Painless gingival anesthesia patch for assisting periodontal subgingival scaling as well as preparation method and application of painless gingival anesthesia patch

Abstract

The invention relates to the technical field of biological medicine, in particular to a painless gingival anesthesia patch for assisting periodontal subgingival scaling as well as a preparation method and application of the painless gingival anesthesia patch. The painless gingival anesthesia patch sequentially comprises a back lining layer, a medicine storage layer and an adhesion layer from bottom to top. A high-adhesion patch containing a high-permeability local anesthesia component is developed, the patch is adhered to the gingival surface of a patient before an operation, needleless anesthesia (especially suitable for children or anxiety patients) is realized, and the pain of the patient in the subgingival scaling process is effectively relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedicine, and in particular to a painless gum anesthesia patch for assisting periodontal subgingival scaling, and a preparation method and application thereof. Background Art

[0002] Periodontitis is the most important cause of tooth loss in adults, and periodontal scaling is the most commonly used method for treating periodontitis. During periodontal scaling, the subgingival scaler needs to be inserted deep into the periodontal pocket under the gums to achieve the therapeutic purpose of removing irritants such as subgingival tartar. This process may cause pain, especially in children, patients with low pain thresholds, or patients with anxiety. Clinically, subgingival scaling under local anesthesia is a commonly used painless treatment method. However, the injection process can also cause pain to patients, especially the special patients mentioned above, or when performed by inexperienced doctors. Therefore, the development of a painless gum anesthesia patch to assist periodontal subgingival scaling can effectively relieve patient discomfort and has good clinical application value and prospects. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a painless gingival anesthesia patch for assisting periodontal subgingival scaling, as well as its preparation method and application. A highly adhesive patch containing a highly permeable local anesthetic component is developed, which is pasted on the gingival surface before surgery to achieve needle-free anesthesia (especially suitable for children or anxious patients), effectively reducing the pain felt by patients during subgingival scaling.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a painless gum anesthesia patch for assisting periodontal subgingival scaling, which comprises, from bottom to top, a backing layer, a drug reservoir layer and an adhesive layer;

[0006] The preparation method of the drug reservoir layer comprises the following steps:

[0007] 1) dissolving carboxymethyl chitosan in phosphate buffer to obtain a carboxymethyl chitosan solution with a mass percentage of 2%;

[0008] 2) mixing the carboxymethyl chitosan obtained in step 1) with an anesthetic, a penetration enhancing system, and auxiliary components to obtain a suspension;

[0009] The anesthetic comprises mepivacaine nanoliposomes and tetracaine-PLGA microspheres; the mass percentage of the mepivacaine nanoliposomes in the painless gum anesthesia patch is 5%, and the mass percentage of the tetracaine-PLGA microspheres in the painless gum anesthesia patch is 3%;

[0010] The penetration-enhancing system comprises 1% by weight of a menthol-β-cyclodextrin inclusion compound and 0.5% by weight of borneol; the menthol-β-cyclodextrin inclusion compound has a mass percentage of 1% in the painless gum anesthesia patch, and the borneol has a mass percentage of 0.5% in the painless gum anesthesia patch;

[0011] The auxiliary components include 0.2% by weight of hyaluronic acid and 0.01% by weight of epinephrine; the mass percentage of the hyaluronic acid in the painless gum anesthesia patch is 0.2%, and the mass percentage of the epinephrine in the painless gum anesthesia patch is 0.01%;

[0012] 3) freeze-drying the suspension obtained in step 2), and irradiating it with gamma rays for cross-linking to obtain a drug reservoir layer.

[0013] Preferably, the thickness of the backing layer is 50-80 μm, the thickness of the drug reservoir layer is 200-300 μm, and the thickness of the adhesive layer is 30-50 μm.

[0014] Preferably, the backing layer is made of medical-grade polyurethane film, which is flexible and saliva-isolating.

[0015] Preferably, the preparation method of the adhesive layer comprises: dissolving thiolated gelatin in 37° C. deionized water to obtain a gelatin solution, wherein the mass percentage of thiolated gelatin in the gelatin solution is 5%;

[0016] The obtained gelatin solution was mixed with a 0.8% by weight citric acid solution, subjected to vacuum degassing treatment, and then a porous structure was constructed on the surface of the backing layer using microfluidic spinning technology, and finally thermally cured to obtain an adhesion layer; the volume ratio of the gelatin solution to the citric acid solution was 1:0.5.

[0017] Preferably, the heat curing conditions include: temperature of 60° C. and time of 30 minutes.

[0018] Preferably, the drug reservoir layer and the adhesive layer are heat-pressed together under nitrogen protection using a medical pressure-sensitive adhesive.

[0019] Preferably, the heat pressing conditions include: temperature of 45° C., pressure of 0.5 MPa, and time of 30 seconds.

[0020] Preferably, the size of the painless gum anesthesia patch is: 5×10 mm oval.

[0021] The present invention also provides a method for preparing the painless gingival anesthesia patch described in the above technical solution, comprising the following steps: constructing a porous structure of the drug reservoir layer on the surface of the backing layer through microfluidic spinning technology, and hot pressing the drug reservoir layer and the adhesion layer under nitrogen protection using a medical pressure-sensitive adhesive.

[0022] The present invention also provides the use of the painless gum anesthesia patch described in the above technical solution in the preparation of a painless gum anesthesia product.

[0023] Beneficial effects of the present invention:

[0024] Cuttable: The multi-size patch body is nested and the patch size can be flexibly adjusted through the preset cutting line.

[0025] Adhesion structure: Elastic contact protrusions (adhesive material) are set on the edge of the patch, combined with a pressure ring to enhance the fit and prevent it from falling off or accidentally swallowed.

[0026] Traditional anesthesia methods use topical anesthetic creams that are easily washed away by saliva, making it difficult to maintain a stable concentration and potentially resulting in suboptimal surface anesthesia. Injectable anesthesia can also cause fear in patients. Advantages of the patch: Painless, long-lasting, and precise, it's particularly suitable for children and anxious patients.

[0027] Biphasic anesthesia system: nanoliposomes (rapid onset) + PLGA microspheres (sustained release) to achieve onset within 5 minutes and maintain effect for 2 hours.

[0028] Smart adhesion technology: Thiolated gelatin forms disulfide bonds with mucosal mucin, and the adhesion force increases by 3 times after saliva activation.

[0029] Directed penetration design: The microporous structure guides the drug to diffuse toward the gingival crevicular fluid, reducing systemic absorption. DETAILED DESCRIPTION

[0030] The present invention provides a painless gum anesthesia patch for assisting periodontal subgingival scaling, which comprises, from bottom to top, a backing layer, a drug reservoir layer and an adhesive layer;

[0031] The preparation method of the drug reservoir layer comprises the following steps:

[0032] 1) A painless gum anesthesia patch for assisting periodontal subgingival scaling, comprising, from bottom to top, a backing layer, a drug reservoir layer, and an adhesive layer;

[0033] The preparation method of the drug reservoir layer comprises the following steps:

[0034] 1) dissolving carboxymethyl chitosan in phosphate buffer to obtain a carboxymethyl chitosan solution with a mass percentage of 2%;

[0035] 2) mixing the carboxymethyl chitosan obtained in step 1) with an anesthetic, a penetration enhancing system, and auxiliary components to obtain a suspension;

[0036] The anesthetic comprises mepivacaine nanoliposomes and tetracaine-PLGA microspheres; the mass percentage of the mepivacaine nanoliposomes in the painless gum anesthesia patch is 5%, and the mass percentage of the tetracaine-PLGA microspheres in the painless gum anesthesia patch is 3%;

[0037] The penetration-enhancing system comprises 1% by weight of a menthol-β-cyclodextrin inclusion compound and 0.5% by weight of borneol; the menthol-β-cyclodextrin inclusion compound has a mass percentage of 1% in the painless gum anesthesia patch, and the borneol has a mass percentage of 0.5% in the painless gum anesthesia patch;

[0038] The auxiliary components include 0.2% by weight of hyaluronic acid and 0.01% by weight of epinephrine; the mass percentage of the hyaluronic acid in the painless gum anesthesia patch is 0.2%, and the mass percentage of the epinephrine in the painless gum anesthesia patch is 0.01%;

[0039] 3) freeze-drying the suspension obtained in step 2), and irradiating it with gamma rays for cross-linking to obtain a drug reservoir layer.

[0040] In the present invention, the method for preparing tetracaine-PLGA microspheres preferably comprises the following steps: dissolving 400 mg of PLGA and 60 mg of tetracaine in 8 mL of dichloromethane (oil phase). This oil phase is poured into 100 mL of a 1% polyvinyl alcohol aqueous phase (4° C.) and homogenized at 10,000 rpm for 2 minutes to form colostrum. The colostrum is transferred to 200 mL of a 1% polyvinyl alcohol aqueous phase and homogenized at 8,000 rpm for 4 minutes to form a double emulsion. The solvent is evaporated by stirring at 25° C. for 4 hours, followed by centrifugation, washing three times with cold water, and freeze-drying to obtain the microspheres.

[0041] In the present invention, the thickness of the backing layer is preferably 50 to 80 μm, the thickness of the drug reservoir layer is preferably 200 to 300 μm, and the thickness of the adhesive layer is preferably 30 to 50 μm. In the present invention, the material of the backing layer is preferably a medical-grade polyurethane film, which has flexibility and saliva isolation. The present invention does not specifically limit the source of the medical-grade polyurethane film, and conventional commercially available ones can be used, such as the finished medical polyurethane film (model JTPU-30) from Jie Te Bio (Guangzhou, China), which has a thickness of 30±5 μm and passes the GB / T 16886 biocompatibility test.

[0042] The present invention freeze-dries the resulting suspension and irradiates it with gamma rays for cross-linking to form a drug reservoir layer. In the present invention, the freeze-drying conditions preferably include: pre-freezing at -20°C for 4 hours, followed by vacuum freezing for 24 hours. In the present invention, the gamma ray irradiation dose is 15 kGy.

[0043] In the present invention, the method for preparing the adhesive layer preferably includes: dissolving thiolated gelatin in 37°C deionized water to obtain a gelatin solution, wherein the mass percentage of thiolated gelatin in the gelatin solution is 5%; mixing the obtained gelatin solution with 0.8% citric acid by mass, vacuum degassing, and then constructing a porous structure on the surface of the backing layer using microfluidic spinning technology, and finally thermally curing to obtain the adhesive layer. The present invention does not specifically limit the vacuum degassing treatment, and conventional methods can be used, such as core parameters: vacuum degree (-0.08MPa to -0.1MPa), temperature (generally 25-37°C, matching the initial temperature of the gelatin solution), treatment time (10-30 minutes, adjusted according to the solution viscosity and equipment performance), and auxiliary conditions (low-speed stirring, intermittent vacuuming). The present invention does not specifically limit the microfluidic spinning technology. Those skilled in the art can adopt conventional methods, such as injecting the degassed gelatin-citric acid mixture (viscosity 800 mPa·s, pH 4.5) into a microfluidic chip (microchannel inner diameter 150 μm), controlling the core layer flow rate to 0.5 mL / h, the sheath layer flow rate to 2 mL / h, the receiving distance to 12 cm, the ambient humidity to 40% RH, and the temperature to 25°C; after spinning is completed, the fiber layer and the polyurethane backing layer are hot-pressed and cured at 55°C and 0.3 MPa for 20 minutes to form a porous adhesion layer with a porosity of 75%.

[0044] In the present invention, the heat curing conditions preferably include: a temperature of 60°C and a time of 30 minutes. In the present invention, the drug reservoir layer and the adhesive layer are preferably heat-pressed together using a medical pressure-sensitive adhesive under nitrogen protection. In the present invention, the heat pressing conditions preferably include: a temperature of 45°C, a pressure of 0.5 MPa, and a time of 30 seconds.

[0045] In the present invention, the size of the painless gum anesthesia patch is preferably: 5×10 mm oval.

[0046] In the present invention, the method for using the painless gum anesthesia patch preferably includes: performing supragingival scaling before surgery to remove tartar and plaque from the tooth surface. Selecting an appropriate patch size based on the depth and extent of the periodontal pocket. Gently attaching the patch to the affected gum surface, pressing lightly to ensure a tight fit. Waiting for 5 minutes for the anesthetic to take effect, the periodontal subgingival scaling procedure is then initiated. There is no need to remove the patch after surgery, as it will naturally degrade and absorb.

[0047] The present invention also provides a method for preparing the painless gingival anesthesia patch described in the above technical solution, comprising the following steps: constructing a porous structure of the drug reservoir layer on the surface of the backing layer through microfluidic spinning technology, and hot pressing the drug reservoir layer and the adhesion layer under nitrogen protection using a medical pressure-sensitive adhesive.

[0048] The present invention also provides the use of the painless gum anesthesia patch described in the above technical solution in the preparation of a painless gum anesthesia product.

[0049] In order to further illustrate the present invention, the present invention is described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] A painless gum anesthesia patch:

[0052] 1. Active ingredient formula (mass percentage)

[0053] Main anesthetic: mepivacaine nanoliposomes (5% w / w) + tetracaine-PLGA microspheres (3% w / w);

[0054] Penetration-enhancing system: 1% menthol-β-cyclodextrin inclusion complex + 0.5% borneol;

[0055] Auxiliary ingredients: 0.2% hyaluronic acid (moisturizing) + 0.01% epinephrine (hemostasis);

[0056] Mechanism of action: It can penetrate the mucous membrane, act on nerve endings, inhibit the generation and conduction of nerve impulses, and produce a strong anesthetic effect.

[0057] 2. Core materials and structural design (three-layer composite system)

[0058] Backing layer: medical-grade polyurethane film (50 μm thick), flexible and saliva-isolating;

[0059] Drug reservoir layer: pH-responsive carboxymethyl chitosan hydrogel (thickness 200 μm);

[0060] Adhesion layer: thiolated gelatin mucoadhesive matrix (thickness 30 μm) containing reverse tapered microporous structure.

[0061] 3. Preparation process (combining medical materials science and sustained-release technology)

[0062] 3.1 Preparation of drug reservoir layer

[0063] 2% carboxymethyl chitosan was dissolved in pH 6.5 phosphate buffer;

[0064] Add the above active ingredients and stir magnetically at 40°C to form a homogeneous suspension;

[0065] After injection into the mold, pre-freeze at -20℃ for 4 hours and vacuum freeze-dry for 24 hours;

[0066] Cross-linking was performed by γ-ray irradiation (dose 15 kGy).

[0067] 3.2 Preparation of adhesion layer

[0068] Dissolve 5% thiolated gelatin in 37°C deionized water;

[0069] Add 0.8% citric acid cross-linking agent and vacuum degassing;

[0070] Microfluidic spinning technology is used to construct a porous structure on the surface of the backing layer;

[0071] Heat curing at 60°C for 30 minutes formed a bioadhesive interface.

[0072] 3.3 Lamination

[0073] The drug layer and the adhesive layer are laminated using a medical pressure-sensitive adhesive;

[0074] Hot pressing was performed under nitrogen protection (temperature 45°C, pressure 0.5 MPa, time 30 s);

[0075] Punching and forming (size: 5×10 mm oval, with rounded edges).

[0076] 4. Key process parameters

[0077] Drug encapsulation efficiency: mepivacaine ≥92%, tetracaine ≥85% (HPLC detection);

[0078] Adhesion force: ≥0.8N / cm on moist mucosal surface 2 (Texture analyzer measurement);

[0079] Sustained release characteristics: Cumulative release rate is 40-50% in 2 hours and more than 80% in 6 hours;

[0080] Storage stability: Valid for 24 months at 25°C / 60%RH.

[0081] 5. Sterilization and packaging

[0082] Electron beam sterilization (absorbed dose 10-15 kGy);

[0083] Individually packaged in aluminum-plastic composite film with a built-in desiccant bag;

[0084] The terminal ethylene oxide residue is less than 10μg / g.

[0085] 6. Functional design and advantages

[0086] 6.1 Cuttable: The multi-size patch body is nested and the patch size can be flexibly adjusted through the preset cutting line.

[0087] 6.2 Adhesion structure: Elastic contact protrusions (adhesive material) are set on the edge of the patch, combined with a pressure ring to enhance the fit and prevent falling off or accidental swallowing.

[0088] 6.3 Surface anesthetic creams used in traditional anesthesia methods are easily washed away by saliva, making it difficult to maintain a stable concentration, which may result in suboptimal surface anesthesia. Injectable anesthesia can easily cause patient fear. Advantages of patches: Painless, long-lasting, and precise, they are particularly suitable for children and anxious patients.

[0089] 7. Usage

[0090] Before the operation, supragingival scaling is performed to remove tartar and plaque from the tooth surface.

[0091] Choose the appropriate veneer size based on the depth and range of the periodontal pocket.

[0092] Gently adhere the patch to the gum surface of the affected area and press lightly to make it fit tightly.

[0093] Wait for 5 minutes until the anesthetic takes effect and then start periodontal subgingival scaling.

[0094] There is no need to remove the patch after surgery as it can be naturally degraded and absorbed.

[0095] 8. Key innovation points

[0096] 1. Biphasic anesthesia system: nanoliposomes (rapid onset) + PLGA microspheres (sustained release) to achieve onset within 5 minutes and last for 2 hours;

[0097] 2. Intelligent Adhesion Technology: Thiolated gelatin forms disulfide bonds with mucosal mucin, and the adhesion force increases by 3 times after saliva activation;

[0098] 3. Directed penetration design: The microporous structure guides the drug to diffuse toward the gingival crevicular fluid, reducing systemic absorption.

[0099] 9. Experiment

[0100] 9.1 In vitro permeation test (Franz diffusion cell method): The Franz diffusion cell method was used to evaluate the in vitro permeation properties of the anesthetic drugs (mepivacaine and tetracaine) in the painless gingival anesthesia patch to verify whether they can effectively penetrate the gingival mucosa and achieve a local anesthetic effect.

[0101] Experimental procedures: Porcine gingival mucosa was fixed in a Franz diffusion cell, and the receptor cell was injected with pH 6.8 PBS (containing 0.5% polysorbate 80). The patch group and free drug group were applied to the donor side, respectively. Samples were taken at 37°C and 600 rpm for 180 minutes, and the cumulative permeation was detected by HPLC.

[0102] Data results: The cumulative permeation of mepivacaine in the patch reached 28.5±2.1μg / cm in 30 minutes 2 The plateau phase was reached in 2 hours, and the cumulative release of tetracaine was 78.5±6.4μg / cm3 in 3 hours. 2 , in line with the design requirements of biphasic anesthesia."

[0103] Experimental conclusion: In vitro permeation data demonstrated that the patch rapidly released mepivacaine through nanoliposomes and sustained-release tetracaine through PLGA microspheres, achieving clinical anesthesia requirements with onset within 5 minutes and maintenance for ≥2 hours.

[0104] 9.2 Clinical Validation Protocol (Visual Analog Scale)

[0105] The preparation process must be carried out under GMP conditions, and process analytical technology (PAT) is used to monitor quality parameters at key steps.

[0106] 9.3 Evaluation of anesthetic effect (clinical study), the specific design is as follows:

[0107] Experimental subjects: 60 patients with severe chronic periodontitis (PD ≥ 6 mm) were selected and randomly divided into an experimental group (using anesthesia patch) and a control group (not using anesthesia patch), with 30 cases in each group.

[0108] Evaluation indicators: The visual analogue scale (VAS) was used to assess the patient's intraoperative pain level, and the onset time and duration of anesthesia were recorded.

[0109] Experimental results: The intraoperative VAS score of the experimental group was significantly lower than that of the control group (P<0.05), and the onset time and duration of anesthesia in the experimental group were significantly better than those in the control group (P<0.05).

[0110] 9.4 Clinical Efficacy Evaluation

[0111] Experimental subjects: Same as the anesthesia effect evaluation experiment.

[0112] Evaluation indicators: The periodontal probing depth (PD), clinical attachment loss (CAL) and bleeding on probing (BOP) were compared between the two groups before surgery, 1 week after surgery and 1 month after surgery.

[0113] Experimental results: The periodontal indices of both groups of patients were significantly improved after surgery compared with those before surgery (P<0.05), but the degree of improvement in the experimental group was better than that in the control group (P<0.05).

[0114] 9.5 Safety Evaluation

[0115] Experimental subjects: Same as the anesthesia effect evaluation experiment.

[0116] Evaluation indicators: Observe and record the occurrence of adverse reactions in the two groups of patients after surgery.

[0117] Experimental results: No serious adverse reactions occurred in either group. The incidence of local numbness in the experimental group was slightly higher than that in the control group, but the difference was not statistically significant (P>0.05).

[0118] 9.6 Clinical Study Conclusions

[0119] Experimental results demonstrate that the painless gum anesthesia patch provided by the present invention has excellent anesthetic and clinical efficacy, effectively alleviating pain during periodontal subgingival scaling and improving patient comfort, and exhibits good safety. The patch is simple to operate, requires no injection, and is readily available for widespread use, demonstrating promising clinical application prospects.

[0120] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A painless gum anesthesia patch for assisting periodontal subgingival scaling, characterized in that: From bottom to top, there are backing layer, drug reservoir layer and adhesive layer; The preparation method of the drug reservoir layer comprises the following steps: 1) dissolving carboxymethyl chitosan in phosphate buffer to obtain a carboxymethyl chitosan solution with a mass percentage of 2%; 2) mixing the carboxymethyl chitosan obtained in step 1) with an anesthetic, a penetration enhancing system, and auxiliary components to obtain a suspension; The anesthetic comprises mepivacaine nanoliposomes and tetracaine-PLGA microspheres; the mass percentage of the mepivacaine nanoliposomes in the painless gum anesthesia patch is 5%, and the mass percentage of the tetracaine-PLGA microspheres in the painless gum anesthesia patch is 3%; The penetration-enhancing system comprises 1% by weight of a menthol-β-cyclodextrin inclusion compound and 0.5% by weight of borneol; the menthol-β-cyclodextrin inclusion compound has a mass percentage of 1% in the painless gum anesthesia patch, and the borneol has a mass percentage of 0.5% in the painless gum anesthesia patch; The auxiliary components include 0.2% by weight of hyaluronic acid and 0.01% by weight of epinephrine; the mass percentage of the hyaluronic acid in the painless gum anesthesia patch is 0.2%, and the mass percentage of the epinephrine in the painless gum anesthesia patch is 0.01%; 3) freeze-drying the suspension obtained in step 2), and irradiating it with gamma rays for cross-linking to obtain a drug reservoir layer.

2. The painless gum anesthesia patch according to claim 1, characterized in that: The thickness of the backing layer is 50-80 μm, the thickness of the drug reservoir layer is 200-300 μm, and the thickness of the adhesive layer is 30-50 μm.

3. The painless gum anesthesia patch according to claim 1, characterized in that: The backing layer is made of medical-grade polyurethane film, which is flexible and has saliva isolation properties.

4. The painless gum anesthesia patch according to claim 1, characterized in that: The preparation method of the adhesive layer comprises: dissolving thiolated gelatin in 37° C. deionized water to obtain a gelatin solution, wherein the mass percentage of thiolated gelatin in the gelatin solution is 5%; The obtained gelatin solution was mixed with a 0.8% by weight citric acid solution, subjected to vacuum degassing treatment, and then a porous structure was constructed on the surface of the backing layer using microfluidic spinning technology, and finally thermally cured to obtain an adhesion layer; the volume ratio of the gelatin solution to the citric acid solution was 1:0.

5.

5. The painless gum anesthesia patch according to claim 4, characterized in that: The heat curing conditions include: temperature of 60° C. and time of 30 minutes.

6. The painless gum anesthesia patch according to claim 1, characterized in that: The drug reservoir layer and the adhesive layer are heat-pressed together under nitrogen protection using a medical pressure-sensitive adhesive.

7. The painless gum anesthesia patch according to claim 6, characterized in that: The heat pressing conditions include: temperature of 45° C., pressure of 0.5 MPa, and time of 30 seconds.

8. The painless gum anesthesia patch according to claim 1, characterized in that: The size of the painless gum anesthesia patch is: 5×10mm oval.

9. A method for preparing the painless gum anesthesia patch according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: constructing a porous structure of the drug reservoir layer on the surface of the backing layer by microfluidic spinning technology, and performing heat pressing on the drug reservoir layer and the adhesion layer by medical pressure-sensitive adhesive under nitrogen protection.

10. Use of the painless gum anesthesia patch according to any one of claims 1 to 8 in the preparation of a painless gum anesthesia product.