A polylactic acid composition, and a method of preparing and using the same

Abstract

The application discloses a polylactic acid composition and a preparation method and application thereof, and belongs to the technical field of polylactic acid external dressings. The polylactic acid composition comprises components A, B and C. The component A comprises the following components in parts by weight: 45-50 parts of gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer, 20-25 parts of dimyristoyl phosphatidyl ethanolamine-polyethylene glycol-sodium alginate modified with amino, and microencapsulated TG enzyme. The component B is a mixed solution of hyaluronic acid oligosaccharide, tannic acid and calcium citrate. The component C is an aqueous solution of hyaluronic acid oligosaccharide and glycerol. The polylactic acid composition is combined with a casein-beta cyclodextrin embedded plant extract to obtain a skin care combination product. The skin care combination product can form a dense and hydrophobic drug application layer on the surface of the skin, and the volatile loss of the plant extract is reduced compared with the prior art.

Description

Technical Field

[0001] This invention belongs to the field of polylactic acid external dressing technology, and relates to a polylactic acid composition, its preparation method and application. Background Technology

[0002] In beauty salon treatments, dressings containing volatile plant essential oils (such as lavender essential oil, peppermint essential oil, and tea tree essential oil) are commonly used for skin care such as acne treatment and insect bite treatment. Currently, when using plant essential oils, they are directly diluted with base oils such as jojoba oil and applied to the skin surface without any anti-volatile protection, resulting in significant volatility loss of plant essential oils during use. Summary of the Invention

[0003] The purpose of this invention is to provide a polylactic acid composition, its preparation method, and its application, which solves the problem of significant volatility loss of volatile plant essential oils during beauty care.

[0004] The technical solution adopted in this invention is as follows: A polylactic acid composition includes component A, component B, and component C; wherein component B is the outer crosslinking liquid of component A; and component C is a surface hydrophilic treatment agent. Component A comprises the following components in parts by weight: 45-50 parts of gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer, 20-25 parts of dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, and microencapsulated TG enzyme. Component B is a mixture of hyaluronic acid oligosaccharides, tannic acid, and calcium citrate; by mass, the spray volume of component B is 70% of the amount of component A used. Component C is an aqueous solution of hyaluronic acid oligosaccharide and glycerol.

[0005] Further, the gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer was prepared by the following method: hydroxyl-terminated polylactic acid-glycolic acid copolymer (provided by Beyotime Biotechnology Research Institute, model Y268850) was dissolved in dimethylformamide to prepare a reaction solution with a mass fraction of 10%; N,N'-dicyclohexylcarbodiimide and N-hydroxysuccinimide were added to the reaction solution, and the mixture was stirred at 25°C for 30 minutes to obtain an activated reaction solution; the mass ratio of N,N'-dicyclohexylcarbodiimide, N-hydroxysuccinimide, and hydroxyl-terminated polylactic acid-glycolic acid copolymer was 2.1:1.2:10; Gelatin was dissolved in a phosphate buffer solution at pH 7.4 to prepare an 8% (w / w) gelatin solution. The gelatin solution was added dropwise to the activation reaction solution while stirring. The reaction was carried out at 40°C with continuous stirring for 24 hours. After the reaction was completed, the reaction solution was placed in a dialysis bag with a molecular weight cutoff of 14,000 and dialyzed in deionized water. The dialyzed solution was freeze-dried to obtain a gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer. The mass ratio of gelatin to hydroxyl-terminated polylactic acid-glycolic acid copolymer is 1:5.

[0006] Further, the dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate is prepared by the following method: sodium alginate is dissolved in MES buffer at pH 5.5 to prepare a 1.0% sodium alginate solution; 50% EDC and 30% NHS (by mass of sodium alginate) are added to the sodium alginate solution, and the carboxyl groups are activated at 25°C for 30 minutes to obtain an activated solution; 80% dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate is added to the activated solution. Dimyristic phosphatidylethanolamine-polyethylene glycol-amino (dimyristic phosphatidylethanolamine-polyethylene glycol-amino is commercially available, in which the molecular weight of polyethylene glycol is 2000) was dissolved in deionized water and then slowly added dropwise to the activation solution. The mixture was stirred at 25°C for 24 hours. After the reaction was completed, the reaction solution was dialyzed in deionized water for 3 days using a dialysis bag with a molecular weight cutoff of 14000. The solution was then freeze-dried to obtain dimyristic phosphatidylethanolamine-polyethylene glycol-amino modified sodium alginate.

[0007] Furthermore, the core material of the microencapsulated TG enzyme includes TG enzyme, and the shell material of the microencapsulated TG enzyme is polyvinyl alcohol.

[0008] Further, component B is prepared by the following method: 1.0% hyaluronic acid oligosaccharide (Mw≈5000) and 0.6% calcium citrate are dissolved in deionized water at 60°C by weight percentage. After cooling to room temperature, 3.0% tannic acid is added, stirred evenly, and then filled and sealed with nitrogen.

[0009] Furthermore, component C is prepared by the following method: 0.5% hyaluronic acid oligosaccharide (Mw≈5000) and 5.0% glycerol are added to deionized water by weight percentage, stirred evenly, and then filled.

[0010] A method for preparing a polylactic acid composition includes the following steps: S1. Dissolve gelatin-based hydroxyl-terminated polylactic acid-glycolic acid copolymer in deionized water at 40°C to prepare a 5% (w / w) solution A; dissolve dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate in deionized water to prepare a 2% (w / w) solution B; under stirring at 40°C and 500 rpm, add solution B dropwise to solution A; after the addition is complete, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinate. The amounts of imide (NHS), EDC, and NHS added were 20% and 12% of the mass of dimyristyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, respectively. The mixture was then stirred at 40°C for 12 hours. After the reaction, the reaction solution was dialyzed in deionized water for 2 days using a dialysis bag with a molecular weight cutoff of 14000. The solution was freeze-dried to obtain an intermediate. The intermediate was then uniformly mixed with microencapsulated TG enzyme to obtain component A. The mass ratio of TG enzyme to intermediate was 0.8:100. S2. Prepare a mixed aqueous solution of hyaluronic acid oligosaccharide, tannic acid, and calcium citrate according to the specified ratio, and fill it into a container to obtain component B. S3. Prepare a mixed aqueous solution of hyaluronic acid oligosaccharide and glycerol according to the ratio, fill it into a container, and obtain component C.

[0011] The use of a polylactic acid composition, wherein the polylactic acid composition is combined with casein-betacyclodextrin to encapsulate plant extracts for use in preparing skin care combination products for forming a medicated dressing layer on the skin surface.

[0012] Further, the casein-beta-cyclodextrin-encapsulated plant extract is prepared by the following method: β-cyclodextrin is dissolved in deionized water at 50°C to prepare a 6-7% (w / w) β-cyclodextrin solution; a plant extract composed of lavender essential oil, peppermint essential oil, and tea tree essential oil mixed in a mass ratio of 2:1:1 is dissolved in 95% ethanol to prepare a 20% (w / w) plant extract solution; under stirring at 40°C and 400 rpm, the plant extract solution is added dropwise to the β-cyclodextrin aqueous solution, and then... The reaction time was 30 minutes; after the addition was complete, stirring was continued for 3 hours, and the mixture was allowed to stand at 4°C for 12 hours before filtration and vacuum drying at 40°C to obtain the β-cyclodextrin inclusion complex; sodium caseinate was dissolved in a phosphate buffer solution at pH 7.0 to prepare a 5% sodium caseinate solution; the above β-cyclodextrin inclusion complex powder, equivalent to 40% of the mass of sodium caseinate, was added to the sodium caseinate solution and stirred at 25°C for 2 hours; spray drying was carried out at an inlet air temperature of 135°C and an outlet air temperature of 65°C to obtain the casein-β-cyclodextrin-encapsulated plant extract.

[0013] Further, component A is mixed with casein-betacyclodextrin-encapsulated plant extract in deionized water to obtain a dressing. The dressing, together with components B and C, forms a medicated dressing layer. The mass ratio of casein-betacyclodextrin-encapsulated plant extract, component A, and deionized water is 1:(2~4):10.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention provides a skin care combination product by combining a polylactic acid composition with a casein-beta-cyclodextrin-encapsulated plant extract. The skin care combination product can form a hydrophobic and dense medicated dressing layer on the skin surface. Component A of the polylactic acid composition and the casein-beta-cyclodextrin-encapsulated plant extract are mixed in deionized water to obtain a dressing. Component C is sprayed onto the skin surface to form a wetting layer. The dressing is coated on the wetting layer to form a dressing layer. Finally, component B is sprayed onto the dressing layer to obtain a hydrophobic and dense medicated dressing layer. Components A, B, C, and the casein-beta-cyclodextrin-encapsulated plant extract are stored and transported independently when not in use, without relying on human skin, forming a separately stored skin care combination product. Component A is mainly composed of amphiphilic polylactic acid. The hydrophilic component combines casein-betacyclodextrin to encapsulate plant extracts and comes into contact with the moisturizing layer after the moisturizing treatment of component C, forming a situation where the hydrophilic end adheres to the skin and the hydrophobic end spreads outward. After component B is sprayed, tannic acid and calcium ions work synergistically to promote the cross-linking of sodium alginate. Based on the hydrophobic modification of sodium alginate, a dense hydrophobic layer is formed, which effectively blocks the outward volatilization of essential oils and the outward volatilization pathway of water vapor carrying essential oil molecules. Compared with the existing technology, the amount of essential oil volatilization loss is reduced. 2. In this invention, the TG enzyme enables the casein-betacyclodextrin-encapsulated plant extract to crosslink with the gelatin-composite hydroxyl-terminated polylactic acid-glycolic acid copolymer, forming a stable dressing layer, which facilitates the overall removal of the entire dressing layer in the later stage and reduces dressing layer residue. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a flowchart of a method for preparing a polylactic acid composition according to the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0018] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0019] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0020] The technical solution adopted in the embodiments of the present invention is as follows: The polylactic acid composition used in the following examples includes component A, component B, and component C; component B is the outer crosslinking liquid of component A; and component C is a surface hydrophilic treatment agent. Component A comprises the following components in parts by weight: 48 parts gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer, 23 parts dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, and microencapsulated TG enzyme. Component B is a mixture of hyaluronic acid oligosaccharides, tannic acid, and calcium citrate. Component C is an aqueous solution of hyaluronic acid oligosaccharide and glycerol.

[0021] In the following examples, the gelatin-composite hydroxyl-terminated polylactic acid-glycolic acid copolymer was prepared by the following method: hydroxyl-terminated polylactic acid-glycolic acid copolymer (provided by Beyotime Biotechnology Research Institute, model Y268850) was dissolved in dimethylformamide to prepare a 10% (w / w) reaction solution; N,N'-dicyclohexylcarbodiimide and N-hydroxysuccinimide were added to the reaction solution, and the mixture was stirred at 25°C for 30 minutes to obtain an activated reaction solution; the mass ratio of N,N'-dicyclohexylcarbodiimide, N-hydroxysuccinimide, and hydroxyl-terminated polylactic acid-glycolic acid copolymer was 2.1:1.2:10; Gelatin was dissolved in a phosphate buffer solution at pH 7.4 to prepare an 8% (w / w) gelatin solution. The gelatin solution was added dropwise to the activation reaction solution while stirring. The reaction was carried out at 40°C with continuous stirring for 24 hours. After the reaction was completed, the reaction solution was placed in a dialysis bag with a molecular weight cutoff of 14,000 and dialyzed in deionized water. The dialyzed solution was freeze-dried to obtain a gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer. The mass ratio of gelatin to hydroxyl-terminated polylactic acid-glycolic acid copolymer is 1:5.

[0022] In the following examples, the dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate was prepared by the following method: sodium alginate was dissolved in MES buffer at pH 5.5 to prepare a 1.0% sodium alginate solution; 50% EDC and 30% NHS (by weight of sodium alginate) were added to the sodium alginate solution, and the carboxyl groups were activated at 25°C for 30 minutes to obtain an activated solution; dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate was added to the sodium alginate solution. Acylphosphatidylethanolamine-polyethylene glycol-amino (dimyristoylphosphatidylethanolamine-polyethylene glycol-amino is commercially available, in which the molecular weight of polyethylene glycol is 2000) was dissolved in deionized water and then slowly added dropwise to the activation solution. The mixture was stirred at 25°C for 24 hours. After the reaction was completed, the reaction solution was dialyzed in deionized water for 3 days using a dialysis bag with a molecular weight cutoff of 14000. After freeze-drying, dimyristoylphosphatidylethanolamine-polyethylene glycol-amino modified sodium alginate was obtained.

[0023] In the following examples, the core material of the microencapsulated TG enzyme includes TG enzyme, the shell material of the microencapsulated TG enzyme is polyvinyl alcohol, the preparation method is existing microencapsulation technology, and the content of TG enzyme in 100g of microencapsulated TG enzyme is 20g.

[0024] In the following embodiments, component B was prepared by the following method: 1.0% hyaluronic acid oligosaccharide (Mw≈5000) and 0.6% calcium citrate were dissolved in deionized water at 60°C by weight percentage. After cooling to room temperature, 3.0% tannic acid was added, stirred evenly, and then filled and sealed with nitrogen.

[0025] In the following examples, component C was prepared by the following method: 0.5% hyaluronic acid oligosaccharide (Mw≈5000) and 5.0% glycerol were added to deionized water by weight percentage, stirred evenly, and then filled into bottles.

[0026] The following examples illustrate a method for preparing a polylactic acid composition, such as... Figure 1 As shown, it includes the following steps: S1. Dissolve gelatin-based hydroxyl-terminated polylactic acid-glycolic acid copolymer in deionized water at 40°C to prepare a 5% (w / w) solution A; dissolve dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate in deionized water to prepare a 2% (w / w) solution B; under stirring at 40°C and 500 rpm, add solution B dropwise to solution A; after the addition is complete, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinyl ester. The amounts of amine (NHS), EDC·HCl, and NHS added were 20% and 12% of the mass of dimyristoylphosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, respectively. The reaction mixture was then stirred at 40°C for 12 hours. After the reaction, the reaction solution was dialyzed in deionized water for 2 days using a dialysis bag with a molecular weight cutoff of 14000. The mixture was freeze-dried to obtain an intermediate. The intermediate was then uniformly mixed with microencapsulated TG enzyme to obtain component A. The mass ratio of TG enzyme to intermediate was 0.8:100. S2. Prepare a mixed aqueous solution of hyaluronic acid oligosaccharide, tannic acid, and calcium citrate according to the specified ratio, and fill it into a container to obtain component B. S3. Prepare a mixed aqueous solution of hyaluronic acid oligosaccharide and glycerol according to the ratio, fill it into a container, and obtain component C.

[0027] In the following examples, the casein-beta-cyclodextrin-encapsulated plant extract was prepared by the following method: β-cyclodextrin was dissolved in deionized water at 50°C to prepare a 7% (w / w) β-cyclodextrin solution; a plant extract composed of lavender essential oil, peppermint essential oil, and tea tree essential oil mixed in a mass ratio of 2:1:1 was dissolved in 95% ethanol to prepare a 20% (w / w) plant extract solution; the plant extract solution was added dropwise to β-cyclodextrin at a mass ratio of 1:6, under stirring at 40°C and 400 rpm. Add the β-cyclodextrin inclusion complex to an aqueous solution of β-cyclodextrin over 30 minutes; after addition, continue stirring for 3 hours, let stand at 4°C for 12 hours, filter, and vacuum dry at 40°C to obtain the β-cyclodextrin inclusion complex; dissolve sodium caseinate in a phosphate buffer solution at pH 7.0 to prepare a 5% sodium caseinate solution; add the above β-cyclodextrin inclusion complex powder, equivalent to 40% of the mass of sodium caseinate, to the sodium caseinate solution, stir at 25°C for 2 hours; spray dry at an inlet air temperature of 135°C and an outlet air temperature of 65°C to obtain the casein-beta-cyclodextrin-encapsulated plant extract. The casein-beta-cyclodextrin-encapsulated plant extract, combined with a polylactic acid composition, yields a skin care combination product for forming a medicated dressing on the skin surface.

[0028] Example 1 A preferred embodiment of the present invention provides a skin care combination product for forming a medicated dressing layer on the skin surface, the skin care combination product comprising the above-mentioned polylactic acid composition and casein-betacyclodextrin-encapsulated plant extract; wherein, the polylactic acid composition comprises component A, component B and component C; Component A comprises the following components in parts by weight: 48 parts gelatin-based hydroxyl-terminated polylactic-co-glycolic acid copolymer, 23 parts dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, and microencapsulated TG enzyme; and Component A is prepared by the following method: dissolving the gelatin-based hydroxyl-terminated polylactic-co-glycolic acid copolymer in deionized water at 40°C to prepare a 5% (w / w) solution A; dissolving dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate in deionized water to prepare a 2% (w / w) solution B; and adding solution B dropwise to solution A under stirring at 40°C and 500 rpm until the mixture is completely added. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinimide (NHS) were then added. The amounts of EDC and NHS added were 20% and 12% of the mass of dimyristoylphosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, respectively. The reaction was then stirred at 40°C for 12 hours. After the reaction was completed, the reaction solution was dialyzed in deionized water for 2 days using a dialysis bag with a molecular weight cutoff of 14,000. The solution was then freeze-dried to obtain an intermediate. The intermediate was then uniformly mixed with microencapsulated TG enzyme to obtain component A, which was then sealed and stored. The mass ratio of TG enzyme to intermediate was 0.8:100. Component B was prepared by the following method: 1.0% hyaluronic acid oligosaccharide (Mw≈5000) and 0.6% calcium citrate were dissolved in deionized water at 60°C, cooled to room temperature, and 3.0% tannic acid was added. After stirring evenly, the mixture was filled with nitrogen and sealed. Component C was prepared by the following method: 0.5% hyaluronic acid oligosaccharide (Mw≈5000) and 5.0% glycerol were added to deionized water by weight percentage, stirred evenly, and then filled into bottles. The method of using the combination product for skin care is as follows: Component A is mixed with casein-beta-cyclodextrin-encapsulated plant extract in deionized water to obtain a dressing; Component C is applied to the skin surface to form a wetting layer; the dressing is then applied to the surface of the wetting layer formed by component C to form a dressing layer; finally, component B is sprayed onto the dressing layer. Components A, B, C, and the casein-beta-cyclodextrin-encapsulated plant extract together form a medicated dressing layer; by weight, the amount of component B sprayed is 70% of the amount of component A used; the amount of component C used is freely adjustable according to the actual skin surface area treated, as long as it can fully cover the treated surface. The mass ratio of the casein-beta-cyclodextrin-encapsulated plant extract, component A, and deionized water is 1:3:10; detailed steps are as follows: Step 1: Apply component C evenly to the surface of the skin to be treated and let it stand at room temperature for 20-30 seconds to form a wetting layer; Step 2: According to the mass ratio of casein-beta-cyclodextrin-encapsulated plant extract, component A, and deionized water of 1:3:10, mix component A and casein-beta-cyclodextrin-encapsulated plant extract evenly in deionized water and let stand for 1 minute to obtain the dressing. Step 3: Stir the dressing after step 2 until it is evenly mixed and then evenly applied to the wetting layer. After application, let it stand for 3 minutes to obtain the dressing layer. After standing, spray component B evenly onto the dressing layer. About 5 minutes after spraying component B, a hydrophobic and dense medicated dressing layer with an outer surface is obtained. Continue to apply the dressing for another 25 minutes after spraying component B before removing it.

[0029] Example 2 This embodiment differs from Embodiment 1 in that the mass ratio of casein-betacyclodextrin-encapsulated plant extract, component A, and deionized water in this embodiment is 1:2:10.

[0030] Example 3 This embodiment differs from Embodiment 1 in that the mass ratio of casein-betacyclodextrin-encapsulated plant extract, component A, and deionized water in this embodiment is 1:4:10.

[0031] Comparative Example 1 Based on Example 1, this comparative example provides a skin care product comprising only casein-betacyclodextrin-encapsulated plant extract; the casein-betacyclodextrin-encapsulated plant extract and deionized water are mixed evenly in a mass ratio of 1:10, and then left to stand for 1 minute to obtain a dressing; the dressing is applied directly to the skin.

[0032] Comparative Example 2 This comparative example provides a skin care product, including plant extracts and jojoba oil; lavender essential oil, peppermint essential oil, and tea tree essential oil are mixed in a mass ratio of 2:1:1 to obtain the plant extract; the method of use is to dilute the plant extract with jojoba oil at a volume ratio of 2:100, and the resulting dressing is applied directly to the skin surface.

[0033] Comparative Example 3 Based on Example 1, this comparative example provides a skin care product that does not include component B; otherwise, it is consistent with Example 1.

[0034] Comparative Example 4 Based on Example 1, this comparative example provides a skin care product that does not include component C; otherwise, it is consistent with Example 1.

[0035] Comparative Example 5 Based on Example 1, this comparative example provides a skin care product in which component A does not include microencapsulated TG enzyme; otherwise, it is consistent with Example 1.

[0036] Experimental Example 1 The volatile barrier properties of the skin care products provided in Examples 1-3 and Comparative Examples 1-5 were tested, and the total weight loss of the samples under the following test conditions was used as the test result. The results are shown in Table 1. Sampling standards for skincare products: 1g of plant extract (plant extract obtained by mixing lavender essential oil, peppermint essential oil and tea tree essential oil in a mass ratio of 2:1:1) is used as the sampling benchmark; the sampling of casein-betacyclodextrin-encapsulated plant extract is calculated based on 1g of plant extract. Sample substrate: A 5cm×5cm glass plate with a thickness of 2mm was used as the sample substrate. The sample substrate was treated as follows: a clean glass plate was wiped and cleaned three times each with acetone and anhydrous ethanol, and then dried in an electric heating drying oven at 105℃ to constant weight (the difference between two weighings ≤0.2mg). The plate was then placed in a desiccator to cool to room temperature, and the mass was accurately weighed (accurate to 0.01mg) and recorded as m0 (substrate). Sample preparation process for Examples 1-3: Weighing glass plate (m0) → uniformly spraying component C (approximately 0.2g) (let stand for 30 seconds) → applying dressing (let stand for 3 minutes) → spraying component B (let stand for 5 minutes after spraying component B) → weighing (m1); Sample preparation process for Comparative Examples 1-2: The dressing was directly applied to the glass plate, and after standing for 5 minutes, it was weighed (m1). The sample preparation process for Comparative Example 3 was as follows: weighing the glass plate (m0) → uniformly spraying approximately 0.2g of component C (let stand for 30 seconds) → applying the dressing (let stand for 8 minutes) → weighing (m1); The sample preparation process for Comparative Example 4 was as follows: weighing of glass plate (m0) → coating with dressing (let stand for 3 minutes) → spraying component B (let stand for 5 minutes after spraying component B) → weighing (m1). The sample preparation process for Comparative Example 5 was as follows: weighing the glass plate (m0) → uniformly spraying approximately 0.2g of component C (let stand for 30 seconds) → applying the dressing (let stand for 3 minutes; component A of the dressing does not include microencapsulated TG enzyme) → spraying component B (let stand for 5 minutes after spraying component B) → weighing (m1). Sample preparation process for blank group 1: The blank dressing for blank group 1 does not include casein-betacyclodextrin-encapsulated plant extract. Component A and deionized water are mixed evenly at a mass ratio of 3:10 and allowed to stand for 1 minute to obtain the blank dressing. The preparation process is the same as the sample preparation process in Examples 1-3, except that the dressing in the examples is replaced with the blank dressing. Sample preparation procedure for blank group 2: Take a 5cm×5cm glass plate with a thickness of 2mm, wipe and clean it three times with acetone and three times with anhydrous ethanol, place it in an electric heating drying oven at 105℃ and dry it to constant weight (the difference between two weighings ≤0.2mg), place it in a desiccator to cool to room temperature, and weigh it (m1). Test method: Weigh the sample (m1) and place it in a constant temperature and humidity chamber at 32℃±0.5℃ and 45%±3%RH. Weigh the sample after 20 minutes, 12 hours, and 24 hours, and record the weight as m. t The weight loss rate after standing for 20 minutes, 12 hours, and 24 hours was measured separately and independently. Total weight loss (%) of samples in Examples 1-3, Comparative Examples 1-5, and Blank Group 1 = (m1-m t (m1-m0)×100%, take the average value of 3 groups of parallel samples, and retain two decimal places; Total weight loss rate (%) in blank group 2 = (m1 - m) t () / m1×100%, the average value of 3 parallel samples is taken, and the result is retained to two decimal places.

[0037] Table 1. Results of total weight loss of samples over 24 hours Experimental Example 2 The hydrophobicity and peel strength of the outer surface of the medicated dressings formed in Example 1, Comparative Example 4, and Comparative Example 5 were tested; the results are shown in Table 2. Hydrophobicity of the outer surface of the medicated dressing: Based on the test example 1, the water contact angle of the outer surface of the medicated dressing was determined by the static contact angle method. During the sample preparation process, after spraying component B, the water contact angle was measured after standing for 5 minutes. The average value of three parallel samples was taken. A contact angle > 90° was considered a hydrophobic surface. Peel strength: A 0.35mm ± 0.05mm thick Weixia simulated skin was used instead of a glass plate as the sample substrate. The remaining steps were based on the sample preparation in Test Example 1. The Weixia simulated skin conformed to the GB15811 standard. After spraying component B, the dressing was allowed to stand for 5 minutes and then applied for another 25 minutes before being removed. The peel strength of the dressing was then measured. The sample was fixed on the test plate of a tensile testing machine, and the peel strength of the dressing was measured using the 180° peel method. The unit was (N / cm). The average value of three parallel samples was taken. The presence of any visible residue on the simulated skin after peeling was observed by the naked eye. The criteria for no visible residue were: no visible sticky substances on the simulated skin, no visible fragments of any shape such as filaments, granules, or films; and the dressing itself had an intact structure without any visible breaks or defects.

[0038] Table 2 Results of tests on the hydrophobicity and peel strength of the outer surface of the coating. Experimental Example 3 The efficacy and biosafety of the skin care combination product in Example 1 were tested, and the efficacy results are shown in Table 3. The biosafety standards implemented are GB / T16886.10-2024 "Biological Evaluation of Medical Devices Part 10: Skin Sensitization Test", GB / T16886.5-2017 "Biological Evaluation of Medical Devices Part 5: In Vitro Cytotoxicity Test", and "Cosmetic Safety Technical Specifications". The skin care combination product obtained in Example 1 of this application has low sensitization, qualified cytotoxicity, and complies with the "Cosmetic Safety Technical Specifications". Efficacy testing: Thirty healthy male New Zealand white rabbits (weighing 2.0-2.5 kg) were selected and acclimatized for one week before the experiment began. A rabbit ear acne model was established using the Kligman method (the standard method for rabbit ear acne models established by the American Academy of Dermatology). Following the Kligman method, 0.5 mL of coal tar was applied to an area of ​​approximately 2 cm × 2 cm on the inner side of the right ear canal of each rabbit, once daily for two consecutive weeks. The left ear was left untreated and served as a normal control. After 14 days of continuous application, compared to the left ear, the rabbit ears showed signs of rough skin, protruding hair follicle openings, visible black keratin plugs, and hardened, thickened skin, indicating successful model establishment. The 30 successfully modeled New Zealand white rabbits were randomly divided into two groups of 15 each. The two groups were grouped according to the following treatment methods: Blank control group: No treatment was given to either the left or right ear; Example 1 group: The left ear was left untreated, and the right ear was treated with a medicated dressing as described in Example 1; the drug was administered once a day, with a single dose of 0.3g of casein-betacyclodextrin-encapsulated plant extract. After spraying component B in a single dose, the dressing was applied for another 25 minutes before being removed; the drug was administered continuously for 14 days. The number of samples from the right ear of the experimental rabbits in the blank control group and the group of Example 1 were calculated according to the following criteria: histological criteria for experimental acne: (-) normal amount of keratinized material in the follicular infundibulum; (+) more keratinized material in the follicular infundibulum; (2+) moderate amount of keratinized material in the follicular infundibulum extending towards the sebaceous gland; (3+) extensive keratinized material in the dilated follicle, similar to human open comedones. The experimental results are shown in Table 3.

[0039] Table 3. Results of product efficacy and biosafety testing Note: Each group consisted of 15 rabbits, and both right ears of each rabbit were taken for histological evaluation. Therefore, the total sample size was 15 ears per group. As shown above, the skin care combination product obtained in this application has a certain care effect on acne (acne is a type of acne), and has a good anti-volatile protective effect on plant extracts during use; in addition, the skin care combination product obtained in this application has low allergenicity, qualified in vitro cytotoxicity and complies with the "Cosmetic Safety Technical Specifications".

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A polylactic acid composition, characterized in that: It includes component A, component B and component C; component B is the outer crosslinking liquid of component A; Component C is a surface hydrophilic treatment agent; Component A comprises the following components in parts by weight: 45-50 parts of gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer, 20-25 parts of dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, and microencapsulated TG enzyme. Component B is a mixture of hyaluronic acid oligosaccharides, tannic acid, and calcium citrate; by mass, the amount of component B used is 70% of the amount of component A used. Component C is an aqueous solution of hyaluronic acid oligosaccharide and glycerol.

2. The polylactic acid composition according to claim 1, characterized in that: The gelatin-composite hydroxyl-terminated polylactic acid-glycolic acid copolymer was prepared by the following method: the hydroxyl-terminated polylactic acid-glycolic acid copolymer was dissolved in dimethylformamide to prepare a reaction solution with a mass fraction of 10%; N,N'-dicyclohexylcarbodiimide and N-hydroxysuccinimide were added to the reaction solution, and the mixture was stirred at 25°C for 30 minutes to obtain an activated reaction solution; the mass ratio of N,N'-dicyclohexylcarbodiimide, N-hydroxysuccinimide, and hydroxyl-terminated polylactic acid-glycolic acid copolymer was 2.1:1.2:10; Gelatin was dissolved in a phosphate buffer solution at pH 7.4 to prepare an 8% (w / w) gelatin solution. The gelatin solution was added dropwise to the activation reaction solution while stirring. The reaction was carried out at 40°C with continuous stirring for 24 hours. After the reaction was completed, the reaction solution was placed in a dialysis bag with a molecular weight cutoff of 14,000 and dialyzed in deionized water. The dialyzed solution was freeze-dried to obtain a gelatin composite hydroxyl-terminated polylactic acid-glycolic acid copolymer. The mass ratio of gelatin to hydroxyl-terminated polylactic acid-glycolic acid copolymer is 1:

5.

3. The polylactic acid composition according to claim 1, characterized in that: The dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino modified sodium alginate was prepared by the following method: sodium alginate was dissolved in MES buffer at pH 5.5 to prepare a 1.0% sodium alginate solution; 50% EDC and 30% NHS (by mass of sodium alginate) were added to the sodium alginate solution, and the carboxyl groups were activated at 25°C for 30 minutes to obtain an activated solution; 80% dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino (by mass of sodium alginate) was dissolved in deionized water and slowly added dropwise to the activated solution, and the mixture was stirred at 25°C for 24 hours; after the reaction was completed, the reaction solution was dialyzed in deionized water for 3 days using a dialysis bag with a molecular weight cutoff of 14000; and then freeze-dried to obtain dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino modified sodium alginate.

4. The polylactic acid composition according to claim 1, characterized in that: The core material of the microencapsulated TG enzyme includes TG enzyme, and the shell material of the microencapsulated TG enzyme is polyvinyl alcohol.

5. The polylactic acid composition according to claim 1, characterized in that: Component B is prepared by the following method: 1.0% hyaluronic acid oligosaccharide and 0.6% calcium citrate are dissolved in deionized water at 60°C by weight percentage. After cooling to room temperature, 3.0% tannic acid is added, stirred evenly, and then filled and sealed with nitrogen.

6. The polylactic acid composition according to claim 1, characterized in that: Component C is prepared by the following method: 0.5% hyaluronic acid oligosaccharide and 5.0% glycerol are added to deionized water by weight percentage, stirred evenly, and then filled.

7. A method for preparing a polylactic acid composition according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Dissolve gelatin-based hydroxyl-terminated polylactic acid-glycolic acid copolymer in deionized water at 40°C to prepare a 5% (w / w) solution A; dissolve dimyristoyl phosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate in deionized water to prepare a 2% (w / w) solution B; under stirring at 40°C and 500 rpm, add solution B dropwise to solution A; after the addition is complete, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. The amounts of (aminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide added were 20% and 12% of the mass of dimyristoylphosphatidylethanolamine-polyethylene glycol-amino-modified sodium alginate, respectively. The reaction mixture was then stirred at 40°C for 12 hours. After the reaction, the reaction solution was dialyzed in deionized water for 2 days using a dialysis bag with a molecular weight cutoff of 14000. The solution was then freeze-dried to obtain an intermediate. The intermediate was then uniformly mixed with microencapsulated TG enzyme to obtain component A. The mass ratio of TG enzyme to intermediate was 0.8:

100. S2. Prepare a mixed aqueous solution of hyaluronic acid oligosaccharide, tannic acid, and calcium citrate according to the specified ratio, and fill it into a container to obtain component B. S3. Prepare a mixed aqueous solution of hyaluronic acid oligosaccharide and glycerol according to the ratio, fill it into a container, and obtain component C.

8. The application of a polylactic acid composition according to any one of claims 1-6, characterized in that: The polylactic acid composition, in combination with casein-betacyclodextrin-encapsulated plant extracts, is used to prepare skin care combination products for forming a medicated dressing layer on the skin surface.

9. The application of the polylactic acid composition according to claim 8, characterized in that: The casein-beta-cyclodextrin-encapsulated plant extract was prepared by the following method: β-cyclodextrin was dissolved in deionized water at 50°C to prepare a 6-7% (w / w) β-cyclodextrin solution; a plant extract composed of lavender essential oil, peppermint essential oil, and tea tree essential oil in a 2:1:1 (w / w) ratio was dissolved in 95% ethanol to prepare a 20% (w / w) plant extract solution; the plant extract solution was added dropwise to the β-cyclodextrin solution at 40°C and 400 rpm with a dropping time of 3 minutes. 0 minutes; after the addition is complete, continue stirring for 3 hours, let stand at 4℃ for 12 hours, filter, and vacuum dry at 40℃ to obtain β-cyclodextrin inclusion complex; dissolve sodium caseinate in phosphate buffer at pH 7.0 to prepare a 5% sodium caseinate solution; add the above β-cyclodextrin inclusion complex powder equivalent to 40% of the mass of sodium caseinate to the sodium caseinate solution, stir at 25℃ for 2 hours; spray dry at an inlet air temperature of 135℃ and an outlet air temperature of 65℃ to obtain casein-β-cyclodextrin encapsulated plant extract.

10. The application of the polylactic acid composition according to claim 8, characterized in that: The component A is mixed with the casein-betacyclodextrin-encapsulated plant extract in deionized water to obtain a dressing. The dressing is then combined with components B and C to form a medicated dressing layer. The mass ratio of the casein-betacyclodextrin-encapsulated plant extract, component A, and deionized water is 1:(2~4):10.

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