A zinc polyphenol complex suppository and a preparation method and application thereof

Abstract

The application discloses a zinc-polyphenol complex suppository and a preparation method and application thereof, and mainly comprises the following two steps: a. preparation of EGCG-Zn metal polyphenol complex nanoparticles; and b. preparation of the nano-complex suppository. The method is simple, green and environmentally friendly, and is suitable for large-scale preparation. The prepared EGCG-Zn nanoparticles are uniform in particle size and good in stability, have a complex network structure formed by self-assembly of EGCG and zinc ions, and have good antioxidant, anti-inflammatory and tissue repair activities. The nanoparticles are first treated by a drug pretreatment carrier, and then loaded in a suppository matrix to construct a rectal drug nano-suppository, so that targeted and sustained local drug release can be realized. In the intervention of radiation-induced intestinal injury, the suppository can not only relieve oxidative stress and inflammatory response, but also promote the regeneration and repair of intestinal mucosa, and has good treatment potential and clinical application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biological medicine and pharmaceutical preparation, and particularly relates to a zinc-polyphenol complex suppository as well as a preparation method and application thereof. BACKGROUND

[0002] Radiation-induced intestinal injury (RIII) is a common and serious complication in tumor radiotherapy, which affects the treatment compliance. The incidence and harm of radiation-induced rectal injury are more prominent in the treatment of pelvic tumors such as rectal cancer, prostate cancer and cervical cancer. Its pathogenesis mainly includes oxidative stress, release of inflammatory factors, intestinal barrier damage and cell apoptosis, which can lead to diarrhea, abdominal pain, intestinal bleeding, infection and even life-threatening serious consequences such as intestinal perforation. At present, the treatment of radiation-induced intestinal injury in the clinic is still mainly symptomatic and supportive treatment, such as antidiarrheal drugs, glucocorticoids, antibiotics and nutritional support, and there is still a lack of effective prevention or treatment drugs with targeting and specificity. Studies have shown that oxidative stress and inflammatory response play a key role in the early stage of RIII, and targeted intervention of these two links may effectively delay the occurrence and development process of intestinal injury.

[0003] Natural polyphenolic compounds, especially epigallocatechin gallate (EGCG), have been widely studied for alleviating radiation-induced tissue damage due to their excellent free radical scavenging, antioxidant and anti-inflammatory activities because of the rich phenolic hydroxyl groups in their structure. However, EGCG itself has problems such as poor stability, easy oxidation, rapid metabolism in vivo and low bioavailability, which limit its application in intestinal injury. Zinc (Zn), as an essential trace element for the human body, has been found to have antioxidant and anti-inflammatory effects, and can also promote the regeneration and repair of intestinal mucosa, which is an important mechanism for intestinal protection. EGCG and zinc ions can form metal polyphenol complexes, which can significantly improve the stability of EGCG and are expected to play a protective role through different mechanisms of EGCG and Zn. In addition, the traditional oral administration method is affected by the environment of the digestive tract and other factors, making it difficult to effectively control the release position of the drug, which may lead to insufficient local drug absorption and therapeutic effect. Therefore, the EGCG-Zn nano complex can be delivered through a suppository form to the rectum, which can achieve in-situ release of the drug at the site of rectal injury, enhance local absorption and action time, and have site-specific protection for rectal injury. In addition, due to the absorption of the rectal venous plexus, the drug can be absorbed and circulated to other parts of the body, which is expected to provide a backup plan for radiation damage in other parts. How to form nano particles with uniform structure and controllable size, and at the same time form a stable controlled-release suppository, so as to play an effective synergistic preventive and therapeutic effect, is a problem that needs to be solved at present.

[0004] In summary, the application provides an EGCG-Zn metal polyphenol complex nano-particle suppository, the EGCG-Zn nano-particle is obtained through PVP-NMP system assisted complexing, ethanol induced precipitation and freeze-drying process, and then is compounded with a suppository base to form a high uniformity suppository, so that the targeted delivery, stable controlled release and the synergistic treatment effect of multiple mechanisms are realized, and a new solution is provided for the prevention and treatment of radiation damage. SUMMARY

[0005] The application aims at the deficiencies of the existing prevention and treatment of radiation damage, and provides a zinc polyphenol (EGCG-Zn) complex suppository and a preparation method and application thereof, through which the EGCG can be reacted with Zn to generate a stable, excellent dispersibility, controllable and uniform metal polyphenol complex nano-particle, the generation of hydrolysis by-products can be avoided, and a high uniformity suppository can be formed with the base, the preparation method is simple and stable, and the suppository can be used for the local protection treatment and the promotion of the repair of mucosa of radiation damage such as radiation intestinal damage.

[0006] In order to achieve the above-mentioned purpose, the following technical measures are adopted in the application:

[0007] The application provides a preparation method of a zinc polyphenol complex suppository, which comprises the following steps:

[0008] 1) preparing the EGCG-Zn complex nano-particle with uniform particle size based on PVP-NMP system assisted complexing, ethanol induced precipitation and freeze-drying process;

[0009] 2) pre-treating the EGCG-Zn complex nano-particle obtained in 1) based on a drug pre-treatment carrier, and then compounding the zinc polyphenol complex suppository with a suppository base.

[0010] In the technical scheme, further, step 1) is specifically as follows:

[0011] Polyvinylpyrrolidone (PVP) powder is dissolved in N-methylpyrrolidone (NMP) to form a PVP-NMP solution, and then zinc salt is added to obtain a zinc ion solution, and the solution is stirred after ultrasonic dissolution;

[0012] Epigallocatechin gallate (EGCG) is dissolved in NMP to form an EGCG-NMP solution through ultrasonic dissolution;

[0013] The EGCG-NMP solution is added dropwise into the zinc ion solution under stirring and in the dark, and then the reaction is carried out; after the reaction is completed, anhydrous ethanol is added to induce precipitation, and then the obtained product is washed with water and vacuum freeze-dried to obtain the EGCG-Zn complex nano-particle.

[0014] Further, the zinc salt is one or more of zinc acetate, zinc nitrate or zinc sulfate.

[0015] Further, the PVP concentration in the PVP-NMP solution is 0.01-150 mM, the zinc concentration in the zinc ion solution is 0.02-200 mM, and the EGCG concentration in the EGCG-NMP solution is 0.01-100 mM, and the EGCG-NMP solution and the zinc ion solution are in equal volume.

[0016] Further, the volume of the anhydrous ethanol is 1-30 times the volume of the reaction solution.

[0017] Further, the step 2) is specifically:

[0018] The EGCG-Zn complex nanoparticles obtained in 1) are mixed with a pre-cooled drug pretreatment carrier to 0-5 DEG C, and are ground to form a paste under ice bath condition, and are sealed for standby;

[0019] The PEG polymer and the drug release regulator are melted and mixed at 60-65 DEG C, and are continuously stirred until completely homogeneous to obtain a suppository base;

[0020] The suppository base is cooled to 52-58 DEG C, and the paste is added and stirred to disperse to form a melt, and then a suppository mold is preheated to 50-55 DEG C, the inner side of the mold is lubricated with a release agent after preheating, and the melt is quickly injected into the preheated mold to avoid air bubbles, and a layer of overflow is formed on the surface of the melt, and gradient cooling solidification is carried out, and after complete solidification, the overflow part is removed to obtain the zinc polyphenol complex suppository.

[0021] Further, the suppository base comprises, in mass parts, 6-10 parts of PEG polymer, 1-2 parts of drug release regulator, and 0-1.5 parts of water, the PEG polymer is a mixture of 2-3 kinds of PEG-1500, PEG-4000 and PEG-6000, and the drug release regulator is a non-ionic surfactant.

[0022] Further, the mass ratio of the nanoparticles to the drug pretreatment carrier is 0.1-100, and more preferably 0.2-4, and the drug pretreatment carrier is at least one of glycerol, propylene glycol and polyethylene glycol 400.

[0023] A zinc polyphenol complex suppository is prepared by the preparation method described in any one of the above.

[0024] The zinc polyphenol complex suppository described above is used for preparing a drug for treating radiation damage.

[0025] Compared with the prior art, the present application has the following advantages and effects:

[0026] The application provides a local delivery type antioxidant nano suppository based on EGCG-Zn metal polyphenol complex nanoparticles and a drug carrier, which has a simple preparation process, a stable process flow, is suitable for large-scale production and has a good clinical application prospect. Through the self-assembly complex mechanism between epigallocatechin gallate (EGCG) and zinc ions, metal polyphenol complex nanoparticles with controllable particle size, stable structure and good dispersity are successfully prepared in a water-free environment. The complex nanoparticles are further mixed with a pretreated drug carrier, and then loaded into a multi-component hydrophilic matrix to construct a suppository system. This method can effectively avoid the influence of hydrolysis byproducts on the purity of the complex, the oxidation of EGCG and the influence of the preparation temperature of the suppository on the complex, and effectively ensures the stability of the complex. The obtained suppository shows good physical and mechanical properties at room temperature, has suitable hardness (about 30-80 N) and formability, and is convenient for rectal administration. At body temperature, the suppository can be quickly softened and disintegrated to realize the combined release characteristics of rapid onset and sustained release. More than 90% of the drug can be released within 1-2 hours, which meets the needs of local treatment for maintaining concentration and sustaining drug effect. The preparation also shows good physicochemical stability and mucosal biocompatibility, can significantly enhance the synergistic antioxidant and anti-inflammatory effects of EGCG and zinc ions, and effectively promote the repair and barrier function reconstruction of intestinal mucosa. The preparation can be applied to the treatment of radiation damage, especially the prevention and adjuvant treatment of intestinal damage caused by tumor radiotherapy or concurrent radiotherapy and chemotherapy, and has good safety and application potential. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A scanning electron microscope (SEM) photo of EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 1.

[0028] Figure 2 A high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) photo and corresponding C (carbon), O (oxygen) and Zn (zinc) element mapping (EDS) of EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 2.

[0029] Figure 3 An absorption spectrum of EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 3 and EGCG.

[0030] Figure 4 A dynamic light scattering (DLS) hydration particle size distribution chart of EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 1 and prepared in a water environment.

[0031] Figure 5 A trend chart of the drug release rate of EGCG-Zn complex suppository synthesized in Example 1 in simulated intestinal fluid with time.

[0032] Figure 6 Figure 6 shows the results of rectal Ki67 immunohistochemical staining of mice treated with the EGCG-Zn complex suppository synthesized in Example 2 for the prevention and treatment of radiation-induced rectal injury. DETAILED DESCRIPTION

[0033] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0034] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0035] According to some embodiments of the present application, the preparation method of the zinc polyphenol complex suppository of the present application comprises the following steps:

[0036] a. Preparation of EGCG-Zn complex nanoparticles

[0037] A certain amount of polyvinylpyrrolidone PVP powder is weighed into a single-mouth flat-bottom flask containing N-methylpyrrolidone NMP, configured into a 0.01-150 mM PVP-NMP solution, and placed in an ultrasonic cleaner for 1-30 min to completely dissolve it. Then a certain amount of zinc salt is weighed and dissolved in the PVP-NMP solution to form a zinc ion solution with a zinc ion molar concentration of 0.02-200 mM. The flask is again subjected to ultrasonic dissolution and then stirred at 800-1200 rpm for at least 30 min (through this stirring, the zinc ions can be pre-tem plated with EGCG through coordination bonding, electrostatic interaction, hydrogen bonding, and other weak forces, as well as space covering, which is beneficial to improve the stability and dispersibility of the material). Another single-mouth flat-bottom flask is added with the same volume of NMP, and a certain amount of epigallocatechin gallate EGCG is weighed and dissolved in NMP to configure a 0.01-100 mM EGCG-NMP solution. The solution volume is consistent with that of the zinc ion solution, and after ultrasonic dissolution for 1-30 min, it is slowly added to the stirring zinc ion solution under light-proof conditions, and continues to be stirred for 1-36 h. After the reaction is completed, 1-30 times the volume of anhydrous ethanol is added to induce precipitation, and after centrifugation, it is washed with water three times or more, and then vacuum freeze-dried to obtain EGCG-Zn complex nanoparticles;

[0038] b. Preparation of EGCG-Zn complex suppository

[0039] The EGCG-Zn complex nanoparticles obtained in step a are mixed with the drug pretreatment carrier pre-cooled to 0-5°C at a mass ratio of 0.1-100 (more preferably 0.2-4), and ground into a paste under ice bath conditions to form a protective film on the surface of the nanoparticles, and sealed for later use. The weight parts of the different components of the suppository base are 2-3 different PEG polymers for a total of 6-10 parts, a drug release regulator for 1-2 parts, and water for 0-1.5 parts. The components are mixed at 60-65°C until homogeneous, and then the temperature is maintained at about 60°C. The base is cooled to 52-58°C, and the EGCG-Zn complex nanoparticle paste is added and stirred to disperse. The suppository mold is preheated in an oven at 50-55°C, and after preheating, the mold is lubricated with release agent. The molten material is quickly injected into the preheated mold to avoid air bubbles, and a layer of excess material is formed on the surface. The material is gradiently cooled and solidified, and after complete solidification, the excess part is removed to obtain the EGCG-Zn complex suppository.

[0040] In some embodiments of the present application, the zinc salt is preferably selected from zinc nitrate, zinc acetate or zinc sulfate.

[0041] In some embodiments of the present application, the drug pretreatment carrier is preferably at least one of glycerol, propylene glycol or polyethylene glycol 400.

[0042] In some embodiments of the present application, the PEG polymer in the suppository base is preferably a mixture of 2-3 of PEG-1500, PEG-4000 and PEG-6000 to meet the requirements of melting temperature and injection molding.

[0043] In some embodiments of the present application, the drug release regulator is preferably a non-ionic surfactant, including but not limited to polyoxyethylene stearate, Tween 80, Span 40, etc.

[0044] In some embodiments of the present application, the release agent is preferably selected from liquid paraffin, glycerol, vegetable oil (such as olive oil), polyethylene glycol 400, etc. which have good biocompatibility and release performance. It is used to coat the inner wall of the suppository mold before molding to facilitate the smooth release of the EGCG-Zn complex suppository.

[0045] The above scheme can effectively avoid the use of water environment in the preparation of the complex, without adjusting the pH, effectively avoiding the oxidation problem of EGCG in the water environment and the problem of Zn ion hydrolysis by-product, etc. In addition, in the present application, after the EGCG-Zn complex nanoparticles are prepared, they are first pretreated with a pre-cooled drug pretreated carrier to form a paste and sealed for standby, and then mixed with the suppository base for suppository preparation. Compared with directly mixing the EGCG-Zn complex nanoparticles with the drug pretreated carrier and the suppository base to prepare the suppository, the high temperature in the suppository preparation process can be effectively avoided to affect the complex, the stability of the EGCG-Zn nanoparticle structure can be protected, the excessive oxidation of EGCG can be prevented, the PVP of the surface modification can be protected, the nanoparticle dispersibility can be maintained, agglomeration can be avoided, and the oxidation of Zn ion to reduce its release capacity can be avoided. The metal polyphenol complex EGCG-Zn nanoparticles prepared by the method of the present application are regular spherical or near-spherical small particle size particles, with uniform particle size and size range of 1-100 nm, and excellent dispersibility. The prepared suppository has a hardness range of 30-80 N and can be stored for a long time at room temperature. At the rectal body temperature (about 37℃), it softens and disintegrates rapidly, and the initial drug release is within 2-5 minutes, more than 50% of the drug is released within 30 minutes, and more than 90% of the drug can be released within 60-120 minutes, with the drug release characteristics of rapid onset and sustained local effect. Through the synergistic effect of the antioxidant and anti-inflammatory effect of EGCG and the promotion of epithelial repair of zinc ion, combined with the rectal local drug release characteristics, it can be used for the treatment of radiation damage.

[0046] Example 1

[0047] A preparation method of a zinc polyphenol EGCG-Zn complex suppository, the steps of which are:

[0048] a. Preparation of EGCG-Zn complex nanoparticles: 30 mg of polyvinylpyrrolidone (PVP) was weighed and dissolved in a single-mouth flat-bottom flask containing 5 ml of N-methylpyrrolidone (NMP) and placed in an ultrasonic cleaner for 5 min to completely dissolve. Another 22.83 mg of zinc acetate dihydrate (Zn(CH3COO)2·2H2O) was dissolved in 5 ml of PVP-NMP solution, and placed in an ultrasonic cleaner for about 5 min to completely dissolve, and the solution was clear and transparent. A magnetic stirrer was added to the zinc acetate-PVP-NMP solution and stirred at 1200 rpm for about 30 min. Another single-mouth flat-bottom flask was weighed with 23.8 mg of epigallocatechin gallate (EGCG) dissolved in 5 mL of N-methylpyrrolidone (NMP), and the solution volume was consistent with the zinc ion solution. After ultrasonic dissolution for 5 min, the solution was completely dissolved, and then it was slowly added to the stirring zinc acetate-PVP-NMP solution using a syringe. Under light-proof conditions, continue to stir for 24 h. After the reaction was completed, 20 mL of anhydrous ethanol was added to induce precipitation, and after centrifugation, it was washed with water three times, and then vacuum freeze-dried to obtain EGCG-Zn complex nanoparticles;

[0049] b. Preparation of EGCG-Zn complex suppository: The EGCG-Zn complex nanoparticles obtained in step a were mixed with pre-cooled propylene glycol at a mass ratio of 1:3, and the paste was ground under ice bath conditions. The suppository base was prepared by mixing different components in a weight ratio of polyethylene glycol 6000 (PEG6000) 4 parts, polyethylene glycol 4000 (PEG4000) 3 parts, Tween 80 (Tween 80) 2 parts, and water 1 part. The mixture was heated and stirred at 65°C for 15 min until it was completely homogeneous. Then the temperature was maintained at about 60°C, and the base was cooled to 56°C. The EGCG-Zn complex nanoparticle paste was added and stirred to disperse. Then the suppository mold was preheated in a 55°C oven, and vegetable oil was applied to the inside of the mold after preheating. The molten material was quickly injected into the preheated mold to avoid air bubbles. A layer of excess material was formed on the surface of the mold, and gradient cooling was performed to solidify the material. After the material was completely solidified, the excess material was removed and the suppository was demolded. Thus, an antioxidant, anti-inflammatory, and pro-repair EGCG-Zn complex suppository was obtained.

[0050] Example 2

[0051] A method for preparing a zinc polyphenol EGCG-Zn complex suppository, comprising the following steps:

[0052] a. Preparation of EGCG-Zn complex nanoparticles: 40 mg of polyvinylpyrrolidone (PVP) was weighed and dissolved in a single-mouth flat-bottom flask containing 10 ml of N-methylpyrrolidone (NMP) and placed in an ultrasonic cleaner for 5 min to completely dissolve. Another 19.66 mg of zinc nitrate (Zn(NO3)2) was dissolved in 10 ml of PVP-NMP solution, and placed in an ultrasonic cleaner for about 5 min to completely dissolve, and the solution was clear and transparent. A magnetic stirrer was added to the zinc acetate-PVP-NMP solution and stirred at 1200 rpm for about 30 min. Another single-mouth flat-bottom flask was weighed with 47.6 mg of epigallocatechin gallate (EGCG) dissolved in 10 mL of N-methylpyrrolidone (NMP), and the solution volume was consistent with the zinc ion solution. After ultrasonic dissolution for 5 min, the solution was completely dissolved, and then it was slowly added to the stirring zinc acetate-PVP-NMP solution using a syringe. Under light-proof conditions, continue to stir for 24 h. After the reaction was completed, 60 mL of anhydrous ethanol was added to induce precipitation, and after centrifugation, it was washed with water three times, and then vacuum freeze-dried to obtain EGCG-Zn complex nanoparticles;

[0053] b. Preparation of EGCG-Zn complex suppository: The EGCG-Zn complex nanoparticles obtained in step a were mixed with glycerol pre-cooled to 4°C at a mass ratio of 1:2, and the paste was ground under ice bath conditions. The suppository base was prepared by mixing different components in a weight ratio of polyethylene glycol 4000 (PEG6000) 5 parts, polyethylene glycol 6000 (PEG4000) 4 parts, polyoxyethylene stearate 2 parts, and water 1 part. The mixture was melted and mixed at 65°C for 15 min until homogeneous. The temperature was then maintained at about 60°C, and the base was cooled to 56°C. The EGCG-Zn complex nanoparticle paste was added and stirred to disperse. The suppository mold was preheated in a 55°C oven, and after preheating, the mold was coated with liquid paraffin to lubricate. The molten material was quickly injected into the preheated mold to avoid air bubbles. A layer of excess base was formed on the surface, and gradient cooling was performed. After complete solidification, the excess part was removed and the suppository was demolded to obtain an antioxidant, anti-inflammatory and repair-promoting EGCG-Zn complex suppository.

[0054] Example 3

[0055] A method for preparing a zinc polyphenol EGCG-Zn complex suppository, comprising the following steps:

[0056] a. Preparation of EGCG-Zn complex nanoparticles: 300 mg of polyvinylpyrrolidone (PVP) was weighed and dissolved in a single-mouth flat-bottom flask containing 50 ml of N-methylpyrrolidone (NMP) and placed in an ultrasonic cleaner for 5 min to completely dissolve. Another 228.3 mg of zinc acetate dihydrate (Zn(CH3COO)2·2H2O) was dissolved in 50 ml of PVP-NMP solution and placed in an ultrasonic cleaner for about 5 min to completely dissolve, and the solution was clear and transparent. A magnetic stirrer was added to the zinc acetate-PVP-NMP solution and stirred at 1200 rpm for about 30 min. Another single-mouth flat-bottom flask was weighed with 238 mg of epigallocatechin gallate (EGCG) dissolved in 50 mL of N-methylpyrrolidone (NMP), and the solution volume was consistent with the zinc ion solution. After ultrasonic dissolution for 5 min, the solution was completely dissolved, and then it was slowly added to the stirring zinc acetate-PVP-NMP solution using a syringe. Under light-proof conditions, continue to stir for 24 h. After the reaction was completed, 200 mL of anhydrous ethanol was added to induce precipitation, and after centrifugation, it was washed with water three times, and then vacuum freeze-dried to obtain EGCG-Zn complex nanoparticles;

[0057] b. Preparation of EGCG-Zn complex suppository: The EGCG-Zn complex nanoparticles obtained in step a were mixed with glycerol pre-cooled to 4°C at a mass ratio of 1:2, and the paste was ground under ice bath conditions. The suppository base was prepared by mixing polyethylene glycol 4000 (PEG6000) 5 parts, polyethylene glycol 6000 (PEG4000) 4 parts, polyoxyethylene stearate 2 parts, and water 1 part at 65°C. The mixture was continuously stirred for 15 min until it was completely homogeneous, and then the temperature was maintained at about 60°C. The base was cooled to 56°C, and the EGCG-Zn complex nanoparticle paste was added and stirred to disperse. The suppository mold was preheated in a 55°C oven, and after preheating, the mold was coated with liquid paraffin to lubricate. The molten material was quickly injected into the preheated mold to avoid air bubbles, and a layer of excess base was formed on the surface. The gradient cooling was performed, and after the complete solidification, the excess part was removed and the suppository was demolded to obtain the antioxidant, anti-inflammatory, and pro-repair EGCG-Zn complex suppository.

[0058] The scanning electron microscope (SEM) photo of the EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 1 is as follows: Figure 1As shown in the figure, it can be clearly seen that the EGCG-Zn complex presents an aggregated nanoparticle structure, the particle size is mainly distributed in the range of tens to hundreds of nanometers, the particle surface is rough, and the morphology is uniform. The high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) photo and the corresponding C (carbon), O (oxygen), and Zn (zinc) element mapping (EDS) of the EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 2 are as follows Figure 2 As shown in the figure, the HAADF-STEM and EDS figures further illustrate the nanostructure and element composition of the EGCG-Zn nano complex. The HAADF photo shows that the particles have obvious pore structure, and the EDS photo shows that the C, O, and Zn elements are uniformly distributed in the particles, indicating that the zinc ions and EGCG are uniformly embedded in the system through self-assembly complexation, forming a stable metal polyphenol complex network. Figure 3 The absorption spectrum of the EGCG-Zn metal polyphenol complex nanoparticles synthesized in Example 3 and EGCG can be seen. EGCG presents a wide peak of hydroxyl characteristic stretching vibration near 3400 cm⁻¹, and there are characteristic peaks of benzene ring skeleton vibration in the region of 1600-1400 cm⁻¹. The peak shape and position of the EGCG-Zn complex in the EGCG hydroxyl and benzene ring related characteristic peaks change significantly, indicating that the active groups in the EGCG molecule coordinate with Zn²⁺, successfully constructing the EGCG-Zn complex structure.

[0059] The PVP-NMP system in Example 1 is replaced by a PVP-water environment system (NMP is replaced by deionized water), and zinc polyphenol complex nanoparticles are also prepared. The dynamic light scattering (DLS) hydration particle size distribution diagram of the two is as follows Figure 4 As shown in the figure, compared with the complex nanoparticles prepared by using the PVP-water environment system, the particle size distribution of the nanoparticles prepared by using the PVP-NMP system presents obvious single peak characteristics without side peak interference, and the main particle size is concentrated around 150 nm (the surface PVP makes the DLS size larger than the dry size under TEM), the particle size distribution width is relatively narrow, and the dispersion is uniform, indicating that the EGCG-Zn complex nanoparticles prepared by using the PVP-NMP system have better monodispersity and better particle size uniformity, which is more conducive to uniform dispersion on the surface of the intestinal tract in subsequent suppository application.

[0060] Figure 5 The trend diagram of the drug release rate of the EGCG-Zn complex suppository synthesized in Example 1 in simulated intestinal fluid with time can be seen. It can be seen that the EGCG dissolution release rate of the synthesized complex suppository in simulated intestinal fluid presents the characteristics of initial flatness, significant release rate increase at about 20-40 minutes, and complete drug dissolution release at later stage. Figure 6The EGCG-Zn complex suppository synthesized in Example 2 was used for the prevention and treatment of radiation-induced rectal injury in mice. The mice were locally irradiated by X-rays to cause radiation-induced rectal injury, and then treated locally with the EGCG-Zn complex suppository. The mice were euthanized on day 10 after treatment. The rectal Ki67 immunohistochemical staining images of healthy control mice, irradiated mice, and irradiated + administered mice were obtained. By comparing the results of the rectal Ki67 immunohistochemical staining of mice in different treatment groups, it can be seen that the EGCG-Zn complex suppository effectively reverses radiation-induced intestinal injury by up-regulating the proportion of intestinal tissue Ki67 positive cells and activating the epithelial cell proliferation repair mechanism.

[0061] The above merely illustrates the embodiments of the present application, and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the scope of the claims of the present application.

Claims

1. A method for preparing a zinc polyphenol complex suppository, characterized in that, Including the following: 1) Uniform EGCG-Zn complex nanoparticles were prepared using a PVP-NMP-assisted complexation, ethanol-induced precipitation, and freeze-drying process; specifically: Polyvinylpyrrolidone (PVP) powder was dissolved in N-methylpyrrolidone (NMP) and completely dissolved by ultrasonication to form a PVP-NMP solution. Zinc salt was added to the solution to obtain a zinc ion solution. The solution was then stirred after ultrasonic dissolution. Epigallocatechin gallate (EGCG) was dissolved in NMP and completely dissolved by ultrasonication to form an EGCG-NMP solution. Under stirring conditions, EGCG-NMP solution was added dropwise to zinc ion solution and stirred in the dark for reaction. After the reaction was completed, anhydrous ethanol was added to induce precipitation. After centrifugation, the mixture was washed with water and then freeze-dried under vacuum to obtain EGCG-Zn complex nanoparticles. 2) The EGCG-Zn complex nanoparticles obtained in 1) are first pretreated on a drug pretreatment carrier, and then compounded with a suppository matrix to prepare the zinc polyphenol complex suppository. The pretreatment is as follows: the EGCG-Zn complex nanoparticles obtained in 1) are mixed with a drug pretreatment carrier precooled to 0-5℃, and ground under ice bath conditions to form a paste, which is then sealed for later use.

2. The method for preparing the zinc polyphenol complex suppository according to claim 1, characterized in that, The zinc salt is one or more of zinc acetate, zinc nitrate, or zinc sulfate.

3. The method for preparing the zinc polyphenol complex suppository according to claim 1, characterized in that, The PVP concentration in the PVP-NMP solution is 0.01-150 mM, the zinc concentration in the zinc ion solution is 0.02-200 mM, and the EGCG concentration in the EGCG-NMP solution is 0.01-100 mM. The EGCG-NMP solution and the zinc ion solution are of equal volume.

4. The method for preparing the zinc polyphenol complex suppository according to claim 1, characterized in that, The volume of the anhydrous ethanol is 1-30 times the volume of the reaction liquid.

5. The method for preparing the zinc polyphenol complex suppository according to claim 1, characterized in that, Step 2) specifically involves: The EGCG-Zn complex nanoparticles obtained in step 1) were mixed with a drug pretreatment carrier pre-cooled to 0-5℃ and ground in an ice bath to form a paste, which was then sealed for later use. The suppository matrix is ​​obtained by melting and mixing PEG polymer and drug release modifier as the main components at 60-65℃ and stirring continuously until completely homogeneous. Cool the suppository base to 52-58℃, add the paste, stir and disperse to obtain a melt, then take the suppository mold and preheat it to 50-55℃. After preheating, apply a release agent to the inside of the mold for lubrication, and quickly pour the melt into the preheated mold to avoid air bubbles. The melt overflows the surface layer and is then subjected to gradient cooling and solidification. After it is completely solidified, cut off the overflow part to demold and obtain the zinc polyphenol complex suppository.

6. The method for preparing the zinc polyphenol complex suppository according to claim 5, characterized in that, The suppository matrix, by weight, comprises: 6-10 parts PEG polymer, 1-2 parts drug release modifier and 0-1.5 parts water, wherein the PEG polymer is a mixture of 2-3 of PEG-1500, PEG-4000 and PEG-6000, and the drug release modifier is a nonionic surfactant.

7. The method for preparing the zinc polyphenol complex suppository according to claim 5, characterized in that, The mass ratio of the nanoparticles to the drug pretreatment carrier is 0.1-100, and the drug pretreatment carrier is at least one of glycerol, propylene glycol, and polyethylene glycol 400.

8. The method for preparing the zinc polyphenol complex suppository according to claim 5, characterized in that, The mass ratio of the nanoparticles to the drug pretreatment carrier is 0.2-4.

9. A zinc polyphenol complex suppository, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. The use of the zinc polyphenol complex suppository as described in claim 9 in the preparation of a drug for treating radiation damage.

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