5.0 mL water (pH 2.0)  50 mL

[0136] Preparation process: n-butyl α-cyanoacrylate was added to anhydrous ethanol to form a clear solution, the anhydrous ethanol solution of n-butyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the solution was dispersed in ice water for 15 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 7.8 with 0.01N sodium hydroxide, the resulting solution was continued to be dispersed overnight, centrifuged at low temperature at 8000 rpm for 15 min, and washed with pure water for 3 times, a precipitate being retained during centrifuging at 8000 rpm for 15 min each time, an appropriate amount of 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

TABLE-US-00006 (6) Formula: methyl α-cyanoacrylate 0.9 mL acetone 5.0 mL water (pH 2.0)  50 mL

[0137] Preparation process: methyl α-cyanoacrylate was added to acetone to form a clear solution, the acetone solution of methyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the solution was dispersed in ice water for 15 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 7.8 with 0.01N sodium hydroxide, the resulting solution was continued to be dispersed overnight, centrifuged at low temperature at 8000 rpm for 15 min, and washed with pure water for 3 times, a precipitate being retained during centrifuging at 8000 rpm for 15 min each time, an appropriate amount of 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

TABLE-US-00007 (7) Formula: ethyl α-cyanoacrylate 0.9 mL acetonitrile 5.0 mL water (pH 2.0)  50 mL

[0138] Preparation process: ethyl α-cyanoacrylate was added to acetonitrile to form a clear solution, the acetonitrile solution of ethyl α-cyanoacrylate was slowly added dropwise under the condition of high-speed dispersion with a rigid plastic rotor within 9 min, the solution was dispersed in ice water for 15 min with a hard plastic tissue disperser, filtering was performed with a 0.45 μm microporous filter membrane, the pH value was adjusted to 7.8 with 0.01N sodium hydroxide, the resulting solution was continued to be dispersed overnight, centrifuged at low temperature at 8000 rpm for 15 min, and washed with pure water for 3 times, a precipitate being retained during centrifuging at 8000 rpm for 15 min each time, an appropriate amount of 95% ethanol was added, hydrolysis was performed with 0.1N sodium hydroxide to obtain a light yellow solution, rotary evaporation was performed to remove the solvent, the pH value was adjusted to 7.4 with 0.1N hydrochloric acid, pure water dialysis was performed with a dialysis bag with a molecular weight lower limit of 10000, a dialysis solution being changed once every 12 hours, and freeze drying was performed to obtain poly[2-carboxyacrylic acid].

Example 5 Preparation of poly[2-carboxyacrylic acid] Nano-Drug Carrier

[0139]

TABLE-US-00008 (1) Formula: poly[2-carboxyacrylic acid]  590 mg aminopolyethylene glycol 2000 2000 mg

[0140] Preparation process: under the condition of magnetic stirring, with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, EDC.HCl), and N-hydroxy succinimide (NHS) as a catalyst, 2 g of NH2-PEG was added to a nano-drug carrier framework solution to modify a nano-drug carrier framework, a reaction was carried out overnight, the above solution was put into a dialysis bag, dialysis was performed with distilled water for 72 h to remove impurities with a molecular weight of less than 10000, water being changed once every 12 hours, so as to obtain a nano-drug carrier covered with PEG2000 on the surface, and a pH value was adjusted to 7.4 to obtain a nano-drug carrier.

TABLE-US-00009 (2) Formula: poly[2-carboxyacrylic acid]  590 mg polyethylene glycol-hydrazide 2000 mg

[0141] Preparation process: under the condition of magnetic stirring, with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, EDC.HCl), and 1-hydroxybenzotriazole (N-hydroxybenzotriazole, HOBT) as a catalyst, 2 g of NH2-PEG was added to a nano-drug carrier framework solution to modify a nano-drug carrier framework, a reaction was carried out overnight, the above solution was put into a dialysis bag, dialysis was performed with distilled water for 72 h to remove impurities with a molecular weight of less than 10000, water being changed once every 12 hours, so as to obtain a nano-drug carrier covered with PEG2000 on the surface, and a pH value was adjusted to 7.4 to obtain a nano-drug carrier.

TABLE-US-00010 (3) Formula: hydrogenated lecithin 60 mmol cholesterol 40 mmol PEG2000-DSPE 10 mmol poly[2-carboxyacrylic acid] 0.5%

[0142] Preparation process: the above materials were dissolved in 50 mL of anhydrous ethanol, the anhydrous ethanol was removed by rotary evaporation to obtain a liposome membrane, 50 mL of water was added, hydration was performed, filtering was performed with a 200 nm microporous filter membrane, a pH value was adjusted to 7.4 with 0.001 N sodium hydroxide, poly[2-carboxyacrylic acid] outside the liposome that was not encapsulated by the liposome was removed by gel chromatography, and filtration was performed to obtain a nanoliposome that can actively load positively charged drugs, that is, a nano-drug carrier.

[0143] Efficacy of poly[2-carboxyacrylic acid] Nano-Drug Carrier

[0144] Under a scanning electron microscope, the new nano-drug carrier has a spherical shape, uniform particle size and uniform distribution, and its Zeta potential can reach −52.5 mV By taking doxorubicin as an example, an animal model of sarcoma 180 in white mice and a C57BL6 tumor lung metastasis animal model proved that this nano-doxorubicin can significantly reduce the cardiotoxicity of doxorubicin, especially significantly reduce the incidence of heart failure caused by doxorubicin, and improve its anti-tumor effect (P<0.01). A rabbit liver cancer model was used to evaluate its efficacy. The results showed that its anti-cancer effect was significantly higher than that of doxorubicin (P<0.01). After the new nano-drug carrier was loaded with doxorubicin, nano-doxorubicin covered with polyethylene glycol on the surface is formed, after entering the body, the nano-doxorubicin covered with polyethylene glycol can circulate in the blood for a long time, and it is difficult for the nano-doxorubicin covered with polyethylene glycol to enter normal tissues with extremely low vascular permeability. However, the nano-doxorubicin covered with polyethylene glycol will passively accumulate into tumor tissues with high vascular permeability. Therefore, the anti-tumor effect of doxorubicin can be improved, and the toxic reaction of doxorubicin can be reduced. This product is added to freeze-dried doxorubicin to be shaken to form a nano-doxorubicin drug and can also transport other positively charged drugs. After entering the blood through intravenous drip, the new nano-drug carrier will accumulate in tumor tissues with high vascular permeability, infection sites or inflammation sites, thereby improving the efficacy of anti-cancer drugs, antibacterial drugs or anti-tumor drugs and reducing their adverse effects. The results of in vivo distribution study showed that the new nanoliposome drug carrier significantly reduced the distribution of doxorubicin to normal tissues and organs such as the heart, and significantly increased the distribution of tumors or infectious and inflammatory lesions. The results are shown in FIGS. 6-8.

[0145] The above-described examples are merely exemplary and illustrative of the invention and are not intended to limit the invention to the scope of the described examples. In addition, it should be understood by those skilled in the art that the present invention is not limited to the above-described examples, numerous variations and modifications may be made in light of the teachings of the present invention, and these variations and modifications all fall within the protection scope of the invention.