A skin healing promoting composition, a soluble microneedle patch and a method for preparing the microneedle patch

Abstract

This invention relates to a skin-healing composition, a soluble microneedle patch thereof, and a method for preparing the microneedle patch. The skin-healing composition comprises the following components in weight percentages: 0.5-1% copper peptide, 5%-15% dextran, 5%-15% trehalose, 15-25% hyaluronic acid, and 44%-74.5% deionized water. This composition has the effect of promoting skin healing, particularly collagen healing and angiogenesis. The composition can be prepared into a soluble microneedle patch with good mechanical strength, further enhancing its skin-healing effect. Compared with topical application, it significantly improves the penetration rate of its active ingredients, is convenient to use, has a rapid onset of action, and exhibits high bioavailability of the copper peptide.

Description

Technical Field

[0001] This invention relates to the field of skin repair, and in particular to a composition for promoting skin healing, a soluble microneedle patch thereof, and a method for preparing the microneedle patch. Background Technology

[0002] The skin is the largest and outermost organ of the human body, protecting the body from biological, chemical, mechanical, and physical factors, protecting it from external microbial invasion, and maintaining body fluids, electrolytes, and nutrients. In daily life, skin injuries of varying degrees, such as abrasions, burns, lacerations, and punctures, are unavoidable, which impair the skin's barrier function.

[0003] The physiological process of skin healing is manifested as follows: The hemostasis and inflammation stages of a wound; During the proliferation phase, wound contraction is characterized by the migration of fibroblasts, the deposition of collagen, and the formation of granulation tissue. Restructuring phase.

[0004] Most commercially available skin healing products are not very effective. This is because the penetration of the medication is poor after the wound has scabbed over, and the various proteases and exudate at the wound site can eliminate the active medication to some extent.

[0005] Furthermore, we believe that improving skin bioavailability involves delivering active ingredients deep into the skin, allowing for optimal absorption. Microneedles are micron-scale fine array structures that facilitate drug delivery through microchannels formed at the needle tip. Their length is insufficient to reach subcutaneous pain nerves, offering advantages such as being non-invasive and painless. Soluble polymer materials can completely dissolve or degrade within the skin, are simple and convenient to use, and possess good biocompatibility, making them widely used in the preparation of soluble microneedle patches.

[0006] The spatial structure of peptide and protein drugs significantly affects their efficacy. Water content influences the spatial unfolding of proteins and peptides, thus affecting their spatial structure. Optimal product formulations can be prepared by controlling water content. Currently, maintaining the drug activity of peptide and protein preparations remains challenging, and many problems need to be solved in practical applications. Summary of the Invention

[0007] In view of the above-mentioned technical problems existing in the prior art, the purpose of the present invention is to provide a composition for promoting skin healing, a soluble microneedle patch, and a method for preparing the microneedle patch.

[0008] The technical solution adopted in this invention is as follows:

[0009] A soluble microneedle patch includes: a sheet-like substrate and a soluble microneedle patch based on the sheet-like substrate; wherein the soluble microneedles are obtained by mixing a copper peptide with a deionized water solvent to form a solution, then mixing the solution with a soluble polymer to form a composition that promotes skin healing, filling the mixture into a PDMS mold, centrifuging, and drying to obtain a soluble microneedle patch embedded with copper peptide.

[0010] The needle body is a solid three-dimensional structure with a gradually decreasing cross-sectional area from the base of the needle body to the tip of the needle. The soluble microneedle patch is a microneedle array composed of at least 2*2 needle bodies, preferably a 2*2*-10*10 microneedle array.

[0011] The needle body is conical or pyramidal in shape. The distance from the bottom surface of the needle body to the tip is 800-1000 μm, preferably 800-1000 μm. The diameter of the circumscribed circle or base circle of the needle body is 190-380 μm, preferably 300-380 μm. The center-to-center distance between the tips of two adjacent needle bodies is 700-950 μm, preferably 800-900 μm.

[0012] A composition for promoting skin healing, comprising the following weight percentages:

[0013] Blue copper peptide 0.5%-1%;

[0014] Soluble polymers 25%-55%;

[0015] Deionized water 44%-74.5%.

[0016] The skin-healing composition uses a hydrophilic polymer with good biocompatibility, such as one or more of hyaluronic acid, sodium alginate, polyvinylpyrrolidone, hydroxypropyl cellulose, dextran, hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, sodium chondroitin sulfate, polylactic acid, and polyethylene glycol. The hyaluronic acid has a molecular weight of 5,000-200,000; the dextran has a molecular weight of 1,000-100,000; the polyvinylpyrrolidone has a molecular weight of 100,000-370,000; the hydroxypropyl methylcellulose has a molecular weight of 10,000-150,000; the sodium chondroitin sulfate has a molecular weight of 40,000-50,000; the polylactic acid has a molecular weight of 30,000-150,000; and the polyethylene glycol has a molecular weight of 200-20,000.

[0017] Further, the preferred hydrophilic polymers are dextran, trehalose, and hyaluronic acid. The dextran has a molecular weight of 1000-100000, preferably 1000-10000. The hyaluronic acid has a molecular weight of 100000-200000.

[0018] Furthermore, a skin-healing composition comprises the following components in weight percentages:

[0019] Blue copper peptide 0.5%-1% (preferably 0.8%-1%)

[0020] 5%-15% dextran (preferably 5%-8%)

[0021] Trehalose 5%-15% (preferably 5%-8%)

[0022] Hyaluronic acid 15%-25% (preferably 20%-25%)

[0023] Deionized water 44%-74.5% (preferably 58%-69.2%).

[0024] The materials selected in the composition of this invention are all biocompatible, water-soluble polymer materials. Among them, copper peptides activate skin stem cells, promote the synthesis of skin collagen and the rational distribution of type I and type III collagen, promote the migration of skin fibroblasts to the wound site, stimulate the formation of blood vessels in the skin, increase the production of nerve growth factor and neurotrophic factor in the skin, and accelerate the regeneration of nerve fibers in collagen tubes; dextran can rapidly restore the ability of lymphocytes in the injured body to produce cytokines to normal, and at the same time has the ability to promote fibroblast proliferation and collagen synthesis, and free radical scavenging; trehalose, as one of the most stable natural disaccharides, has very good stability, and its strong water molecule binding effect can effectively bind water to prevent protein denaturation; hyaluronic acid is a multifunctional glycosaminoglycan distributed throughout the human body, with a wide range of biological functions, playing an important role in the inflammatory, proliferative, and remodeling phases of cells, and also serving as an important component of microneedle scaffold materials. The components are mixed in a specific ratio, and they have a synergistic effect, which can significantly improve the skin healing effect of blue copper peptides and protect blue copper peptides from being destroyed by surrounding environmental substances.

[0025] This invention analyzes the efficacy of each component in a microneedle that promotes skin healing.

[0026] The skin-healing composition, soluble microneedle patch, and preparation method of the present invention have the following advantages and efficacy:

[0027] Based on extensive literature review and experiments, this invention combines copper peptides, dextran, trehalose, and hyaluronic acid in a specific ratio to create a composition that promotes skin healing, normalizes collagen synthesis, and enhances angiogenesis.

[0028] The soluble microneedle patch prepared from the skin-healing composition of this invention exhibits good solubility and mechanical strength. The patch has a good overall appearance with neatly arranged needle tips, and it can effectively penetrate the skin. The soluble microneedle patch penetrates the stratum corneum, opening microchannels, and the microneedle tips dissolve rapidly. This allows the active substances and excipients contained in the needle tips, such as copper peptides and dextran, to penetrate the skin barrier and exert their effects within the skin. Multiple excipients synergistically enhance the skin-healing effect of the composition. Compared to direct application, this method significantly improves the permeability of each substance in the composition, thereby increasing the bioavailability of copper peptides.

[0029] Blue copper peptide is a low molecular weight polypeptide that is easily degraded by blood. In this invention, it is mixed with a water-soluble polymer to prepare a soluble microneedle patch. The polymer material encapsulates the blue copper peptide, effectively improving the stability of the blue copper peptide during drug delivery.

[0030] The skin-healing composition of this invention is dissolved in deionized water, stirred and swollen appropriately, then filled into a negative mold and centrifuged and dried to prepare a uniformly shaped soluble microneedle patch. This patch contains active substances such as copper peptides uniformly within the microneedles. The soluble microneedle patch possesses good mechanical strength and solubility, allowing the microneedles to penetrate the stratum corneum and scab layer of the skin effectively. This allows active substances such as copper peptides to act directly within the skin through the microchannels pierced by the needle tip, resulting in a better skin-healing effect. Compared to direct application, this method effectively improves the penetration rate of the ingredients and protects the copper peptides from elimination by wound proteases, thereby increasing the utilization rate of the copper peptides.

[0031] The specific selection and proportions of each material in the composition jointly affect the mechanical strength, solubility, and efficacy of the microneedle patch. Only by mixing them within a specific range can the soluble microneedle patch be guaranteed to have good wound healing properties, good biocompatibility, rapid dissolution, and good mechanical strength, resulting in a uniform patch. For example, when the weight percentage of dextran in the needle body is 5%-15%, it can effectively enhance the skin healing effect of the microneedles; less than 5% is not ideal; more than 15% increases the proportion of sugar substances in the microneedles, increasing the brittleness of the soluble microneedle patch, making the base prone to breakage, and reducing stability. The weight percentage of hyaluronic acid in the needle body is best between 15%-25%. If it is less than 15%, the mechanical strength of the microneedle patch skeleton is insufficient to achieve the desired effect; if it is greater than 25%, the fluidity of the composition is poor, making it difficult to manufacture by casting.

[0032] This invention also provides a method for preparing the above-mentioned soluble microneedle patch that promotes skin healing. The specific technical solution is as follows:

[0033] A method for preparing a soluble microneedle patch that promotes skin healing includes the following steps:

[0034] 1) Using the skin-healing composition described in this invention as a raw material, the blue copper peptide and soluble polymer of the skin-healing composition are dissolved in deionized water, and the resulting mixed solution is used as the microneedle preparation solution. Then, the microneedle preparation solution is poured into a negative mold, centrifuged, and excess microneedle preparation solution is removed from the surface of the negative mold after centrifugation.

[0035] 2) Dry the negative mold covered with microneedle preparation solution to obtain the soluble microneedle patch that promotes skin healing.

[0036] In some embodiments, the centrifugation speed is 2500-3000 rpm / min, the temperature is 0-5℃, the centrifugation time is 8-15 min, and the number of centrifugations is 2-4.

[0037] In some embodiments, the negative mold covered with microneedle preparation solution is placed in a constant temperature drying oven at 20-30°C and 10-15% humidity for 2-8 hours to dry, and the water content of the microneedles after drying is 4.86%-67.92%. Attached Figure Description

[0038] Figure 1 This is an appearance diagram of the soluble microneedle patch provided in Embodiment 1 of the present invention;

[0039] Figure 2 This is a scanning electron microscope image of the soluble microneedle patch provided in Embodiment 1 of the present invention;

[0040] Figure 3 This refers to the insertion efficiency of the soluble microneedle patches provided in Embodiments 1-5 of the present invention;

[0041] Figure 4 The diagram shows the wound healing effects of the soluble microneedle patch provided in Example 1 of this invention compared to the blank control group, the blank microneedle patch group, the topical application group, and the positive control group.

[0042] Figure 5 The images show the wound inflammation response of the soluble microneedle patch provided in Example 1 of this invention compared with the blank control group, the blank microneedle patch group, the application group, and the positive control group.

[0043] Figure 6The diagram shows the wound angiogenesis promotion effect of the soluble microneedle patch provided in Example 1 of this invention compared with the blank control group, the blank microneedle patch group, the application group, and the positive control group. Detailed Implementation

[0044] The following detailed description of the skin-healing composition, soluble microneedle patch, and preparation method of the present invention, with reference to specific embodiments, provides further details.

[0045] All raw materials used in the following examples are commercially available common raw materials. The hydrophilic polymers are dextran, trehalose, and hyaluronic acid. The dextran has an average molecular weight of 5000. The hyaluronic acid has an average molecular weight of 150000.

[0046] The female molds used in the following implementation examples were prepared using the following methods:

[0047] Preparation of the male mold: The size of the male mold is determined by computer, and it is processed through digital-to-analog conversion. Copper is selected as the processing material for the male mold, and it is processed according to the designed proportions and dimensions.

[0048] Preparation of the female mold: Take polydimethylsiloxane and curing agent at a ratio of 10:1 (w / w), mix them, and carefully pour them into a vacuum drying oven for 30 minutes to remove air bubbles. Carefully pour the liquid into a circular six-hole plate (avoid generating air bubbles). Slowly insert the prepared male mold into the completely static polydimethylsiloxane and place it in a 60℃ oven for 12 hours. After cooling, remove the male mold to obtain the PDMS female mold.

[0049] Example 1: Preparation of a soluble microneedle patch to promote skin healing

[0050] Preparation of microneedle preparation solution: Dissolve 0.05g of copper peptide in 5ml of purified water, weigh 1.25g of hyaluronic acid, 0.25g of dextran and 0.25g of trehalose, add them to the copper peptide aqueous solution, stir and mix well, allow to swell fully, and let stand overnight to obtain the microneedle preparation solution.

[0051] Take 200 μl of microneedle preparation solution and fill it into a DPMS mold with a needle tip height of 1000 μm, so that the microneedle preparation solution can completely cover the negative mold. Place the mold in a six-well plate to balance the weight, and then centrifuge it in a centrifuge. Set the speed to 3000 rpm / min, the temperature to 5℃, and centrifuge for 10 min. After the centrifugation, rotate the six-well plate 180° and continue to centrifuge for 10 min under the same conditions. After centrifugation, remove the excess microneedle preparation solution from the surface of the mold.

[0052] The mold was placed in a constant temperature drying oven (temperature 35℃, humidity 15%) and dried for 5 hours until the moisture content was 7.74%, thus obtaining the soluble microneedle patch that promotes skin healing. The needle tip height was 1000μm and the bottom diameter was 200μm.

[0053] The appearance of the soluble microneedle patch provided in Example 1 is shown in the figure below. Figure 1 Scanning electron microscopy image of soluble microneedle patch is shown below. Figure 2 .

[0054] The soluble microneedle patch prepared in this embodiment was applied to the skin of healthy female volunteers. After 10 minutes, the microneedle patch was peeled off, and the condition of the needles was observed under a microscope. The results showed that the needle tips of the patch had completely dissolved, indicating that the copper peptides encapsulated in the microneedle tips had completely entered the skin. Furthermore, the needle holes disappeared and returned to normal on the female volunteers' skin within 3 hours, without any redness or swelling, demonstrating that the copper peptide soluble microneedle patch has good biocompatibility.

[0055] Example 2: Preparation of soluble microneedle patches to promote skin healing

[0056] Preparation of microneedle preparation solution: Same as in Example 1.

[0057] Same as Example 1.

[0058] The mold was placed in a constant temperature drying oven (temperature 35℃, humidity 15%) and dried for 2 hours. The moisture content was 32.87%, which yielded the soluble microneedle patch that promotes skin healing. The needle tip height was 1000μm and the bottom diameter was 200μm.

[0059] Example 3: Preparation of soluble microneedle patches to promote skin healing

[0060] Preparation of microneedle preparation solution: Same as in Example 1.

[0061] Same as Example 1.

[0062] The mold was placed in a constant temperature drying oven (temperature 35℃, humidity 15%) and dried for 3 hours to obtain the soluble microneedle patch that promotes skin healing. The tip height was 1000μm and the bottom diameter was 200μm.

[0063] Example 4: Preparation of soluble microneedle patches to promote skin healing

[0064] Preparation of microneedle preparation solution: Same as in Example 1.

[0065] Same as Example 1.

[0066] The mold was placed in a constant temperature drying oven (temperature 35℃, humidity 15%) and dried for 4 hours until the moisture content was 9.87%, thus obtaining the soluble microneedle patch that promotes skin healing. The needle tip height was 1000μm and the bottom diameter was 200μm.

[0067] Example 5: Preparation of a soluble microneedle patch to promote skin healing

[0068] Preparation of microneedle preparation solution: Same as in Example 1.

[0069] Same as Example 1.

[0070] The mold was placed in a constant temperature drying oven (temperature 35℃, humidity 15%) and dried for 6 hours until the moisture content was 6.5%, thus obtaining the soluble microneedle patch that promotes skin healing. The needle tip height was 1000μm and the bottom diameter was 200μm.

[0071] The mechanical strength of the soluble microneedle patches in Examples 1-5 was observed using trypan blue staining, and the microneedle penetration rate was used to reflect whether the microneedles met the application requirements. Results are shown below. Figure 3 Test method: Take a fresh mouse skin, fully open and fix it, place the soluble microneedle patch face down, gently press for 1 minute, remove it, and use a dropper to add 1% trypan blue to fully cover the puncture site. After staining for 15 minutes, first use a pipette to remove the trypan blue from the surface, and then use a cotton ball soaked in anhydrous ethanol to wipe away the excess trypan blue from the surface. The puncture site is blue, and the puncture rate is calculated.

[0072] Depend on Figure 3 It is known that the microneedles of the soluble microneedle patches prepared in Examples 1 and 5 have a higher hardness than those in Examples 2-4. Insufficient drying time and excessive moisture content lead to a decrease in the hardness of the microneedle tips. In contrast to Examples 1 and 5, the relatively sufficient drying time enables the prepared microneedles to have sufficient penetration strength and achieve the desired effect.

[0073] Efficacy experiment of soluble microneedle patch in Example 1

[0074] 1. Thirty healthy 7-week-old male SD rats were selected as subjects for this experiment and randomly divided into 5 groups of 6 rats each: blank control group, soluble microneedle patch group, blank microneedle patch group, topical application group, and positive control group. There were no significant differences in weight, age, etc., among the groups, making them comparable. A mechanical skin excision model was established in the rats to simulate a wound and observe the efficacy of the microneedle patch. Application method: The drug was applied or applied to the wound and secured with adhesive tape and breathable gauze.

[0075] 2. The soluble microneedle patch for promoting skin healing from Example 1 was used as the test product and applied to the soluble microneedle patch group; the blank control group was not treated; the blank microneedle group used soluble microneedle patches without copper peptide, and the preparation method was the same as in Example 1; the topical group used a composition for promoting skin healing that was applied directly, and the composition is described in Example 1; the positive control group used a commercially available Centella asiatica cream that is effective for wound healing applied directly as a comparison of the efficacy of the copper peptide soluble microneedle patch.

[0076] 3. The efficacy criteria are as follows: Significant effect: Compared with the control group, the wound heals significantly, the inflammation disappears, and there is more blood vessel regeneration; Effective: Compared with the control group, the wound becomes shallower, the inflammation is reduced, and there is blood vessel regeneration; Ineffective: There is no significant change compared with the control group.

[0077] Experimental results are as follows Figure 4-6 The results in the figure show that the soluble microneedle patch prepared in Example 1 has better wound healing, inflammation reduction, and angiogenesis promotion abilities than other experimental groups, and the effects are significant, even better than the positive control group. The blank microneedle group, lacking copper peptide, had poor efficacy, but its efficacy was still better than the control group. This is attributed to the fact that the pharmaceutical excipients used in the microneedle patch itself have a certain skin healing-aiding effect. The positive control group, as a commercially available wound healing drug, showed significant effects. The topical application group showed effective efficacy. Its materials were no different from the copper peptide soluble microneedle patch group, but its efficacy was inferior to the microneedle patch. This may be because the skin-healing gel composition forms a dense polymer film at the wound site, resulting in insufficient air exchange between the wound and the wound exudate, which cannot be smoothly carried away by the flowing air, leading to slower scab formation. The needle-tip structure of the microneedle patch makes it more advantageous than direct application.

[0078] The following is a detailed description of each group.

[0079] 1. Blank control group: After animal modeling, no drug administration was performed; other procedures were the same as in other groups. Wounds healed spontaneously in the rats, serving as a control group. Figure 4-6 The control group had the worst healing condition among the five groups, with the most severe inflammation and sparse angiogenesis at the wound site.

[0080] 2. Blue Copper Peptide Soluble Microneedle Patch Group: After animal modeling, the skin-healing-promoting soluble microneedle patches prepared in Example 1 were applied to the wound site and secured with breathable gauze and medical tape. The patches were removed after two days. Figure 4-6 It can be seen that the wound is healing well, the wound area has shrunk considerably, the wound is small, the inflammation at the wound site has been greatly reduced, the inflammatory response has almost disappeared, and there is a lot of angiogenesis.

[0081] 3. Blank Microneedle Group: After animal modeling, blank microneedle patches without blue copper peptides and prepared using the same method as in Example 1 were applied to the wound site and secured with breathable gauze and medical tape. The patches were removed after two days. Figure 4-6 It can be seen that the wound healing was generally good. The contraction of the wound area was not significantly different from that of the control group. The inflammation at the wound site was greatly reduced, but still present. There was a small amount of angiogenesis compared to the control group.

[0082] 4. Topical Application Group: After animal modeling, the same proportion of the skin-healing composition as in Example 1 was used. 200 μl was applied directly to the wound, secured with breathable gauze and medical tape, and removed after two days. Figure 4-6 It can be seen that the wound healing was good, the wound area contracted significantly, the number of wounds was relatively smaller than that of the blank control group, the inflammation at the wound site was greatly reduced, the inflammatory response almost disappeared, and angiogenesis was present in a certain number compared to the control group. However, the application effect of the topical group was somewhat different from that of the blue copper peptide soluble microneedle patch group.

[0083] 5. Positive control group: After animal modeling, commercially available Centella asiatica extract cream was applied directly to the wound, and secured with breathable gauze and medical tape. The gauze was removed after two days. Figure 4-6 It can be seen that the wound healing is good, the wound area shrinks significantly, the number of wounds is significantly reduced compared with the control group, the inflammation at the wound site is greatly reduced, the inflammatory response almost disappears, and angiogenesis is generated to a certain extent compared with the control group.

[0084] In this embodiment, a soluble microneedle patch is obtained by mixing a copper peptide solution with a biocompatible hydrophilic polymer to form a composition and then drying it for a certain period of time. During this drying period, the microneedle patch ensures both sufficient penetration strength and a certain water content to prevent the activity of the copper peptide from being affected, effectively avoiding some of the problems currently encountered in maintaining drug activity in polypeptide protein formulations.

[0085] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. All modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A soluble microneedle patch, characterized in that, The invention includes a sheet-like substrate and a soluble microneedle patch formed on the sheet-like substrate; wherein the soluble microneedle patch is made from a composition that promotes skin healing, by mixing a copper peptide with a deionized water solvent to form a solution, then mixing it with a soluble polymer to form a composition that promotes skin healing, filling it into a PDMS mold, centrifuging and drying it to obtain the soluble microneedle patch. The skin-healing composition comprises the following weight percentages: Blue copper peptide 0.5%-1%; Glucan 5%-15%; Trehalose 5%-15%; Hyaluronic acid 15%-25%; Deionized water 44%-74.5%; The dextran has a molecular weight of 1,000-10,000, and the hyaluronic acid has a molecular weight of 100,000-200,000.

2. The soluble microneedle patch as described in claim 1, characterized in that, The skin-healing composition comprises the following components in weight percentage: Blue copper peptide 0.8%-1%; Glucan 5%-8%; Trehalose 5%-8%; Hyaluronic acid 20%-25%; Deionized water 58%-69.2%.

3. The soluble microneedle patch as described in claim 1, characterized in that, The soluble microneedle patch is a microneedle array composed of at least 2*2 needles, wherein the needles are solid three-dimensional structures with a cross-sectional area that gradually decreases from the needle base to the needle tip.

4. The soluble microneedle patch as described in claim 3, characterized in that, The needle body is conical or pyramidal in shape. The distance between the bottom surface of the needle body and the tip of the needle is 800-1000μm. The center distance between the tips of two adjacent needle bodies is 700-950μm. The diameter of the circumscribed circle or the bottom circle of the needle body is 190-380μm.

5. The method for preparing a soluble microneedle patch as described in claim 1, characterized in that, Includes the following steps: 1) Using the skin-healing composition as a raw material, the blue copper peptide and soluble polymer of the skin-healing composition are dissolved in deionized water, and the resulting mixed solution is used as a microneedle preparation solution. 2) Apply the microneedle preparation solution to the negative mold and centrifuge; 3) Dry the negative mold covered with microneedle preparation solution to obtain the soluble microneedle patch that promotes skin healing.

6. The method for preparing the soluble microneedle patch for promoting skin healing as described in claim 5, characterized in that, The centrifugation speed is 2500-3000 rpm / min, the temperature is 0-5℃, the centrifugation time is 8-15 min, and the number of centrifugations is 2-4.

7. The method for preparing the soluble microneedle patch for promoting skin healing as described in claim 5, characterized in that, The negative mold is placed in a constant temperature drying oven at 20-35℃ and 10-15% humidity for 2-8 hours. After drying, the moisture content of the microneedles is 4.86%-67.92%.

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