A gel preparation of a duiyiwai water extract for improving the adhesion of oral mucosa, a preparation method and application thereof

Abstract

The application discloses a Duyuwei water extract gel preparation for improving oral mucosa adhesion, a preparation method and application thereof, and belongs to the field of traditional Chinese medicine gel preparations. The gel preparation comprises, in percentage by mass, 0.2-0.6% of Duyuwei water extract, 0.5-1.5% of carbomer 940, 0.5-3% of triethanolamine, 5-15% of glycerol, 0.3-0.5% of sodium benzoate, and the balance of purified water. The gel product is prepared by using a 15 DEG C low-temperature one-way grinding process. The ordered gel network structure is constructed by using the low-temperature one-way grinding process, and the ratio of the Duyuwei water extract and the gel matrix is optimized, so that the oral retention time of the preparation under the condition of a simulated saliva flow rate is more than 4 hours, and the preparation is significantly better than existing products. In an oral ulcer model of SD rats, the ulcer area of the gel preparation of the application is reduced by about 70% in 48 hours, and the treatment effect is better than that of the positive control drug watermelon cream spray.

Description

Technical Field

[0001] This invention relates to the field of traditional Chinese medicine gel preparations, specifically to a method for preparing a gel from a water extract of *Duyiwei* that enhances oral mucosal adhesion and its use in the treatment of recurrent oral ulcers. Background Technology

[0002] Recurrent aphthous stomatitis (RAS) is a common oral mucosal disease affecting approximately 20% of patients. It causes severe pain, impacting eating and speech. Current clinical treatment primarily involves topical medications, including corticosteroids, anti-inflammatory drugs, local anesthetics, and traditional Chinese medicine preparations. Existing technologies mainly employ two approaches: traditional solutions (such as mouthwashes and sprays) and conventional gel formulations.

[0003] In the field of oral topical drug delivery systems, existing technologies mainly employ two approaches: traditional solutions (mouthwashes, sprays) and conventional gel formulations. Traditional solutions deliver medication through frequent rinsing or spraying, resulting in extremely short drug retention time in the oral cavity and low bioavailability. Conventional gel formulations often use polymers such as carbomer 940 and sodium carboxymethyl cellulose as a matrix, which are simply mixed with the drug and then applied to the wound. However, the preparation process for these gels is usually room temperature stirring and swelling, without optimization for the unique physiological environment of the oral cavity. The oral environment is characterized by continuous saliva rinsing (flow rate of approximately 0.5-1.5 mL / min), tongue mechanical movement, pH fluctuations (6.2-7.4), and a rich mucosal enzyme system, placing special demands on the adhesive properties of topical formulations. Due to the lack of cross-linking density optimization and adhesion mechanism design for these factors, the actual retention time of existing gel formulations in the oral cavity is generally less than 0.5-1 hour, far below the time window required for the drug to exert its anti-inflammatory and healing-promoting effects (usually requiring 4-6 hours of continuous action). This forces patients to increase the frequency of administration, leading to poor patient compliance.

[0004] In particular, as an anionic polyacrylic acid resin, Carbomer 940's adhesive properties are highly dependent on the molecular chain order controlled by the swelling process and the gel network density adjusted by the neutralizing agent ratio. Existing technologies mostly employ a room-temperature (20-25°C) stirring swelling process. Under this process, the carbomer molecular chains are in a disordered, entangled state, resulting in a loose gel network structure with low mechanical strength, which is easily lost rapidly under the dynamic shear environment of the oral cavity. Furthermore, the adhesion mechanism of carbomer is mainly based on electrostatic and hydrogen bonding interactions, and its adhesive strength is closely related to pH value. However, existing gel formulations do not precisely control the physiological pH of the oral mucosa, resulting in insufficient adhesive performance.

[0005] More importantly, the components of traditional Chinese medicine (TCM) extracts are complex, containing a large number of polar macromolecules such as tannins, polysaccharides, and proteins, posing a potential risk of interaction with high-molecular-weight matrices such as carbomer. When the concentration or pH conditions of TCM extracts are inappropriate, they are prone to flocculation, precipitation, or phase separation with carbomer, compromising the integrity of the gel matrix. Therefore, the compatibility regulation of TCM active ingredients and the construction of synergistic adhesion mechanisms are a technological bottleneck for TCM oral gel formulations. Currently, optimizing the oral adhesion properties of carbomer gels for specific TCM active ingredients and establishing a targeted regulation method for "component-process-structure-performance" is still a technological gap.

[0006] In summary, the existing technology has the following technical defects: (1) The traditional application fields of Duyiwei are not related to the treatment of oral mucosal diseases, and the pharmacodynamics and compatibility studies of its active ingredients in the oral cavity are lacking; (2) The conventional carbomer gel preparation process is not optimized for the oral environment and has insufficient adhesion performance; (3) The compatibility rules and synergistic adhesion mechanism between the active ingredients of traditional Chinese medicine and the carbomer matrix are unclear, and there is a lack of directional design methods. Summary of the Invention

[0007] The purpose of this invention is to provide a unique water extract gel formulation that improves the adhesion performance of oral mucosa, as well as its preparation method and application.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a unique water extract gel formulation for improving the adhesion properties of oral mucosa, comprising the following components by mass percentage: The water extract of *Ligusticum striatum* is 0.2%-0.6%; Carbomer 9400.75%-1.5%; Triethanolamine 0.5%-3%; Glycerin 5%-15%; Sodium benzoate 0.3%-0.5%; The remainder is purified water.

[0009] Preferably, the mass ratio of triethanolamine to carbomer 940 is (0.5-2):1.

[0010] Preferably, the water extract of the unique flavor has a mass percentage of 0.4%, the carbomer 940 has a mass percentage of 1.5%, and the mass ratio of triethanolamine to carbomer 940 is 1:2.

[0011] Secondly, the present invention provides a method for preparing the aforementioned *Duyiwei* water extract gel formulation, comprising the following steps: Step 1: Prepare the water extract of *Duyiwei*. Step 2: At 15°C, evenly sprinkle the prescribed amount of Carbomer 940 on the surface of purified water at 4°C. After standing still, grind it in the same direction to obtain a Carbomer swelling solution. Step 3: Add the prescribed amount of triethanolamine to the Carbomer swelling solution obtained in Step 2, and adjust the pH to 6.5 - 7.0 to form a gel matrix. Step 4: Add the prescribed amount of glycerol, sodium benzoate, and the water extract of Lamiophlomis rotata prepared in Step 1 to the gel matrix obtained in Step 3, and stir and mix evenly. Step 5: Perform vacuum degassing on the gel obtained in Step 4 to obtain the finished gel product.

[0012] Preferably, the grinding time in Step 2 is 30 minutes; the stirring speed in Step 4 is 200 - 300 rpm, and the time is 15 - 20 minutes; the conditions for vacuum degassing in Step 5 are vacuum degassing for 30 minutes under the condition of -0.08 MPa.

[0013] Preferably, the standing time in Step 2 is 30 minutes, the amount of purified water used is 1 / 3 of the total amount of water in the prescription, and the remaining 4°C purified water is supplemented during the grinding process.

[0014] Preferably, the preparation method of the water extract of Lamiophlomis rotata in Step 1 includes: Take the Lamiophlomis rotata slices, decoct with water, combine the decoction liquids, concentrate, and dry to obtain the dry extract of the water extract of Lamiophlomis rotata; configure the dry extract of the water extract of Lamiophlomis rotata into a medicinal liquid with a mass fraction of 0.2% - 0.6% by adding purified water.

[0015] In the third aspect, the present invention provides the use of the gel preparation of the water extract of Lamiophlomis rotata as described above in the preparation of a drug for treating oral mucosal diseases.

[0016] Preferably, the oral mucosal disease is recurrent oral ulcer.

[0017] The present invention has the following beneficial effects: (1) Significantly improve the adhesion performance of oral mucosa and prolong the drug retention time By optimizing the ratio of the water extract of Lamiophlomis rotata, Carbomer 940, and triethanolamine, and adopting a low-temperature unidirectional grinding process, the present invention constructs an ordered gel network structure, effectively regulating the gel adhesion force and adhesion strength. Using an in vitro model of porcine buccal mucosa, under the condition of a simulated saliva flow rate of 0.5 mL / min, the retention time of the optimal formulation exceeds 4 hours (4.1 ± 0.1 h), which is significantly better than the retention time of generally less than 0.5 - 1 hour of the existing oral gel products on the market, providing a sufficient time window for the drug to exert its effect.

[0018] (2) Improve the drug utilization rate and reduce the dosing frequency Because the gel formulation of this invention has a retention time in the oral cavity of more than 4 hours, it effectively resists the rinsing effect of saliva and tongue movement, significantly improving the local drug utilization of the active ingredient. Compared with traditional solutions that require frequent rinsing or spraying, this invention can reduce the number of administrations and improve patient compliance.

[0019] (3) Enhance the treatment effect of oral ulcers In a rat model of oral ulcer treatment, the experimental group with the optimal formulation of this invention showed a reduction of approximately 70% in ulcer area after 48 hours (from 900±10 mm² to 300±10 mm²), significantly better than the positive control group (watermelon frost spray, ulcer area reduction of approximately 55%) and the blank gel group (ulcer area reduction of approximately 47%). The experimental group achieved a reduction of approximately 45% in ulcer area within 24 hours, demonstrating rapid onset of action.

[0020] (4) The gel has good stability and a uniform and transparent appearance. This invention obtains a uniform and transparent gel product by strictly controlling the concentration of *Ligusticum striatum* aqueous extract (0.2%-0.6%) and the ratio of triethanolamine to carbomer, and adjusting the pH to 6.5-7.0. When the concentration of *Ligusticum striatum* exceeds this range (e.g., 1.0%) or the ratio of triethanolamine is too high (e.g., 4:1, pH 8.0-8.5), flocculent precipitation occurs in the gel, proving the rationality and necessity of the formulation range of this invention.

[0021] (5) The preparation process is controllable and suitable for industrial production. This invention employs a 15°C low-temperature unidirectional grinding process. By controlling the grinding time (30 minutes), stirring speed (200-300 rpm), and vacuum degassing conditions (-0.08 MPa, 30 minutes), an ordered long-chain structure of the gel matrix is ​​formed. The process parameters are well-defined, with good repeatability, making it suitable for large-scale production. Compared with conventional room-temperature stirring methods, low-temperature unidirectional grinding increases the gel loss modulus by approximately 18 times, significantly improving the viscoelastic properties of the gel.

[0022] (6) Good biosafety Cytotoxicity experiments showed that the aqueous extract of *Ligusticum striatum* had no significant toxicity to HaCaT cells at low concentrations (0.2%-0.6%), and cell viability remained good; even at a high concentration of 6.4 mg / mL, cell survival rate was maintained at approximately 75%. The concentration range of *Ligusticum striatum* selected in this invention is within a safe window, ensuring the safety of the formulation for clinical use.

[0023] (7) Raw materials are readily available and costs are controllable. The raw materials used in this invention are all pharmaceutical-grade conventional excipients (carbomer 940, triethanolamine, glycerin, sodium benzoate) and traditional Chinese medicine Duyiwei decoction pieces, which are widely available and inexpensive. The preparation process does not require special equipment and has good economic benefits and industrialization prospects. Attached Figure Description

[0024] Figure 1 : A diagram illustrating the cytotoxicity experiment of the aqueous extract of *Duyiwei* on HaCaT cells; Figure 2 Figure 1: Changes in body weight of rats during treatment in the model group, positive drug group, experimental group, and blank gel group; Figure 3 Image showing the area of ​​oral ulcers in rats from 0 to 48 hours in the model group, positive drug group, experimental group, and blank gel group. Figure 4 Rheological tests of Comparative Example 1, Example 4 (2:1), Example 4 (1:2), and Example 1; Figure 5 Comparison of gel appearance in Comparative Examples 3, 4, and 1 (from left to right). Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the embodiments. The test materials used in the embodiments can all be purchased through conventional means.

[0026] Example 1 (Optimal Formulation) 1. Preparation of water extract of *Duyiwei* (1) Take the unique Chinese medicinal material, remove mud and debris by passing it through a perforated plate sieve, and manually pick out impurities, non-medicinal parts and moldy products to obtain the unique Chinese medicinal slices. (2) Add 10 times the amount (w / w) of purified water to the sliced ​​herbs, soak for 30 minutes, then heat to boiling and simmer for 1 hour. While hot, filter through a 200-mesh filter cloth and collect the filtrate. Add 10 times the amount of purified water to the dregs again, simmer for 1 hour in the same way, and filter while hot. (3) Combine the two filtrates and concentrate them under reduced pressure in a rotary evaporator at 60°C water bath to obtain an extract with a relative density of 1.10-1.15; (4) After the extract is pre-frozen at -80℃ for 4 hours, it is transferred to a freeze dryer and freeze-dried for 48-72 hours to obtain the dried extract. After sealing, it is stored at -20℃. (5) Before use, accurately weigh the dried extract and add an appropriate amount of purified water to prepare a 0.4% mass fraction of the Du Yi Wei extract solution as an intermediate for gel preparation.

[0027] 2. Preparation of Duyiwei Gel (1) At 15°C, evenly sprinkle 1.5% carbomer 940 onto the surface of 4°C distilled water, which accounts for 1 / 3 of the total water volume of the prescription. Let it stand for 30 minutes to fully wet it. Then grind it in the same direction with a glass rod for 30 minutes, adding the remaining 4°C distilled water in small amounts several times during this period to avoid clumping and heating. This operation ensures that the carbomer swells fully and forms a uniformly dispersed system with an ordered long-chain structure. (2) While stirring continuously, slowly add triethanolamine solution, control the mass ratio of triethanolamine to carbomer 940 to be 1:2, adjust the pH of the solution to 6.5-7.0, and form a gel matrix; (3) Add 5% glycerol to the gel matrix and continue grinding in the same direction for 10 minutes to disperse evenly. Add 0.2% sodium benzoate preservative and 0.4% Du Yi Wei extract solution in sequence, and control the mechanical stirring speed at 200-300 rpm for 15-20 minutes to form a uniform and stable gel; (4) Place the gel in a vacuum drying oven and degas it under vacuum at -0.08 MPa for 30 minutes to obtain a uniform and transparent gel product.

[0028] Example 2: Gel preparation with different concentrations of *Illicium verum* water extract According to the preparation method of Example 1, only the amount of Du Yi Wei water extract in step 2 (3) was changed. Du Yi Wei water extract with a mass fraction of 0.2% and 0.6% was weighed respectively. The other components and operations were the same as in Example 1 to obtain gels with different active ingredient contents.

[0029] Example 3: Preparation of gels with different carbomer concentrations According to the preparation method of Example 1, only the amount of carbomer 940 in step 2 (1) was changed. Carbomer 940 with mass fractions of 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.5%, 1.75% and 2% was weighed, and the total mass of purified water was adjusted accordingly. The amount of triethanolamine was adjusted according to the mass ratio of triethanolamine to carbomer 1:2. The other components and operations were the same as in Example 1, and gels with different matrix contents were obtained.

[0030] Example 4: Preparation of gels with different mass ratios of triethanolamine and carbomer 940 According to the preparation method of Example 1, only the mass ratio of triethanolamine to carbomer 940 in step 2 (2) was changed to 1:1 and 2:1 respectively, and the other components and operations were the same as in Example 1, to obtain gels with different matrix contents.

[0031] Comparative Example 1: Preparation by conventional room temperature stirring method (1) At room temperature of 25°C, evenly sprinkle 1.5% carbomer 940 on the surface of 4°C distilled water, which accounts for 1 / 3 of the total water volume of the prescription. After standing for 30 minutes, stir with a glass rod for 30 minutes until dissolved. (2) Add triethanolamine slowly, controlling the mass ratio of triethanolamine to carbomer 940 to be 1:2, and adjust the pH to 6.5-7.0; (3) Add 5% glycerin, 0.2% sodium benzoate (preservative) and 0.4% *Lysimachia christinae* extract (same as in Example 1) by mass fraction, and stir for 15-20 minutes; (4) Vacuum degassing for 30 minutes to obtain gel.

[0032] Result: As Figure 4 Rheological tests showed that Comparative Example 1, which used ordinary temperature stirring, produced a gel with a loss modulus of only about 1 Pa. In contrast, Comparative Example 1, which used low-temperature unidirectional grinding, obtained an optimal gel loss modulus that was 18 times higher. This reflects the effect of low-temperature unidirectional grinding on improving gel adhesion performance through molecular orientation and network structure formation.

[0033] Comparative Example 2: Preparation of Carbomer-Free Gel Following the preparation method of Example 1, except for the absence of carbomer, the other components and operations were the same as in Example 1, resulting in a gel. This gel could not form a uniform matrix, remaining in a thin liquid state, and therefore could not be used for mucosal adhesion.

[0034] Comparative Example 3: Effect of the shift in the mass fraction ratio of triethanolamine to carbomer 940 Following the preparation method of Example 1, triethanolamine and carbomer 940 were added at a mass ratio of 4:1, and the pH of the solution was controlled to 8.0-8.5. The remaining components and procedures were the same as in Example 1, and the results were as follows: Figure 5 As shown, an increase in the concentration of triethanolamine will cause a change in the pH of the solution, leading to a decrease in gel stability, the formation of flocculent precipitates, and a deviation from the optimal conditions.

[0035] Comparative Example 4: Effect of the Concentration Range of *Lysimachia christinae* Following the preparation method of Example 1, 1.0% of *Ligusticum striatum* extract was added, and the remaining components and operations were the same as in Example 1. The results are as follows: Figure 5 As shown, when the concentration of the unique flavoring exceeds the range, flocculent precipitate appears in the gel, deviating from the optimal conditions.

[0036] Experimental Example 1: Cytotoxicity Test of Water Extract of *Duyiwei* 1) Harvest HaCaT cells in the logarithmic growth phase at a density of 1×10⁻⁶. 5 100 μL of cells / mL was seeded into each well of a 96-well plate, and 100 μL of PBS was added to each well around the perimeter to reduce evaporation. The cells were cultured in an incubator for 24 h. 2) Remove the original culture medium and add culture medium containing different concentrations of *Duyiwei* (0, 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4 mg / ml). Set up 5 replicates for each concentration and incubate for 24 h. 3) Aspirate the original culture medium, rinse each well twice with an appropriate amount of PBS, aspirate any remaining PBS, add 100 μL of MTT working solution, incubate for 4 h, aspirate the supernatant, add 100 μL of DMSO to each well and shake to dissolve the generated formazan, and measure the absorbance at 570 nm using a microplate reader. Calculate the effect of different concentrations of *Impatiens balsamina* on cell viability using the following formula to determine the concentration range in which it has no significant effect on HaCaT cell viability.

[0037] Cell viability (%) =

[0038] Result: As Figure 1 As shown, *Ligusticum striatum* showed no cytotoxicity at low concentrations, but at a high concentration of 6.4 mg / ml, cell viability decreased to approximately 75%. Therefore, the concentration range of *Ligusticum striatum* was selected as 0.2-0.6% during gel preparation.

[0039] Experimental Example 2: Oral Retention Performance Test of Gel 1) Take porcine buccal mucosa tissue, ensuring the basement membrane is intact, control the section thickness to 2.1-2.5 mm, and store in PBS solution at pH 6.8 at 4°C. 2) The gel sample was evenly spread on the surface of the pig buccal mucosa with a coating area of ​​2cm x 2cm. Parafilm was used to cover the sample to prevent the moisture from evaporating too quickly. The flow rate of saliva was simulated by the flow cell method at 0.5mL / min. The sample was rinsed at a constant rate until the gel was completely detached from the mucosa. Each group was measured 6 times and the average value was taken to obtain the mucosal residence time.

[0040] Table 1. Gel formulation optimization and oral retention time (h)

[0041] Results: The optimal oral retention time was achieved when the carbomer concentration was controlled at 1.5%. Variations in the concentration of *Duyiwei* (a type of herb) between 0.2% and 0.6% did not significantly affect oral retention time; however, excessively high concentrations (1%) resulted in unstable gel formation and flocculent precipitation. Figure 5 As shown. In summary, the optimization of gel formulation mainly focuses on controlling the concentration of carbomer 940 at low concentrations of unicornuate, and adjusting the ratio of triethanolamine to carbomer, ultimately forming a stable gel formulation with strong adhesion.

[0042] Experimental Example 3: Therapeutic Effect of Treating Oral Ulcers in Rats

[0043] 1. Animal grouping and model establishment 1) Thirty qualified SPF-grade SD rats weighing 210-230g were selected and divided into 5 groups according to weight and sex, with 6 rats in each group. The groups were: model group, positive drug group (commercially available watermelon frost spray), experimental group (gel prepared in Example 1), and blank gel group (excluding Du Yiwei, otherwise the same as in Example 1). 2) For each group of rats, cauterize the mouth and inner oral mucosa on one side or the buccal mucosa / lower lip near the corner of the mouth with 0.3cm NaOH crystals; another 6 normal control rats were selected and no treatment was given.

[0044] 2. Dosing regimen and observation indicators The positive control group, experimental group, and blank gel group were administered the drug three times a day, with a 4-hour interval between administrations. The size of the ulcer surface was photographed and analyzed before administration on the second day.

[0045] 3. Results (1) Changes in ulcer area: such as Figure 3 As shown, the control group, positive control group, and experimental group all showed significant reduction in ulcer area after 48 hours. Comparing the quantitative data in Table 2, the optimal gel in the experimental group reduced the ulcer area by approximately 45% within 24 hours, and by approximately 70% after 48 hours of treatment. In contrast, commercially available watermelon frost spray reduced the ulcer area by approximately 55%. Therefore, the Duyiwei gel has a better ulcer treatment effect.

[0046] (2) Weight changes: such as Figure 2 As shown, compared with the positive drug group, the experimental group showed less change in body weight.

[0047] Table 2. Effects of gel on oral ulcer area in rats (mm) 2 (n=6)

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. However, the above description is merely a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other embodiments derived by those skilled in the art without departing from the technical solution of the present invention should be covered within the patent scope of the present invention.

Claims

1. A unique water extract gel formulation for improving the adhesion properties of oral mucosa, characterized in that, It comprises the following components by mass percentage: Lamiophlomis rotata water extract 0.2% - 0.6%; Carbomer 940 0.75% - 1.5%; Triethanolamine 0.5% - 3%; Glycerol 5% - 15%; Sodium benzoate 0.3% - 0.5%; The balance is purified water.

2. The unique herb water extract gel formulation according to claim 1, characterized in that, The mass ratio of the triethanolamine to Carbomer 940 is (0.5 - 2):

1.

3. The unique flavor water extract gel formulation according to claim 1, characterized in that, The mass percentage of the Lamiophlomis rotata water extract is 0.4%, the mass percentage of Carbomer 940 is 1.5%, and the mass ratio of triethanolamine to Carbomer 940 is 1:

2.

4. A method for preparing a gel formulation of *Duyiwei* water extract as described in any one of claims 1-3, characterized in that, It comprises the following steps: Step 1, prepare the Lamiophlomis rotata water extract; Step 2, at 15°C, evenly sprinkle the prescribed amount of Carbomer 940 on the surface of purified water at 4°C, let it stand, and then grind it in the same direction to obtain a Carbomer swelling solution; Step 3, add the prescribed amount of triethanolamine to the Carbomer swelling solution obtained in Step 2, adjust the pH to 6.5 - 7.0 to form a gel matrix; Step 4, add the prescribed amount of glycerol, sodium benzoate and the Lamiophlomis rotata water extract prepared in Step 1 to the gel matrix obtained in Step 3, and stir and mix evenly; Step 5, perform vacuum degassing treatment on the gel obtained in Step 4 to obtain the finished gel product.

5. The preparation method according to claim 4, characterized in that, The grinding time in Step 2 is 30 minutes; the stirring speed in Step 4 is 200 - 300 rpm and the time is 15 - 20 minutes; the vacuum degassing condition in Step 5 is vacuum degassing for 30 minutes under the condition of -0.08 MPa.

6. The preparation method according to claim 4, characterized in that, The standing time in Step 2 is 30 minutes, the amount of purified water used is 1 / 3 of the total amount of water in the prescription, and the remaining 4°C purified water is added during the grinding process.

7. The preparation method according to claim 4, characterized in that, The preparation method of the Lamiophlomis rotata water extract described in Step 1 includes: Take Lamiophlomis rotata cut crude drugs, decoct with water, combine the decoction liquids, concentrate and dry to obtain the dry extract of Lamiophlomis rotata water extract; configure the dry extract of Lamiophlomis rotata water extract into a medicinal liquid with a mass fraction of 0.2% - 0.6% by adding purified water.

8. Use of a Lamiophlomis rotata water extract gel preparation as described in any one of claims 1 - 3 in the preparation of a drug for treating oral mucosal diseases.

9. The use according to claim 8, characterized in that, The oral mucosal disease is recurrent oral ulcer.

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