A low-irritation bacteriostatic repairing dual-effect external composition for allergic skin problems and a preparation method thereof

Abstract

This invention discloses a low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems and its preparation method. The composition is a compound of herbal extracts such as Coptis chinensis and Sophora flavescens, and plant essential oils such as clove oil and tea tree oil. An essential oil phospholipid nano-dispersion is prepared by ultrasonic emulsification of phospholipids, followed by cross-linking with a polysaccharide encapsulation material to construct a double-layer microcapsule structure, and finally spray-dried. The composition exhibits pH-responsive release characteristics, with accelerated release of active ingredients under acidic conditions, and maintains stability and antibacterial activity over a wide temperature range of -18℃ to 100℃. This invention effectively solves the problems of poor dispersibility and easy inactivation due to temperature sensitivity of natural active ingredients through a double-layer encapsulation system, achieving broad-spectrum and highly effective antibacterial activity (antibacterial rate > 99.7%), while maintaining a skin irritation index below 0.15. It combines low irritation with highly effective antibacterial and repairing effects, and the preparation process is simple and controllable, making it suitable for sensitive skin care and personal care products.

Description

Technical Field

[0001] This invention relates to the field of biomedical industry technology, and in particular to a low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems and its preparation method. Background Technology

[0002] Currently, traditional antibacterial products mainly rely on chemically synthesized antibacterial agents such as sorbates and benzoates for preservation. However, these substances have raised concerns about safety, residue risks, and declining consumer acceptance over long-term use, making it difficult to meet the current demand for natural, green, and clean-label products. Therefore, naturally derived herbs and their extracts with certain antibacterial activity are gradually becoming an important research direction in food preservation, daily chemical products, and environmental disinfection.

[0003] Eight-angled hemp, with its bitter and neutral properties, possesses the effects of dispelling wind and dampness, reducing swelling and relieving pain, and promoting blood circulation and unblocking collaterals. It is especially suitable for symptoms such as redness, swelling, pain, and poor local circulation associated with allergic skin problems. However, single herbs generally have defects such as a narrow antibacterial spectrum, limited efficacy, and insufficient stability, which limits their practical application. Eight-angled hemp combined with heat-clearing and dampness-drying herbs such as Coptis chinensis and Lonicera japonica can enhance anti-inflammatory and swelling-reducing effects and promote repair on the basis of antibacterial activity. At the same time, existing external compositions still face multiple technical bottlenecks in complex application environments: First, water-soluble herbal active ingredients are difficult to disperse evenly in oily matrices, and the antibacterial effect fluctuates greatly under different pH conditions; second, under low-temperature refrigeration (0-4℃) and freezing conditions (-18℃), the diffusion and efficacy of active ingredients decrease significantly, making it difficult to meet the requirements of cold chain preservation; third, during high-temperature sterilization or heat processing (70-121℃), heat-sensitive ingredients are prone to volatilization, oxidation, or degradation and inactivation.

[0004] Therefore, how to provide a preparation technology for topical compositions that combines broad-spectrum antibacterial properties, adaptability to oil-water systems, wide temperature range stability, and processing tolerance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems and its preparation method. By constructing a double-layer encapsulation system using herbal extracts, plant essential oils, phospholipids, and polysaccharide encapsulation materials, and combining it with organic acids, low-temperature diffusion promoters, and antioxidant stabilizers, stable loading and synergistic release of active ingredients are achieved.

[0006] This invention can be achieved through the following technical solutions:

[0007] A method for preparing a low-irritation, antibacterial, and repairing topical composition for allergic skin problems includes the following steps:

[0008] Step 1: After pre-processing the herbal raw materials, extract the herbal extract. The herbal raw materials include at least three of the following: Coptis chinensis, Ephedra sinica, Sophora flavescens, Lonicera japonica, Isatis indigotica, and Artemisia argyi.

[0009] Step 2: Mix the plant essential oil with phospholipids and an aqueous system, and then perform ultrasonic emulsification to obtain an essential oil phospholipid nano-dispersion; the plant essential oil includes at least one of clove oil, cinnamon oil, thyme oil, and tea tree oil;

[0010] Step 3: Add the herbal extract to the essential oil phospholipid nano-dispersion and mix. Then add the polysaccharide encapsulation material to form a double-layer encapsulation system with the herbal extract and plant essential oil as the middle layer and the polysaccharide layer as the outer layer. Continue to add natural organic acid, low-temperature diffusion promoter and antioxidant stabilizer, mix evenly, and then spray dry to obtain the external composition. The double-layer encapsulation system has pH-responsive release characteristics. The release rate of active ingredients increases under acidic conditions, maintains dispersion stability under refrigeration or freezing conditions, and maintains antibacterial activity under heating conditions.

[0011] Preferably, the herbal raw materials are pulverized and then subjected to water-alcohol composite extraction at an extraction temperature of 50-95℃ for 1-5 hours. After extraction, the residue is separated, concentrated, and dried to obtain herbal extract powder.

[0012] Preferably, the phospholipid is selected from one or more of soybean lecithin, sunflower phospholipid, phosphatidylcholine, and short-chain phospholipids; the average particle size of the essential oil phospholipid nanodispersion is 100-200 nm.

[0013] Preferably, the polysaccharide encapsulating material is selected from one or more of sodium alginate, chitosan, gum arabic, high amylose, and gum arabic; the double-layer encapsulation system is formed by ionic crosslinking, electrostatic compounding, or hydrogen bonding.

[0014] Preferably, the natural organic acid is selected from one or more of citric acid, malic acid, lactic acid, and tartaric acid; the low-temperature diffusion promoter is selected from one or more of trehalose, glycerol, betaine, proline, monoglyceride fatty acid esters, and short-chain phospholipids; and the antioxidant stabilizer is selected from one or more of ascorbate palmitate, vitamin E, sodium citrate, and calcium sodium EDTA.

[0015] Preferably, when spray drying is used, the inlet air temperature is 130-180℃ and the outlet air temperature is 60-90℃; the resulting external composition has a water content of 2%-6%.

[0016] Preferably, the topical composition comprises the following components by weight percentage: 20-35% herbal extract, 5-12% active plant essential oil ingredients, 3-8% phospholipids, 10-20% polysaccharide encapsulating material, 3-8% natural organic acids, 2-6% low-temperature diffusion promoter, 0.2-2% antioxidant stabilizer, and the balance being excipients.

[0017] Preferably, the excipients are selected from one or more of maltodextrin, resistant dextrin, soluble starch, glucose, and silicon dioxide; the topical composition is a powder formulation with a double-layer microcapsule structure, wherein the outer layer is a polysaccharide layer, the middle layer is a phospholipid layer, and the inner layer is a phospholipid layer containing herbal extracts and plant essential oil active components.

[0018] Preferably, the topical composition has pH-responsive release properties, with the release rate of the active ingredient being higher at pH 3.0-5.5 than at pH 6.0-7.0; and the topical composition maintains antibacterial activity in the range of -18 to 100°C.

[0019] The beneficial effects of this invention are:

[0020] This invention develops a topical composition with both low irritation and highly effective antibacterial and repairing effects through a double-layer encapsulation system and synergistic formulation of components. The technical solution first encapsulates herbal extracts and plant essential oils within a phospholipid layer, then coats them with a polysaccharide material on the outer layer, constructing a double-layer microcapsule structure characterized by "internal active ingredient - middle phospholipid - outer polysaccharide." This not only achieves stable co-loading of water-soluble herbal components and oil-soluble essential oils, solving the technical challenge of uniform dispersion of natural active ingredients, but also endows the system with excellent pH-responsive release characteristics through ionic cross-linking and electrostatic compounding mechanisms. It can intelligently regulate the release rate of active ingredients in acidic skin environments, significantly improving targeted action efficiency. Furthermore, this invention introduces a low-temperature diffusion promoter and an antioxidant stabilizer, enabling the composition to maintain good dispersion stability and antibacterial activity within an extreme temperature range of -18℃ to 100℃, overcoming the application bottleneck of traditional natural antibacterial products where activity easily decreases during cold chain preservation and heat processing. Thanks to its complete encapsulation barrier and gentle formulation design, this composition achieves an antibacterial rate of over 99.7% against common pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans, while maintaining a skin irritation index below 0.15, thus achieving a harmonious balance between high efficacy and safety. Furthermore, the preparation process utilizes ultrasonic emulsification combined with spray drying technology, resulting in a simple and controllable process. The resulting powder formulation exhibits good flowability, low moisture content, excellent storage stability, and ease of application, making it widely applicable in sensitive skin care, skin antibacterial repair, and personal care products. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 The antibacterial rate of the topical composition under normal temperature conditions;

[0023] Figure 2 The primary irritation index of the topical composition in rabbits during skin irritation tests. Detailed Implementation

[0024] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0025] Example 1: A method for preparing a low-irritation, antibacterial, and repairing topical composition for allergic skin problems, comprising the following steps:

[0026] Step 1: Select three herbal raw materials: Coptis chinensis, Hemp seed, and Lonicera japonica, with 350g of Coptis chinensis, 350g of Hemp seed, and 300g of Lonicera japonica, totaling 1kg. Wash and dry the above herbal raw materials, then pulverize them to 40 mesh and place them in an extraction tank. Add 8L of 70% (v / v) ethanol aqueous solution as the extraction solvent and reflux at 50℃ for 5h. After extraction, filter and collect the filtrate. Add another 4L of 70% (v / v) ethanol aqueous solution to the filter residue and extract again at 50℃ for 5h. Combine the two extracts. Concentrate the combined extract under reduced pressure to 1.5L, and then dry under reduced pressure at 60℃ to obtain 200g of herbal extract powder, which will be used as the herbal extract component in the final formula.

[0027] Step 2: Weigh 50g of tea tree oil as the active component of the plant essential oil and 30g of soybean lecithin as the phospholipid component. First, add the soybean lecithin to 1.2L of purified water and stir at 45℃ for 30min to fully hydrate it. Then, add 50g of tea tree oil and prepare an essential oil phospholipid nano-dispersion by ultrasonic emulsification. Control the ultrasonic power at 400W and intermittently sonicate for 20min to control the average particle size of the resulting dispersion at 100nm. The essential oil phospholipid nano-dispersion is thus obtained and set aside for later use.

[0028] Step 3: Slowly add 200g of the herbal extract powder obtained in Step 1 to the essential oil phospholipid nano-dispersion obtained in Step 2, and stir for 20 minutes to ensure uniform dispersion; separately weigh 100g of sodium alginate as the polysaccharide embedding material, add it to 1.5mL of purified water, and stir to dissolve at room temperature to prepare a sodium alginate solution; then slowly add the sodium alginate solution to the above mixed system, and continue stirring for 30 minutes to form a bilayer embedding precursor solution with a phospholipid layer as the middle layer and a polysaccharide layer as the outer layer; then prepare 1L of 2% (w / v) calcium chloride solution, and slowly add it dropwise to the above system to carry out ionic cross-linking, and continue stirring for 30 minutes to form a bilayer embedding system;

[0029] Step 4: Weigh out 30g of citric acid as a natural organic acid, 20g of trehalose as a low-temperature diffusion promoter, 2g of ascorbate palmitate as an antioxidant stabilizer, and 560g of maltodextrin and 8g of silicon dioxide as excipients; first, dissolve 30g of citric acid in 200mL of purified water, and dissolve 20g of trehalose in 150mL of purified water; pre-disperse 2g of ascorbate palmitate in 20mL of 95% ethanol; dissolve 560g of maltodextrin in 1.8L of purified water, and dissolve 8g of silicon dioxide... 8g of silicon dioxide was added directly; the above components were added sequentially to the double-layer encapsulation system, and 330mL of purified water was added to adjust the state of the liquid. The mixture was stirred continuously for 30 minutes to obtain a uniform spray-dried liquid. At this point, the total solids in the liquid were 1kg, corresponding to the following final product ratio: herbal extract 20%, plant essential oil active components 5%, phospholipids 3%, polysaccharide encapsulation material 10%, natural organic acid 3%, low-temperature diffusion promoter 2%, antioxidant stabilizer 0.2%, and excipients 56.8%.

[0030] Step 5: Send the above liquid material into a spray dryer for spray drying, control the inlet air temperature at 130℃ and the outlet air temperature at 60℃. After drying, collect the powder to obtain 1kg of the finished external composition. The resulting external composition has a moisture content of 2%, is a light yellow to yellowish-brown uniform powder, and has a double-layer microcapsule structure. The outer layer is a polysaccharide layer, the middle layer is a phospholipid layer, and the inner layer is the herbal extract and plant essential oil active components encapsulated in the phospholipid layer. It also has pH-responsive release properties, with the release rate of active ingredients at pH 3.0-5.5 being higher than that at pH 6.0-7.0, and maintaining antibacterial activity in the range of -18℃ to 100℃.

[0031] Example 2: A method for preparing a low-irritation, antibacterial, and repairing topical composition for allergic skin problems, comprising the following steps:

[0032] Step 1: Select Coptis chinensis, Hemp seed, and honeysuckle as herbal raw materials, with 400g of Coptis chinensis, 350g of Hemp seed, and 250g of honeysuckle, totaling 1kg. Wash and dry the above raw materials, then pulverize them to 40 mesh, place them in an extraction tank, add 10L of 70% (v / v) ethanol aqueous solution as the extraction solvent, and reflux extract at 72℃ for 3h. After extraction, filter, add 6L of 70% (v / v) ethanol aqueous solution to the filter residue, and extract a second time at 72℃ for 3h. Combine the two extracts, concentrate under reduced pressure to 2.5L, and then dry under reduced pressure at 60℃ to obtain 275g of herbal extract powder for later use.

[0033] Step 2: Weigh 40g of clove oil and 45g of cinnamon oil, totaling 85g of active plant essential oil components; weigh 30g of soybean lecithin and 25g of sunflower lecithin, totaling 55g of phospholipids; first, add the phospholipids to 1.8mL of purified water and stir at 50℃ for 40min to fully hydrate them, then add the above plant essential oil mixture; use a high-speed shear emulsifier to shear at 12000rpm for 15min, and then ultrasonically emulsify at 500W for 25min to obtain an essential oil phospholipid nano-dispersion with an average particle size of 150nm;

[0034] Step 3: Slowly add 300g of the herbal extract powder obtained in Step 1 to the essential oil phospholipid nano-dispersion obtained in Step 2, and stir for 30 minutes to ensure uniform dispersion; separately weigh out 100g of sodium alginate and 50g of chitosan, for a total of 150g of polysaccharide embedding material; dissolve sodium alginate in 2200mL of purified water by stirring; dissolve chitosan in 800mL of 1% (v / v) glacial acetic acid aqueous solution by stirring; first add the sodium alginate solution to the above mixture, then slowly add the chitosan solution, and continue stirring for 40 minutes to form a bilayer embedding precursor solution; then prepare 1500mL of 3% (w / v) calcium chloride solution, and slowly add it dropwise to the precursor solution for ionic cross-linking, and continue stirring for 30 minutes to form a bilayer embedding system with a phospholipid layer as the middle layer and a polysaccharide layer as the outer layer;

[0035] Step 4: Weigh 35g of citric acid and 20g of malic acid, totaling 55g of natural organic acids; weigh 20g of trehalose and 20g of betaine, totaling 40g of low-temperature diffusion promoter; weigh 6g of ascorbyl palmitate and 5g of vitamin E, totaling 11g of antioxidant stabilizer; the excipients are 310g of maltodextrin and 19g of silicon dioxide, totaling 329g; first, dissolve citric acid and malic acid in 500mL of purified water, and dissolve trehalose and betaine in 400mL of purified water; pre-disperse ascorbyl palmitate and vitamin E in 120mL of 95% ethanol; dissolve maltodextrin in 1200mL of purified water, add silicon dioxide directly, add the above components sequentially to the double-layer encapsulation system, add 600mL of purified water, stir for 40min, and obtain a uniform spray-dried liquid;

[0036] Step 5: Send the obtained liquid material into a spray dryer for spray drying, control the inlet air temperature to 155℃ and the outlet air temperature to 75℃; after drying, collect the powder, pass it through a 100-mesh sieve to granulate, and obtain 1 kg of the external composition product. The obtained product has a moisture content of 4.0%, is a yellowish-brown uniform powder, and has good flowability and dispersibility.

[0037] Example 3: A method for preparing a low-irritation, antibacterial, and repairing topical composition for allergic skin problems, comprising the following steps:

[0038] Step 1: Select 500g of Coptis chinensis, 450g of Ephedra sinica, 300g of Lonicera japonica, and 250g of Isatis indigotica, totaling 1500g. Wash and dry each raw material, then pulverize it to 50 mesh. Place it in an extraction tank, add 15L of 75% (v / v) ethanol aqueous solution, and reflux extract at 95℃ for 1h. After extraction, filter, add 8000mL of 75% (v / v) ethanol aqueous solution to the filter residue, and extract at 95℃ for 1h. Combine the extracts and concentrate under reduced pressure to about 3500mL, then dry under reduced pressure at 60℃ to obtain 350g of herbal extract powder.

[0039] Step 2: Weigh 60g of cinnamon oil, 40g of thyme oil, and 20g of tea tree oil, totaling 120g of active plant essential oil components; weigh 50g of soybean lecithin and 30g of phosphatidylcholine, totaling 80g of phospholipids; add the phospholipids to 2.2L of purified water and stir to hydrate at 55℃ for 50min, then add the plant essential oil mixture, shear at 15000rpm for 20min using a high-speed shear emulsifier, and then ultrasonically emulsify at 600W for 30min to obtain an essential oil phospholipid nano-dispersion with an average particle size of 200nm;

[0040] Step 3: Add 450g of the herbal extract powder obtained in Step 1 to the essential oil phospholipid nano-dispersion obtained in Step 2 and stir for 30 minutes; separately weigh 120g of sodium alginate and 80g of chitosan, for a total of 200g of polysaccharide encapsulation material. Dissolve sodium alginate in 2.5L of purified water and chitosan in 1L of 1% (v / v) glacial acetic acid aqueous solution; add the sodium alginate solution to the above mixture and stir evenly, then slowly add the chitosan solution and continue stirring for 45 minutes. Then prepare 1.8L of 4% (w / v) calcium chloride solution and slowly add it dropwise for cross-linking for 30 minutes to obtain a double-layer encapsulation system.

[0041] Step 4: Weigh 40g of citric acid and 40g of lactic acid powder, totaling 80g of natural organic acids; weigh 25g of trehalose, 15g of glycerin powder, and 10g of betaine, totaling 50g of low-temperature diffusion promoter; weigh 10g of ascorbyl palmitate and 10g of vitamin E, totaling 20g of antioxidant stabilizer; use 70g of maltodextrin and 30g of silicon dioxide as excipients, totaling 100g; first, dissolve citric acid and lactic acid powder in 400mL of purified water, and dissolve trehalose, glycerin powder, and betaine in 350mL of purified water; disperse ascorbyl palmitate and vitamin E in 180mL of 95% ethanol; dissolve maltodextrin in 1.2L of purified water, and add silicon dioxide directly; then add the above components sequentially to the double-layer encapsulation system, add 500mL of purified water, stir for 40min, and obtain a uniform spray-dried liquid;

[0042] Step 5: Send the obtained liquid into a spray dryer for spray drying, control the inlet air temperature to 180℃ and the outlet air temperature to 90℃. After drying, collect the powder, pass it through a 120-mesh sieve to granulate, and obtain 1 kg of the external composition product. The obtained product has a moisture content of 6.0%, a darker color, a higher content of active ingredients, strong broad-spectrum antibacterial properties, and good thermal stability.

[0043] Comparative Example 1: The difference between this comparative example and Example 1 is that no phospholipids and polysaccharide encapsulating materials are added.

[0044] A method for preparing a low-irritation, antibacterial, and repairing topical composition for allergic skin problems includes the following steps:

[0045] Step 1: Select three herbal raw materials: Coptis chinensis, Hemp seed, and Lonicera japonica, with 350g of Coptis chinensis, 350g of Hemp seed, and 300g of Lonicera japonica, totaling 1kg. Wash and dry the above herbal raw materials, then pulverize them to 40 mesh and place them in an extraction tank. Add 8L of 70% (v / v) ethanol aqueous solution as the extraction solvent and reflux at 50℃ for 5h. After extraction, filter and collect the filtrate. Add another 4L of 70% (v / v) ethanol aqueous solution to the filter residue and extract again at 50℃ for 5h. Combine the two extracts. Concentrate the combined extract under reduced pressure to 1.5L, and then dry under reduced pressure at 60℃ to obtain 200g of herbal extract powder, which will be used as the herbal extract component in the final formula.

[0046] Step 2: Weigh 50g of tea tree oil as the active component of the plant essential oil, add it directly to 1.2L of purified water, and stir at 45℃ for 30 minutes to fully hydrate it. Then add 200g of the herbal extract powder obtained in Step 1, and stir for 20 minutes to disperse it evenly. Then add 30g of citric acid, 20g of trehalose, and 2g of ascorbyl palmitate. The 30g of citric acid is first dissolved in 200mL of purified water, the 20g of trehalose is dissolved in 150mL of purified water, and the 2g of ascorbyl palmitate is pre-dispersed in 20mL of 95% ethanol. Then add 560g of maltodextrin and 8g of silicon dioxide. The 560g of maltodextrin is first dissolved in 1.8L of purified water, and the 8g of silicon dioxide is added directly. Add 1830mL of purified water and continue stirring for 30 minutes to obtain a mixed solution.

[0047] Step 3: Send the above liquid material into a spray dryer for spray drying, control the inlet air temperature to 130℃ and the outlet air temperature to 60℃. After drying, collect the powder to obtain 1kg of the external composition product.

[0048] Comparative Example 2: The difference between this comparative example and Example 1 is that no low-temperature diffusion promoter and antioxidant stabilizer are added.

[0049] A method for preparing a low-irritation, antibacterial, and repairing topical composition for allergic skin problems includes the following steps:

[0050] Step 1: Select three herbal raw materials: Coptis chinensis, Hemp seed, and Lonicera japonica, with 350g of Coptis chinensis, 350g of Hemp seed, and 300g of Lonicera japonica, totaling 1kg. Wash and dry the above herbal raw materials, then pulverize them to 40 mesh and place them in an extraction tank. Add 8L of 70% (v / v) ethanol aqueous solution as the extraction solvent and reflux at 50℃ for 5h. After extraction, filter and collect the filtrate. Add another 4L of 70% (v / v) ethanol aqueous solution to the filter residue and extract again at 50℃ for 5h. Combine the two extracts. Concentrate the combined extract under reduced pressure to 1.5L, and then dry under reduced pressure at 60℃ to obtain 200g of herbal extract powder, which will be used as the herbal extract component in the final formula.

[0051] Step 2: Weigh 50g of tea tree oil as the active component of the plant essential oil and 30g of soybean lecithin as the phospholipid component. First, add the soybean lecithin to 1.2L of purified water and stir at 45℃ for 30min to fully hydrate it. Then, add 50g of tea tree oil and prepare an essential oil phospholipid nano-dispersion by ultrasonic emulsification. Control the ultrasonic power at 400W and intermittently sonicate for 20min to control the average particle size of the resulting dispersion at 100nm. The essential oil phospholipid nano-dispersion is thus obtained and set aside for later use.

[0052] Step 3: Slowly add 200g of the herbal extract powder obtained in Step 1 to the essential oil phospholipid nano-dispersion obtained in Step 2, and stir for 20 minutes to ensure uniform dispersion; separately weigh 100g of sodium alginate as the polysaccharide embedding material, add it to 1.5mL of purified water, and stir to dissolve at room temperature to prepare a sodium alginate solution; then slowly add the sodium alginate solution to the above mixed system, and continue stirring for 30 minutes to form a bilayer embedding precursor solution with a phospholipid layer as the middle layer and a polysaccharide layer as the outer layer; then prepare 1L of 2% (w / v) calcium chloride solution, and slowly add it dropwise to the above system to carry out ionic cross-linking, and continue stirring for 30 minutes to form a bilayer embedding system;

[0053] Step 4: Weigh 30g of citric acid as a natural organic acid and dissolve it in 200mL of purified water beforehand; then add 560g of maltodextrin and 8g of silicon dioxide as excipients, wherein the maltodextrin is pre-dissolved in 1.8L of purified water and the silicon dioxide is added directly; add 210mL of purified water to adjust the state of the liquid, and stir continuously for 30min to obtain a uniform spray-dried liquid.

[0054] Step 5: Send the above liquid material into a spray dryer for spray drying, control the inlet air temperature to 130℃ and the outlet air temperature to 60℃. After drying, collect the powder to obtain 1kg of the external composition product.

[0055] Performance testing

[0056] 1. Broad-spectrum antibacterial performance test

[0057] The antibacterial effect of the external composition was tested in accordance with the WS / T 650-2019 standard, and Staphylococcus aureus (ATCC 6528), Escherichia coli (8099), and Candida albicans (ATCC 10231) were selected as test strains.

[0058] Table 1. Antibacterial rate under normal temperature conditions

[0059] sample Staphylococcus aureus E. coli Candida albicans Example 1 99.92 99.85 99.76 Example 2 99.98 99.93 99.91 Example 3 99.96 99.90 99.95 Comparative Example 1 85.30 82.14 78.39 Comparative Example 2 92.51 90.27 88.63

[0060] As shown in Table 1, the antibacterial rate of all examples reached over 99.7%, demonstrating potent and broad-spectrum antibacterial activity. The antibacterial rate of Comparative Example 1 (without encapsulation system) decreased significantly, confirming the protective and synergistic effect of the double-layer encapsulation system on the active ingredients; the antibacterial rate of Comparative Example 2 (without low-temperature diffusion promoter and antioxidant) was also lower than that of Example 1.

[0061] 2. Low-temperature antibacterial retention rate test

[0062] After sealing the external composition sample, it was refrigerated at 4°C for 24 hours and frozen at -18°C for 24 hours. After returning to room temperature, the antibacterial rate against Staphylococcus aureus was determined according to the above-mentioned WS / T 650-2019 standard, and calculated as "low temperature antibacterial retention rate = low temperature antibacterial rate / room temperature antibacterial rate × 100%".

[0063] Table 2. Antibacterial effect against Staphylococcus aureus under low temperature conditions

[0064] sample Antibacterial rate at room temperature (%) Antibacterial rate at 4℃ (%) 4℃ retention rate (%) -18℃ Antibacterial rate (%) -18℃ retention rate (%) Example 1 99.96 99.53 99.58 98.32 98.38 Example 2 99.98 99.85 99.87 99.54 99.51 Example 3 99.93 99.97 99.96 99.81 99.83 Comparative Example 1 85.35 60.24 70.52 45.35 53.12 Comparative Example 2 92.51 70.10 75.79 55.60 60.47

[0065] As shown in Table 2, all examples maintained an antibacterial activity retention rate of over 98% after refrigeration at 4°C and freezing at -18°C, with almost no attenuation. This demonstrates that the phospholipid bilayer structure effectively prevents the aggregation and precipitation of low-temperature active ingredients. Comparative Example 1, lacking encapsulation protection, experienced a sharp drop in antibacterial activity at low temperatures, with a retention rate of only 53.12% at -18°C. Comparative Example 2, lacking a low-temperature diffusion promoter, suffered insufficient protection under freezing conditions, resulting in a retention rate that also decreased to 60.47%. This highlights the crucial role of low-temperature diffusion promoters in maintaining the dispersion stability of the system under freezing conditions.

[0066] 3. Activity retention test after heat treatment

[0067] The sample was prepared into a 10% (m / v) dispersion and treated at 80℃ for 30 min and 100℃ for 30 min, respectively. After cooling, the inhibition rate against Staphylococcus aureus was determined according to the quantitative suspension inhibition test of WS / T 650-2019. The berberine retention rate was used as the activity retention index. The change in peak area before and after heat treatment was determined by HPLC. The retention rate was calculated as "content after heat treatment / content before heat treatment × 100%".

[0068] Table 3. Berberine retention rate and antibacterial activity retention rate after heat treatment (80℃ / 30min)

[0069] sample Berberine retention rate (%) Antibacterial rate (%) Antibacterial activity retention rate (%) Example 1 95.64 99.59 99.58 Example 2 97.25 99.92 99.93 Example 3 98.53 99.98 99.97 Comparative Example 1 52.36 62.57 73.26 Comparative Example 2 90.10 88.21 95.35

[0070] As shown in Table 3, after heat treatment at 80℃, the berberine retention rate of the examples was as high as 98.53%, and the antibacterial activity was almost unaffected (99.58%-99.97%). This is attributed to the physical barrier protection of the heat-sensitive components by the polysaccharide-phospholipid bilayer wall material. In Comparative Example 1, due to the lack of any protection, berberine was largely degraded, with a retention rate of 52.36%, and the antibacterial activity was severely reduced. In Comparative Example 2, due to the lack of antioxidant stabilizers, other heat-sensitive active components such as essential oils underwent oxidation or structural changes, affecting the overall synergistic antibacterial effect, and the antibacterial activity retention rate (95.35%) was lower than that of Example 1.

[0071] 4. Skin irritation test

[0072] A closed-loop single-skin irritation test was conducted on rabbits. Three healthy New Zealand white rabbits were used. 24 hours before the test, hair was clipped from both sides of the back to form a test area of ​​approximately 2.5cm × 2.5cm. One side served as the sample area, and the other side as the blank control area. 0.5g of the topical composition sample was weighed and diluted with purified water to prepare a 20% (m / v) paste dispersion. The paste was evenly spread on a gauze pad and then applied to the test area. The contact was closed for 4 hours. After removing the sample, erythema and edema were observed and scored at 1 hour, 24 hours, 48 ​​hours, and 72 hours. The primary irritation index (PII) was calculated.

[0073] Table 4 Results of Skin Irritation Test

[0074] sample Primary Stimulus Index Stimulus intensity grading Example 1 0.12 Non-irritating Example 2 0.08 Non-irritating Example 3 0.15 Non-irritating Comparative Example 1 0.85 Mild irritation Comparative Example 2 0.43 Non-irritating

[0075] As shown in Table 4, the primary irritation index of all embodiments was below 0.2, indicating they were non-irritating. Comparative Example 1 showed mild irritation because the unencapsulated herbal extracts and essential oils came into direct contact with the skin, exposing some of the more irritating components (such as alkaloids and phenols).

[0076] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a topical composition for allergic skin problems with low irritation, antibacterial, and repairing effects, characterized in that, Includes the following steps: Step 1: After pre-processing the herbal raw materials, extract the herbal extract. The herbal raw materials include at least three of the following: Coptis chinensis, Ephedra sinica, Sophora flavescens, Lonicera japonica, Isatis indigotica, and Artemisia argyi. Step 2: Mix the plant essential oil with phospholipids and an aqueous system, and then perform ultrasonic emulsification to obtain an essential oil phospholipid nano-dispersion; the plant essential oil includes at least one of clove oil, cinnamon oil, thyme oil, and tea tree oil; Step 3: Mix the herbal extract with the essential oil phospholipid nano-dispersion, and then add the polysaccharide encapsulation material to form a double-layer encapsulation system with the herbal extract and plant essential oil as the middle layer and the polysaccharide layer as the outer layer. Continue to add natural organic acids, low-temperature diffusion promoters and antioxidant stabilizers, mix evenly, and then spray dry to obtain a topical composition; wherein, the double-layer encapsulation system has pH-responsive release characteristics, the release rate of active ingredients increases under acidic conditions, maintains dispersion stability under refrigeration or freezing conditions, and maintains antibacterial activity under heating conditions.

2. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 1, characterized in that, The herbal raw materials are pulverized and then extracted using a water-alcohol composite extraction method at a temperature of 50-95℃ for 1-5 hours. After extraction, the residue is separated, concentrated, and dried to obtain herbal extract powder.

3. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 1, characterized in that, The phospholipids are selected from one or more of soybean lecithin, sunflower phospholipids, phosphatidylcholine, and short-chain phospholipids; the average particle size of the essential oil phospholipid nanodispersion is 100-200 nm.

4. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 1, characterized in that, The polysaccharide encapsulation material is selected from one or more of sodium alginate, chitosan, gum arabic, high amylose, and gum arabic; the bilayer encapsulation system is formed by ionic crosslinking, electrostatic compounding, or hydrogen bonding association.

5. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 1, characterized in that, The natural organic acid is selected from one or more of citric acid, malic acid, lactic acid, and tartaric acid; the low-temperature diffusion promoter is selected from one or more of trehalose, glycerol, betaine, proline, monoglyceride fatty acid esters, and short-chain phospholipids; and the antioxidant stabilizer is selected from one or more of ascorbate palmitate, vitamin E, sodium citrate, and calcium sodium EDTA.

6. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 1, characterized in that, When spray drying is used, the inlet air temperature is 130-180℃ and the outlet air temperature is 60-90℃; the resulting external composition has a water content of 2%-6%.

7. A topical composition prepared by the method according to claims 1-6, characterized in that, The topical composition comprises the following components by weight percentage: 20-35% herbal extracts, 5-12% active plant essential oils, 3-8% phospholipids, 10-20% polysaccharide encapsulating material, 3-8% natural organic acids, 2-6% low-temperature diffusion promoters, 0.2-2% antioxidant stabilizers, and the balance being excipients.

8. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 7, characterized in that, The excipients are selected from one or more of maltodextrin, resistant dextrin, soluble starch, glucose, and silicon dioxide; the topical composition is a powder formulation with a double-layer microcapsule structure, wherein the outer layer is a polysaccharide layer, the middle layer is a phospholipid layer, and the inner layer is a phospholipid layer containing herbal extracts and plant essential oil active components.

9. The method for preparing the low-irritation, antibacterial, and repairing dual-effect topical composition for allergic skin problems according to claim 7, characterized in that, The topical composition exhibits pH-responsive release properties, with the release rate of the active ingredient being higher at pH 3.0-5.5 than at pH 6.0-7.0; and the topical composition maintains antibacterial activity within the temperature range of -18 to 100°C.

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