Self-assembled hydrogel for treating ulcerative colitis as well as preparation method and application of self-assembled hydrogel

Abstract

The invention discloses a self-assembled hydrogel for treating ulcerative colitis and a preparation method and application thereof.The SPV-GA hydrogel with pH responsiveness and temperature-sensitive injectability is formed by dissolving and mixing evergreen gelsemine (SPV) and glycyrrhizic acid (GA) according to a certain molar ratio at the high temperature and conducting self-assembly at the temperature of 4 DEG C. The hydrogel can be rapidly degraded to release medicine in the intestinal pH environment (pH 7.4), and the hydrogel can be used for treating ulcerative colitis. The intestinal inflammation and barrier injury of ulcerative colitis are improved in a targeted manner, and the proinflammatory factor level is remarkably reduced; the temperature-sensitive injectable property is adapted to rectal administration, so that the problem of first-pass effect of a traditional oral preparation is solved, meanwhile, the preparation process is simple, the biocompatibility is excellent, and a novel targeted treatment strategy is provided for ulcerative colitis.

Description

[Technical Field]

[0001] This invention relates to the field of pharmaceutical technology, specifically to a self-assembled hydrogel based on eugenol (SPV) and glycyrrhizic acid (GA), its preparation method and application, for targeted treatment of ulcerative colitis. [Background Technology]

[0002] Gelsemium elegans (Gardn. et Champ.) Benth., also known as Gelsemium elegans, is a plant belonging to the genus Gelsemium in the family Loganiaceae. It is warm in nature, bitter and pungent in taste, and is a poisonous plant. In my country, it is mainly distributed in Zhejiang, Fujian, Guangdong, Guangxi, Guizhou, and Yunnan provinces. Gelsemium elegans is used to break up masses and accumulations. Modern pharmacological studies have found that it has analgesic, anti-inflammatory, and anti-tumor effects. Sempervirine (SPV) is an indole alkaloid isolated from Gelsemium elegans. Current research on SPV mainly focuses on its physicochemical properties, pharmacokinetic studies, and anti-tumor mechanisms. Multiple studies have shown that SPV exhibits significant inhibitory effects on various tumor cells by targeting different signaling pathways. SPV has a dual mechanism of action against human colon cancer cells: on the one hand, it inhibits HT-29 cell proliferation and induces apoptosis by regulating the Bcl-2 / Bax pathway; on the other hand, it exhibits a stronger inhibitory effect on HCT-8 cells by activating endoplasmic reticulum stress and autophagy pathways. Chronic colitis is a significant risk factor for colon cancer development, and inflammatory responses play a crucial role in this process. SPV may exert potential therapeutic effects through its multi-pathway regulatory capabilities and anti-inflammatory properties. Traditional dosage forms for UC have drawbacks such as first-pass effect, short retention time, and inaccurate targeting. Formulating SPV into a hydrogel offers advantages such as avoiding the first-pass effect, increasing drug retention time, improving bioavailability, and enhancing mucosal adhesion, achieving targeted drug delivery and providing more options for clinical treatment of UC.

[0003] Glycyrrhizic acid (GA), also known as glycyrrhizin or glycyrrhizin, is derived from the roots and rhizomes of the legume *Glycyrrhiza uralensis* Fisch. It is the most important active ingredient in licorice and is a natural triterpenoid saponin with diverse biological activities. It possesses various pharmacological activities, including anti-inflammatory, antitumor, antiviral, hepatoprotective, antioxidant, immunomodulatory, and cell membrane stabilizing effects. Clinically, it is commonly used to treat bronchitis, AIDS, hepatitis, and cirrhosis. Experiments have shown that glycyrrhizic acid exhibits unique self-assembly properties in aqueous solution driven by non-covalent interactions. By heating in aqueous solution to form nanofibers, further self-assembly can form supramolecular hydrogels with a three-dimensional network structure. In recent years, studies have utilized glycyrrhizic acid with other drugs to self-assemble into hydrogels for arthritis, wound infection, cerebral ischemia-reperfusion injury, and tumor immunotherapy.

[0004] Ulcerative colitis (UC) is a chronic, nonspecific inflammatory disease affecting the colon and rectum, severely impacting patients' quality of life. In recent years, the incidence and prevalence of UC have been steadily increasing, with a significant tendency for relapse. Clinically, antibiotics are commonly used to treat UC, but long-term use leads to problems such as bacterial resistance, drug residues, and serious toxic side effects. Therefore, developing safe and effective new methods and drug formulations for treating UC is essential. SPV (sparganum vesicle propagule) possesses anti-inflammatory and anti-tumor activity; the excellent properties of hydrogels make them an effective carrier for the development and treatment of UC drugs; GA (glucose glycosides) can self-assemble into hydrogels, but studies on its synergistic treatment with SPV for UC have not yet been reported. [Summary of the Invention]

[0005] The technical problem to be solved by this invention is to provide a self-assembled hydrogel for treating ulcerative colitis, its preparation method and application. It forms a pH-responsive, temperature-sensitive, injectable SPV-GA hydrogel through the molecular self-assembly of eugenol and glycyrrhizic acid. The hydrogel rapidly degrades and releases drugs in the intestinal pH environment (pH 7.4), targeting and improving intestinal inflammation and barrier damage in ulcerative colitis, and significantly reducing the level of pro-inflammatory factors. At the same time, its preparation process is simple and has excellent biocompatibility, providing a novel targeted treatment strategy for ulcerative colitis.

[0006] This invention is implemented as follows:

[0007] A self-assembled hydrogel for treating ulcerative colitis, the hydrogel being formed by molecular self-assembly of eugenol alkaloid SPV and glycyrrhizic acid GA, wherein the molar ratio of SPV to GA is 0.5-2:10.

[0008] Furthermore, the molar ratio of SPV to GA is 1:10.

[0009] Furthermore, the hydrogel is pH responsive, rapidly degrading and releasing drugs in an environment of pH 7.4±1, and structurally stable in an environment of pH 1.5-4.5.

[0010] Furthermore, the hydrogel is thermosensitive and injectable, with a viscosity of 2140±9.50 mPa·S at 4°C and a viscosity that decreases to 686±3.61 mPa·S at 37°C.

[0011] Furthermore, the method for preparing the self-assembled hydrogel for treating ulcerative colitis includes the following steps:

[0012] (1) Dissolve SPV in ultrapure water at 80±10℃ and stir magnetically until completely dissolved;

[0013] (2) Keep at 80±10℃, add GA to the SPV solution and stir until completely dissolved;

[0014] (3) Place the mixed solution at 4℃ and let it stand for 30±5 minutes to form a hydrogel.

[0015] Furthermore, the self-assembled hydrogel is used in the preparation of drugs for treating ulcerative colitis.

[0016] The present invention has the following advantages:

[0017] This invention's targeted delivery system utilizes the self-assembly of SPV and GA in a 1:10 ratio to form a stable hydrogen bond network. Leveraging pH-responsive degradation (achieving colon targeting at pH 7.4), it avoids drug degradation by gastric acid, effectively increasing local drug concentration in the colon and reducing side effects caused by systemic exposure. It possesses excellent physical properties and clinical applicability, exhibiting thermosensitive injectable characteristics (a gel state at 4°C for easy storage, transforming into a sol state at 37°C for release, with viscosity reduced to 686 mPa·s). It is suitable for rectal administration to address the first-pass effect problem of traditional oral formulations, and its high zeta potential (-32.5 mV) ensures storage stability and prevents aggregation and precipitation (compared to free SPV solution). In terms of efficacy, the synergistic effect of the two components improves key colitis indicators by more than 30%. Furthermore, the system uses natural raw materials (SPV is gelsemium extract, GA is the active ingredient of licorice), exhibits good biocompatibility, and has a simple preparation process requiring only three steps: dissolution, mixing, and cooling. It requires no complex carriers or chemical modifications, making it ideal for industrial-scale production. [Attached Image Description]

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1This is a schematic diagram illustrating the flowability of the SPV-GA hydrogel prepared with a fixed SPV addition amount in an embodiment of the present invention.

[0020] Figure 2 This is a tilt diagram of the SPV-GA hydrogel prepared with a fixed GA addition amount in an embodiment of the present invention.

[0021] Figure 3 This is an inverted view of the SPV-GA hydrogel prepared with a fixed GA addition amount in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of irradiating SPV-GA hydrogel with a laser pointer in an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the SPV-GA hydrogel morphology in an embodiment of the present invention.

[0024] Figure 6 This is a UV absorbance diagram of the hydrogel and its components in an embodiment of the present invention.

[0025] Figure 7 This is a Zeta-potential diagram of the SPV solution, GA gel, and SPV-GA hydrogel in an embodiment of the present invention.

[0026] Figure 8 This is a Fourier transform infrared analysis image of the SPV-GA hydrogel in an embodiment of the present invention.

[0027] Figure 9 This is a graph showing the viscosity changes of the SPV-GA hydrogel at different temperatures in an embodiment of the present invention.

[0028] Figure 10 This is an injection drawing and a schematic diagram of the SPV-GA hydrogel injected into water, as shown in the embodiment of the present invention.

[0029] Figure 11 This is a schematic diagram illustrating the degradation capacity of SPV-GA hydrogel at different pH values ​​in an embodiment of the present invention.

[0030] Figure 12 This is a schematic diagram of the average daily weight change rate of mice in the grouped embodiments of the present invention. Compared with the Control group, **** indicates P<0.0001; compared with the Model group, # indicates P<0.05.

[0031] Figure 13 This is a schematic diagram of the daily average Disease Activity Index (DAI) scores of grouped mice in an embodiment of the present invention.

[0032] Figure 14 This is a schematic diagram of the colon and rectum (cecum to colon and rectum) of mice in different groups in this embodiment of the invention.

[0033] Figure 15 This is a schematic diagram comparing serum DAO (diamine oxidase) levels in different groups in an embodiment of the present invention. Compared with the Control group, *** indicates P < 0.001; compared with the Model group, ### indicates P < 0.001.

[0034] Figure 16 This is a schematic diagram comparing the serum IL-1β content of different groups in an embodiment of the present invention. Compared with the Control group, *** indicates P < 0.001; compared with the Model group, ### indicates P < 0.001.

[0035] Figure 17 This is a schematic diagram comparing the serum IL-6 content of different groups in an embodiment of the present invention. Compared with the Control group, *** indicates P < 0.001; compared with the Model group, ### indicates P < 0.001.

Detailed Implementation Methods

[0036] The following will be combined with the appendix Figure 1-17 The technical solution of the present invention will be clearly and completely described in detail with specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0037] Example

[0038] 1. Preparation of SPV-GA hydrogel

[0039] An SPV solution was prepared by dissolving SPV (1 mmol, 2.72 mg) in 10 mL of ultrapure water at 80 °C with stirring until completely dissolved. While maintaining the temperature, GA (10 mmol, 82.3 mg) was added to the SPV solution and heated until completely dissolved. The solution was then placed in a 4 °C refrigerator, where a stable SPV-GA hydrogel formed after 30 min. SPV-GA hydrogels with different proportions were prepared using a similar method.

[0040] SPV-GA hydrogel samples with different proportions were prepared using the method described above. The prepared hydrogel samples were then placed into transparent containers, ensuring the containers were properly sealed.

[0041] (1) First, conduct a tilt observation. Slowly tilt the container containing the hydrogel to the same angle and observe the morphological changes of the hydrogel in the container. Record whether there are phenomena such as flow, deformation or layering.

[0042] (2) Next, invert the container and keep it upside down for 1 minute to observe whether the hydrogel will flow in the container and whether its shape remains intact.

[0043] (3) In a relatively dark environment, illuminate the hydrogel sample with a laser pointer and observe it from a direction perpendicular to the laser beam. If a bright "pathway" can be seen, it indicates that the hydrogel system has produced the Tyndall effect, suggesting that a micelle structure may have been formed in the hydrogel, making the system exhibit colloidal properties; if no bright "pathway" can be seen, it indicates that the hydrogel system may not have formed a micelle structure, or the micelle concentration is too low, the size is not suitable, etc., and no obvious light scattering phenomenon is produced.

[0044] By comparing the morphological changes of SPV-GA hydrogel samples with different proportions within the container, we can obtain the following results:

[0045] (1) With the amount of SPV fixed at 1 mmol, the amount of GA added was varied. It was observed that when the ratio of SPV to GA was 1:10, the hydrogel began to stabilize and its fluidity decreased (see results). Figure 1 ).

[0046] (2) When the amount of GA added was set at 10 mmol, the amount of SPV added was varied. It was observed that the hydrogel was most stable when the ratio of SPV to GA was 1:10 (see results). Figure 2 , 3 ).

[0047] (3) The hydrogel sample (SPV∶GA=1∶10) was illuminated with a laser pointer. The following figure was obtained when observed from a direction perpendicular to the laser beam, indicating that the hydrogel system formed a relatively stable micelle structure (see results). Figure 4 ).

[0048] Therefore, the optimal preparation method for SPV-GA hydrogel is determined as follows:

[0049] Raw material ratio:

[0050] SPV (laboratory-prepared, molecular weight 272.3 Da): 1 mmol (2.72 mg)

[0051] GA (Shanghai Yuanye Biotechnology Co., Ltd., molecular weight 822.93 Da): 10 mmol (82.3 mg)

[0052] Ultrapure water: 10mL

[0053] Preparation steps:

[0054] (1) Dissolve SPV in 10 mL of ultrapure water and stir magnetically at 80 °C until completely transparent (about 15 min);

[0055] (2) Keep at 80°C, add GA to the SPV solution and continue stirring until completely dissolved (about 20 min);

[0056] (3) Transfer the mixed solution to a 4°C refrigerator and let it stand for 30 minutes to form a pale yellow semi-solid SPV-GA hydrogel (see Figure 5 )

[0057] 2. Properties and characterization of SPV-GA hydrogel

[0058] 2.1 Measurement of absorbance under ultraviolet light

[0059] Using ultrapure water as a reference, the UV absorption spectra of SPV solution (1 mmol / 10 ml), GA solution (10 mmol / 10 ml), and SPV-GA hydrogel in the wavelength range of 190-500 nm were scanned using a UV-Vis spectrophotometer. See details in [link to relevant documentation]. Figure 6 And Table 1 below.

[0060] Table 1. Absorbance determination of hydrogels and their components under ultraviolet light.

[0061]

[0062] As can be seen from the above, the maximum absorption wavelength of SPV-GA mixture redshifts and the absorbance increases significantly (1.628), indicating intermolecular electronic interactions.

[0063] 2.2 Determination of Zeta-potential of hydrogels

[0064] Take an appropriate amount of the prepared SPV-GA hydrogel and place it in a cuvette. Measure the surface zeta potential of the hydrogel using a laser particle size analyzer. Repeat the test three times at room temperature and take the average value. See details. Figure 7 There is an electrostatic interaction between SPV and GA nanofibers. The zeta potentials of both SPV-GA hydrogel and GA are below -30mV, indicating good physical stability.

[0065] 2.3 Fourier Transform Infrared (FT-IR) Analysis

[0066] To investigate the interactions between chemical groups in the synthesis of SPV-GA hydrogels, the Fourier transform infrared (FTIR) spectra of the hydrogel materials were measured using a Fourier transform infrared spectroscopy (FTIR) instrument. (See details...) Figure 8 .

[0067] Fourier transform infrared spectroscopy was used to test the SPV-GA hydrogel. Vibrational analysis revealed that the vibrational peaks of hydroxyl and amino groups in SPV and GA shifted and broadened, indicating that they may form hydrogen bonds. The carboxylic acid groups of GA were partially deprotonated, and they formed ionic or hydrogen bonds with the amino groups of SPV. The CO / CN groups of SPV may participate in the interaction, and the aliphatic chain structure was not significantly affected. New peaks appeared in SPV-GA, forming new interaction modes. At the same time, some groups of GA may have been encapsulated or their vibrations were restricted, resulting in the disappearance of certain peaks.

[0068] 2.4 Effect of Temperature on Rheological Properties

[0069] To investigate the viscosity of SPV-GA hydrogel, an NDJ-5S rotational viscometer was used. To ensure accuracy, multiple measurements were performed and averaged. The viscosity of SPV-GA hydrogel at different temperatures was also investigated using an NDJ-5S rotational viscometer at 6 rpm. The results are shown in Table 2. Figure 9 As shown:

[0070] Table 2 Viscosity variation of SPV-GA hydrogel at different temperatures (n=3, )

[0071]

[0072] From Table 2 and Figure 9 As can be seen from the data, from 4 to 15℃, the viscosity of the SPV-GA hydrogel decreases slightly from 2200 mPa·s to 1900 mPa·s, and the structure remains stable. From 15 to 25℃, the viscosity drops sharply to 1100 mPa·s, indicating significant structural damage and weakened intermolecular forces. From 25 to 37℃, the viscosity gradually decreases to 700 mPa·s, and the structure continuously adjusts to adapt to the temperature.

[0073] This indicates that SPV-GA hydrogel, as a drug carrier, has a high viscosity at 4℃-15℃, which facilitates drug storage and prevents leakage. The viscosity decreases near body temperature (37℃), which is beneficial for drug release and diffusion in the body.

[0074] 2.5SPV-GA hydrogel's injectability

[0075] Use a syringe to draw simple lines in a culture dish using SPV-GA hydrogel. Observe whether the hydrogel can be easily drawn into the syringe without obvious blockage or difficulty in aspiration; and whether it can be evenly squeezed out of the syringe as expected, forming continuous and clear lines (see details). Figure 10 ).

[0076] The hydrogel was easily drawn into the syringe without any obvious blockage or difficulty in aspiration; the hydrogel was extruded from the syringe as expected, forming a continuous and clear line, which verified its good injectability.

[0077] When SPV-GA hydrogel is drawn up with a syringe and injected into water, it can be observed that after being extruded from the syringe, the SPV-GA hydrogel exhibits a relatively coherent morphology in the water, forming a columnar structure with a certain degree of flexibility and continuity. It does not break into fragments, indicating that the hydrogel has a certain degree of cohesion and structural stability.

[0078] 2.6 In vitro drug degradation

[0079] Each sample vial received 2 ml of SPV-GA hydrogel using a pipette. The hydrogel was left to stand overnight to form cylindrical gels. The degradation ability of the hydrogel was assessed in vitro using 8 ml of various buffer solutions (pH 1.5, 4.5, and 7.4). When degradation reached specific time points (0, 6, 12, 24, 36, 48, and 60 h), the supernatant was removed from each sample vial. The samples were then placed in a freezer at -80°C overnight, and all sample vials were lyophilized for 48 h. All lyophilized samples were weighed. The degradation rate of the SPV-GA hydrogel at different time points was then calculated, and degradation curves were plotted. As a control, one group of hydrogels did not undergo any degradation treatment. Each experiment was repeated three times, and the average value of the results was calculated. See details in the attached document. Figure 11 The results indicate that in acidic environments such as the stomach (close to pH 1.5-4.5), SPV-GA hydrogels can maintain their structural integrity well, which is beneficial for preventing premature drug release before reaching the target site. Furthermore, SPV-GA hydrogels degrade rapidly in the intestinal environment (close to pH 7.4), enabling effective drug release and achieving targeted drug delivery.

[0080] 3. Study on the effect of SPV-GA hydrogel in improving DSS-induced ulcerative colitis in mice

[0081] 3.1 Grouping and Modeling

[0082] Eighteen male C57BL / 6 mice were randomly divided into three groups (n=6 per group) after one week of acclimatization: a control group, a model group, and an SPV-GA hydrogel treatment group. Except for the control group, the other two groups of mice had free access to 2% DSS solution (prepared by accurately weighing 20.00g of DSS powder and dissolving it in 1L of ultrapure water, then sonicating and stirring until completely dissolved) for 7 consecutive days, with fresh DSS solution every 2 days. On the 7th day, the 2% DSS solution was replaced with water. The mice gradually developed increased frequency of defecation with pus and blood, and decreased body weight, indicating successful model establishment. While the mice had free access to the 2% DSS solution, the SPV-GA hydrogel treatment group was simultaneously administered the solution via gavage at a dose of 85.82mg / kg (2.72mg / kg SPV + 82.3mg / kg GA), with a gavage volume of 0.1ml / 10g. Mouse modeling and drug administration were carried out simultaneously. Drug administration continued until the day before sample collection. On the last day after drug administration, the mice were fasted for 24 hours before sample collection.

[0083] 3.2 Evaluation Indicators for Animal Models

[0084] During the modeling period, changes in body weight and activity levels of mice were monitored, and their condition, including hair, coat color, and the presence of symptoms such as rectal bleeding and rectal prolapse, was observed. The mice were scored based on daily fecal consistency and rectal bleeding, and the scores for weight change, fecal consistency, and rectal bleeding (measured using a fecal occult blood test kit) were summed to obtain the Disease Activity Index (DAI) score, which was used as an indicator for model evaluation (scoring criteria are shown in Table 3).

[0085] Table 3. Disease Activity Index (DAI) Scoring Table for Mice

[0086]

[0087] Note: The method for calculating the mouse body weight loss rate is: (Mouse's body weight on a certain day / Mouse's body weight on the first day) * 100%.

[0088] During the modeling process, the body weight changes of each group of mice were monitored and recorded, and the results are shown in Table 4. Figure 12 As shown:

[0089] Table 4. Average daily body weight change rate of mice in each group

[0090]

[0091] Throughout the observation period, the body weight of mice in the Control group remained relatively stable between 100% and 110%, with no significant trend in weight change. The body weight of mice in the Model group remained relatively constant for the first four days, then gradually decreased, reaching its lowest point around days 10-12, before starting to recover around days 13-14. The rate of weight loss in the Model group was significantly greater than that in the Control group (P<0.0001), indicating successful establishment of the DSS-induced ulcerative colitis model in mice. The body weight changes in the SPV-GA group were similar to the other two groups in the early stages, with a smaller rate of weight loss than the Model group. The body weight began to recover around days 10-12, with a significantly higher recovery trend than the Model group (P<0.05), indicating that SPV-GA hydrogel administration has a certain alleviating effect on weight loss caused by ulcerative colitis in mice.

[0092] During the modeling period, mice were scored based on daily fecal consistency and bloody stools. The scores for these three components—body weight change, fecal consistency, and bloody stools—were summed to obtain the Disease Activity Index (DAI) score. See details below. Figure 13 .

[0093] During this period, the average DAI scores of mice in the Model and Control groups started from day 4. The Control group, being normally fed and showing no symptoms, was not included in the scoring. The Model group's average DAI score initially increased at a greater rate and magnitude than the SPV-GA group, while its subsequent decline was roughly the same as the SPV-GA group, but its average score was still higher. This indicates that SPV-GA hydrogel administration has a certain effect on improving weight loss, looser stool consistency, and bloody stool in diseased mice.

[0094] After the treatment cycle in mice, they were fasted for 24 hours, their eyeballs were enucleated to collect blood, and they were euthanized by cervical dislocation. The abdominal cavity was opened along the midline to expose the abdominal tissues, and the spleens of the mice were removed, weighed, and recorded. The entire colon tissue was quickly removed, placed at its natural length next to a ruler, labeled, photographed, and recorded. 0.5-1 cm of the distal colon without feces was cut off and immersed in 4% paraformaldehyde fixative. The remaining colon was aliquoted into cryovials, flash-frozen in liquid nitrogen, and then transferred to -80°C for storage.

[0095] 3.3 Comparison of mouse colon length

[0096] Comparing the average colon length of the three groups of mice (see Table 5), it can be seen that the average colon length of the Control group mice is significantly greater than that of the Model group and the SPV-GA group, while the average colon length of the SPV-GA group is greater than that of the Model group.

[0097] Observation of mouse colon (see) Figure 14It can be seen that the control group mice have a longer colon, a thinner intestinal wall, and clearly visible contents, with granular feces in the intestine; while the model group mice have a slightly thickened colon wall, looser feces in the intestine, and a shorter colon; while the SPV-GA group mice have a longer colon than the model group, looser feces in the intestine, and no obvious thickening of the intestinal wall.

[0098] Table 5 Comparison of colon (cecum to colon and rectum) length in each group of mice (n=6, )

[0099]

[0100] 3.4 Effects of SPV-GA hydrogel on the intestinal barrier in mice

[0101] Blood was collected from mouse eyeballs and centrifuged at 3000 r / min for 20 min. The supernatant was then collected, and the serum DAO (diamine oxidase) content in mice was detected by ELISA to investigate the effect of SPV-GA hydrogel on the intestinal barrier of mice and to clarify the efficacy of SPV-GA hydrogel on DSS-induced ulcerative colitis in mice.

[0102] The DAO content in mouse serum was detected by ELISA, and the results are shown in Table 6. Figure 15 As shown in the figure. The results showed that, compared with the control group, the DAO content in the serum of mice in the model group was significantly increased (P<0.001), indicating that the DSS-induced UC model in mice was successfully established; compared with the model group, the DAO content in the serum of mice in the SPV-GA treatment group was significantly decreased (P<0.001), indicating that the inflammatory response in mice was reduced after administration of SPV-GA hydrogel, suggesting that the therapeutic effect of SPV-GA hydrogel may be related to improving intestinal mucosal barrier function.

[0103] Table 6 Comparison of DAO content in serum of three groups of animals (n=6, )

[0104]

[0105] Effects of 3.5SPV-GA hydrogel on serum inflammation levels in mice

[0106] The effect of SPV-GA hydrogel on the level of inflammation in mouse serum was investigated by detecting the levels of two inflammatory factors, IL-1β and IL-6, in mouse serum using ELISA.

[0107] Table 7 Comparison of serum inflammatory factor levels in three groups of animals (n=6, )

[0108]

[0109] ELISA results are shown in Table 7. Figure 16 , 17 Compared with the control group, the serum IL-1β and IL-6 levels in the model group mice were significantly increased (P<0.001, P<0.001), indicating that the DSS-induced UC mouse model was successfully established. Compared with the model group, the serum IL-1β and IL-6 levels in the SPV-GA treatment group mice were significantly decreased (P<0.01, P<0.001), indicating that the inflammation level in mice decreased after administration of SPV-GA hydrogel, suggesting that SPV-GA hydrogel can reduce the serum IL-1β and IL-6 levels in UC mice, thereby alleviating UC.

[0110] In summary, the targeted delivery system of this invention utilizes the molecular self-assembly of SPV and GA in a 1:10 ratio to form a stable hydrogen bond network. It leverages pH-responsive degradation (achieving colon targeting at pH 7.4) to prevent drug degradation by gastric acid, effectively increasing local drug concentration in the colon and reducing side effects caused by systemic exposure. It possesses excellent physical properties and clinical applicability, exhibiting thermosensitive injectable characteristics (a gel state at 4°C for easy storage, transforming into a sol state at 37°C for release, with viscosity reduced to 686 mPa·s). It is suitable for rectal administration to address the first-pass effect problem of traditional oral formulations, and its high zeta potential (-32.5 mV) ensures storage stability and prevents aggregation and precipitation (compared to free SPV solution). In terms of efficacy, the synergistic effect of the two components improves key colitis indicators by more than 30%. Furthermore, the system uses natural raw materials (SPV is gelsemium extract, GA is the active ingredient of licorice), exhibits good biocompatibility, and has a simple preparation process requiring only three steps: dissolution, mixing, and cooling. It requires no complex carriers or chemical modifications, making it highly suitable for industrial-scale production.

[0111] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A self-assembling hydrogel for treating ulcerative colitis, characterized in that: The hydrogel is formed by molecular self-assembly of eugenol base SPV and glycyrrhizic acid GA, wherein the molar ratio of SPV to GA is 0.5-2:

10.

2. The self-assembling hydrogel for treating ulcerative colitis according to claim 1, characterized in that: The molar ratio of SPV to GA is 1:

10.

3. The self-assembling hydrogel for treating ulcerative colitis according to claim 1, characterized in that: The hydrogel is pH responsive, rapidly degrading and releasing drugs in an environment of pH 7.4±1, and structurally stable in an environment of pH 1.5-4.

5.

4. The self-assembling hydrogel for treating ulcerative colitis according to claim 1, characterized in that: The hydrogel is thermosensitive and injectable, with a viscosity of 2140±9.50 mPa·S at 4°C and a viscosity that decreases to 686±3.61 mPa·S at 37°C.

5. A method for preparing a self-assembled hydrogel for treating ulcerative colitis according to any one of claims 1-4, characterized in that: Includes the following steps: (1) Dissolve SPV in ultrapure water at 80±10℃ and stir magnetically until completely dissolved; (2) Keep at 80±10℃, add GA to the SPV solution and stir until completely dissolved; (3) Place the mixed solution at 4℃ and let it stand for 30±5 minutes to form a hydrogel.

6. The use of the self-assembled hydrogel according to any one of claims 1-4 in the preparation of a medicament for treating ulcerative colitis.

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