Adhesive hydrogel drug-loaded microsphere for acupoint stimulation, and preparation method and application thereof

Abstract

The invention provides an adhesive hydrogel drug-loaded microsphere for acupoint stimulation as well as a preparation method and application thereof, and relates to the technical field of medicines. Comprising the following steps: S1, weighing phosphatidylserine and cholesterol powder, dissolving the phosphatidylserine and cholesterol powder in trichloromethane, and performing rotary evaporation to remove a solvent until the phosphatidylserine and cholesterol powder is dried to form a lipid film; s2, pouring a PBS (Phosphate Buffer Solution) added with adenosine into the lipid film, and hydrating to form a liposome solution; s3, preparing mineral oil and a Ge MA solution, uniformly mixing the liposome solution with the Ge MA solution, and adding a photoinitiator to obtain a mixed solution; s4, the mixed solution is subjected to a photo-crosslinking reaction under the condition of ultraviolet lamp irradiation, and hydrogel drug-loaded microspheres are formed; and S5, adding the hydrogel drug-loaded microspheres into a dopamine solution, and forming a polydopamine coating on the surfaces of the microspheres. According to the invention, the free adenosine is embedded in the hydrogel microspheres with adhesion to acupuncture points, so that the sustained release of the adenosine can be realized, the problem of short half-life period of the adenosine can be overcome, and the lasting time of the drug effect can be prolonged.

Description

Technical Field

[0001] The invention belongs to the field of medical technology, and particularly relates to an adhesive hydrogel drug-loaded microsphere for acupoint stimulation, a preparation method and an application thereof. Background Art

[0002] Chronic pain, as a disease, not only causes serious physical and psychological distress to patients, but also brings huge economic burden to patients' families. It is one of the health problems that urgently needs to be solved. Acupuncture treatment, such as acupuncture, is not only effective in treating chronic pain, but also has a small economic burden and is easily accepted by the general public. It is a safe and effective method.

[0003] However, conventional acupuncture therapy cannot meet the clinical long-term analgesia needs due to its short-term efficacy, poor after-effects, and "ceiling effect" in analgesia. Therefore, improving acupuncture therapy and optimizing the long-term analgesic effect of acupoint stimulation have become common key issues that need to be urgently addressed in pain management and acupuncture clinical practice.

[0004] Current studies have shown that the release of endogenous adenosine is crucial for triggering the analgesic effect of acupuncture, and the injection of adenosine and other adenosine A1 receptor agonists into acupoints can exert an analgesic effect. However, due to the short half-life of free drugs, frequent administration is required to achieve sustained analgesia, which increases the incidence of cardiovascular side effects. Moreover, the direct injection of free adenosine A1 receptor agonists into acupoints can easily cause acupoints to be off-target due to rapid subcutaneous diffusion, thus failing to achieve the effect of sustained stimulation of acupoints.

[0005] In summary, how to provide a drug carrier that can help injectable drugs to be locally slowly released at acupuncture points is a technical problem that urgently needs to be solved. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an adhesive hydrogel drug-loaded microsphere for acupoint stimulation, a preparation method and an application thereof. The obtained hydrogel drug-loaded microsphere can adhere to the acupoints. By embedding free adenosine A1 receptor agonist in the hydrogel drug-loaded microsphere, the sustained release of adenosine A1 receptor agonist can be achieved, thereby overcoming the problem of its short half-life and prolonging the duration of the drug effect.

[0007] The invention provides an adhesive hydrogel drug-loaded microsphere for acupoint stimulation. The surface of the drug-loaded hydrogel drug-loaded microsphere is modified with polydopamine to obtain the adhesive hydrogel drug-loaded microsphere. The hydrogel drug-loaded microsphere is loaded with an adenosine A1 receptor agonist.

[0008] Furthermore, the microspheres have a particle size of 100-160 μm and a smooth surface.

[0009] The present invention provides a method for preparing the adhesive hydrogel drug-loaded microspheres as described in any one of the above, the method comprising the following steps:

[0010] S1 Weigh phosphatidylserine and cholesterol powders, dissolve them in chloroform, and then remove the solvent by rotary evaporation until dry to form a lipid film;

[0011] S2 pours a PBS solution containing adenosine into the lipid film to hydrate it and form a liposome solution;

[0012] S3: preparing mineral oil and Gel MA solution, uniformly mixing the liposome solution and the Gel MA solution, and then adding a photoinitiator to obtain a mixed solution;

[0013] S4: irradiating the mixed solution with ultraviolet light to form hydrogel drug-loaded microspheres through photo-crosslinking reaction;

[0014] S5 prepares a dopamine solution, adds the hydrogel drug-loaded microspheres into the dopamine solution, forms a polydopamine coating on the surface of the hydrogel drug-loaded microspheres, and obtains adhered hydrogel drug-loaded microspheres.

[0015] Further, S2 includes preheating the PBS solution to 37-45° C. and then pouring the solution into the lipid film.

[0016] Furthermore, after the liposome solution is formed in S2, the liposome solution is placed in an ultrasonic disruptor for homogenization to form monodisperse liposomes.

[0017] Further, S4 includes adding the mixed solution and mineral oil into the coaxial microfluidic device and reacting under ultraviolet light.

[0018] Furthermore, after the hydrogel drug-loaded microspheres are formed in S4, the step further includes washing the hydrogel drug-loaded microspheres with ether and ultrapure water.

[0019] Further, S5 preparing the dopamine solution includes using an alkaline Tris-HCl buffer to dissolve dopamine, wherein the pH of the buffer is 8.5.

[0020] Further, S5 includes adding the hydrogel drug-loaded microspheres to the dopamine solution and stirring at room temperature for 3-24 hours;

[0021] After obtaining the adherent hydrogel drug-loaded microspheres in S5, the dopamine solution is transferred into a centrifuge tube, and the adherent hydrogel drug-loaded microspheres in the solution are allowed to settle to the bottom, and the supernatant is removed, and then the microspheres are washed twice with PBS.

[0022] Furthermore, the adhered hydrogel drug-loaded microspheres are used for local acupuncture analgesia at acupoints.

[0023] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art, as an example:

[0024] Adhesive hydrogel drug-loaded microspheres are adhesive to acupuncture points. When loaded with adenosine, they can help adhere adenosine to the acupuncture points to avoid off-target effects of adenosine. In addition, the release rate of adenosine in the microspheres is low, which can achieve the effect of local sustained release. A single injection can exert a long-term stimulation effect on the acupuncture points, reduce the frequency of administration, reduce the incidence of cardiovascular side effects, improve safety, and achieve toxicity reduction and efficacy enhancement in pain management. It has great application potential in acupuncture practice and pain management.

[0025] In addition, the injectable feature of the present invention makes its application scenarios wider, is more conducive to clinical transformation, and is convenient for medical staff to perform injection operations. It has wide clinical applications and great economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the steps of the method for preparing the adherent hydrogel drug-loaded microspheres provided by the present invention.

[0027] Figure 2 This is a schematic diagram of the principle of polydopamine modification provided by the present invention.

[0028] Figure 3 This is a macroscopic morphological image of the microspheres before and after polydopamine modification under a microscope provided by the present invention.

[0029] Figure 4 This is a microscopic morphology of the microspheres before and after polydopamine modification under a microscope provided by the present invention.

[0030] Figure 5 The particle size values ​​of the microspheres before and after polydopamine modification provided by the present invention.

[0031] Figure 6 This is the drug release behavior curve of the adherent hydrogel drug-loaded microspheres provided by the present invention.

[0032] Figure 7 This is a diagram of the pain behavior experiment within 24 hours provided by the present invention.

[0033] Figure 8 This is a diagram of the pain behavior experiment within 10 days provided by the present invention.

[0034] Fig. 9 This is a diagram of a local tissue adhesion experiment provided by the present invention.

[0035] Fig.10 This is a diagram of the in vivo fluorescence experiment provided by the present invention.

[0036] Fig.11 This is a biocompatibility experiment diagram provided by the present invention. DETAILED DESCRIPTION

[0037] The technical solution disclosed in the present invention is described in detail below in conjunction with specific embodiments.

[0038] Techniques and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0039] The present invention provides a method for preparing adherent hydrogel drug-loaded microspheres, such as Figure 1 and Figure 2 shown.

[0040] The method comprises the following steps:

[0041] S1: Weigh phosphatidylserine and cholesterol powders, dissolve them in chloroform, and then remove the solvent chloroform by rotary evaporation until dry to form a lipid film.

[0042] S2 pours PBS solution into the lipid film to hydrate it and form a liposome solution;

[0043] Optionally, S2 includes preheating the PBS solution to 37-45° C. before pouring it into the lipid film. Preheating the PBS can improve the hydration efficiency, promote the self-assembly of lipids, and help form uniform liposomes.

[0044] Optionally, after the liposome solution is formed in S2, the liposome solution is placed in an ultrasonic disruptor for homogenization to form monodisperse liposomes.

[0045] Preferably, in the case where adenosine needs to be introduced, S2 further comprises dissolving adenosine powder using physiological saline to a concentration of 1 mM, adding adenosine to the PBS solution, and then pouring the adenosine into the lipid film.

[0046] S3: preparing mineral oil and Gel MA solution, uniformly mixing the aforementioned liposome solution with the Gel MA solution, and then adding a photoinitiator to obtain a mixed solution.

[0047] S4 places the mixed solution under ultraviolet light irradiation conditions to form hydrogel drug-loaded microspheres loaded with adenosine through photo-crosslinking reaction.

[0048] Optionally, S4 includes adding the mixed solution and mineral oil together into a coaxial microfluidic device, and reacting under ultraviolet light to avoid the mutual aggregation of hydrogel drug-loaded microspheres that may occur in the absence of an oil phase, forming larger clumps, and insufficient penetration depth of ultraviolet light, resulting in uneven cross-linking efficiency, affecting the dispersibility, physical and chemical properties of the microspheres. Affecting the dispersibility and performance of the microspheres. In a coaxial microfluidic device, the particle size of the microspheres can be controlled by adjusting the flow rate of the oil phase to form hydrogel drug-loaded microspheres with a particle size of 100-160 μm.

[0049] After the hydrogel drug-loaded microspheres are formed, S4 also includes washing the hydrogel drug-loaded microspheres with ether and ultrapure water.

[0050] S5 prepares a dopamine solution. As a typical implementation, an alkaline buffer solution, such as Tris-HCl buffer solution, is used to dissolve dopamine. The pH of the buffer solution is 8.5.

[0051] S5: adding the hydrogel drug-loaded microspheres into the dopamine solution, stirring at room temperature for 3-24 hours, forming a polydopamine coating on the surface of the hydrogel drug-loaded microspheres, and obtaining adhered hydrogel drug-loaded microspheres.

[0052] After obtaining the adherent hydrogel drug-loaded microspheres in S5, the process also includes transferring the dopamine solution into a centrifuge tube, allowing the adherent hydrogel drug-loaded microspheres in the solution to settle to the bottom, removing the supernatant, and washing twice with PBS to remove free polydopamine.

[0053] The obtained adherent hydrogel drug-loaded microspheres can then be suspended in a PBS solution for storage.

[0054] The obtained microspheres have a particle size of 100-160 μm and a dark black and smooth surface morphology.

[0055] The specific examples of the above preparation process are as follows:

[0056] Example 1

[0057] Weigh 5 mg of serine and 1 mg of cholesterol, add them to chloroform to fully dissolve, place them in a rotary evaporator, and rotary evaporate them at 48°C for 2 hours until they are completely dry to form a uniform lipid film; preheat the PBS solution added with adenosine to 37°C and add it to the lipid film to hydrate the lipids; place the liposome solution in an ultrasonic disruptor for homogenization.

[0058] 99% Span805mL + mineral oil 45mL mixed for use; liposome nanoparticle solution and Gel MA solution were mixed and 0.2% g / mL of photoinitiator phenyl-2,4,6-trimethylbenzoyl lithium phosphite was added, and the reaction was carried out in a coaxial microfluidic device, and ultraviolet light was used for light cross-linking. The hydrogel drug-loaded microspheres formed had a particle size of 100μm. The hydrogel drug-loaded microspheres were washed with ether and ultrapure water respectively for use.

[0059] Dopamine was dissolved in alkaline Tris-HCl buffer (pH=8.5), and the hydrogel drug-loaded microspheres prepared previously were added to the dopamine solution and stirred at room temperature for 12 hours. After stirring, the liquid was transferred to a centrifuge tube, and the microspheres were allowed to settle to the bottom, the supernatant was removed, and the microspheres were washed twice with PBS.

[0060] Example 2

[0061] Weigh 5 mg of serine and 1 mg of cholesterol, add them to chloroform to fully dissolve, place them in a rotary evaporator, and rotary evaporate them at 50°C for 1.5 hours until they are completely dry to form a uniform lipid film; preheat the PBS solution added with adenosine to 45°C and add it to the lipid film to hydrate the lipids; place the liposome solution in an ultrasonic disruptor for homogenization.

[0062] 99% Span805mL + mineral oil 45mL mixed for use; liposome nanoparticle solution and Gel MA solution were mixed and 0.2% g / mL of photoinitiator phenyl-2,4,6-trimethylbenzoyl lithium phosphite was added, and the reaction was carried out in a coaxial microfluidic device, and ultraviolet light was used for light cross-linking. The hydrogel drug-loaded microspheres formed had a particle size of 1000μm. The hydrogel drug-loaded microspheres were washed with ether and ultrapure water respectively for use.

[0063] Dopamine was dissolved in alkaline Tris-HCl buffer (pH = 8.5), and the hydrogel drug-loaded microspheres prepared previously were added to the dopamine solution and stirred at room temperature for 24 hours. After stirring, the liquid was transferred to a centrifuge tube, and the microspheres were allowed to settle to the bottom, the supernatant was removed, and the microspheres were washed twice with PBS.

[0064] Example 3

[0065] Weigh 5 mg of serine and 1 mg of cholesterol, add them to chloroform to fully dissolve, place them in a rotary evaporator, and rotary evaporate them at 40°C for 2.5 hours until they are completely dry to form a uniform lipid film; preheat the PBS solution added with adenosine to 40°C and add it to the lipid film to hydrate the lipids; place the liposome solution in an ultrasonic disruptor for homogenization.

[0066] 99% Span805mL + mineral oil 45mL mixed for use; liposome nanoparticle solution and Gel MA solution were mixed and 0.2% g / mL of photoinitiator phenyl-2,4,6-trimethylbenzoyl lithium phosphite was added, and the reaction was carried out in a coaxial microfluidic device, and ultraviolet light was used for light cross-linking. The hydrogel drug-loaded microspheres formed had a particle size of 10μm. The hydrogel drug-loaded microspheres were washed with ether and ultrapure water respectively and set aside.

[0067] Dopamine was dissolved in alkaline Tris-HCl buffer (pH=8.5), and the hydrogel drug-loaded microspheres prepared previously were added to the dopamine solution and stirred at room temperature for 3 hours. After stirring, the liquid was transferred to a centrifuge tube, and the microspheres were allowed to settle to the bottom, the supernatant was removed, and the microspheres were washed twice with PBS.

[0068] like Figure 3 As shown, from left to right are the macroscopic morphology of the microspheres before and after polydopamine modification under a microscope.

[0069] like Figure 4 As shown, from left to right are the microscopic morphology of the microspheres before and after polydopamine modification under a microscope.

[0070] like Figure 5 As shown, from left to right are the particle size values ​​of the microspheres before and after polydopamine modification.

[0071] Release behavior test:

[0072] The adhered microspheres loaded with adenosine were placed in a PBS solution and placed in a shaker at 37 degrees Celsius. The PBS solution was collected every other day, and the concentration of adenosine released in the solution was measured by a UV spectrophotometer to draw a release curve.

[0073] The results are as follows Figure 6 As shown, dopamine-modified microspheres can achieve stable sustained drug release, with no drug burst release in the early stage of release and complete drug release after 7 days.

[0074] The prepared adherent hydrogel drug-loaded microspheres were used for in vivo experiments. The experimental steps are as follows:

[0075] Inflammatory pain mouse model:

[0076] Twenty-four male C57 / BL6 mice were randomly divided into the model group CFA (n=6), CFA+ADO group (n=6), CFA+li po@Gel MA MS group (n=6), and CFA+PDA / ADO li po@Gel MA MS group (n=6). All mice were anesthetized with isoflurane and subcutaneously injected with 20uL of CFA into the plantar of the left hind foot (middle of the sole, near the root of the third toe) to establish the model. 1mL of CFA contained 1mg of heat-killed and dried Mycobacterium tuberculosis, 0.85mL of paraffin oil, and 0.15mL of mannose ester. The CFA+ADO group was then injected with a pre-prepared adenosine solution at the Zusanli acupoint on the left lower limb of the mice, the CFA+li po@Gel MA MS group was injected with an equal volume of liposome hydrogel drug-loaded microsphere solution at the Zusanli acupoint on the left lower limb of the mice, and the CFA+PDA / ADO li po@Gel MA MS group was injected with an equal volume of adhesive hydrogel drug-loaded microsphere solution at the Zusanli acupoint on the left lower limb of the mice. Behavioral tests were performed after the mice woke up naturally.

[0077] Pain behavior experiment:

[0078] The leg-raising reaction threshold was detected by the up-down method, and the changes in the pain threshold and time course of the mice were observed to evaluate the mechanical pain threshold. Eight von Frey hairs of different strengths were used (0.97, 2, 3.87, 5.9, 8.3, 10.1, 14.4, 27.5 g). The mice were placed in a transparent plexiglass box with a metal mesh at the bottom (the mesh was 0.8×0.8 cm). The skin at the bottom of the mouse's hind paw was stimulated with the von Frey hair through the mesh. Each stimulation lasted 2-3 seconds, the interval between each stimulation was 5 minutes, and each intensity was applied 10 times. The behavior of the mouse quickly raising its hind paw or licking its hind paw was indicated as a positive reaction. The 50% positive reaction threshold was calculated as the leg-raising reaction threshold of the mouse.

[0079] like Figure 7 The results showed that the mechanical pain threshold of mice was significantly reduced after successful modeling. The pain threshold increased after the application of adherent hydrogel drug-loaded microspheres at the acupoints and remained at a high level for 24 hours. After direct injection of ADO at the acupoints, the pain threshold increased significantly in the first hour, but decreased again after 6 hours and continued to remain at a low level. There was no significant difference in the pain threshold after liposome microspheres were administered at the acupoints compared with the model group.

[0080] Figure 8 The results showed that the mechanical pain threshold of mice was significantly reduced after successful modeling, and the pain threshold increased and maintained for nearly 10 days after acupoint application of adherent hydrogel drug-loaded microspheres; there was no significant difference in the changes in pain thresholds of the other three groups.

[0081] Blood drug concentration test:

[0082] The peripheral blood ADO concentration of each group of mice was detected by ELISA. Blood was collected by cutting the tail on days 1, 3, 5, 7, and 10 after modeling, placed in anticoagulant tubes, and centrifuged at 3000 rpm for 30 min. The supernatant was taken and operated according to the steps in the ELISA kit manual.

[0083] Peripheral blood cytokine level detection:

[0084] The levels of IL-6, IL-10, and TNF-α in the peripheral blood of each group of mice were detected by ELISA. Blood was collected by cutting the tails on days 1, 3, 5, 7, and 10 after modeling, placed in anticoagulant tubes, and centrifuged at 3000 rpm for 30 min. The supernatant was taken and operated according to the steps in the ELISA kit instructions.

[0085] Local adhesion assay:

[0086] The adhesion properties of hydrogel drug-loaded microspheres were investigated using depilated mouse skin tissue. Polydopamine-modified microspheres and control microspheres were dropped onto the skin, and then PBS was added to rinse the skin to investigate the retention of the microspheres on the skin surface after rinsing.

[0087] like Fig. 9 As shown, the brown adhesive hydrogel drug-loaded microspheres modified with polydopamine still mostly remain on the skin surface after being washed with PBS, and have stronger adhesion to the skin compared with the unmodified transparent hydrogel drug-loaded microspheres next to them.

[0088] In vivo tracking of hydrogel drug-loaded microspheres:

[0089] Liposomes were labeled with ICG dye, and then ICG-labeled microspheres were prepared. Polydopamine-modified microspheres and control microspheres were injected into the Zusanli acupoint of two groups of mice, respectively. In vivo fluorescence imaging was used to investigate the retention of ICG at the acupoints of mice on the 1st, 3rd, 5th, 7th, and 10th days of administration.

[0090] The results are as follows Fig.10 As shown, it can be clearly found that the fluorescence attenuation and dissipation of the polydopamine-modified adhesive hydrogel drug-loaded microspheres experimental group is slower than that of the control group of hydrogel drug-loaded microspheres not modified with polydopamine.

[0091] Biocompatibility test:

[0092] The adherent hydrogel drug-loaded microspheres were co-cultured with fibroblasts and macrophages, respectively, and the cytotoxicity and proliferation behavior were investigated using live and dead cell staining and CCK8 assay on the 3rd and 5th days.

[0093] The results are as follows Fig.11As shown, the cell proliferation behavior of each group on the 3rd and 5th days of co-culture was good and there was no significant difference in the proportion of live cells, indicating that the adherent hydrogel drug-loaded microspheres were non-cytotoxic.

[0094] In the scope of the intended protection of the present disclosure, terms such as "including" and the like should be interpreted as inclusive or open by default, rather than exclusive or closed, unless they are expressly defined to the contrary. All technical, scientific or other terms have the meanings understood by those skilled in the art unless they are defined to the contrary. Common terms found in dictionaries should not be interpreted too idealistically or too impractically in the context of relevant technical documents, unless the present disclosure expressly defines them as such.

[0095] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0096] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An adhesive hydrogel drug-loaded microsphere for acupoint stimulation, characterized in that: The surface of the hydrogel microspheres is modified with polydopamine to obtain adherent hydrogel drug-loaded microspheres, wherein the hydrogel microspheres are loaded with adenosine A1 receptor agonists.

2. The adhesive hydrogel drug-loaded microspheres according to claim 1, characterized in that: The microspheres have a particle size of 100-160 μm and a smooth surface.

3. A method for preparing the adherent hydrogel drug-loaded microspheres as described in any one of claims 1-2, characterized in that The method comprises the following steps: S1 Weigh phosphatidylserine and cholesterol powders, dissolve them in chloroform, and then remove the solvent by rotary evaporation until dry to form a lipid film; S2 pours a PBS solution containing adenosine into the lipid film to hydrate it and form a liposome solution; S3: preparing mineral oil and GelMA solution, uniformly mixing the liposome solution and the GelMA solution, and adding a photoinitiator to obtain a mixed solution; S4: irradiating the mixed solution with ultraviolet light to form hydrogel drug-loaded microspheres through photo-crosslinking reaction; S5 prepares a dopamine solution, adds the hydrogel drug-loaded microspheres into the dopamine solution, forms a polydopamine coating on the surface of the hydrogel drug-loaded microspheres, and obtains adhered hydrogel drug-loaded microspheres.

4. The preparation method according to claim 3, characterized in that: S2 includes preheating the PBS solution to 37-45° C. and then pouring the solution into the lipid film.

5. The preparation method according to claim 3, characterized in that: After the liposome solution is formed in S2, the liposome solution is placed in an ultrasonic disruptor for homogenization to form monodisperse liposomes.

6. The preparation method according to claim 3, characterized in that: S4 includes adding the mixed solution and mineral oil into the coaxial microfluidic device and reacting under ultraviolet light.

7. The preparation method according to claim 3, characterized in that: After the hydrogel drug-loaded microspheres are formed, S4 also includes washing the hydrogel microspheres with ether and ultrapure water.

8. The preparation method according to claim 3, characterized in that: S5: preparing the dopamine solution comprises dissolving dopamine in an alkaline buffer solution, wherein the pH of the buffer solution is 8.

5.

9. The preparation method according to claim 3, characterized in that: S5 includes adding the hydrogel drug-loaded microspheres to the dopamine solution and stirring at room temperature for 3-24 hours; After obtaining the adherent hydrogel drug-loaded microspheres in S5, the dopamine solution is transferred into a centrifuge tube, and the adherent hydrogel drug-loaded microspheres in the solution are allowed to settle to the bottom, and the supernatant is removed, and then the microspheres are washed twice with PBS.

10. The adhesive hydrogel drug-loaded microspheres according to any one of 1-2, characterized in that: Adhesive hydrogel drug-loaded microspheres are used as acupoint local acupuncture analgesic drug delivery.

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