Soluble adhesive microneedle patch for treating severe oral ulcer as well as preparation method and application of soluble adhesive microneedle patch

Abstract

The invention provides a soluble adhesive microneedle patch for treating severe oral ulceration and a preparation method and application thereof, and belongs to the technical field of biomedical materials.The soluble adhesive microneedle patch comprises an adhesive substrate and soluble microneedles distributed on one side of the adhesive substrate in an array mode; the adhesion substrate is prepared from an adhesion material and a natural polymer, has wet responsiveness, can generate softening and adhesion effects when meeting wet tissues, and is more fit with an irregular ulcer surface; the soluble microneedle is prepared from a drug-loaded biopolymeric material; after the soluble adhesive microneedle patch acts on the oral cavity of a patient, the microneedle firstly dissolves and releases the medicine to play the anti-inflammatory and ulcer surface healing promoting roles, and the adhesive substrate continuously adheres to the wound surface to play the wound surface protecting, antibacterial and antioxidant roles; the problem that an existing oral ulcer treatment medicine is easily limited by the flushing effect of saliva in the oral cavity and the epithelial barrier, and the curative effect is affected is solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biomedical materials, and particularly relates to a soluble adhesive microneedle patch for treating severe oral ulcers and a preparation method and application thereof. BACKGROUND

[0002] Recurrent Aphthous Ulcer (RAU) is one of the most common oral mucosa diseases in clinical practice, and its high prevalence and significant population tendency have become a health problem that has attracted much attention in the field of stomatology. According to epidemiological survey data, the prevalence rate of RAU in the general population is as high as 20%, and the 10-40 year-old population is a high-risk group. The quality of life and work efficiency of this group are often significantly affected by the disease.

[0003] In the disease classification of RAU, severe oral ulcer is a severe type of RAU, and its clinical symptoms are more prominent and more harmful to patients. Such ulcers usually have a larger area (diameter > 1 cm) and a greater depth, and the ulcer shape is mostly crater-like depression, and in some cases, irregular shapes such as erosion, bleeding, and edge elevation may also occur; the pain symptoms of patients are extremely severe, which often seriously interferes with normal eating, speaking, and sleeping, greatly reducing the quality of life of patients. At the same time, the healing process of severe oral ulcers is very slow, and the duration of the ulcer usually lasts more than 1 week, and the disease has a high recurrence rate. Some patients also have infection symptoms or systemic inflammatory responses such as fever, fatigue, submandibular or cervical lymph node enlargement, further increasing the physical burden of patients.

[0004] For the clinical treatment of RAU, the current main treatment is symptomatic treatment, aiming to relieve symptoms, promote ulcer healing, and reduce the recurrence rate of the disease. Among them, drug treatment is the most widely used treatment in current clinical practice. However, due to the special nature of the oral environment, conventional drug formulations (such as solutions, powders, ointments, polymer patches, and hydrogels) face many challenges in application: the continuous secretion of saliva in the oral cavity can cause flushing of the drug formulation, leading to rapid dilution of the drug; the barrier function of the oral mucosa epithelial layer can hinder the effective penetration of the drug; at the same time, the frequent movement of the tongue also easily causes the drug formulation to separate from the ulcer lesion area. These factors together make it difficult to achieve an effective therapeutic level of drug concentration in the lesion area, which affects the treatment effect and cannot achieve the best clinical efficacy.

[0005] In recent years, with the continuous innovation of drug delivery technology, microneedle (MN) as a new transdermal drug delivery material in oral mucosa drug delivery system has shown a good application prospect in the field of RAU treatment due to its unique advantages of micro-invasion, high efficiency and painlessness. Microneedle can create a micro-channel on the surface of oral mucosa, break the barrier limitation of mucosal epithelial layer, significantly improve the permeability of drugs, and make drugs more efficiently transported to the systemic circulation, thereby improving the bioavailability of drugs.

[0006] In the research of drug-loaded microneedles for RAU treatment, soluble microneedles are currently the focus of research. This type of microneedle has good biocompatibility. After being implanted into the oral mucosa tissue, the needle body of the microneedle will gradually dissolve in the body, releasing the loaded drugs, achieving sustained drug delivery and further ensuring the treatment effect. SUMMARY

[0007] Therefore, the purpose of the present application is to provide a soluble adhesive microneedle patch for treating severe oral ulcers and a preparation method and application thereof.

[0008] The needle body of the soluble adhesive microneedle patch of the present application can first act on the wound surface, dissolve rapidly through the skin and release drugs, thereby playing a role in anti-inflammation and promoting the healing of the ulcer surface.

[0009] Further, the unique adhesive base design of the present application can make the microneedle patch adhere to the ulcer wound surface for a long time, forming a physical barrier to protect the wound surface from bacterial infection. The adhesive base has a wet response, and can become soft and sticky when it comes into contact with wet tissue, thereby better adhering to the irregular ulcer surface. This long-lasting and moisture-resistant adhesive property of the microneedle patch acting on the severe oral ulcer wound can effectively prevent wound infection caused by food residues and microorganisms, and at the same time play a role in anti-bacterial infection and inhibition of excessive active oxygen, thereby promoting the regeneration and remodeling of the oral mucosa.

[0010] The soluble adhesive microneedle patch of the present application can first dissolve and release drugs after acting on the oral cavity of the patient, thereby playing a role in anti-inflammation. The adhesive base continuously adheres to the wound surface, thereby playing a role in protecting the wound surface and antibacterial and antioxidant effects, so as to solve the problem that the existing oral ulcer treatment drugs are easily affected by the flushing action of saliva in the oral cavity and the limitation of the epithelial layer barrier, thereby affecting the therapeutic effect.

[0011] The present application provides a soluble adhesive microneedle patch for treating severe oral ulcers, which comprises an adhesive base and soluble microneedles arrayed on one side of the adhesive base. The adhesive base is prepared from an adhesive material and a natural polymer; The adhesive material is alpha-lipoic acid, and the natural polymer is methacrylanated gelatin; The adhesive base is circular, elliptical or rectangular. The soluble microneedle is prepared from a drug-loaded biopolymer material, and the needle body of the soluble microneedle is a cone.

[0012] Preferably, the adhesion material is used in the form of an adhesion solution, the adhesion solution further comprising Tris, the concentration of alpha-lipoic acid in the adhesion solution being 12-14% w / v, the concentration of methacrylated gelatin being 3-4% w / v, and the concentration of Tris being 4-6% w / v.

[0013] Preferably, the drug-loaded biopolymer material is hyaluronic acid and polyvinylpyrrolidone; the hyaluronic acid and polyvinylpyrrolidone are dissolved in a phosphate buffer to obtain an injection molding material, the concentration of hyaluronic acid in the injection molding material being 8-12% w / v, and the concentration of polyvinylpyrrolidone being 25-35% w / v.

[0014] Preferably, the loaded drug is quercetin, and the mass ratio of quercetin to the biopolymer material is 3: (300-500).

[0015] Preferably, the needle body of the soluble microneedle has a bottom diameter of 200-500 μm, a height of 300-1000 μm, and a tip diameter of 15-30 μm.

[0016] The application provides a preparation method of the soluble adhesion microneedle patch, comprising the following steps: 1) preparing a negative mold of the soluble adhesion microneedle patch; 2) pouring the negative mold with a drug-loaded biopolymer material, and drying to obtain a mold loaded with a microneedle array; 3) dissolving an adhesion material and a natural polymer, and then spreading the adhesion material and the natural polymer on the top end of the mold to form an adhesion base; 4) drying and solidifying the mold loaded with the microneedle array and the adhesion base, and demolding to obtain the soluble adhesion microneedle patch.

[0017] Preferably, the temperature of the drying in step 2) is 15-25°C, and the time of the drying is 5-7 h.

[0018] Preferably, step 2) further comprises a step of centrifuging the poured mold before drying.

[0019] Preferably, the temperature of the drying and solidifying in step 4) is 15-25°C, and the time of the drying and solidifying is 40-60 h.

[0020] The application provides the soluble adhesion microneedle patch and application of the soluble adhesion microneedle patch prepared by the preparation method in the preparation of a drug for treating severe oral ulcers.

[0021] Compared with the prior art, the present application has the following beneficial effects: The negative mold shape of the traditional micro-needle is single, and the prepared micro-needle patch backing layer is mostly rectangular structure, while the severe oral ulcer has a circular / elliptical or irregular crater-like structure with a diameter greater than 1 cm, so the needle body is easy to pierce into the normal tissue around the ulcer, causing damage to the normal area and wasting the loaded drugs and preparation materials, etc. The adhesive base of the soluble adhesive micro-needle patch in the present application is circular or elliptical, the circular diameter is 1-2 cm, the short axis of the elliptical is 1-2 cm, the needle body of the soluble micro-needle is conical, the bottom diameter of the needle body is 200-500 μm, the height is 300-1000 μm, and the tip diameter is 15-30 μm. The soluble adhesive micro-needle patch provided in the present application has a shape that highly fits the ulcer area of the severe oral ulcer patient, and the needle body will not pierce into the surrounding normal tissue.

[0022] The soluble adhesive micro-needle patch of the present application, after acting on the oral cavity of the patient, the micro-needle first dissolves to release the drug, and plays its anti-inflammatory effect, and the adhesive base continuously adheres to the wound surface, and can produce softening and adhesion effect when encountering wet tissue, and is more fitted to the irregular ulcer surface. This long-lasting and moisture-resistant adhesive property on the severe oral ulcer wound can effectively prevent wound infection caused by food residues and microorganisms, and at the same time plays a role in resisting bacterial infection and inhibiting excessive active oxygen, and promotes the regeneration and remodeling of the oral mucosa. To solve the problem that the existing severe oral ulcer drug treatment is easily affected by the flushing effect of saliva in the oral cavity and the limitation of the epithelial layer barrier.

[0023] The soluble adhesive micro-needle patch of the present application has good mechanical properties, and the mechanical strength is mainly provided by the base material, and the loading of the drug basically does not affect the mechanical strength. The in-vitro penetration experiment shows that the soluble adhesive micro-needle patch provided in the present application can penetrate the oral mucosa epithelium of rats, and has the application potential of delivering drugs to the mucosal basal layer cells and the surrounding connective tissue.

[0024] The drug loaded by the soluble adhesive micro-needle patch of the present application is preferably Chinese herbal medicine extract, and more preferably quercetin. The existing severe oral ulcer treatment drugs are mostly limited to loading of chemically synthesized drugs, which have rapid effect, but long-term application can easily induce drug resistance, bacterial flora imbalance and local adverse reactions, and are difficult to meet the long-term management needs of the clinic. Therefore, the soluble adhesive micro-needle patch of the present application loads the Chinese herbal medicine component quercetin which is efficient, safe and has small side effects, and plays its anti-inflammatory effect.

[0025] The use mode of the soluble adhesive microneedle patch is convenient, when the soluble adhesive microneedle patch is attached to an ulcer wound surface, the backing layer of the patch is attached to the ulcer surface, and the needle body layer delivers the drug to the mucosal basal layer cells and the surrounding connective tissue, rapidly releases quercetin, and plays an anti-inflammatory role, so that the patch has a good clinical application prospect.

[0026] The application further provides a preparation method of the soluble adhesive microneedle patch for treating severe oral ulcers, the method is simple in operation, mild in conditions, and beneficial to protecting the activity of the loaded drug, and meanwhile, the drug loading amount and the type of the loaded drug can be adjusted according to actual requirements. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The overall appearance of the soluble adhesive microneedle patch prepared for Example 1; Figure 2 The scanning electron microscope image of the soluble adhesive microneedle patch prepared for Example 1; Figure 3 The schematic diagram of the negative mold structure of the soluble adhesive microneedle patch; Figure 4 The schematic diagram of the microneedle structure of the soluble adhesive microneedle patch; Figure 5 The mechanical property test results of the soluble adhesive microneedle patch and the blank microneedle patch prepared for Example 1; Figure 6 The in-vitro transdermal experiment of the soluble adhesive microneedle patch prepared for Example 1, wherein (a) is a needle hole trace diagram of the microneedle penetrating into the oral mucosa of a rat, and (b) is a tissue section diagram of the oral mucosa of the rat after penetration; Figure 7 The in-vitro dissolution experiment of the soluble adhesive microneedle patch prepared for Example 1, the dissolution of the microneedle after penetrating into the oral mucosa of a rat for different time; Figure 8 The shear experiment of the soluble adhesive microneedle patch prepared for Example 1, the adhesive strength of the microneedle adhering to the oral mucosa of a rat in vitro; Figure 9 The cytotoxicity experiment of the soluble adhesive microneedle patch prepared for Example 1, the effect of the microneedle extract with different concentrations on the activity of human oral keratinocytes (HOKs); Figure 10 The morphological observation results of the blank control group, the watermelon cream group, the blank microneedle group, the adhesive microneedle group and the quercetin adhesive microneedle group after treating severe oral ulcers for 0, 2, 4 and 6 days. DETAILED DESCRIPTION

[0028] The application provides a soluble adhesive microneedle patch for treating severe oral ulcers, comprising an adhesive substrate and soluble microneedles arranged on one side of the adhesive substrate; the adhesive substrate is prepared from an adhesive material and a natural polymer; the soluble microneedles are prepared from a biopolymer loaded with drugs; and the backing layer of the soluble adhesive microneedle patch is in a circular or elliptical structure suitable for severe oral ulcers.

[0029] The adhesive substrate of the soluble adhesive microneedle patch in the application is in a circular, elliptical or rectangular shape, the circular shape has a diameter of 1-2 cm, and the elliptical shape has a short axis of 1-2 cm; the needle body of the soluble microneedle is conical, has a bottom diameter of 200-500 μm, a height of 300-1000 μm, and a tip diameter of 15-30 μm, and can reach the submucosal layer and muscle layer to play a role. The soluble adhesive microneedle patch provided by the application has a shape that is highly compatible with the ulcer area of a patient with severe oral ulcers, and the needle body will not penetrate into the surrounding normal tissue.

[0030] In the application, the soluble adhesive microneedle patch comprises an adhesive substrate prepared from an adhesive material and a natural polymer; the adhesive material is preferably alpha-lipoic acid, and the natural polymer comprises methacrylated gelatin and tris(hydroxymethyl)aminomethane. In the application, the adhesive material is used in the form of an adhesive solution, and in the specific implementation process of the application, the adhesive material and the natural polymer are dissolved in ultrapure water to obtain an adhesive solution, the concentration of alpha-lipoic acid in the adhesive solution is 12-14% w / v, preferably 12.5-13.5% w / v, and more preferably 13.33% w / v; the concentration of methacrylated gelatin in the adhesive solution is preferably 3-4% w / v, more preferably 3.2-3.5% w / v, and most preferably 3.33% w / v; and the concentration of tris(hydroxymethyl)aminomethane is preferably 4-6% w / v, further preferably 4.5-5.5% w / v, and more preferably 5.33% w / v.

[0031] The adhesive substrate has a wet responsiveness, and can become soft and adhesive when encountering wet tissue, thereby being more compatible with irregular ulcer surfaces. This durable and wet-adhesive property of the soluble adhesive microneedle patch for treating severe oral ulcer surfaces can effectively prevent wound infection caused by food residues and microorganisms, and can also play a role in resisting bacterial infection and inhibiting excessive reactive oxygen species, thereby promoting the regeneration and remodeling of oral mucosa.

[0032] In the present application, the soluble adhesive microneedle patch comprises soluble microneedles arranged on one side of the adhesive substrate; in the present application, the soluble microneedles are prepared from drug-loaded biopolymer materials; the drug-loaded biopolymer materials are preferably hyaluronic acid and polyvinylpyrrolidone; preferably, the hyaluronic acid and polyvinylpyrrolidone are dissolved in a phosphate buffer to obtain an injection molding material, the concentration of hyaluronic acid in the injection molding material is preferably 8-12% w / v, further preferably 9-11% w / v, and more preferably 10% w / v, and the concentration of polyvinylpyrrolidone in the injection molding material is preferably 25-35% w / v, further preferably 28-32% w / v, and more preferably 30% w / v. In the present application, the injection molding material is injected into a mold to obtain soluble microneedles, the needle body of the soluble microneedles is preferably conical, the bottom diameter of the needle body is preferably 200-500 μm, and more preferably 300 μm; the height is preferably 300-1000 μm, and more preferably 500-700 μm; and the tip diameter is preferably 15-30 μm, and more preferably 20 μm.

[0033] In the present application, the loaded drug is preferably quercetin, and the mass ratio of quercetin to biopolymer material is 3:300-500, preferably 3: (350-450), and more preferably 3:400. Network pharmacology research shows that the core active ingredient with the highest correlation with RAU treatment is quercetin. Quercetin is a potent natural flavonoid compound, widely exists in many Chinese herbal medicines such as radix astragali, cortex phellodendri, and agarwood, and compound preparations such as licorice root heart soup, has multiple pharmacological activities such as antioxidant, anti-inflammatory, antibacterial, and antiviral. The present application selects to load quercetin, which can better treat RAU, and combines with the administration form of the soluble adhesive microneedle patch to overcome the defects of the administration mode for treating RAU in clinical practice, and has the functions of rapid drug release and long-acting wound protection, which has important clinical significance for the treatment of severe oral ulcers.

[0034] In the specific implementation process of the present application, 10 ml of injection molding material contains 0.03 g of quercetin, 1 g of hyaluronic acid, and 3 g of polyvinylpyrrolidone.

[0035] The present application also provides a preparation method of the soluble adhesive microneedle patch, comprising the following steps: 1) preparing a negative mold of the soluble adhesive microneedle patch; 2) pouring the negative mold with drug-loaded biopolymer materials, and drying to obtain a mold loaded with microneedle body array; 3) dissolving the adhesive material and the natural polymer and spreading on the top end of the mold to form an adhesive substrate; 4) drying and solidifying the mold loaded with the microneedle body array and the adhesive substrate, and demolding to obtain the soluble adhesive microneedle patch.

[0036] In the present application, a negative mold of the soluble adhesive microneedle patch is first prepared according to the structure and size of the microneedles of the soluble adhesive microneedle patch.

[0037] In the present application, the drug-loaded biopolymer material is cast into the negative mold, and the mold loaded with the array of microneedle bodies is dried. In the present application, the biopolymer material is dissolved in a phosphate buffer to obtain a casting material, and then the casting material is mixed with quercetin before being cast into the negative mold. Preferably, after the drug-loaded biopolymer material is cast into the negative mold, a step of centrifuging the cast mold is further included before drying; the centrifugation serves to fully fill the mold with the casting material while removing excess casting material. In the present application, the temperature of the drying is preferably 15-25℃, and the time of the drying is preferably 5-7h, more preferably 5.5-6.5h, and most preferably 6h.

[0038] In the present application, the adhesive material and the natural polymer are dissolved and then spread on the top end of the mold to form an adhesive base; in the present application, the adhesive material and the natural polymer are dissolved in water to obtain an adhesive solution, and the adhesive solution is heated at 60-70℃ for 1-3h, and then cooled and spread on the top end of the mold to form an adhesive base.

[0039] In the present application, the mold loaded with the array of microneedle bodies and the adhesive base is dried, solidified, and demolded to obtain the soluble adhesive microneedle patch; the temperature of the drying and solidification is preferably 15-25℃, and the time of the drying and solidification is preferably 40-60h, more preferably 45-50h, and most preferably 48h.

[0040] The present application also provides the soluble adhesive microneedle patch and the use of the soluble adhesive microneedle patch prepared by the preparation method in the preparation of a drug for treating severe oral ulcers.

[0041] The technical solutions provided by the present application will be described in detail below with reference to the examples, but they should not be understood as limiting the scope of protection of the present application.

[0042] Example 1

[0043] Preparation of a soluble adhesive microneedle patch

[0044] The present example provides a soluble microneedle patch for oral ulcer treatment, using a quercetin drug model to prepare a soluble microneedle patch for oral ulcer treatment, and the preparation process steps are as follows:

[0045] (1) Dissolve hyaluronic acid HA (molecular weight 50kDa), PVPK30, and quercetin in a phosphate buffer, mix thoroughly, and centrifuge at high speed to remove air bubbles to obtain a microneedle base material solution; in the microneedle base material solution, the concentration of HA is 10% w / v, the concentration of PVPK30 is 30% w / v, and the concentration of quercetin is 0.3% w / v.

[0046] (2) The alpha-lipoic acid LA and tris were added to ultrapure water at 65°C, mixed thoroughly, and then methyl methacrylate anhydride gelatin GELMA was added, stirred for 2 h, and left to stand to remove bubbles to obtain a base matrix material solution; in the base matrix material solution, the concentration of LA was 13.33% w / v, the concentration of tris was 5.33% w / v, and the concentration of GELMA was 3.33% w / v.

[0047] (3) A polydimethylsiloxane (PDMS) mold was used, which included arrayed conical microneedle cavities and base cavities in communication with the opening ends of the microneedle cavities, the base cavities had a bottom surface size of 10 mm x 10 mm, the arrayed distribution in the mold was a 9 x 9 matrix, there were a total of 81 microneedle cavities, the microneedle height was 600 μm, the conical bottom surface diameter was 300 μm, and the distance between the needle tips was 600 μm; The microneedle matrix material solution was added to the mold, centrifuged at 4000 rpm for 10 min to uniformly fill the microneedle cavities with the solution, the solution that did not enter the microneedle cavities was recovered, the mold was placed in room temperature drying for 6 h to remove part of the water in the solution to form needle tips.

[0048] Then the base matrix material solution was added to the mold to fill the mold with the solution, the mold was placed in room temperature drying for 48 h to remove part of the water in the solution to solidify, and then it was carefully peeled off from the mold to obtain a soluble microneedle patch.

[0049] This example also prepared a blank microneedle patch without adding quercetin according to the above steps.

[0050] Test Example 1

[0051] The morphology and structure of the soluble adhesive microneedle patch prepared in Example 1 were detected, and the specific process was as follows: The morphology and structure of the soluble adhesive microneedle patch prepared in this example were observed and the size was measured by using a stereomicroscope and a scanning electron microscope. The soluble adhesive microneedle patch was placed on the sample stage, and the overall morphology was observed by using a stereomicroscope, and the results are shown in Figure 1 The soluble adhesive microneedle patch was pasted on the sample stage, gold spraying was performed for 60 s, and then nitrogen blowing was performed, and the microstructure was observed by using a scanning electron microscope and the microneedle size was measured, and the results are shown in Figure 2 .

[0052] From Figure 1 and Figure 2 it can be seen that the soluble adhesive microneedle patch prepared in this example is a solid conical microneedle, the structure of the microneedle is uniform and complete, the needle shape is sharp, the height of the microneedle is about 600 μm, the bottom side length is 300 μm, and the distance between adjacent needle tips is about 600 μm.

[0053] Experimental Example 2

[0054] This experiment measured the mechanical properties of the soluble adhesive microneedle patch and the blank microneedle patch prepared in Example 1. The specific process is as follows: The mechanical strength of the soluble adhesive microneedle patch and the blank microneedle patch prepared in Example 1 were determined using a universal tensile testing machine. The soluble adhesive microneedle patch and the blank microneedle patch prepared in Example 1 were placed horizontally on a stainless steel platform, with the microneedle tips pointing vertically upwards. A 100N pressure sensor was moved vertically downwards at a constant speed (10 μm / s) to continuously apply pressure to the microneedles. The compression displacement and pressure experienced by the microneedles during the compression process were continuously recorded, and variation curves were plotted, such as... Figure 5 As shown, the curves of both the soluble adhesive microneedle patch and the blank microneedle patch are rising and continuous, indicating that they both underwent continuous deformation without breakage. When the compression displacement reaches 0.3 mm, the drug-loaded soluble adhesive microneedle patch prepared in Example 1 withstands stronger pressure and has greater mechanical strength than the blank microneedle patch, exceeding the mechanical strength required to pierce the skin (≈0.1 N), indicating that the addition of quercetin enhances the mechanical strength of the microneedle patch.

[0055] Experimental Example 3

[0056] This experiment uses an in vitro transdermal test to study the ability of the soluble adhesive microneedle patch prepared in Example 1 to penetrate the oral mucosa. The specific process is as follows: The soluble adhesive microneedle patch prepared in Example 1 was vertically inserted into the oral mucosa of rats using a force of 50 N, held for 5 minutes, and then removed. The patch was then stained with trypan blue. Figure 6 As shown in (a). Mucosal tissue was embedded in OCT and rapidly frozen. Sections were prepared to a thickness of 10 μm using a rotary sectioning machine for hematoxylin extraction. After eosin staining, observe the tissue cross-section under an optical microscope, such as... Figure 6 As shown in (b). From Figure 6 As shown in Figure (b), the penetration depth of the soluble adhesive microneedle patch in the oral mucosa is approximately 190 μm. This indicates that the soluble adhesive microneedle patch prepared in Example 1 has the ability to penetrate the oral mucosa, breaking through the physiological barrier of the mucosal epithelium and delivering the drug directly to the mucosal tissue.

[0057] Test Example 4

[0058] This experiment investigated the solubility of the soluble adhesive microneedle patch prepared in Example 1. The specific process is as follows: Soluble adhesive microneedle patches were pressed into the lower lip mucosa of rats for 5 seconds, 15 seconds, 30 seconds, 1 minute, and 1.5 minutes, respectively. The patches were removed at different time points, and their dissolution was observed under a microscope.Figure 7 It can be seen that the patch is almost completely dissolved after 1.5 min, with good dissolution performance.

[0059] Test Example 5

[0060] This test example studies the adhesion of the soluble adhesive microneedle patch prepared in Example 1, and the specific process is as follows: At a temperature of 37°C, the patch is attached to the surface of the rat's isolated oral mucosa tissue, and before being attached to the glass surface, the patch is placed in a 90% relative humidity environment for 10 min, and then attached to the glass surface. After adhesion, the two ends of the substrate are clamped. Then, the substrate is pulled upward at a constant speed of 50 mm / min, and the F is recorded. The bonding strength is calculated as F / WL, where F is the maximum load force during the lap shear tension, and W and L are the width and length of the rectangular patch, respectively, which are 6 mm x 8 mm. Figure 8 The maximum shear strength is 3.2 KPa, and previous studies have shown that the bonding strength of commercially available patches is 0.4 KPa, indicating that the soluble adhesive microneedle patch prepared in Example 1 has good bonding performance.

[0061] Test Example 6

[0062] This test example studies the cytotoxicity of the soluble adhesive microneedle patch prepared in Example 1, and the specific process is as follows: The CCK-8 method is used to measure cell activity, and the microneedles are dissolved in sterile PBS solution to prepare a microneedle stock solution, which is sterilized and filtered using a 0.22 μm filter for subsequent experiments. Human HOK cells are selected for this experiment, and logarithmic growth phase HOK cells are digested with 0.25% trypsin-EDTA to prepare a single cell suspension. The cells are inoculated into a 96-well plate at 100 μL per well, with a density of 1.3 x 10 4 cells per well, and placed in a 37°C, 5% CO2 incubator for 24 h. After the cells adhere, the culture medium is removed, and 100 μL of fresh culture medium containing the microneedle solution is added. After 24 h, 48 h, and 72 h of culture, 10 μL of CCK-8 solution is added to each well, and the incubation is continued for 2 h. The absorbance at 450 nm of each well is measured using a microplate reader. The final values of the experimental group, control group, and blank group are obtained from the average of the absorbance values of 3 wells. The results are shown in Figure 9 The average value of HOK cell activity is around 100% or above, and no significant biological toxicity is found.

[0063] Test Example 7

[0064] This test example studies the treatment effect of the soluble adhesive microneedle patch prepared in Example 1 on severe oral ulcers, and the specific process is as follows: Select 15 healthy male Sprague Dawley rats (240-260g, 8 weeks) for experiment, the selected rats have no inflammation and other pathological manifestations in the oral mucosa. After anesthesia with 1% sodium pentobarbital (40mg / kg), a round filter paper (5x5mm) soaked in 90% acetic acid is placed on the oral mucosa for 1 minute to induce severe oral ulcer for 48 hours. After the ulcer is formed, the rats are randomly divided into 5 groups, 3 rats in each group, namely the blank control group, the watermelon cream group, the blank microneedle group, the blank adhesive microneedle group and the quercetin-loaded adhesive microneedle group. After the ulcer is formed, general observation is performed on the 0th, 2nd, 4th and 6th days, and the oral mucosa ulcer morphology of each group of rats is as shown in Figure 10 It can be seen that the wound area of the soluble adhesive microneedle patch rapidly decreases, achieving faster ulcer repair.

[0065] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A dissolvable adhesive microneedle patch for treating severe oral ulcers, characterized by, The soluble adhesion microneedle patch comprises an adhesion substrate and soluble microneedles arranged on one side of the adhesion substrate. The adhesion substrate is prepared from an adhesion material and a natural polymer. The adhesion material is alpha-lipoic acid, and the natural polymer is methacrylated gelatin. The soluble microneedles are prepared from a drug-loaded biopolymer material, and the needle body of the soluble microneedles is a cone.

2. The dissolvable adhesive microneedle patch of claim 1, wherein, The adhesion material is used in the form of an adhesion solution, and the adhesion solution further comprises tris-hydroxymethyl aminomethane, the concentration of alpha-lipoic acid in the adhesion solution is 12-14% w / v, the concentration of methacrylated gelatin is 3-4% w / v, and the concentration of tris-hydroxymethyl aminomethane is 4-6% w / v.

3. The dissolvable adhesive microneedle patch of claim 1 or 2, wherein, The drug-loaded biopolymer material is hyaluronic acid and polyvinylpyrrolidone; the hyaluronic acid and polyvinylpyrrolidone are dissolved in a phosphate buffer to obtain an injection molding material, and the concentration of hyaluronic acid in the injection molding material is 8-12% w / v, and the concentration of polyvinylpyrrolidone is 25-35% w / v.

4. The dissolvable adhesive microneedle patch of claim 3, wherein, The loaded drug is quercetin, and the mass ratio of quercetin to biopolymer material is 3: (300-500).

5. The dissolvable adhesive microneedle patch of claim 1, wherein, The bottom diameter of the needle body of the soluble microneedle is 200-500 μm, the height is 300-1000 μm, and the tip diameter is 15-30 μm.

6. The method of making the dissolvable adhesive microneedle patch of any one of claims 1-5, wherein, The method comprises the following steps: 1) preparing a negative mold of the soluble adhesion microneedle patch; 2) pouring the negative mold with a drug-loaded biopolymer material, and drying to obtain a mold loaded with a microneedle array; 3) dissolving the adhesion material and the natural polymer and spreading them on the top end of the mold to form an adhesion substrate; 4) drying and solidifying the mold loaded with the microneedle array and the adhesion substrate, and demolding to obtain the soluble adhesion microneedle patch.

7. The preparation method according to claim 6, characterized in that, The drying temperature in step 2) is 15-25°C, and the drying time is 5-7 h.

8. The preparation method according to claim 7, characterized in that, Step 2) further comprises a step of centrifuging the poured mold after pouring the drug-loaded biopolymer material and before drying.

9. The preparation method according to claim 6, characterized in that, The drying and solidifying temperature in step 4) is 15-25°C, and the drying and solidifying time is 40-60 h.

10. Use of the soluble adhesion microneedle patch of any one of claims 1-5 or the soluble adhesion microneedle patch prepared by the preparation method of any one of claims 6-9 in the preparation of a drug for treating severe oral ulcers.

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