Patch for treating gout based on folium apocyni veneti and preparation method thereof
By developing a topical patch of Apocynum venetum leaves, the problem of significant side effects from oral medications in gout treatment has been solved, providing a localized, convenient, and long-lasting treatment option suitable for a variety of patient groups.
Patent Information
- Application Number
- CN202511057474.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-18
AI Technical Summary
Most existing gout medications are oral preparations, and long-term use can cause side effects on organs such as the gastrointestinal tract, liver, and kidneys. There is also limited research on topical patches.
A topical patch based on Apocynum venetum leaves was developed, comprising a backing layer, an adhesive layer, and an anti-adhesive layer. The adhesive layer contains total flavonoid extracts from Apocynum venetum leaves, transdermal absorption enhancers, excipients, and an adhesive matrix. It is designed to act directly on the affected area through transdermal absorption, incorporating modern transdermal technology.
It achieves localized targeted therapy, reduces systemic side effects, is easy to use, continuously releases drugs, reduces drug interactions and toxicity, and is suitable for long-term use.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of Apocynum venetum leaf technology, specifically to a patch for treating gout based on Apocynum venetum leaves and its preparation method. Background Technology
[0002] Gout is a disease caused by abnormal uric acid metabolism, often manifesting as joint pain, swelling, and inflammation. Currently, most medications for gout are oral preparations, and long-term use may cause side effects on the gastrointestinal tract, liver, and kidneys. Modern separation and analysis show that Apocynum venetum leaves contain various components such as flavonoids, tannins, organic acids, saponins, and volatile oils, with flavonoids and organic acids being the main active ingredients. The most important flavonoid components in Apocynum venetum are hyperoside, isoquercitrin, rutin, quercetin, etc., which have multiple effects including lowering blood pressure, sedation, diuresis, anti-aging, and improving immunity. However, its application in gout treatment is mostly limited to oral or herbal forms, with limited research on topical patches. Therefore, this patent develops a topical patch based on Apocynum venetum leaves, which has significant clinical application value. Summary of the Invention
[0003] This invention provides a gout patch based on Apocynum venetum leaves and its preparation method. Based on the uric acid-lowering effect of total flavonoids in Apocynum venetum leaves, this invention offers a novel dosage form for gout treatment. The gout patch combines traditional Chinese herbal medicine with modern transdermal technology and materials science design, providing a safe, effective, and convenient treatment solution. This product not only improves the efficacy and comfort of the patch but also reduces side effects. The technical solution provided by this invention is as follows: On one hand, embodiments of the present invention provide a patch for treating gout based on Apocynum venetum leaves, comprising a backing layer, an adhesive layer, and an anti-adhesive layer, wherein the adhesive layer comprises, by weight percentage: Apocynum venetum leaf total flavonoid extract 5-10%; Transdermal absorption enhancer 1-3%; 2-5% of auxiliary materials; Remaining amount of adhesive substrate.
[0004] The preparation method of the total flavonoid extract of Apocynum venetum leaves is as follows: Apocynum venetum leaves are extracted by ultrasonic extraction with ethanol and then purified by macroporous resin column.
[0005] The backing layer is made of non-woven fabric, etc., and the anti-adhesive layer is made of polyethylene film, etc.
[0006] Among them, the transdermal absorption enhancer is selected from azone or menthol, etc.
[0007] The adhesive matrix is selected from hydrogels or pressure-sensitive adhesives, etc.
[0008] The excipients include humectants and preservatives, with the humectant accounting for 2-5% by weight and the preservative accounting for 0.1-0.5% by weight. The humectant is selected from glycerin, etc., and the preservative is selected from sodium benzoate, etc.
[0009] The preparation method of the total flavonoid extract from Apocynum venetum leaves is as follows: Dried Apocynum venetum leaves are pulverized, sieved, and ultrasonically extracted with 50-80 vol% ethanol solution at a temperature of 45-55℃ for 25-120 minutes. The extract is filtered and concentrated under reduced pressure until no alcohol odor is detected, yielding a crude extract of total flavonoids from Apocynum venetum leaves. This crude extract is then purified using a macroporous resin column to obtain the total flavonoid extract from Apocynum venetum leaves. The purification process using the macroporous resin column is as follows: the adsorption resin used is selected from AB-8 type macroporous resin; the concentration of the added sample is 1-4 mg / mL, the pH value is 4.8-5.2; the sample loading amount is 2.0-3.0 mL / g resin mass, and the adsorption time is 3-6 h; then elution is performed with 2-4 column volumes of 50-80 vol% ethanol solution for 1.5-3.0 h.
[0010] Preferably, the preparation method of the total flavonoid extract from Apocynum venetum leaves is as follows: dried Apocynum venetum leaves are pulverized, sieved, and ultrasonically extracted with 75 vol% ethanol solution at 50°C for 60 minutes. The extract is filtered and concentrated under reduced pressure until no alcohol odor is detected, yielding a crude extract of total flavonoids from Apocynum venetum leaves. This crude extract is then purified using a macroporous resin column to obtain a high-purity extract of total flavonoids from Apocynum venetum leaves. The macroporous resin column purification process is as follows: the adsorption resin used is selected from AB-8 type macroporous resin; the concentration of the added sample is 2 mg / mL, the pH value is 5.0; the sample loading amount is 2.5 mL / g resin mass, the adsorption time is 4 h; and elution is performed with 3 column volumes of 70 vol% ethanol solution for 2 h.
[0011] Specifically, the adhesive layer comprises, by weight percentage: 5% total flavonoid extract of Apocynum venetum leaves, 1% azone, 3% glycerin, 0.2% sodium benzoate, and the remainder being the hydrogel matrix.
[0012] Specifically, the adhesive layer comprises, by weight percentage: 7% total flavonoid extract of Apocynum venetum leaves, 2% menthol, 4% glycerin, 0.3% sodium benzoate, and the remainder being the pressure-sensitive adhesive matrix.
[0013] On the other hand, embodiments of the present invention also provide a method for preparing a patch for treating gout based on Apocynum venetum leaves, the method comprising: S1: The total flavonoid extract of Apocynum venetum leaves, transdermal absorption promoter, excipients and adhesive matrix are mixed according to the formula to obtain the adhesive layer material.
[0014] The preparation method of the total flavonoid extract from Apocynum venetum leaves is as follows: dried Apocynum venetum leaves are pulverized, sieved, and ultrasonically extracted with 65-80 vol% ethanol solution at an extraction temperature of 45-55℃ for 25-120 minutes; the extract is filtered and concentrated under reduced pressure until no alcohol odor is detected to obtain crude extract of total flavonoids from Apocynum venetum leaves. This is then purified using a macroporous resin column to obtain a high-purity extract of total flavonoids from Apocynum venetum leaves. The purification process using the macroporous resin column is as follows: the adsorption resin used is selected from AB-8 type macroporous resin; the concentration of the added sample is 1-4 mg / mL, the pH value is 4.8-5.2; the sample loading amount is 2.0-3.0 mL / g resin mass, and the adsorption time is 3-6 h; then elution is performed with 2-4 column volumes of 65-80 vol% ethanol solution for 1.5-3.0 h.
[0015] S2: Apply the adhesive layer material evenly to the backing layer to form an adhesive layer, then cover it with an anti-adhesive layer and cut it into patches of the required size.
[0016] S3: Pack the patch into an aluminum-plastic packaging bag, seal it, and sterilize it using ultraviolet light or gamma rays.
[0017] This patent has the following advantages: 1. Local targeted therapy, acting directly on the affected area: The patch can be applied directly to the painful or swollen area to quickly relieve symptoms; Reduced systemic side effects: Compared with oral medications, the patch is absorbed through the skin, reducing irritation to organs such as the gastrointestinal tract, liver, and kidneys.
[0018] 2. Convenient to use, no oral or injection required: especially suitable for patients with difficulty swallowing or fear of injections. Can be used anytime, anywhere: does not interfere with daily activities, offering flexible use.
[0019] 3. Continuous drug release and long-lasting sustained release: The patch can slowly release the drug, providing a continuous therapeutic effect and reducing the inconvenience of frequent medication.
[0020] 4. Reduce gastrointestinal irritation and avoid gastrointestinal discomfort: It does not pass through the digestive tract and is suitable for patients with weak gastrointestinal function or those who are sensitive to oral medications.
[0021] 5. Reduced drug interactions and conflicts with other medications: Topical patches have fewer interactions with other oral medications, making them suitable for patients taking multiple medications simultaneously.
[0022] 6. Suitable for long-term use and reduces systemic toxicity: Long-term use of the patch has lower systemic toxicity, making it suitable for patients requiring long-term treatment.
[0023] 7. The applicant discovered that by using a special extraction method, the total flavonoid extract obtained retained more substances beneficial to the treatment of gout (in smaller quantities, but with significant effects) and had a high yield of total flavonoids.
[0024] In summary, gout patches have advantages such as local treatment, ease of use, and few side effects. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.
[0026] Example 1 Example 1 provides a method for preparing a patch for treating gout based on Apocynum venetum leaves, the method comprising: (1) Take 180g of dried Apocynum venetum leaves, crush them, and extract them with 75 vol% ethanol by ultrasonic extraction for 0.5 hours at an extraction temperature of 50℃. Filter and concentrate to obtain 5g of crude extract of total flavonoids from Apocynum venetum leaves.
[0027] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 2.5g of high-purity total flavonoid extract.
[0028] (3) Mix 2.5g of total flavonoid extract with 0.5g of azone, 45g of hydrogel matrix, 2.0g of glycerin and 0.15g of sodium benzoate, and stir well.
[0029] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 5cm×5cm patches.
[0030] (5) After packaging, sterilize to obtain the finished product.
[0031] Example 2 Example 2 provides a method for preparing a patch for treating gout based on Apocynum venetum leaves, the method comprising: (1) Take 350g of dried Apocynum venetum leaves, crush them and extract them with 75 vol% ethanol by ultrasonic extraction for 1 hour at an extraction temperature of 50℃. Filter and concentrate to obtain 10g of crude extract of total flavonoids from Apocynum venetum leaves.
[0032] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 5g of high-purity total flavonoid extract.
[0033] (3) Mix 5g of total flavonoid extract with 1.0g of azone, 90g of hydrogel matrix, 3g of glycerin and 0.2g of sodium benzoate and stir well.
[0034] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 7cm×7cm patches.
[0035] (5) After packaging, sterilize to obtain the finished product.
[0036] Example 3 Example 3 provides a method for preparing a patch for treating gout based on Apocynum venetum leaves, the method comprising: (1) Take 300g of dried Apocynum venetum leaves, crush them and extract them with 50 vol% ethanol by ultrasonic extraction for 1 hour at an extraction temperature of 52℃. Filter and concentrate to obtain 7.5g of crude extract of total flavonoids from Apocynum venetum leaves.
[0037] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 3g of high-purity total flavonoid extract.
[0038] (3) Mix 3g of total flavonoid extract with 1.2g of menthol, 40g of pressure-sensitive adhesive matrix, 1.6g of glycerin and 0.15g of sodium benzoate, and stir well.
[0039] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 7cm×7cm patches.
[0040] (5) After packaging, sterilize to obtain the finished product.
[0041] Example 4 Example 4 provides a method for preparing a patch for treating gout based on Apocynum venetum leaves, the method comprising: (1) Take 600g of dried Apocynum venetum leaves, crush them and extract them with 75 vol% ethanol by ultrasonic extraction for 1 hour at an extraction temperature of 50℃. Filter and concentrate to obtain 16g of crude extract of total flavonoids from Apocynum venetum leaves.
[0042] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 8g of high-purity total flavonoid extract.
[0043] (3) Mix 7g of total flavonoid extract with 2g of menthol, 85g of pressure-sensitive adhesive matrix, 4g of glycerin and 0.3g of sodium benzoate, and stir well.
[0044] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 10cm×10cm patches.
[0045] (5) After packaging, sterilize to obtain the finished product.
[0046] Comparative Example 1: Comparative Example 1 provides a method for preparing a patch, the method comprising: (1) Take 1200g of dried Apocynum venetum leaves from Example 1, crush them, and extract them with distilled water using ultrasound for 1 hour at an extraction temperature of 50℃. Filter and concentrate to obtain 14g of crude extract of total flavonoids from Apocynum venetum leaves.
[0047] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 4g of total flavonoid extract.
[0048] (3) Mix 2.5g of total flavonoid extract with 0.5g of azone, 45g of hydrogel matrix, 1.5g of glycerin and 0.1g of sodium benzoate and stir well.
[0049] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 5cm×5cm patches.
[0050] (5) After packaging, sterilize to obtain the finished product.
[0051] As can be seen from Comparative Example 1, when water extraction is used, the yield of step (1) is less than half that of Example 4, and the yield of step (2) is about 60% of that of Example 4.
[0052] Comparative Example 2: Comparative Example 2 provides a method for preparing a patch, the method comprising: (1) Take 600g of dried Apocynum venetum leaves from Example 1, pulverize them, and extract them with anhydrous ethanol by ultrasonic extraction for 1 hour at an extraction temperature of 50℃. Filter and concentrate to obtain 10g of crude extract of total flavonoids from Apocynum venetum leaves.
[0053] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 4g of total flavonoid extract.
[0054] (3) Mix 2.5g of total flavonoid extract with 0.5g of azone, 45g of hydrogel matrix, 1.5g of glycerin and 0.1g of sodium benzoate and stir well.
[0055] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 5cm×5cm patches.
[0056] (5) After packaging, sterilize to obtain the finished product.
[0057] As can be seen from Comparative Example 2, when using anhydrous ethanol extraction, the yield of step (1) is only 2 / 3 of that of Example 4, and the yield of step (2) is about 80% of that of Example 4.
[0058] Comparative Example 3: Comparative Example 3 provides a method for preparing a patch, the method comprising: (1) Take 1200g of dried Apocynum venetum leaves from Example 1, pulverize them, and extract them with methanol using ultrasonic extraction for 1 hour at a temperature of 50℃. Filter and concentrate to obtain 16g of crude extract of total flavonoids from Apocynum venetum leaves.
[0059] (2) The crude extract was purified by passing it through a macroporous resin column to obtain 6g of total flavonoid extract.
[0060] (3) Mix 2.5g of total flavonoid extract with 0.5g of azone, 45g of hydrogel matrix, 1.5g of glycerin and 0.1g of sodium benzoate and stir well.
[0061] (4) Coat the mixture onto non-woven fabric, cover with an anti-adhesive layer, and cut into 5cm×5cm patches.
[0062] (5) After packaging, sterilize to obtain the finished product.
[0063] As can be seen from Comparative Example 3, methanol extraction is not as effective as ethanol extraction.
[0064] Application Experiment A mouse gout model was established, and uric acid concentration was used as the indicator to investigate the therapeutic effects of four Apocynum venetum leaf patch examples and three comparative examples (water extract, anhydrous ethanol extract, and methanol extract) on mouse gout.
[0065] 1. Experimental Materials 1.1 Experimental animals: Healthy male mice, weighing 20±2g, were acclimatized for one week under constant temperature and humidity.
[0066] 1.2 Experimental materials, reagents and medicines Patches containing different concentrations of total flavonoids from Apocynum venetum leaves, water-extracted total flavonoid patch (comparative example 1), anhydrous ethanol-extracted total flavonoid patch (comparative example 2), methanol-extracted total flavonoid patch (comparative example 3), male rats, uric acid detection kit, ultraviolet spectrophotometer, uric acid sodium urate crystal suspension, and allopurinol.
[0067] 2 Experimental Methods Effects of Apocynum venetum leaf patch, water extract, anhydrous ethanol extract, and methanol extract on gout induced by hyperuricemia in mice. 2.1.1 Establishment of experimental animals and models: Animal selection: Select healthy adult male rats (SD rats) with similar weights (200-250g).
[0068] Establishment of a gout model: Induction of hyperuricemia model by direct injection of sodium urate crystal suspension.
[0069] Injection dosage: 0.1 mL of sodium urate crystal suspension (containing 10 mg sodium urate) is injected into the joint cavity.
[0070] Model validation: Blood samples were collected 24 hours after modeling to detect serum uric acid levels, confirming the model's success (significantly elevated serum uric acid levels).
[0071] 2.1.2 Experimental grouping and drug administration: Blank control group: normal animals, without modeling or any treatment.
[0072] Control group: No treatment was given after modeling.
[0073] Positive control group: After modeling, the patient was given a known uric acid-lowering drug (allopurinol, 10 mg / kg / day, intraperitoneal injection).
[0074] Experimental groups: After modeling, mice were given different concentrations of total flavonoid patches from Apocynum venetum leaves (based on the total flavonoid extract obtained in Example 1 (adjusting the proportion of excipients accordingly), low, medium, and high dose groups containing 1 mg / cm², 2 mg / cm², and 4 mg / cm² of total flavonoids, respectively), Apocynum venetum leaf decoction (oral administration, the decoction was concentrated and freeze-dried, the oral dose was between 0.1-0.2 g / kg), kaempferol and quercetin (oral administration, supplemented with 2% HP-β-CD, 5% PEG-400, and physiological saline, 2 mL (20g mouse) by gavage and slow injection (≥10 seconds)), total flavonoid extract oral solution (commercially available total flavonoid extract, dissolved in a small amount of warm water, CMC-Na added, and diluted to 0.2 mL (5 mg / mL). 2 mL (20g mouse) by gavage and slow injection (≥10 seconds)), water extraction comparative example 1, anhydrous ethanol extraction comparative example 2, and methanol extraction comparative example 3.
[0075] Administration method: Cut the patch to an appropriate size (e.g., 2cm×2cm) and fix it to the shaved area on the animal's back to ensure transdermal absorption of the drug.
[0076] Experimental period: The patch was changed once a day and the medication was administered continuously for a certain period of time (such as 7 days, 14 days, etc.), and uric acid levels were monitored regularly.
[0077] 2.1.3 Detection Indicators Blood uric acid level: Blood samples are collected regularly to test uric acid concentration.
[0078] Sampling time points: before modeling (baseline level); 24 hours after modeling (model validation); day 3, day 7, and day 14 after drug administration (adjusted according to the experimental cycle).
[0079] Sampling method: Collect blood from the orbital venous plexus or tail vein, about 0.5-1 mL of blood each time; place the blood sample in an anticoagulant tube and centrifuge (3000 rpm, 10 minutes) to separate the plasma.
[0080] Detection method: The changes in serum uric acid levels in each group of animals were calculated using an enzyme colorimetric method with a uric acid detection kit.
[0081] Plasma sample: Collect animal blood (such as blood from the orbital venous plexus or tail vein), place it in an anticoagulant tube, centrifuge (3000 rpm, 10 minutes) to separate the plasma, and take the supernatant (plasma) for testing.
[0082] Preparation of standard curve: Use uric acid standard, diluted to different concentrations (0 mg / dL, 2 mg / dL, 4 mg / dL, 6 mg / dL, 8 mg / dL, 10 mg / dL), and set 2-3 replicates for each concentration point.
[0083] 2.1.4 Uric acid level index measurement Operating steps: Reagent preparation: Mix R1 and R2 in the specified ratio (e.g., R1:R2 = 4:1) according to the kit instructions to prepare the working solution (the working solution should be prepared and used immediately to avoid prolonged storage).
[0084] Adding samples Add the sample to a 96-well plate or colorimetric tube as follows: Blank well: 50μL distilled water + 100μL working solution.
[0085] Standard well: 50 μL standard + 100 μL working solution.
[0086] Sample well: 50 μL plasma sample + 100 μL working solution.
[0087] Reaction: Gently mix the liquid in the wells to avoid generating air bubbles, and place the 96-well plate or colorimetric tubes in a 37°C constant temperature water bath or incubator for 10-15 minutes.
[0088] Colorimetric determination: The absorbance (OD value) of each well was measured at a wavelength of 520 nm using a spectrophotometer, with the blank well used for zeroing.
[0089] 3. Data Analysis 3.1 Plotting the Standard Curve Plot a standard curve with the concentration of the standard as the x-axis and the corresponding OD value as the y-axis.
[0090] The standard curve is fitted using linear regression to obtain the regression equation (e.g., y=ax+b).
[0091] 3.2 Calculation of Sample Concentration Substitute the OD value of the sample well into the regression equation to calculate the concentration of uric acid in the sample.
[0092] Formula: Uric acid concentration (mg / dL) = (sample OD value - b) / a.
[0093] 4. Experimental Results 4.1 Expected Results: The serum uric acid level in the model control group was significantly higher than that in the blank control group, indicating that the model was successful. The serum uric acid level in the experimental group (total flavonoids from Apocynum venetum leaf patch) gradually decreased with the duration of administration and was dose-dependent. The serum uric acid level in the high-dose experimental group was close to that in the positive control group.
[0094] 4.2 Experimental Results 4.2.1 Examples 1 (75 vol% ethanol), 2 (75 vol% ethanol), 3 (50 vol% ethanol), 4 (75 vol% ethanol), 1 (water extraction), 2 (anhydrous ethanol extraction), and 3 (methanol extraction) are shown in Table 1. Table 1
[0095] Regression equation: y = 0.099x + 0.01 (R² = 0.999).
[0096] Sample number: Sample 1: Plasma from animal 1 in the blank control group; Sample 2: Plasma from animal 1 in the model control group; Sample 3: Plasma from animal 1 in the positive control group; Sample 4: Plasma from experimental group animals (Example 1, low dose); Sample 5: Plasma from experimental group animals (dose in Example 1) 1; Sample 6: Plasma from experimental group animals (high dose of Example 1) 1; Sample 7: Plasma from experimental animal (decoction of Apocynum venetum leaves) 1; Sample 8: Plasma from experimental animals (kaempferol and quercetin) 1; Sample 9: Plasma from experimental animal (oral solution of total flavonoid extract) 1; Sample 10: Plasma from the experimental group animals (comparative example 1, total flavonoids extracted by water) 1; Sample 11: Plasma from experimental group animals (comparative example 2, total flavonoids extracted with anhydrous ethanol) 1; Sample 12: Plasma from experimental group animals (comparative example 3, total flavonoids extracted from methanol) 1.
[0097] The sample test results are shown in Table 2: Table 2
[0098] 5. Results and Conclusions Results: The experimental group showed a significant reduction in uric acid levels. The high-dose level in the experimental group was close to that in the positive control group, and the medium-dose group was more effective than the oral group.
[0099] Conclusion: Total flavonoids from Apocynum venetum leaves effectively reduce uric acid levels via transdermal administration, supporting their application in the treatment of gout.
[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A patch for treating gout based on Apocynum venetum leaves, comprising a backing layer, an adhesive layer, and an anti-adhesive layer, characterized in that, The adhesive layer comprises, by weight percentage: Apocynum venetum leaf total flavonoid extract 5-10%; Transdermal absorption enhancer 1-3%; 2-5% of auxiliary materials; Remaining adhesive substrate; The preparation method of the total flavonoid extract of Apocynum venetum leaves is as follows: Apocynum venetum leaves are extracted by ultrasonic extraction with ethanol and then purified by macroporous resin column.
2. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The backing layer is a non-woven fabric, and the anti-stick layer is a polyethylene film.
3. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The transdermal absorption enhancer is selected from azone or menthol.
4. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The adhesive matrix is selected from hydrogels or pressure-sensitive adhesives.
5. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The excipients include a humectant and a preservative, wherein the humectant has a weight percentage content of 2-5% and the preservative has a weight percentage content of 0.1-0.5%; the humectant is selected from glycerin and the preservative is selected from sodium benzoate.
6. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The preparation method of the total flavonoid extract from Apocynum venetum leaves is as follows: The dried Apocynum venetum leaves were pulverized, sieved, and extracted with 50-80 vol% ethanol solution by ultrasonic extraction at a temperature of 45-55℃ for 25-120 minutes. The extract was filtered and concentrated under reduced pressure until no alcohol odor was detected to obtain a crude extract of total flavonoids from Apocynum venetum leaves. The crude extract was then purified by macroporous resin column to obtain a total flavonoid extract from Apocynum venetum leaves. The purification process of the macroporous resin column is as follows: the adsorption resin used is selected from AB-8 type macroporous resin; the concentration of the added sample is 1-4 mg / mL, the pH value is 4.8-5.2; the sample loading amount is 2.0-3.0 mL / g resin mass, the adsorption time is 3-6 h; then elution is performed with 2-4 column volumes of 50-80 vol% ethanol solution, and the elution time is 1.5-3.0 h.
7. The patch for treating gout based on Apocynum venetum leaves according to claim 6, characterized in that, The preparation method of the total flavonoid extract of Apocynum venetum leaves is as follows: dried Apocynum venetum leaves are pulverized, sieved, and ultrasonically extracted with 75 vol% ethanol solution at an extraction temperature of 50℃ for 60 minutes; the extract is filtered and concentrated under reduced pressure until no alcohol odor is detected to obtain crude extract of total flavonoids from Apocynum venetum leaves; then purified by macroporous resin column to obtain high-purity total flavonoid extract from Apocynum venetum leaves; the purification process of macroporous resin column is as follows: the adsorption resin used is selected from AB-8 type macroporous resin; the concentration of the sample added is 2 mg / mL, the pH value is 5.0; the sample loading amount is 2.5 mL / g resin mass, the adsorption time is 4 h; then elution is performed with 3 column volumes of 70 vol% ethanol solution for 2 h.
8. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The adhesive layer comprises, by weight percentage: 5% total flavonoid extract of Apocynum venetum leaves, 1% azone, 3% glycerin, 0.2% sodium benzoate, and the balance being the hydrogel matrix.
9. The patch for treating gout based on Apocynum venetum leaves according to claim 1, characterized in that, The adhesive layer comprises, by weight percentage: 7% total flavonoid extract of Apocynum venetum leaves, 2% menthol, 4% glycerin, 0.3% sodium benzoate, and the balance being the pressure-sensitive adhesive matrix.
10. A method for preparing a patch for treating gout based on Apocynum venetum leaves, characterized in that, The method includes: S1: The total flavonoid extract of Apocynum venetum leaves, transdermal absorption enhancer, excipients and adhesive matrix are mixed according to the formula to obtain the adhesive layer material; S2: Apply the adhesive layer material evenly to the backing layer to form an adhesive layer, then cover it with an anti-adhesive layer and cut it into patches of the required size; S3: Pack the patch into an aluminum-plastic packaging bag, seal it, and sterilize it using ultraviolet or gamma rays; The preparation method of the total flavonoid extract of Apocynum venetum leaves is as follows: dried Apocynum venetum leaves are pulverized, sieved, and ultrasonically extracted with 65-80 vol% ethanol solution at an extraction temperature of 45-55℃ for 25-120 minutes; the extract is filtered and concentrated under reduced pressure until no alcohol odor is detected to obtain crude extract of total flavonoids from Apocynum venetum leaves; then purified by macroporous resin column to obtain high-purity total flavonoid extract of Apocynum venetum leaves; the purification process of macroporous resin column is as follows: the adsorption resin used is selected from AB-8 type macroporous resin; the concentration of the added sample is 1-4 mg / mL, the pH value is 4.8-5.2; the sample loading amount is 2.0-3.0 mL / g resin mass, and the adsorption time is 3-6 h; then elution is performed with 2-4 column volumes of 65-80 vol% ethanol solution for 1.5-3.0 h.