Soluble microneedle patch for skin tumor as well as preparation method and application of soluble microneedle patch

Abstract

The invention discloses a soluble microneedle patch for skin tumors and a preparation method and application thereof, and belongs to the technical field of soluble microneedles, gel formed by a microneedle matrix which is excellent in biocompatibility and contains disulfide bonds is injected into a microneedle mold, and the soluble microneedle patch is prepared. Then vacuumizing, centrifuging, adding viscous microneedle substrate polyacrylic acid gel, and drying to obtain the specific soluble microneedle patch of which the dissolution rate in a tumor microenvironment is obviously higher than that of normal tissues. The microneedle matrix with disulfide bonds specifically responds to the high reducibility of a tumor microenvironment, the drug is rapidly broken and released, the drug release amount in a normal skin area is reduced, stimulation to healthy tissue is avoided, potential damage to normal tissue is reduced, and more accurate targeted therapy is achieved.

Description

Technical Field

[0001] This invention relates to the field of soluble microneedles, and in particular to a soluble microneedle patch for skin tumors, its preparation method, and its application. Background Technology

[0002] Cancer remains a major threat to human health globally, and melanoma plays a crucial role in the treatment of skin cancer. Currently, treatment for melanoma primarily relies on traditional methods such as surgical removal and chemotherapy.

[0003] Surgical resection is often difficult to cure advanced tumors. It is suitable for early-stage tumors, but it is highly invasive, easily leaves scars, and can damage surrounding normal tissues, affecting appearance and function. Systemic chemotherapy involves oral or intravenous administration of chemotherapy drugs, but the drugs accumulate at low concentrations in the tumor site, easily causing systemic side effects such as nausea and bone marrow suppression. Patients have poor tolerance to these side effects, and the drugs can easily lead to drug resistance in tumor cells. Furthermore, while novel therapies hold great theoretical potential, their low accumulation efficiency in tumor tissue has hindered their clinical translation. Existing microneedling techniques include solid microneedles that can only penetrate the stratum corneum, requiring subsequent drug application and posing problems of secondary contamination and drug loss; while soluble microneedles can carry drugs, their matrix lacks tumor-targeted release capabilities, and drug residues on normal skin can easily cause irritation.

[0004] Based on the above problems, a soluble microneedle patch for skin tumors and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a soluble microneedle patch for skin tumors, its preparation method, and its application, in order to solve the problems in the background art.

[0006] To achieve the above objectives, the present invention provides a soluble microneedle patch for skin tumors, wherein the soluble microneedle patch is composed of a microneedle matrix and a microneedle base, and the chemical structural formula of the microneedle matrix is ​​as follows: ; The microneedle substrate is polyacrylic acid gel.

[0007] Preferably, the volume of the microneedle matrix is ​​0.1~0.5mL, and the volume of the microneedle substrate is 0.5~1mL; the area of ​​each microneedle is 4cm². 2 It uses a 26×26 array arrangement.

[0008] This invention also provides a method for preparing the above-mentioned soluble microneedle patch for skin tumors, comprising the following steps: S1. Using hyaluronic acid and cystine dihydrochloride as raw materials, an amidation reaction was carried out to prepare microneedle matrix material, which was then freeze-dried and stored for subsequent use. The concentration of the microneedle matrix material was adjusted to obtain a microneedle matrix gel; polyacrylic acid was prepared into a polyacrylic acid gel; S2. Fill the microneedle matrix gel into the microneedle mold, remove the air bubbles of the microneedle matrix gel under vacuum, and then centrifuge. Subsequently, add the microneedle base gel into the microneedle mold and dry at low temperature to obtain a soluble microneedle patch.

[0009] Preferably, in S1, the molecular weight of hyaluronic acid is 20-40W, the molar ratio of hyaluronic acid to cystamine dihydrochloride is 1:3, and the molecular weight of polyacrylic acid is 45W.

[0010] Preferably, in step S1, the specific preparation steps of the microneedle matrix gel are as follows: Hyaluronic acid was dissolved in phosphate buffer, followed by the addition of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. The mixture was stirred and activated. After activation, cystamine dihydrochloride was added to the solution and stirred in the dark. After the activation was completed, the mixture was dialyzed to obtain the microneedle matrix material. The material was then lyophilized and stored for later use. In subsequent use, the concentration of the freeze-dried microneedle matrix material is adjusted with deionized water until it is within the set range to obtain the microneedle matrix gel. The chemical reaction formula is as follows: ; Where n is between 500 and 2000.

[0011] Preferably, in step S1, the concentration of the microneedle matrix gel is 35~50 mg / mL, which is the range for adjusting the concentration of the microneedle matrix material after freeze-drying; the concentration of the polyacrylic acid gel is 5~10 wt%.

[0012] Preferably, in step S2, the specific operation for removing air bubbles from the microneedle matrix gel is as follows: the microneedle mold filled with microneedle matrix gel is placed in a 4°C refrigerator and left to stand for 12 hours, and then placed in a vacuum degassing device with a pressure of (-0.07) to (-0.05) MPa for degassing operation, repeated 3 times, each time for 4 minutes.

[0013] Preferably, in step S2, the centrifugation process uses a low-speed centrifuge with a rotation speed of 2500 rpm, repeated 4 times, each time for 5 minutes.

[0014] Preferably, in step S2, the low-temperature drying temperature is 30°C and the drying time is 12 hours.

[0015] Preferably, the area of ​​the microneedle mold is 4 cm². 2 The needle height of the soluble microneedle patch is 440~500μm, and the needle base diameter is 250μm.

[0016] The present invention also provides the application of the above-mentioned soluble microneedle patch for skin tumors, wherein the soluble microneedle patch is loaded with drugs and applied to the tumor microenvironment to promote rapid drug release; This invention focuses on melanoma.

[0017] The mechanism of action of this invention is as follows: The microneedle matrix used in this invention contains disulfide bonds in its molecular structure. As a type of covalent bond, the disulfide bond exhibits significant redox activity. In vivo, disulfide bonds can undergo breakage and reconstruction under redox conditions, thereby affecting the conformation and activity of molecules. The microenvironments of normal and tumor tissues differ significantly. Tumor cells are metabolically abnormally active and are in a state of relative hypoxia for extended periods, resulting in a much higher concentration of glutathione (GSH) in the tumor microenvironment compared to normal tissues. Research data shows that the extracellular GSH concentration in normal tissues is typically between 2 and 20 μmol / L, while the extracellular GSH concentration in the tumor microenvironment can reach as high as 0.5 to 10 mmol / L. This concentration difference has a decisive impact on the microneedle patch, leading to the breakage of disulfide bonds. The high concentration of GSH provides ample reactants for the disulfide bond cleavage reaction; in the tumor microenvironment, microneedle patch matrix molecules containing disulfide bonds are more prone to disulfide bond cleavage. Therefore, compared to normal tissue, microneedle patches exhibit a significantly enhanced dissolution rate in the tumor microenvironment. In drug delivery applications, when microneedle patches adhere to the tumor site, their rapid dissolution within the tumor microenvironment leads to a substantial increase in drug release rate compared to normal tissue. This allows drugs to act more efficiently on the tumor site while reducing non-specific release in normal tissue, thereby minimizing potential damage to normal tissue and achieving more precise targeted therapy.

[0018] Therefore, the soluble microneedle patch for skin tumors, its preparation method, and its application, as described in this invention, have the following beneficial effects: (1) The disulfide bonds in the microneedle matrix can specifically respond to the high reducing properties of the tumor microenvironment, break quickly and release the drug, reduce the amount of drug released in the normal skin area, avoid stimulation of healthy tissue, and solve the problem of "large side effects of systemic chemotherapy and poor targeting of topical preparations".

[0019] (2) Both the microneedle matrix and the base have good biocompatibility and can be completely degraded in the skin without foreign body residue. At the same time, hyaluronic acid can promote skin repair and reduce scar formation after treatment. The polyacrylic acid base provides sufficient puncture strength for the microneedles to avoid breakage after molding. The volume ratio of the microneedle matrix gel to the base ensures the balance between drug loading and transdermal efficiency, and improves the transdermal absorption rate of drugs.

[0020] (3) The soluble microneedle patch can be loaded with a variety of anti-skin tumor drugs such as chemotherapy drugs and targeted drugs. By adjusting the matrix concentration and drug loading, it can be adapted to the treatment needs of different tumor stages, and has strong practicality and promotion value.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 The above are the 1H NMR spectra of the microneedle matrix material and hyaluronic acid in Example 1 of this invention. Figure 2 The Fourier transform infrared spectra of the microneedle matrix material and hyaluronic acid in Example 1 of this invention are shown below. Figure 3 This is a topographic image of the microneedle patch according to an embodiment of the present invention; Figure 4 This is a comparison chart of the dissolution trends of microneedle patches in Application Examples 1-3 and Application Comparative Example 1 of the present invention; Figure 5 This is a schematic diagram of the microneedle patch of the present invention applied to the skin of a mouse in Application Example 4 of the present invention; Figure 6 This is a diagram showing the dissolution state of the microneedle patch in Application Example 4 of the present invention; Figure 7 This is a diagram showing the dissolution state of the microneedle patch used in Comparative Example 2 of this invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0025] Example 1 This embodiment prepares a specific soluble microneedle patch, and the specific steps are as follows: S1. Weigh 1g of hyaluronic acid (HA) and dissolve it in 180mL of phosphate buffered saline (PBS) at pH=5. Then, add 1.5836g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 1.1739g of N-hydroxysuccinimide (NHS) and stir for 15 minutes to activate the carboxyl groups of hyaluronic acid. After the carboxyl group was activated, 1.7115 g of cystamine dihydrochloride (SS) was added to the solution and stirred in the dark at 4°C for 12 hours. The resulting product was then subjected to dialysis for three days to obtain the microneedle matrix material.

[0026] The obtained microneedle matrix material was freeze-dried and stored for later use.

[0027] Microneedle matrix gel was prepared by adjusting the concentration of microneedle matrix material to 35 mg / mL; at the same time, the concentration of polyacrylic acid was adjusted to 10 wt% to obtain microneedle base gel.

[0028] S2. Inject 0.5 mL of microneedle matrix gel into a cavity with a surface area of ​​4 cm². 2 The microneedle mold, with a height of 500 μm and a needle base diameter of 250 μm, was placed in a 4°C refrigerator and left to stand for 12 hours. After removal, it was placed in a vacuum degassing device with a pressure of -0.07 MPa to -0.05 MPa for degassing, each time for 4 minutes, repeated 3 times. After completion, it was removed and transferred to a specially designed low-speed centrifuge and centrifuged at 2500 rpm for 5 minutes each time, repeated 4 times.

[0029] After processing, inject 0.5 mL of microneedle base gel again, place in an oven at 30°C and bake for 12 hours. Remove and peel off with tweezers to obtain a microneedle patch with specific solubility.

[0030] Nuclear magnetic resonance (NMR) spectroscopy was performed on the microneedle matrix material and hyaluronic acid (HA) prepared in Example 1. An organic solution of the microneedle matrix material was prepared using deuterium water as the organic solvent. The proton NMR spectrum is shown below. Figure 1 As shown, the corresponding characteristic proton signals can be observed. Additionally, using KBr as a background, solid powder of the microneedle matrix material was prepared, and Fourier transform infrared spectroscopy was performed on it and hyaluronic acid, respectively, as shown... Figure 2 As shown, the peak positions of each functional group can be observed.

[0031] The microneedle patch prepared in Example 1 was photographed and observed under an inverted microscope to obtain morphological images of the microneedle patch, such as... Figure 3As shown. From right to left, the scale bars are 1 cm, 100 μm, and 200 μm. The observation results show that the microneedles exhibit a high degree of order, with a needle height of approximately 440 μm and a needle base diameter of approximately 250 μm. The achievement rate of the microneedle height is 88%.

[0032] Example 2 The preparation steps in this embodiment are the same as in Example 1, except that the concentration of the microneedle matrix gel in S1 is modified to 42 mg / mL and the concentration of the microneedle base gel is modified to 8 wt%.

[0033] Example 3 This embodiment is prepared in the same way as in Example 1, except that the concentration of the microneedle matrix gel in S1 is changed to 50 mg / mL and the concentration of the microneedle base gel is changed to 10 wt%.

[0034] Application Example 1 Agarose hydrogel was used as a model to simulate the microenvironment of normal tissue and tumors. Specifically, 2 grams of agarose were dissolved in a 0.5 mmol / L glutathione (GSH) solution and heated in a microwave oven at a low to medium temperature until transparent. The prepared agarose solution was then quickly poured into a mold and cooled at 4°C for 30 minutes to form a simulated skin tissue sample. The microneedle patch prepared in Example 1 was then placed in the simulated skin tissue sample.

[0035] Application Example 2 This application example follows the same steps as application example 1, except that the concentration of the glutathione solution is changed to 10 mmol / L.

[0036] Application Example 3 This application example follows the same steps as Application Example 1, except that the concentration of the glutathione solution is changed to 2.5 mmol / L.

[0037] Application Comparative Example 1 The steps for this comparative application are the same as in Application Example 1, except that the concentration of the glutathione solution is changed to 0.02 mmol / L.

[0038] The dissolution performance of the application examples 1-3 and application comparative example 1 were tested respectively, and the dissolution state of the microneedle patch was recorded at 0 minutes, 5 minutes, and 10 minutes. The results are as follows. Figure 4 As shown, high concentrations of GSH provide sufficient reactants for the disulfide bond cleavage reaction. In the tumor microenvironment, the matrix molecules of microneedle patches containing disulfide bonds are more prone to disulfide bond cleavage. Compared with normal tissue, the dissolution rate of microneedle patches in the tumor microenvironment is significantly improved.

[0039] Application Example 4 The microneedle patch prepared in Example 1 was inserted into the skin of a live melanoma mouse. A schematic diagram of the microneedle patch adhering to the mouse skin is shown below. Figure 5 As shown.

[0040] Application Comparative Example 2 The microneedle patch prepared in Example 1 was inserted into the skin of a normal mouse.

[0041] The dissolution process of the microneedle patches in Application Example 4 and Application Comparative Example 2 was observed under an inverted microscope at different magnifications. The results are as follows: Figure 6 , Figure 7 As shown in the figure. The results showed that the microneedle patch completely dissolved in about 50 minutes on the skin of normal mice, while it completely dissolved in about 30 minutes on the skin of mice inoculated with melanoma cells.

[0042] By comparing the above application comparison examples and application embodiments, it is concluded that the specific soluble microneedle patch prepared in this invention exhibits a significantly improved dissolution rate in the tumor microenvironment compared to normal tissue. In drug loading applications, when the microneedle patch adheres to the tumor site, its rapid dissolution rate in the tumor microenvironment leads to a significantly increased drug release rate compared to normal tissue. This allows the drug to act more efficiently on the tumor site, reducing non-specific release in normal tissue and thus minimizing potential damage to normal tissue, achieving more precise targeted therapy.

[0043] Therefore, the present invention provides a soluble microneedle patch for skin tumors, its preparation method and application, which utilizes the disulfide bond-containing microneedle matrix to specifically respond to the high reducing properties of the tumor microenvironment, rapidly break down and release the drug, reduce the amount of drug released in normal skin areas, avoid stimulation of healthy tissues, reduce potential damage to normal tissues, and achieve more precise targeted therapy.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A soluble microneedle patch for skin tumors, characterized in that: the soluble microneedle patch is composed of a microneedle matrix and a microneedle base, the chemical structure of the microneedle matrix is: the microneedle base is a polyacrylic acid gel. The volume of the microneedle matrix is 0.1-0.5 mL, and the volume of the microneedle base is 0.5-1 mL. ； Comprising the following steps:

2. The dissolvable microneedle patch for skin tumors according to claim 1, wherein: S1, taking hyaluronic acid and cystamine dihydrochloride as raw materials, carrying out amidation reaction to prepare microneedle matrix material, adjusting the concentration of the microneedle matrix material to obtain microneedle matrix gel; polyacrylic acid is made into polyacrylic acid gel; 3. A method of manufacturing the dissolvable microneedle patch against skin tumors according to any one of claims 1-2, characterized in that, S2, fill the microneedle matrix gel into the microneedle mold, remove the air bubbles of the microneedle matrix gel under vacuum condition, then centrifuge, then add microneedle base gel into the microneedle mold, and dry at low temperature to obtain the soluble microneedle patch. In S1, the molecular weight of hyaluronic acid is 20-40W, the molar ratio of hyaluronic acid to cystamine dihydrochloride is 1:3, and the molecular weight of polyacrylic acid is 45W. In S1, the specific preparation steps of the microneedle matrix gel are:

4. The method of claim 3, wherein: Dissolve hyaluronic acid in phosphate buffer, then add 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride and N-hydroxysuccinimide, stir and activate, then add cystamine dihydrochloride to the solution, stir in the dark, dialyze after completion, obtain the microneedle matrix material, then adjust the concentration of the microneedle matrix material to obtain the microneedle matrix gel.

5. The method of claim 3, wherein: In S1, the concentration of the microneedle matrix gel is 35-50 mg / mL, and the concentration of the polyacrylic acid gel is 5-10 wt%. In S2, the specific operation for removing the air bubbles of the microneedle matrix gel is: place the microneedle mold filled with the microneedle matrix gel in a 4℃ refrigerator for 12h, then put it into a vacuum bubble removal device with a pressure of (-0.07) to (-0.05) Mpa for bubble removal operation.

6. The method of claim 3, wherein: In S2, the centrifugation process uses a low-speed centrifuge with a speed of 2500 rpm.

7. The method of claim 3, wherein: In S2, the temperature of low-temperature drying is 30℃, and the drying time is 12h.

8. The method of claim 3, wherein: The soluble microneedle patch is loaded with drugs and applied to the tumor microenvironment to promote rapid drug release.

9. The method of claim 3, wherein: ​ 10. Use of a dissolvable microneedle patch against skin tumors according to any one of claims 1-2, characterized in that: ​

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