A kind of plant polypeptide drug-loaded nanoparticles and preparation method thereof

Abstract

The present invention relates to the technical field of biomedical polymers, and specifically to a type of coated sustained-release plant polypeptide drug-loaded nanoparticles and a preparation method thereof, in which the plant polypeptide itself is used to coat the drug-loaded nanoparticles through electrostatic adsorption and cross-linking. The plant polypeptide drug-loaded nanoparticles of the present invention have redox-sensitive response capabilities, can be released at designated locations, reduce the toxicity of drugs to the human body, and improve the therapeutic effects of drugs. The coated sustained-release plant polypeptide drug-loaded nanoparticles of the present invention have a certain sustained-release ability, and the preparation of drug-loaded nanoparticles using natural polymers as materials can be used for a variety of wide applications such as controlled release of drugs, tissue engineering and gene therapy. The preparation method of the present invention is simple to operate and has stable quality. The particle size of the prepared drug-loaded nanoparticles is controllable, the dispersion is concentrated, the stability is good, and it is suitable for mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical macromolecules, and in particular to a kind of coated plant polypeptide drug-loaded nanoparticles and a preparation method thereof. Background Art

[0002] Chemotherapy is currently the mainstay of cancer treatment. It can treat some localized and metastatic cancers and can be used alone or in combination with other forms of treatment. Traditional chemotherapeutic drugs have certain peculiarities in actual clinical application. For example, traditional chemotherapy drugs have extremely poor water solubility, and many traditional chemotherapy drugs must be used in conjunction with their corresponding solvents, which increases the burden of the drugs on the human body and increases side effects. They lack selectivity, meaning that while traditional chemotherapy drugs inhibit cancer cells, they also affect rapidly growing normal human cells, leading to their death. They also develop multidrug resistance, which is primarily due to an increase in efflux pumps in the cell membrane, which are responsible for transporting various anticancer drugs out of the cell. In fact, the damage caused by chemotherapy drugs to normal tissues and organs in the human body is a significant factor contributing to the high mortality rate among cancer patients.

[0003] Most available anticancer drugs, such as paclitaxel, cyclophosphamide, and doxorubicin (DOX), are highly toxic and are administered systemically to patients. Their indiscriminate cytotoxicity limits the concentration of drugs that can accumulate in tumor tissue. Although intelligent drug controlled-release systems have been investigated for cancer treatment over the past few decades, only a few have been approved and entered clinical trials. Key challenges remain, including insufficient drug loading, appropriate drug release kinetics at the lesion site, low cellular uptake, accumulation of drugs in off-target organs (such as the liver and spleen), inadequate drug release, and a lack of control over the drug release pattern.

[0004] In the past few years, in order to solve these problems of currently used controlled drug release systems, various controlled drug release systems have been studied, designed and manufactured to better control drug release, including increasing drug accumulation at the tumor site through passive, active and sensitive response mechanisms; using appropriate stimulation to control the release of loaded drugs; releasing loaded drugs at a controllable rate over a sufficiently long period of time; and circulating in the blood for at least 24-30 hours before reaching the tumor, during which time the drug should be released slowly. Through these methods, controlled drug release systems can partially solve the two main problems associated with traditional drug release systems: burst release and uncontrolled release of drugs. In addition to controlling the drug concentration at the effective concentration required for treatment, they can also reduce the damage of drugs to normal tissues and reduce the frequency of administration, thereby potentially improving patient compliance with the drug.

[0005] Therefore, it is necessary to develop a peptide drug-loaded nanoparticle that can be used to release hydrophobic drugs, reduce drug damage to normal tissues, and reduce the frequency of drug administration. Summary of the Invention

[0006] The purpose of the present invention is to provide a coated sustained-release plant polypeptide drug-loaded nanoparticle, which is prepared by coating the outer surface of the redox-sensitive plant polypeptide drug-loaded nanoparticle with a plant polypeptide. The nanoparticle can be used to release hydrophobic drugs, improve the water solubility of hydrophobic drugs, have a certain sustained-release ability, reduce the toxicity of the drug to the human body, and improve the therapeutic efficiency of the drug.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect of the present invention, a coated sustained-release plant polypeptide drug-loaded nanoparticle is provided. The coated sustained-release plant polypeptide drug-loaded nanoparticle is prepared by coating the outer surface of the redox-sensitive plant polypeptide drug-loaded nanoparticle with a plant polypeptide;

[0009] The redox-sensitive plant polypeptide drug-loaded nanoparticles are prepared by using plant polypeptides and hydrophobic drugs as raw materials, introducing redox-sensitive monomers, and using a mixed solution of alcohol and water as solvent under the action of a cross-linking agent.

[0010] Preferably, in the coating, the mass ratio of the plant polypeptide to the redox-sensitive plant polypeptide drug-loaded nanoparticles is in the range of 3-6:20. If the ratio is too low, effective coating cannot be formed, and if the ratio is too high, the particle size of the drug-loaded nanoparticles will be too large, which is not conducive to drug delivery.

[0011] Preferably, the plant polypeptide comprises at least one of millet polypeptide, soybean polypeptide, peanut polypeptide and corn polypeptide. The millet polypeptide, soybean polypeptide, peanut polypeptide and corn polypeptide can be directly purchased as commercial products.

[0012] Preferably, the hydrophobic drug includes at least one of doxorubicin or its hydrochloride, erlotinib or its hydrochloride, curcumin or its hydrochloride, paclitaxel or its hydrochloride, methotrexate or its hydrochloride, and ibuprofen or its hydrochloride.

[0013] Preferably, the monomer of the redox-sensitive structure includes at least one of cystamine hydrochloride, dithiodipropionic acid, diacrylamide, and dithiodicarboxylic acid.

[0014] In a second aspect of the present invention, a method for preparing the coated sustained-release plant polypeptide drug-loaded nanoparticles is provided, the method comprising the following steps:

[0015] S1. Mixing the plant polypeptide and the aqueous solution containing the redox-sensitive structural monomer, adjusting the pH to 8.0-9.0, and continuing the reaction until the reaction is complete to obtain a mixed system;

[0016] S2, adding the alcohol solution of the hydrophobic drug to the mixed system and mixing, and then adding the cross-linking agent until the reaction is complete to obtain a product;

[0017] S3. After removing the alcohol solution from the product, the product is filtered, the remaining system is centrifuged, the supernatant is collected, and the supernatant is freeze-dried to obtain redox-sensitive plant polypeptide drug-loaded nanoparticles.

[0018] S4, dissolving the redox-sensitive plant polypeptide drug-loaded nanoparticles in an alcohol solution, adding the plant polypeptide and a cross-linking agent, stirring evenly, and continuing the reaction;

[0019] S5. After the reaction is completed, the alcohol solution is removed and insoluble matter is precipitated. The remaining system after filtration is centrifuged and the supernatant is removed and freeze-dried to obtain coated plant polypeptide drug-loaded nanoparticles.

[0020] Furthermore, when the hydrophobic drug is in the form of a hydrochloride salt, step S2 specifically includes:

[0021] The alcohol solution of the hydrophobic drug is added to the mixed system and mixed evenly, and then a cross-linking agent is added. The pH of the solution is adjusted to 8.0-9.0 and the reaction is continued until the reaction is complete to obtain a product.

[0022] Sodium hydroxide or potassium hydroxide can be used to adjust the pH of the solution to 8.0-9.0.

[0023] Preferably, the mass ratio of the hydrophobic drug to the plant polypeptide is 1-8:20. If the mass ratio is too small, the drug content in the drug-loaded nanoparticles cannot meet the actual use requirements; if the mass ratio is too large, the drug cannot be completely encapsulated, resulting in large losses.

[0024] Preferably, in step S1, the ratio of the monomer containing a redox-sensitive structure to the plant polypeptide is in the range of 2-8:20. If the ratio is too small, the redox sensitivity is not significant; if the ratio is too large, it is not conducive to the encapsulation of hydrophobic drugs and the formation of drug-loaded nanoparticles. Preferably, in step S1, the mass ratio of the monomer containing a redox-sensitive structure to the plant polypeptide is 2-8:20. If the mass ratio is too small, the redox performance of the drug-loaded nanoparticles is not significant; if the mass ratio is too large, the drug encapsulation performance of the drug-loaded nanoparticles is reduced and the structural stability is reduced.

[0025] The concentration of the aqueous solution containing the redox-sensitive structural monomer is in the range of 1 mg / mL to 4 mg / mL (preferably 2 mg / mL).

[0026] In the above technical solution, in step S1, the plant polypeptide and the aqueous solution containing the redox-sensitive structural monomer are mixed, and the pH of the solution is adjusted to 8.0-9.0 using sodium hydroxide or potassium hydroxide, and then the reaction is continued until the reaction is complete to obtain a mixed system;

[0027] This is because the hydrochloric acid on the redox-sensitive structural monomer needs to be removed to expose the reactive groups, so the pH of the solution needs to be adjusted to 8.0-9.0.

[0028] Preferably, in step S2, the cross-linking agent is glutaraldehyde, and the ratio of the cross-linking agent to the plant polypeptide is between 10 μL / 20 mg and 100 μL / 20 mg. If this ratio is too low, the drug-loaded nanoparticle structure may not be well formed and may be relatively loose. If this ratio is too high, the carrier has a high degree of cross-linking and is dense, which may result in poor drug entrapment and release.

[0029] Preferably, in step S2, the alcohol solution is an ethanol-water solution, wherein the volume ratio of water to ethanol in the ethanol-water solution is 1:2-4. If this volume ratio is too low, the hydrophobic drug will precipitate from the water, resulting in a decrease in drug loading; if this volume ratio is too high, the solubility of the polypeptide carrier decreases, resulting in a decrease in yield.

[0030] Preferably, when the hydrophobic drug is in the form of a hydrochloride salt, step S2 specifically comprises:

[0031] The alcohol solution of the hydrophobic drug is added to the mixed system and mixed evenly, and then a cross-linking agent is added. The pH of the solution is adjusted to 8.0-9.0 with sodium hydroxide or potassium hydroxide, and the reaction is continued until the reaction is complete to obtain a product.

[0032] This is because the hydrochloric acid on the hydrochloride drug needs to be removed to expose the reactive groups, so the pH of the solution needs to be adjusted to 8.0-9.0.

[0033] Preferably, when both the redox-sensitive monomer and the hydrophobic drug are in the hydrochloride form, the pH should be adjusted to 8.0-9.0 after the redox-sensitive monomer is introduced, and the reaction should continue for a period of time before the hydrophobic drug is added to adjust the pH. This is because the carrier must be formed first before the drug is encapsulated; adding the drug in the opposite order or simultaneously is not conducive to drug encapsulation.

[0034] Preferably, in step S2, the alcohol solution of the hydrophobic drug is added dropwise to the mixed system of step S1 at a dropping speed of 1-2 mL / min.

[0035] Preferably, the dehydrated dry particle size of the plant polypeptide drug-loaded nanoparticles under a transmission electron microscope is in the range of 30-50 nm, and the hydrated particle size of the plant polypeptide drug-loaded nanoparticles under a dynamic light scattering analyzer is in the range of 100 nm-360 nm.

[0036] Plant peptides are natural macromolecules with excellent compatibility with human tissues. After entering the human body, under the action of microorganisms or enzymes, the molecular chains break and degrade, and are eventually converted into monomers in the body or metabolized into water and carbon dioxide.

[0037] Preferably, in step S4, the ratio of the volume of the cross-linking agent to the mass of the plant polypeptide is in the range of 2-4 μL / mg.

[0038] Preferably, in step S4, the cross-linking agent includes at least one of glutaraldehyde, glyoxal and o-phthalaldehyde.

[0039] Preferably, in step S4, the mass ratio or mass-to-volume ratio of the redox-sensitive plant polypeptide drug-loaded nanoparticles to the alcohol solution is 9-11 mg / mL, the alcohol solution is ethanol, and the volume ratio of water to ethanol is 1:2-4.

[0040] The present invention has the following advantages and beneficial effects:

[0041] 1. The coated sustained-release plant polypeptide drug-loaded nanoparticles of the present invention are prepared by coating the plant polypeptide on the outer surface of the redox-sensitive plant polypeptide drug-loaded nanoparticles. The plant polypeptide and the redox-sensitive plant polypeptide drug-loaded nanoparticles have a synergistic effect of electrostatic adsorption and cross-linking, so that the prepared coated drug-loaded nanoparticles have good stability, producing an unexpected technical effect: they show smooth and long-lasting drug release performance in PBS containing 10μM GSH, which simulates normal human tissue.

[0042] 2. The coated plant polypeptide drug-loaded nanoparticles of the present invention can not only improve the water solubility of hydrophobic drugs, reduce the toxicity of drugs to the human body, and improve the therapeutic efficiency of drugs; but also provide sustained-release properties, releasing the loaded drugs at a controllable rate over a sufficiently long period of time.

[0043] 3. The coated plant polypeptide drug-loaded nanoparticles of the present invention retain their excellent properties after coating. Furthermore, the preparation method is simple to operate, using the plant polypeptide itself to coat the drug-loaded nanoparticles, resulting in stable quality. The prepared drug-loaded nanoparticles have controllable particle size, concentrated dispersion, and excellent stability, making them suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the hydrated particle size distribution diagram of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1;

[0045] Figure 2 This is a stability diagram of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1;

[0046] Figure 3 This is a transmission electron micrograph of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1;

[0047] Figure 4 The in vitro drug release performance of millet polypeptide-doxorubicin loaded nanoparticles prepared in Example 1. The groups in the figure are PBS, ABS, PBS containing 10 μM GSH, PBS containing 10 mM GSH, and ABS containing 10 mM GSH.

[0048] Figure 5 In vitro drug release performance of millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1; the groups in the figure are PBS, ABS, PBS containing 10 μM GSH, PBS containing 10 mM GSH, and ABS containing 10 mM GSH;

[0049] Figure 6 The toxicity of the coated millet polypeptide nanoparticles prepared in Example 1 to NCI-H1299 cells and MCF-10A cells;

[0050] Figure 7 The toxicity of the millet polypeptide-doxorubicin-coated drug-loaded nanoparticles prepared in Example 1 to NCI-H1299 cells;

[0051] Figure 8 The toxicity of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1 to MCF-10A cells;

[0052] Figure 9 This is the hydrated particle size distribution diagram of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Comparative Example 2;

[0053] Figure 10 This is a stability diagram of millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Comparative Example 2;

[0054] Figure 11 This is the in vitro drug release performance of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Comparative Example 2. The groups in the figure are PBS, ABS, PBS containing 10 μM GSH, PBS containing 10 mM GSH, and ABS containing 10 mM GSH. DETAILED DESCRIPTION

[0055] For a better understanding of the present invention, the following examples are provided to further illustrate the present invention, but the present invention is not limited to the following examples.

[0056] Example 1

[0057] Step S1, preparing a 2 mg / mL aqueous solution of cystamine hydrochloride, adjusting its pH to 8 using a 0.1 M NaOH aqueous solution, weighing 20 mg of millet polypeptide, adding 2 mL of the prepared aqueous solution of cystamine, and stirring evenly with a magnetic stirrer to obtain a mixed system;

[0058] Step S2, preparing a 1.5 mg / mL doxorubicin hydrochloride ethanol solution, slowly dropping 4 mL of the doxorubicin hydrochloride ethanol solution into the mixed system, stirring evenly, adding a certain amount of 2.5 wt% glutaraldehyde, and continuing to stir for 6 hours, then dropping a 0.1 M NaOH aqueous solution to adjust the pH to 8, and stirring for 24 hours to obtain the product;

[0059] Step S3: vacuum-remove ethanol from the product, centrifuge, and freeze-dry the supernatant to obtain millet polypeptide drug-loaded nanoparticles (i.e., redox-sensitive plant polypeptide drug-loaded nanoparticles).

[0060] Step S4: Take 20 mg of the prepared millet polypeptide drug-loaded nanoparticles, add 2 mL of deionized water and 4 mL of ethanol, stir evenly using a magnetic stirrer, add 3 mg of millet polypeptide, stir for 24 hours, then add 9 μL of glutaraldehyde and react for another 24 hours.

[0061] Step S5: After the reaction is completed, the ethanol is removed in vacuo, and the supernatant is taken out for lyophilization after centrifugation to obtain the coated plant polypeptide drug-loaded nanoparticles.

[0062] The hydrated particle size distribution of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1 is shown in FIG. Figure 1 shown; from Figure 1 It can be seen that the hydrated particle size of millet polypeptide-doxorubicin drug-loaded nanoparticles is 392nm.

[0063] The stability of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1 is as follows: Figure 2 shown; from Figure 2 It can be seen that within the measured 96 hours, the particle size and distribution of the drug-loaded nanoparticles changed little, indicating good stability.

[0064] The transmission electron microscopy image of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1 is as follows: Figure 3 As shown, the millet polypeptide-doxorubicin drug-loaded nanoparticles have regular spherical shapes and a dry particle size of approximately 52 nm.

[0065] The in vitro drug release performance of the uncoated millet polypeptide-doxorubicin loaded nanoparticles prepared in Example 1 is as follows: Figure 4As shown in the figure, it can be seen that the drug release rate of the uncoated millet polypeptide-doxorubicin drug-loaded nanoparticles changes significantly when the pH environment and GSH concentration change, showing good dual sensitivity to pH and redox.

[0066] The in vitro drug release performance of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1 is as follows: Figure 5 As shown. Figure 5 It can be seen that the coated drug-loaded nanoparticles can effectively release drugs, showing a stable and long-lasting drug release performance, and effectively retaining the redox and pH dual response characteristics of the drug-loaded nanoparticles. The release rate in the 10mM GSH environment is faster than that in the 10μM GSH environment, and the release rate in the acidic environment is faster than that in the neutral environment.

[0067] The toxicity of the coated millet polypeptide nanoparticles prepared in Example 1 to NCI-H1299 cells and MCF-10A cells is as follows: Figure 6 As shown. Figure 6 It can be clearly observed that millet polypeptide nanoparticles exhibit extremely low cytotoxicity.

[0068] The toxicity of the millet / soybean polypeptide-doxorubicin loaded nanoparticles prepared in Example 1 to NCI-H299 cells before and after coating (MP-ss@DOX is before coating, MPB-ss@DOX is after coating) is shown in Figure 1. Figure 7 As shown. Figure 7 It can be seen that millet polypeptide-doxorubicin coated drug-loaded nanoparticles have a good growth inhibitory effect on NCI-H299 cells.

[0069] The toxicity of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in Example 1 to MCF-10A cells before and after coating is as follows: Figure 8 As shown. Figure 8 It can be seen that millet polypeptide-doxorubicin drug-loaded nanoparticles have a certain inhibitory effect on the toxicity of DOX.

[0070] As can be seen from the above, Example 1 is a combination of electrostatic adsorption and cross-linking, and the obtained coated drug-loaded nanoparticles have good stability and show steady and long-lasting drug release performance in 10 μM GSH-containing PBS simulating normal human tissue.

[0071] Comparative Example 1

[0072] In this comparative example, except that no crosslinking agent is added in the wrapping step, which is different from Example 1, the other steps are the same as Example 1. The specific operations are as follows:

[0073] Prepare 2 mg / mL of cystamine hydrochloride aqueous solution, adjust its pH to 8 using 0.1M NaOH aqueous solution, prepare 1.5 mg / mL of doxorubicin hydrochloride ethanol solution, weigh 20 mg of millet polypeptide MP, add 2 mL of the prepared cystamine aqueous solution, stir evenly with a magnetic stirrer, and then slowly drip 4 mL of doxorubicin hydrochloride ethanol solution at a certain rate. After stirring evenly, add a certain amount of 2.5 wt% glutaraldehyde, react for 6 hours, add 0.1 M NaOH aqueous solution to adjust the pH to 8, continue stirring for 24 hours, then add 5 mg of millet polypeptide and stir for 48 hours. After the reaction is complete, remove ethanol in vacuo, centrifuge, and lyophilize the supernatant to obtain coated sustained-release plant polypeptide drug-loaded nanoparticles.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 1 is that millet polypeptide and glutaraldehyde are added before freeze-drying. The specific operation steps are as follows:

[0076] Step S1, preparing a 2 mg / mL aqueous solution of cystamine hydrochloride, adjusting its pH to 8 using a 0.1 M NaOH aqueous solution, weighing 20 mg of millet polypeptide MP, adding 2 mL of the prepared aqueous solution of cystamine, and stirring evenly with a magnetic stirrer to obtain a mixed system;

[0077] Step S2: prepare a 1.5 mg / mL doxorubicin hydrochloride ethanol solution, slowly add 4 mL of doxorubicin hydrochloride ethanol solution at a constant rate, stir evenly, add a certain amount of 2.5 wt% glutaraldehyde, react for 6 hours, add 0.1 M NaOH aqueous solution to adjust the pH to 8, and continue stirring for 24 hours to obtain the product.

[0078] Step S3: add 5 mg of millet polypeptide to the product and stir for 24 hours, then add 15 μL of glutaraldehyde and react for 24 hours.

[0079] Step S4: Afterwards, the ethanol is removed by vacuum, the mixture is centrifuged, and the supernatant is freeze-dried to obtain the coated sustained-release plant polypeptide drug-loaded nanoparticles.

[0080] The hydrated particle size distribution of millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in comparative example 2 is shown in FIG. Figure 9 shown; from Figure 9 It can be seen that the hydrated particle size of soybean polypeptide-doxorubicin drug-loaded nanoparticles is 232.5 nm.

[0081] The stability of millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in comparative example 2 is shown in the figure below: Figure 10 shown; from Figure 10 It can be seen that within the measured 96 hours, the particle size and distribution of the drug-loaded nanoparticles changed little, indicating good stability.

[0082] The in vitro drug release performance of the millet polypeptide-doxorubicin coated drug-loaded nanoparticles prepared in comparative example 2 is as follows: Figure 11 As shown. Figure 11 It can be seen that the coated drug-loaded nanoparticles can effectively release the drug and effectively retain the redox and pH dual response characteristics of the drug-loaded nanoparticles. The release rate in the 10mM GSH environment is faster than that in the 10μM GSH environment, and the release rate in the acidic environment is faster than that in the neutral environment.

[0083] Experimental Example 1: Performance Comparison

[0084] 1. Comparison between Example 1 and Comparative Example 1

[0085] The stability of the composite drug-loaded nanoparticles prepared in Example 1 and Comparative Example 1 was compared with the amount of millet polypeptide wrapped in the outer layer of the composite drug-loaded nanoparticles.

[0086] In Example 1, electrostatic adsorption and cross-linking act together to obtain coated drug-loaded nanoparticles with good stability, and exhibited steady and long-lasting drug release in PBS containing 10 μM GSH, which simulates normal human tissue.

[0087] In comparative example 1, electrostatic adsorption acts alone, and the amount of millet polypeptide wrapped in the outer layer of the obtained composite drug-loaded nanoparticles is less than that of the composite drug-loaded nanoparticles prepared in example 1.

[0088] The hydrated particle size of the drug-loaded nanoparticles prepared in Example 1 was 392.5 nm, while the hydrated particle size of the drug-loaded nanoparticles prepared in Comparative Example 1 was 367.2 nm).

[0089] 2. Comparison between Example 1 and Comparative Example 2

[0090] In comparative example 2, millet polypeptide and glutaraldehyde are added before freeze-drying, and the wrapped drug-loaded nanoparticles have a compact structure and uniform particle size, but the wrapping effect is not as good as the wrapping effect of the wrapped drug-loaded nanoparticles obtained by re-adding millet polypeptide and glutaraldehyde after freeze-drying in Example 1 of the present invention. Compared with Example 1, the drug release rate of comparative example 2 is slowed down to a certain extent, but the sustained-release effect is not obvious. The in vitro drug release performance of the millet polypeptide-doxorubicin wrapped drug-loaded nanoparticles prepared in comparative example 2, the groups in the figure are PBS, ABS, PBS containing 10μM GSH, PBS containing 10mM GSH and ABS containing 10mM GSH, as shown in FIG. Figure 11 shown.

[0091] As can be seen from the above, in Example 1 of the present invention, millet polypeptide and glutaraldehyde are added for re-coating after freeze-drying, and the re-coating effect is good. The sustained-release effect of the obtained re-coated drug-loaded nanoparticles is more obvious than that of Comparative Example 2.

[0092] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0093] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0094] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A coated sustained-release plant polypeptide drug-loaded nanoparticle, characterized by: The coated sustained-release plant polypeptide drug-loaded nanoparticles are prepared by coating the plant polypeptide on the outer surface of the redox-sensitive plant polypeptide drug-loaded nanoparticles; The redox-sensitive plant polypeptide drug-loaded nanoparticles are prepared by using plant polypeptides and hydrophobic drugs as raw materials, introducing redox-sensitive structure monomers, and using a mixed solution of alcohol and water as solvent under the action of a cross-linking agent; wherein the redox-sensitive structure monomer is cystamine hydrochloride; the plant polypeptide is millet polypeptide; and the hydrophobic drug is doxorubicin or its hydrochloride.

2. The coated sustained-release plant polypeptide drug-loaded nanoparticles according to claim 1, characterized in that: In the coating, the mass ratio of the plant polypeptide to the redox-sensitive plant polypeptide drug-loaded nanoparticles is 3-6:

20.

3. A method for preparing the coated sustained-release plant polypeptide drug-loaded nanoparticles according to any one of claims 1-2, characterized in that: The preparation method comprises the following steps: S1. Mixing the plant polypeptide and the aqueous solution containing the redox-sensitive structural monomer, adjusting the pH to 8.0-9.0, and continuing the reaction until the reaction is complete to obtain a mixed system; S2, adding the alcohol solution of the hydrophobic drug to the mixed system and mixing, and then adding the cross-linking agent until the reaction is complete to obtain a product; S3, removing the alcohol solution from the product and filtering it, centrifuging the remaining system, taking the supernatant, and freeze-drying it to obtain redox-sensitive plant polypeptide drug-loaded nanoparticles; S4, dissolving the redox-sensitive plant polypeptide drug-loaded nanoparticles in an alcohol solution, adding the plant polypeptide and a cross-linking agent, stirring evenly, and continuing the reaction; S5. After the reaction is completed, the alcohol solution is removed and insoluble matter is precipitated. The remaining system after filtration is centrifuged and the supernatant is removed and freeze-dried to obtain coated plant polypeptide drug-loaded nanoparticles.

4. The preparation method according to claim 3, wherein: In step S4, the ratio of the volume of the cross-linking agent to the mass of the plant polypeptide is in the range of 2-4 μL / mg.

5. The preparation method according to claim 3, wherein: In step S4, the cross-linking agent includes at least one of glutaraldehyde, glyoxal or o-phthalaldehyde.

6. The preparation method according to claim 3, wherein: In step S4, the mass volume ratio of the redox-sensitive plant polypeptide drug-loaded nanoparticles to the alcohol solution is 9-11 mg / mL, and the alcohol solution is an ethanol aqueous solution, in which the volume ratio of water to ethanol is 1:2-4.

7. The preparation method according to claim 3, wherein: When the hydrophobic drug is in the form of hydrochloride, step S2 specifically includes: The alcohol solution of the hydrophobic drug is added to the mixed system and mixed evenly, and then a cross-linking agent is added. After adjusting the pH to 8.0-9.0, the reaction is continued until the reaction is complete to obtain a product.

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