Eutectic gel, preparation method thereof and application of eutectic gel in promoting mucous membrane drug delivery

Abstract

The invention belongs to the technical field of biological medicine, and particularly relates to eutectic gel, a preparation method thereof and application of the eutectic gel in promoting mucous membrane drug delivery. The invention provides eutectic gel. The eutectic gel comprises a eutectic solvent and a polymer solution, the eutectic solvent comprises a hydrogen bond acceptor and a hydrogen bond donor; the polymer solution is selected from one or more of a gelatin solution, a polyvinyl alcohol solution, a polyethylene solution or a pyrrolidone solution. The eutecticevaporate gel provided by the invention can realize rapid and tight adhesion and continuous administration on mucous membranes which continuously secrete mucus, and has the following advantages: tight adhesion can be formed on mucous membranes with dynamically updated mucus, so that the residence time of an administration system on the mucous membranes is prolonged; and a drug delivery channel is established by penetrating through a mucous layer, so that the drug is efficiently and continuously delivered to mucous membrane tissues. The deep eutectic gel effectively solves the problem that an existing mucous membrane drug delivery system is low in drug delivery efficiency.

Description

Technical Field

[0001] This application belongs to the field of biomedical technology, and in particular relates to eutectic gels, their preparation methods and their applications in promoting mucosal drug delivery. Background Technology

[0002] Mucosal tissues (such as the digestive tract, upper respiratory tract, vagina, and conjunctiva) are important components of the human body, accounting for a large proportion of its composition. Direct application of drug delivery systems such as sprays, patches, gels, and suspensions to mucosa can significantly improve drug bioavailability and reduce systemic toxicity by achieving high local concentration exposure and avoiding the first-pass effect. However, traditional mucosal local drug delivery systems still face the following challenges: 1) The continuous secretion of mucus by mucosal tissue forms a dynamic and dense mucus layer, which hinders drug penetration, leading to poor drug delivery efficacy. 2) The slippery, rough, and highly dynamic nature of mucosal tissue makes it difficult for drug delivery systems to adhere to it for extended periods, resulting in short delivery times. To overcome these bottlenecks, there is an urgent need to develop a novel drug delivery system that can form an effective drug delivery channel and achieve strong adhesion on mucosal tissue. This would not only provide a new solution for improving drug bioavailability but also promote the development of advanced formulation technologies for mucosal local drug delivery.

[0003] In recent years, gels that can form strong adhesion on moist biological tissues have been increasingly used for drug delivery: 1) Dry gel patches that absorb liquid: Scientists reported on dry gel patches in Nature (Peng X, Xia X, Xu X, et al. Ultrafast self-gelling powder mediates robust wet adhesion to promote healing of gastrointestinal perforations. Sci Adv. 2021;7(23):eabe8739. Published2021 Jun 2. doi:10.1126 / sciadv.abe8739), which can absorb liquid on the tissue surface to promote instantaneous adhesion between the gel and the tissue; at the same time, the succinimide ester of the gel and the amino group on the tissue surface are chemically bonded to achieve long-term adhesion. Other scientists have also prepared polyvinylpyrrolidone / gallic acid (PVP / GA) sublingual patches using solvent evaporation annealing. When this film is placed under the tongue, it can quickly absorb water to form a hydrogel in situ and form a tight interface anchoring and firm adhesion with the tissue, efficiently delivering glucose into the blood through the sublingual capillaries and raising blood sugar levels (Yu M, Chen Y, Lei J, et al. Infant friendly adhesive film containing glucose for neonatal hypoglycemia. J Control Release. 2024;370:643-652. doi:10.1016 / j.jconrel.2024.05.019). 2) Solvent-Exchange-Based Injectable Gels (Yu J, Xie R, Zhang M, et al. Molecular architecture regulation for the design of instant and robust underwater adhesives. Sci Adv. 2023;9(22):eadg4031. doi:10.1126 / sciadv.adg4031): Recently, scientists polymerized lipoic acid (LA) and gallic acid (GA) monomers in ethanol to obtain PLG ethanol gels. They utilized a solvent exchange strategy to treat interfacial water, promoting gel-tissue interfacial anchoring.This PLG ethanol gel can not only ablate and kill most tumor tissues with ethanol, but also firmly adhere to the tumor in situ to precisely and long-lastingly release chemotherapy drugs to the remaining tumor, achieving a highly effective anti-tumor effect (Chen Y, Yu M, Liu M, et al. A Solvent Exchange Induced Robust Wet Adhesive Hydrogels to Treat Solid Tumor Through Synchronous Ethanol Ablation and Chemotherapy. Adv Sci (Weinh). 2024;11(24):e2309760. doi:10.1002 / advs.202309760). However, this strategy can only treat a small amount of interfacial water, and organic solvents such as ethanol can damage normal biological tissues. 3) Hydrophobic gel patch (Yuk H, Wu J, Sarrafian TL, et al. Rapid and coagulation-independent haemostatic sealing by a paste inspired by barnacle glue. Nat Biomed Eng. 2021;5(10):1131-1142. doi:10.1038 / s41551-021-00769-y): In 2023, scientists discovered that by grafting hydrophobic flexible polymer chains onto a substrate, the content of hydrophobic polymers in hydrogels can be significantly increased, transforming the originally hydrophilic surface of the hydrogel into a hydrophobic surface. Hydrophobic surfaces help to displace liquids from the surface of biological tissues, promoting tight anchoring and strong adhesion between gels and tissues, thereby facilitating transdermal drug delivery (Yi B, Li T, Yang B, et al. Surface hydrophobization of hydrogels via interface dynamics-induced network reconfiguration. Nat Commun. 2024;15(1):239. Published 2024 Jan 3. doi:10.1038 / s41467-023-44646-5).

[0004] However, the aforementioned adhesive gels are primarily designed for non-mucosal tissues and do not consider the influence of the mucus layer on their adhesion and drug delivery efficacy. Therefore, developing a gel system that can establish effective drug delivery channels and strong adhesion on mucosal tissues has become a key breakthrough in solving the problem of low mucosal drug delivery efficiency. Summary of the Invention

[0005] In view of this, the present invention provides a eutectic gel capable of rapid and tight adhesion and continuous drug delivery on mucous membranes that continuously secrete mucus, its preparation method, and its applications. The eutectic gel of the present invention not only forms tight adhesion on mucous membranes that are dynamically renewing mucus, prolonging the residence time of the drug delivery system on the mucous membrane; but also penetrates the mucus layer to establish a drug delivery channel, promoting efficient and continuous delivery of drugs to the mucous tissue.

[0006] This application provides a eutectic gel comprising a eutectic solvent and a polymer solution; the eutectic solvent comprises hydrogen bond acceptors and hydrogen bond donors; the solute of the polymer solution is selected from one or more of gelatin, polyvinyl alcohol, polyethylene, or pyrrolidone.

[0007] In some embodiments, the hydrogen bond acceptor is selected from one or more of choline chloride, betaine, proline, citric acid, bicarbonate choline, or tartrate choline; and the hydrogen bond donor is selected from one or more of tannic acid, gallic acid, urea, glycerol, lactic acid, malic acid, or geranilic acid.

[0008] In some embodiments, the mass ratio of the eutectic solvent to the polymer solution is (1~2):(1~2).

[0009] In some embodiments, the polymer solution has a mass percentage of 10% to 40%.

[0010] In some embodiments, the solvent for the polymer solution may be one or more of deionized water, physiological saline, PBS, and purified water.

[0011] In some embodiments, the polymer solution is an aqueous gelatin solution. Preferably, the aqueous gelatin solution has a mass percentage of 10% to 40%; more preferably, the aqueous gelatin solution has a mass percentage of 20% to 30%; more preferably, the aqueous gelatin solution has a mass percentage of 30%. Specifically, the aqueous gelatin solution can be formed by mixing gelatin powder and water under heating conditions. Preferably, the heating temperature is 50-60°C.

[0012] In some embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution.

[0013] In some embodiments, the eutectic solvent is composed of choline chloride and tannic acid. Preferably, the eutectic solvent is prepared by mixing choline chloride and tannic acid in a molar ratio of 20:1 and reacting them under heating conditions. Preferably, the heating temperature is 90~120 °C.

[0014] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the eutectic solvent is composed of choline chloride and tannic acid.

[0015] In some embodiments, the polymer solution has a mass percentage of 10% to 40%; and the mass ratio of the eutectic solvent to the polymer solution is (1 to 2):(1 to 2).

[0016] In some embodiments, the polymer solution has a mass percentage of 30%; and the mass ratio of the eutectic solvent to the polymer solution is (1~2):(1~2).

[0017] In some embodiments, the eutectic gel comprises a eutectic solvent and a polymer solution; and the eutectic solvent is composed of choline chloride and tannic acid; and the polymer solution has a mass percentage of 10% to 40%; and the mass ratio of the eutectic solvent to the polymer solution is (1 to 2):(1 to 2).

[0018] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and a polymer solution; and the eutectic solvent is composed of choline chloride and tannic acid; and the polymer solution has a mass percentage of 30%; and the mass ratio of the eutectic solvent to the polymer solution is (1~2):(1~2).

[0019] In some preferred embodiments, the eutectic solvent is composed of choline chloride and tannic acid; and the polymer solution has a mass percentage of 30%; and the mass ratio of the eutectic solvent to the polymer solution is 1:1, 1:2 or 2:1.

[0020] In some preferred embodiments, the eutectic solvent is composed of choline chloride and tannic acid; and the polymer solution has a mass percentage of 30%; and the mass ratio of the eutectic solvent to the polymer solution is 1:1.

[0021] In some embodiments, the polymer solution is an aqueous gelatin solution; the mass percentage of the aqueous gelatin solution is 30%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is (1~2):(1~2).

[0022] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the eutectic solvent is composed of choline chloride and tannic acid; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is (1~2):(1~2).

[0023] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the eutectic solvent is composed of choline chloride and tannic acid; and the aqueous gelatin solution has a mass percentage of 10% to 40%.

[0024] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the mass percentage of the aqueous gelatin solution is 10% to 40%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is (1 to 2):(1 to 2).

[0025] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the mass percentage of the aqueous gelatin solution is 10% to 40%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is 1:1, 1:2, or 2:1.

[0026] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the mass percentage of the aqueous gelatin solution is 10% to 40%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is 1:1.

[0027] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the eutectic solvent is composed of choline chloride and tannic acid; and the aqueous gelatin solution has a mass percentage of 30%.

[0028] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the aqueous gelatin solution has a mass percentage of 30%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is (1~2):(1~2).

[0029] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the mass percentage of the aqueous gelatin solution is 30%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is 1:1, 1:2, or 2:1.

[0030] In some preferred embodiments, the eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; and the mass percentage of the aqueous gelatin solution is 10% to 40%; and the mass ratio of the eutectic solvent to the aqueous gelatin solution is 1:1.

[0031] In some embodiments, when the mass percentage of the gelatin aqueous solution is 10%, the mass ratio of the eutectic solvent to the gelatin aqueous solution is not 2:1; or, when the mass ratio of the eutectic solvent to the gelatin aqueous solution is 2:1, the mass percentage of the gelatin aqueous solution is not 10%; wherein the eutectic solvent is composed of choline chloride and tannic acid.

[0032] Another aspect of this application provides a method for preparing the eutectic gel provided in this application, which includes the following steps: mixing a eutectic solvent and a polymer solution under heating conditions to obtain a eutectic gel.

[0033] In some embodiments, in the above preparation method, the eutectic solvent and the polymer solution are heated, mixed, and then cooled to obtain the eutectic gel.

[0034] In some embodiments, the heating temperature in the above preparation method is 70-120 °C.

[0035] In some preferred embodiments, the heating temperature in the above preparation method is 90 °C.

[0036] This application also discloses the use of the eutectic gel provided in this application in the preparation of drugs or medical gel dressings for the repair of mucosal injuries.

[0037] In some embodiments, the mucosa described above can be a digestive system mucosa, a respiratory system mucosa, a reproductive system mucosa, a urinary system mucosa, or a sensory system mucosa.

[0038] In some preferred embodiments, the mucosa may be oral mucosa, pharyngeal mucosa, anal canal mucosa, nasal mucosa, urethral mucosa, vaginal mucosa, vulvar mucosa, or lingual mucosa.

[0039] In some embodiments, the eutectic gel provided in this application can be used as a medical gel dressing in the above applications.

[0040] In some embodiments, the eutectic gel is viscoelastic, the adhesion strength of the eutectic gel is greater than or equal to 1 kPa, and the gel storage modulus of the eutectic gel is 2 to 6 kPa.

[0041] In some embodiments, the phase transition temperature of the eutectic gel is 10-50°C. Preferably, the phase transition temperature of the eutectic gel is 10-46°C; more preferably, the phase transition temperature of the eutectic gel is 20-36°C.

[0042] In some embodiments, the degradation rate of the eutectic gel is 40%-100% over one week; preferably, the degradation rate of the eutectic gel is 60%-100% over one week.

[0043] Specifically, the eutectic gel provided in this application is placed on the mucosal surface. At body temperature, the eutectic gel undergoes a phase transition, transforming into a sol that adheres to the mucosa. Subsequently, the eutectic solvent forms competitive hydrogen bonds with the mucins in the mucus, disrupting the cross-linking network of the mucus and improving the permeability of the sol. Simultaneously, the sol and mucus undergo solvent exchange, forming an adhesive colloid in situ, which adheres tightly to the mucosa, increasing the colloid's residence time on the mucosa. Therefore, the drug within the gel can be continuously delivered to the mucosa, achieving the purpose of long-term drug delivery.

[0044] This application also discloses the use of the eutectic gel provided in this application as a carrier in the preparation of a treatment for mucosal diseases or solid tumors.

[0045] Specifically, the eutectic gel provided in this application can encapsulate the drug and deliver it to the mucosa in situ.

[0046] In some embodiments, the medicine may be a therapeutic medicine, a preventive medicine, a diagnostic medicine, a health care medicine, or / and an adjuvant medicine.

[0047] Specifically, the eutectic gel provided in this application is placed on the mucosal surface. At body temperature, the eutectic gel undergoes a phase transition, transforming into a sol that adheres to the mucosa. Subsequently, the eutectic solvent forms competitive hydrogen bonds with the mucins in the mucus, disrupting the cross-linking network of the mucus and improving the permeability of the sol. Simultaneously, the sol and mucus undergo solvent exchange, forming an adhesive colloid in situ, which adheres tightly to the mucosa, increasing the colloid's residence time on the mucosa. Therefore, the drug within the gel can be continuously delivered to the mucosa, achieving the purpose of long-term drug delivery.

[0048] It should be noted that the therapeutic drugs are drugs used to treat diseases; the preventive drugs are drugs that can prevent the occurrence, development, or recurrence of diseases; the diagnostic drugs are drugs that can assist in the diagnosis of diseases; and the health care drugs or the auxiliary drugs are drugs that are not targeted at the treatment of specific diseases, but are mainly used to regulate the body's physiological functions, supplement nutrition, or improve sub-health conditions.

[0049] In some embodiments, the therapeutic agent may be an anti-inflammatory drug, an antibacterial drug, or an antitumor drug.

[0050] In some embodiments, the health-promoting medicine may be a probiotic medicine.

[0051] To address the technical bottleneck of low drug delivery efficiency in existing mucosal drug delivery systems, this application provides an innovative eutectic gel suitable for mucosal drug delivery. This gel is prepared by blending a eutectic solvent with a polymer solution, possessing both excellent physical and biological functional properties, including mucus layer permeability, strong mucosal adhesion, good tensile properties, suitable temperature-responsive solvent exchange capacity, controllable phase transition temperature, excellent biocompatibility, and biodegradability. It also exhibits multiple pharmacological activities such as high-efficiency drug delivery, anti-inflammatory, antibacterial, and probiotic growth promotion, enabling targeted treatment of mucosal-related diseases.

[0052] The synergistic effect of the above properties stems from the unique mechanism of action of the eutectic gel: it utilizes the eutectic solvent to penetrate the mucus barrier and construct a direct drug delivery channel; at the same time, in the complex mucosal microenvironment where mucus is constantly being renewed, the gel can quickly absorb water and swell and adhere tightly to the mucosal surface, significantly prolonging the residence time of the drug delivery system at the mucosal site, and ultimately achieving efficient and continuous targeted delivery of drugs to mucosal tissues. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0054] Figure 1 A schematic diagram illustrating the structural changes during the preparation of DESG gel according to embodiments of this application;

[0055] Figure 2 The DESG gel phase transition and solvent exchange process provided in the embodiments of this application;

[0056] Figure 3 Infrared spectra of choline chloride (ChCl), tannic acid (TA), gelatin, and DESG gel, and rheological test diagram of DESG gel provided for embodiments of this application;

[0057] Figure 4 The DESG gel adhesion effect provided in the embodiments of this application and its adhesion performance results compared with those of commercial mucosal adhesion hydrogels;

[0058] Figure 5 This is a schematic diagram of the DESG gel adhesion mechanism to the mucosa provided in the embodiments of this application;

[0059] Figure 6 Results of DESG gel, DES, and PBS mucosal drug delivery at 6 h (a), 12 h (b), and 24 h (c) provided in the embodiments of this application;

[0060] Figure 7 Biocompatibility results of the DESG gel provided in the embodiments of this application;

[0061] Figure 8 The anti-inflammatory results of the DESG gel provided in the embodiments of this application;

[0062] Figure 9 The results of promoting probiotic growth using the DESG gel provided in the embodiments of this application;

[0063] Figure 10 The DESG gel provided in the embodiments of this application demonstrates its broad-spectrum antibacterial properties;

[0064] Figure 11The therapeutic results of the DESG gel provided in the embodiments of this application in bacterial vaginosis; Detailed Implementation

[0065] This application provides a eutectic gel and its preparation method that can achieve rapid and tight adhesion and continuous drug delivery on mucous membranes that continuously secrete mucus. This addresses the technical shortcomings of traditional local mucosal drug delivery formulations, which are unable to achieve rapid and firm adhesion to the dynamically updated mucous membrane environment, cannot achieve long-term drug delivery, and cannot penetrate the mucus layer, resulting in the inability of the local mucosa to maintain a high concentration of drug exposure environment for a long time.

[0066] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0067] The raw materials used in the following examples are all commercially available or self-made.

[0068] Example 1

[0069] This embodiment describes a method for preparing a eutectic gel, specifically including:

[0070] 1. According to Figure 1 Preparation of deep eutectic solvents (DES), gelatin aqueous solution, and deep eutectic gel (DESG gel):

[0071] ① Choline chloride (ChCl) and tannic acid (TA) are mixed evenly in a molar ratio of 20:1 and reacted at 90 °C to form a deep eutectic solvent (DES). ChCl is linked to TA through hydrogen bonds to form the deep eutectic solvent (DES).

[0072] ② Heat and mix gelatin powder and deionized water at 55 ℃ until the gelatin is completely dissolved to obtain a 10 wt% (mass percentage) gelatin aqueous solution. Prepare 20 wt% gelatin aqueous solution, 30 wt% gelatin aqueous solution and 40 wt% gelatin aqueous solution in the same way.

[0073] ③ According to the proportions in Table 1, DES was mixed with gelatin aqueous solutions of different mass percentages at mass ratios of 2:1, 1:1, and 1:2 at 90 °C to prepare eutectic gels (DESG gels) under different parameters. Gelatin is linked to DES through hydrogen bonds to form DESG gels.

[0074] like Figure 2 As shown, the DESG gel exhibits poor flowability at room temperature or 4 °C, remaining nearly solid. Figure 2 (a) In the text; DESG gel exhibits a certain degree of fluidity under high temperature conditions ( Figure 2 (b) In this context, when DESG gel is placed at body temperature, it transforms into a more fluid DESG sol, capable of adapting to different shapes; when DESG sol is injected into water, it undergoes solvent exchange, transforming into a gel / TA / MP hydrogel with mucosal adhesion. Figure 2 (c)

[0075] ④ The phase transition temperature, one-week degradation rate, mucosal adhesion, and gel storage modulus of DESG gels under various preparation conditions were determined. The results are shown in Table 1.

[0076] Among them, a) the phase transition temperature was determined by temperature scanning rheological testing;

[0077] b. Method for determining the degradation rate in one week: Weigh the DESG gel and record it as m0. Then place the DESG gel in PBS and place it in a shaker at 37 ℃ and shake it slowly and evenly at 30 rpm. After one week, freeze-dry the remaining eutectic gel and record it as m1. Calculate the degradation rate in one week.

[0078] Degradation rate in one week = (m0-m1) / m0 × 100%;

[0079] c. Method for determining mucosal adhesion: Mucosal tissue is adhered to a glass slide with glue. Then, two pieces of mucosal tissue with simulated mucus added are bonded together with DESG gel at 37 ℃. An lap tensile shear test is performed on a universal tensile testing machine. The maximum adhesive force Fmax at which the eutectic gel breaks is recorded. Adhesion strength = Fmax / adhesion area. Adhesion evaluation criteria: Good (adhesion strength 1-2 kPa); Average (adhesion strength 3-4 kPa); Excellent (adhesion strength 5-6 kPa);

[0080] d. The storage modulus of the gel was measured using a rheometer.

[0081] Table 1. Effects of phase transition temperature, degradation efficiency, and mechanical properties of Gel / TA / MP hydrogels prepared under different parameters.

[0082]

[0083] Table 1 shows that DESG gels could be prepared with all parameters except for a 10 wt% gelatin aqueous solution and a 2:1 DES to gelatin aqueous solution ratio, where DESG gels could not be obtained. Different gelatin aqueous solution concentrations and DES to gelatin aqueous solution ratios can regulate the phase transition temperature, degradation efficiency, and mechanical strength of the derived hydrogel (Gel / TA / MP hydrogel). Preferably, when the gelatin aqueous solution concentration is 30 wt% and the DES to gelatin aqueous solution ratios are 2:1, 1:1, and 1:2, the DESG gel exhibits superior performance in all aspects. In particular, when the gelatin aqueous solution concentration is 30 wt% and the DES to gelatin aqueous solution ratio is 1:1, the prepared DESG gel has the most suitable phase transition temperature, the best degradation efficiency, and the best mechanical strength. Therefore, in subsequent examples, a DESG gel with a 30 wt% gelatin aqueous solution and a 1:1 DES to gelatin aqueous solution ratio was selected for testing.

[0084] Example 2

[0085] This embodiment uses spectroscopy, energy dispersive spectroscopy, and other methods to determine the structural changes and crosslinking mechanism of DESG gel before and after crosslinking, specifically including:

[0086] 1. The chemical composition and functional group characterization of the DESG gel were determined using Fourier transform infrared spectroscopy (FTIR), and the results are as follows: Figure 3 a, the amide I band in gelatin (1631 cm) -1 ) and the carboxylic acid group in tannic acid TA (1718 cm) -1 The infrared characteristic peaks of the sample shifted within the DESG gel, rather than forming new characteristic peaks (1722 cm⁻¹). -1 1644 cm -1 This indicates that choline chloride (ChCl), tannic acid (TA), and gelatin in the DESG gel are physically cross-linked via hydrogen bonds, rather than chemically cross-linked into a gel.

[0087] 2. The storage and loss modulus of the DESG gel were tested by frequency scanning rheology, and the results are as follows: Figure 3 In b, the storage and loss moduli of the DESG gel increase with increasing frequency, and the storage modulus is higher than the loss modulus, which also proves that the DESG gel forms a stable physical crosslink.

[0088] 3. The adhesion of the DESG gel and the adhesion stress were measured by visual inspection, light microscopy, and scanning electron microscopy. For example... Figure 4For a in [reference], apply the DESG gel to the porcine small intestine mucosa, and then place it in an environment of 37 °C. The DESG gel undergoes a phase change and transforms into a more fluid DESG sol. Under a light microscope and a scanning electron microscope, the DESG sol fills into the folds and crevices of the porcine small intestine mucosa, forming a close contact with the mucosa. Subsequently, the DESG sol undergoes a solvent exchange with the water molecules on the mucosa surface, and a Gel / TA / MP hydrogel with mucosal adhesiveness is formed in situ, forming a tight adhesion with the mucosa. The results show that the DESG gel forms a tight adhesion with the mucosa surface. As Figure 4 For b in [reference], perform a lap shear test on a universal testing tensile machine to determine the adhesion performance of the DESG gel and a commercial glue (trade name: Oligoisomaltose Vaginal Packing Gel, registration number: Jilin Medical Device Approval 20212180008). The results show that the adhesion stress of the DESG gel is 5.41 ± 0.21 kPa, which is higher than the adhesion stress of the commercial glue (0.34 ± 0.06 kPa). Moreover, from this test, it can be seen that after the mucosal adhesion of the DESG gel is damaged, the failure type belongs to cohesive failure, which also indicates that the DESG gel forms a tight adhesion to the mucosa.

[0089] Based on the above tests and results, the adhesion mechanism of the DESG gel of this application is as follows: As Figure 5 : The DESG gel encapsulates the drug and covers it on the mucosa surface. Triggered by body temperature (about 37 °C), it undergoes a phase change and transforms into a more fluid DESG sol, which can fill into the folds and crevices of the mucosa to form a close contact with the mucosa. Subsequently, the DESG sol undergoes a solvent exchange with the water molecules on the mucosa surface, and the Schiff base bonds, π-π stacking, and hydrophobic association between gelatin, tannic acid, and mucin are enhanced, and a Gel / TA / MP hydrogel is formed in situ. The in-situ formed Gel / TA / MP hydrogel produces mechanical interlocking with the mucosal folds through the surface microtopography; functional groups such as phenolic hydroxyl groups in the hydrogel can form stable interfacial anchoring and firm adhesion with the amino and sulfhydryl groups on the tissue surface through multiple intermolecular interactions such as hydrogen bonds (phenolic hydroxyl group - amino group), carbon-nitrogen bonds (addition reaction between polyphenols and amino groups), and carbon-sulfur bonds (addition reaction between polyphenols and sulfhydryl groups); at the same time, the drug in the DESG gel is delivered to the mucosa.

[0090] Example 3

[0091] This example tests the drug delivery efficiency of the DESG gel as a carrier on the mucosa, specifically including:

[0092] Using a fluorescent dye (rhodamine) as a drug simulant, the efficiency of DESG gel, DES, and PBS prepared in Example 1 in delivering drugs to the mucosa was tested. The rats were divided into DESG gel group, DES group, and PBS group. Specifically: the DESG gel group was prepared by mixing rhodamine and DESG gel at a mass ratio of 1:1000; the DES group was prepared by mixing rhodamine and DES at a mass ratio of 1:1000; and the PBS group was prepared by mixing rhodamine and PBS at a mass ratio of 1:1000. The rhodamine-containing DESG gel, DES, and PBS were then injected into the vagina of rats, respectively. Samples were taken at 6 h, 12 h, and 24 h to observe the mucosal penetration depth of rhodamine. The results are as follows: Figure 6 The DESG gel achieved a drug penetration depth of 30 µm at 6 h and 50 µm at 12 h. While the rhodamine penetration depth remained at 50 µm at 24 h, its fluorescence intensity was stronger than at 12 h, indicating that the DESG gel adheres to the mucosa and can continuously deliver the drug. In the DES group, rhodamine remained on the mucosal surface at both 6 and 12 h, but the fluorescence intensity at 6 h was stronger than at 12 h. In the PBS group, the drug was completely lost at 24 h, possibly because DES can only temporarily adhere to the mucosal surface and is lost with the turnover of mucus, thus failing to deliver the drug continuously. In the PBS group, the drug was completely lost at 6 h, 12 h, and 24 h. These results demonstrate that the DESG gel has a continuous and efficient mucosal drug delivery function.

[0093] Example 4

[0094] This embodiment tests the biocompatibility of DESG gel, specifically including:

[0095] 1. Cell Experiments: DESG gel assays and control groups were set up. In the DESG gel assay, 1 g of DESG gel was immersed in 10 mL of DMEM medium and incubated at 37 ºC for 24 hours to prepare a DESG gel extract. This extract was then added to wells containing L929 cells. In the control group, an equal volume of DMEM medium was added to wells containing L929 cells. Both the DESG gel extract and DMEM medium were co-incubated with L929 cells for 24 hours. Afterward, the DESG gel extract and medium were removed, and a prepared live / dead cell staining reagent was added. The cells were then incubated at 37 ºC for 20 minutes, and the morphology and viability of the L929 cells were observed using a fluorescence microscope. Figure 7 As shown in figure a, the cells in the DESG gel group were similar to those in the positive control group, exhibiting a spindle shape and similar cell viability. This result indicates that the DESG gel has good cell biocompatibility.

[0096] 2. Animal experiments: DESG gel group and control group were set up. DESG gel group: DESG gel was injected into the vagina of rats. Control group: no operation was performed on rats. After 24 hours, the blood routine and blood biochemical indicators of rats were detected, and samples were taken, sections were stained with HE. Figure 7 The results of blood routine tests, blood biochemical indicators, and tissue HE staining in the DESG gel group showed no significant differences compared to the positive control group. This result indicates that DESG gel has good tissue biocompatibility, which is of great significance for its application in biomedical materials.

[0097] Example 5

[0098] This embodiment tests the anti-inflammatory effect of DESG gel, specifically including:

[0099] The DESG gel group and control group were set up. The DESG gel group was prepared by adding 20 µL of DESG gel extract to lipopolysaccharide (LPS). The control group consisted of LPS. The testing method was as follows: RAW 264.7 cells (mouse mononuclear macrophages) were cultured at 2 × 10⁶ cells per well. 5 Cells were seeded at a density of [number] cells per well in DMEM medium and cultured at 37 °C under 5% CO2 humidification for 12 hours. LPS was then added to the wells to bring the LPS concentration in the medium to 200 ng / mL. Subsequently, 20 µL of DESG gel extract was added to the DESG gel group, while no additional liquid was added to the control group. Cytokines and macrophage types in the supernatant were then analyzed. Results are shown below. Figure 8 The level of pro-inflammatory cytokine (IL-6) in the LPS group (positive control group) was 208.28±2.53 pg / mL, significantly higher than that in the LPS / DESG gel group (106.17±14.03 pg / mL). Meanwhile, the levels in both the LPS group and the LPS / DESG gel group... Logo CD86 + The percentages were 11.53±0.57% and 7.19±0.39%, respectively. Figure 8 (ab) In contrast, the anti-inflammatory cytokine (IL-10) in the LPS and LPS / DESG gel groups was 260.55±25.82 pg / mL and 328.82±10.99 pg / mL, respectively. (ab) Marker arginase-1 (ARG1) + The percentages of the LPS group were 57.83 ± 4.93%, which was much higher than that of the LPS group (34.33 ± 2.73%). Figure 8 (cd in the text). These results indicate that DESG gel containing tannic acid exhibits good anti-inflammatory effects on LPS-stimulated RAW264.7 cells.

[0100] Example 6

[0101] This embodiment tests the effect of DESG gel on promoting probiotic growth, specifically including:

[0102] A DESG gel group and a control group were set up. In the DESG gel group, DESG gel was added to the liquid culture medium of Lactobacillus and incubated for 8 hours. The control group was a blank control group, receiving no treatment for Lactobacillus. The Lactobacillus content in both groups was consistent. Subsequent dilution, plating, and counting were performed, and the results are as follows: Figure 9 The number of colonies in the DESG group was 90±11 CFU, significantly higher than that in the positive control group (48±14 CFU). Under a microscope, the colony morphology and color of the DESG group were not significantly different from those of the positive control group. These results indicate that DESG gel promotes the growth of probiotics.

[0103] Example 7

[0104] This embodiment tests the broad-spectrum antibacterial effect of DESG gel, and the specific methods include:

[0105] 1. Staphylococcus aureus, Escherichia coli, and Gardnerella vaginalis were selected to evaluate the antibacterial properties of DESG gel. A DESG gel group and a control group were set up. In the DESG gel group, DESG gel was added to the liquid culture medium of Staphylococcus aureus, Escherichia coli, and Gardnerella vaginalis and incubated for 6 h. The control group was a blank control group, without any treatment of these bacteria. The bacterial content in both groups was the same. Subsequently, the bacteria were diluted, spread, and counted. The results are as follows: Figure 10 . Figure 10 The results showed that the number of Staphylococcus aureus, Escherichia coli, and Gardnerella vaginalis colonies in the DESG group (209±14 CFU, 144±8 CFU, and 146±33 CFU, respectively) was significantly lower than that in the positive control group (0 CFU, 104±5 CFU, and 14±8 CFU, respectively). Figure 10 (ab in the text). DESG gel showed an antibacterial rate of 100% against Staphylococcus aureus, 27.78±0.20% against Escherichia coli, and 90.43±1.42% against Gardnerella vaginalis. Figure 10 (c) The above results indicate that DESG gel has broad-spectrum antibacterial properties.

[0106] 2. The therapeutic effect of DESG gel was evaluated using a rat model of bacterial vaginosis, specifically including:

[0107] Methods for establishing rats with bacterial vaginosis ( Figure 11a) Rats were injected subcutaneously with 2 ml (2 mg / ml) estradiol benzoate injection twice a day for a total of 3 days. On day 7, 50 µl of pre-cultured Gardnerella vaginalis was injected, and the rats were observed for 1 day. The injected rats were then randomly divided into 4 groups: control group, DESG gel treatment group, DESG gel probiotic treatment group, and probiotic treatment group. Day 0 of treatment was defined as the day after injection. On days 1, 3, 5, and 7 of treatment, DESG gel (III. DESG gel group), DESG gel encapsulated with probiotics (IV. DESG gel probiotic treatment group), and probiotics (V. probiotic treatment group) were injected into the vagina of rats with bacterial vaginosis, according to their respective groups. I. The healthy group consisted of normal, untreated rats. II. The control group consisted of untreated rats with bacterial vaginosis. The method for preparing DESG gel encapsulating probiotics is as follows: 1 g of DESG gel is placed at 37 ºC to transform into DESG sol, then sterilized and 10 g of the sol is added. 5 CFU probiotic powder was thoroughly mixed to form DESG probiotic gel, wherein all probiotics were vaginal lactobacilli (Lactobacillus crispatus). Antibacterial results were then recorded periodically in the healthy group, positive control group, DESG gel group, DESG gel probiotic treatment group, and probiotic treatment group. Results are as follows: Figure 11 .

[0108] Record the degree of vulvar redness and swelling in rats on days 0, 3, and 7 of treatment. Figure 11 As shown in b), on day 3 of treatment, the vulvar redness and swelling disappeared in the DESG gel probiotic treatment group, while the vulva remained red and swollen in both the DESG gel group and the probiotic treatment group. On day 7 of treatment, the vulva in the positive control group remained red and swollen, while the vulvar redness and swelling in the DESG gel group and the probiotic treatment group improved, and the vulva in the DESG gel probiotic treatment group returned to normal. On day 8, vaginal douche fluid was collected, and 50 µl of the vaginal douche fluid was evenly spread onto pre-prepared Gardnerella vaginalis selective agar medium. The medium was incubated at 37 °C for 24 h, and the resulting colonies were photographed, recorded, and counted. Figure 11The results (cd) show that, compared to the positive control group (1405±152 CFU), the DESG gel group (145±48 CFU), the DESG gel probiotic treatment group (3.3±2 CFU), and the probiotic group (607.3±202 CFU) all showed varying degrees of reduction in Gardnerella vaginalis counts after treatment, with statistically significant differences. HE staining of vaginal tissue revealed a large number of inflammatory cells infiltrating the positive control group, while the DESG gel group, DESG gel probiotic treatment group, and probiotic treatment group showed a significant reduction in inflammatory cells. These results indicate that the DESG gel probiotic treatment group is more effective than DESG gel or probiotic treatment alone in treating bacterial vaginosis primarily caused by Gardnerella vaginalis infection. It can kill harmful bacteria more quickly and restore the beneficial vaginal flora environment, demonstrating a synergistic effect of DESG gel and probiotics (1+1>2).

[0109] The results of the above in vitro mucosal adhesion experiments show that after the eutectic gel is coated on the mucosal surface, observations using optical and scanning electron microscopy confirm that the gel can form a tightly adhered interface with the mucosal tissue. The mechanism of action is as follows: under body temperature, solvent exchange occurs between the gel and the mucosal mucus, driving the interaction between the polymer matrix and hydrogen bond donors within the system, thereby forming a complex and derivatizing into a hydrogel. During this process, the intermolecular forces such as Schiff base bonds, π-π stacking, and hydrophobic association between gelatin, tannic acid, and mucin are significantly enhanced, ultimately leading to the in-situ formation of a Gel / TA / MP composite hydrogel. This in-situ hydrogel, on the one hand, mechanically interlocks with mucosal folds through its surface microtopology; on the other hand, the active functional groups such as phenolic hydroxyl groups in the gel can specifically interact with amino and thiol groups on the tissue surface, constructing a multi-molecular interaction network through hydrogen bonds (phenolic hydroxyl-amino), carbon-nitrogen bonds (addition reaction of polyphenols with amino groups), and carbon-sulfur bonds (addition reaction of polyphenols with thiol groups), achieving stable interfacial anchoring and firm adhesion of the drug delivery system on the mucosal surface. These results fully demonstrate that the eutectic gel described in this application can rapidly absorb water and swell in the dynamic mucosal microenvironment of continuous mucus renewal, forming a tight and stable adhesion to the mucosa.

[0110] The results of the in vivo mucosal adhesion experiment and animal model pharmacodynamic test show that when the eutectic gel loaded with fluorescently labeled drugs is directly applied to the vaginal mucosa of animals, the gel can not only maintain a tight adhesion with the vaginal mucosa, but also effectively deliver fluorescent drugs to the deep layers of the mucosa. The animal model experiment further confirms that the eutectic gel described in this application has the potential to treat mucosal-related diseases and solid tumors in vivo.

[0111] In summary, the DESG gel provided in this application exhibits temperature-responsive phase transition properties, transforming into a highly fluid sol state under body temperature conditions. Through solvent exchange, the gel demonstrates excellent mucosal adhesion properties and high efficiency in mucosal drug delivery. Simultaneously, it also possesses bioactivity that promotes probiotic proliferation and restores the inherent beneficial bacterial microenvironment of the mucosa, effectively preventing and controlling mucosal lesions caused by mixed bacterial infections, thus providing a novel drug delivery strategy for the treatment of mucosal diseases.

[0112] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A eutectic gel, characterized in that, It contains eutectic solvents and polymer solutions; The eutectic solvent comprises hydrogen bond acceptors and hydrogen bond donors; the solute of the polymer solution is selected from one or more of gelatin, polyvinyl alcohol, polyethylene, or pyrrolidone.

2. The eutectic gel according to claim 1, characterized in that, The hydrogen bond acceptor is selected from one or more of choline chloride, betaine, proline, citric acid, bicarbonate choline, or tartrate choline; the hydrogen bond donor is selected from one or more of tannic acid, gallic acid, urea, glycerol, lactic acid, malic acid, or geranilic acid.

3. The eutectic gel according to claim 1, characterized in that, The mass ratio of the eutectic solvent to the polymer solution is (1~2):(1~2).

4. The eutectic gel according to claim 1, characterized in that, The polymer solution has a mass percentage of 10% to 40%.

5. The eutectic gel according to claim 1, characterized in that, The eutectic gel comprises a eutectic solvent and an aqueous gelatin solution; the eutectic solvent is composed of choline chloride and tannic acid; the polymer solution has a mass percentage of 30%.

6. A method for preparing the eutectic gel according to any one of claims 1 to 5, comprising the following steps: A eutectic gel is prepared by mixing a eutectic solvent and a polymer solution under heating conditions.

7. The use of the eutectic gel according to any one of claims 1 to 5 or the eutectic gel prepared by the preparation method according to claim 6 in the preparation of drugs or medical gel dressings for mucosal injury repair.

8. In the application according to claim 7, the eutectic gel is viscoelastic, the adhesion strength of the eutectic gel is greater than or equal to 1 kPa, and the gel storage modulus of the eutectic gel is 2~6 kPa.

9. In the application according to claim 7, the phase transition temperature of the eutectic gel is 10-50 °C.

10. The use of the eutectic gel according to any one of claims 1 to 5 or the eutectic gel prepared by the preparation method according to claim 6 as a carrier in the preparation of a drug for treating mucosal-related diseases; The eutectic gel serves as a carrier to encapsulate the drug, which may be a therapeutic drug, a preventative drug, a diagnostic drug, a health care drug, or / and an adjuvant drug.

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