A physical sunscreen cream and its preparation method and application

Abstract

This application discloses a physical sunscreen emulsion, its preparation method, and its application, belonging to the field of cosmetic technology. A physical sunscreen emulsion, by mass percentage, comprises the following components: 45%–55% physical sunscreen powder, 1.5%–5% emulsifier, 1.5%–2.5% film-forming agent, 8%–15% oil phase, 0.5%–3% polymethylsilsesquioxane, 1%–4% suspension stabilizer, 1%–3% butyl octyl salicylate, 4%–10% moisturizer, 0.1%–1.2% active ingredient, 0.03%–0.10% thickener, 0.02%–0.10% chelating agent, 0.5%–1.5% inorganic salt, 0.3%–0.8% preservative, and the balance being water. It improves the dispersion stability of physical sunscreen agents and the water and abrasion resistance of sunscreen films, reduces skin migration of sunscreen components, and balances sun protection effect, skin feel and soothing effect.

Description

Technical Field

[0001] This application relates to a physical sunscreen lotion, its preparation method, and its application, belonging to the field of cosmetic technology. Background Technology

[0002] Prolonged exposure to ultraviolet (UV) radiation is a major factor contributing to photoaging of the skin, causing erythema, pigmentation, and decreased barrier function. Therefore, sun protection is crucial for reducing UV damage and delaying photoaging. Current sunscreens are mainly categorized into chemical sunscreens, physical sunscreens, and combination sunscreens. For sensitive skin or skin with a damaged barrier, some chemical sunscreens may cause stinging, redness, and other discomfort. Physical sunscreens primarily include titanium dioxide and zinc oxide; when used together, they provide comprehensive protection against both UVA and UVB rays and are generally gentler on the skin.

[0003] However, to achieve high sun protection performance, physical sunscreens typically require a high concentration of physical sunscreen powder, which can easily lead to problems such as particle aggregation, sedimentation, and uneven distribution. This results in decreased system stability and a heavy, whitening effect on the skin, as well as uneven application. Furthermore, the protective film formed by physical sunscreen particles is easily detached upon contact with water, sweat, or friction, affecting the durability of the sun protection effect.

[0004] Sensitive skin and skin that has undergone microneedling have a weakened skin barrier function, and UV exposure may further aggravate inflammation and pigmentation. This type of skin not only requires effective sun protection but also needs to reduce the migration of sunscreen components into the skin, while also receiving soothing care.

[0005] Therefore, it is necessary to provide a physical sunscreen suitable for sensitive skin and skin after microneedling to address the shortcomings of existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a physical sunscreen emulsion, its preparation method, and its application, so as to improve the dispersion stability of physical sunscreen agents and the water and abrasion resistance of sunscreen films, reduce the skin migration of sunscreen components, and take into account the sun protection effect, skin feel, and soothing effect.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On one hand, this application provides a physical sunscreen emulsion, comprising the following components by weight: 45-55 parts of physical sunscreen powder, 1.5-5 parts of emulsifier, 1.5-2.5 parts of film-forming agent, 8-15 parts of oil phase, 0.5-3 parts of polymethylsilsesquioxane, 1-4 parts of suspension stabilizer, 1-3 parts of butyl octyl salicylate, 4-10 parts of moisturizer, 0.1-1.2 parts of active ingredient, 0.03-0.10 parts of thickener, 0.02-0.10 parts of chelating agent, 0.5-1.5 parts of inorganic salt, 0.3-0.8 parts of preservative, and the balance being water.

[0008] In some embodiments, the physical sunscreen agent powder content is 45% to 55% by mass, based on the total mass of the physical sunscreen lotion.

[0009] For example, the mass percentage of the physical sunscreen powder can be 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, or any range thereof.

[0010] In some embodiments, the physical sunscreen powder paste includes titanium dioxide powder paste and zinc oxide powder paste, wherein the mass ratio of titanium dioxide powder paste to zinc oxide powder paste is (0.6-0.8):1.

[0011] For example, the mass ratio of the titanium dioxide slurry to the zinc oxide slurry can be 0.60:1, 0.65:1, 0.70:1, 0.75:1, 0.80:1, or any range thereof.

[0012] In some embodiments, the emulsifier has a mass percentage content of 1.5% to 5% based on the total mass of the physical sunscreen lotion, for example, it can be 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or any range therebetween.

[0013] In some embodiments, the emulsifier is selected from one or more of polyglycerol-4 diisostearate / polyhydroxystearate / sebacate, lauryl PEG-9 polydimethylsiloxane, cetyl PEG / PPG-10 / 1 polydimethylsiloxane, and PEG-10 polydimethylsiloxane.

[0014] In some embodiments, the film-forming agent has a mass percentage content of 1.5% to 2.5% based on the total mass of the physical sunscreen lotion, for example, it can be 1.5%, 1.8%, 2.0%, 2.2%, 2.5% or any range therebetween.

[0015] In some embodiments, the film-forming agent is selected from one or more of KP545, KP7312J, SUNUP, 4003, acrylate copolymers and VP / eicosene copolymers.

[0016] In some embodiments, the oil phase has a mass percentage of 8% to 15% based on the total mass of the physical sunscreen, for example, it can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or any range therebetween.

[0017] In some embodiments, the oil phase is selected from those with a viscosity of 2 mm. 2 Polydimethylsiloxane with a viscosity of 6 mm² / s, polydimethylsiloxane with a viscosity of 350 mm² / s, and polydimethylsiloxane with a viscosity of 350 mm² / s. 2 / s contains one or more of polydimethylsiloxane, dioctyl carbonate, and caprylic / capric triglyceride.

[0018] In some embodiments, the polymethylsilsesquioxane content is 0.5% to 3% by mass based on the total mass of the physical sunscreen lotion, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or any range therebetween.

[0019] In some embodiments, the mass percentage of the suspending stabilizer is 1% to 4% based on the total mass of the physical sunscreen lotion, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or any range therebetween.

[0020] In some embodiments, the suspension stabilizer includes one or more of cyclopentamethoxysiloxane, lithium distearate dimethylammonium montmorillonite, and propylene glycol carbonate.

[0021] In some embodiments, the butyl octyl salicylate content is 1% to 3% by weight of the total mass of the physical sunscreen lotion, for example, it can be 1%, 1.5%, 2%, 2.5%, 3% or any range therebetween.

[0022] In some embodiments, the humectant content is 4% to 10% by mass percentage based on the total mass of the physical sunscreen lotion, for example, it can be 4%, 5%, 6%, 7%, 8%, 9%, 10% or any range therebetween.

[0023] In some embodiments, the humectant includes glycerin and 1,3-butanediol.

[0024] In some embodiments, the mass percentage of the active ingredient, based on the total mass of the physical sunscreen lotion, is 0.1% to 1.2%, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, or any range therebetween.

[0025] In some embodiments, the active ingredient is selected from one or more of the following: European cork oak bark extract, stearyl glycyrrhetinic acid liposome dispersion, Bacillus fermentation product, ozogrin 10W, and bisabolol.

[0026] In some embodiments, the stearyl glycyrrhetinic acid liposome dispersion contains 1.5% to 2.0% by mass, for example, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0% or any range thereof.

[0027] In some embodiments, the thickener has a mass percentage of 0.03% to 0.10%, the chelating agent has a mass percentage of 0.02% to 0.10%, the inorganic salt has a mass percentage of 0.5% to 1.5%, and the preservative has a mass percentage of 0.3% to 0.8%, based on the total mass of the physical sunscreen lotion.

[0028] In some embodiments, the thickener is xanthan gum, the chelating agent is disodium EDTA, and the inorganic salt is sodium chloride.

[0029] On the other hand, this application also provides a method for preparing the above-mentioned physical sunscreen lotion, comprising the following steps: (1) Heat and stir the emulsifier at 70-80℃ to obtain phase A; (2) Mix the oil phase, polymethylsilsesquioxane, suspension stabilizer and physical sunscreen powder, heat and stir at 70-80℃ to obtain phase B; add phase A to phase B and stir to obtain phase AB. (3) Mix the film-forming agent and butyl octyl salicylate evenly to obtain phase D; add phase D to phase AB, homogenize at 2000-3000 rpm for 3-8 min, then heat to 70-80℃ and stir evenly to obtain phase ABD; (4) Mix water, humectant, thickener, chelating agent and inorganic salt, heat and stir evenly at 70-80℃ to obtain phase C; (5) Add phase C to phase ABD, stir and homogenize at 2000-3000 rpm for 3-8 min to obtain phase ABCD; (6) Mix the active ingredients evenly to obtain phase E, and use the preservative as phase F; cool phase ABCD to 40-50℃, add phase E and phase F, stir evenly to obtain phase ABCDEF, discharge the material, and obtain physical sunscreen emulsion.

[0030] In some embodiments, the method for preparing the stearyl glycyrrhetinic acid liposome dispersion includes the following steps: S1. Phosphatidylcholine, cholesterol, and stearyl glycyrrhetinic acid ester are added to an organic solvent and sonicated in a water bath for 5-10 minutes to obtain a drug-loaded lipid solution. S2. The drug-loaded lipid solution is subjected to rotary evaporation to remove organic solvents, so that phosphatidylcholine, cholesterol and stearyl glycyrrhetinic acid form a drug-loaded lipid film on the inner wall of the rotary evaporation container, and the drug-loaded lipid film is vacuum dried. S3. Mix water and 1,3-butanediol to obtain an hydrated solution; preheat the hydrated solution to 45-55°C and add it to the drug-loaded lipid film, hydrate for 20-60 min, and then sonicate in a water bath for 10-20 min to obtain a stearyl glycyrrhetinic acid liposome dispersion.

[0031] In some embodiments, the mass ratio of phosphatidylcholine to cholesterol is (3-8):1, for example, it can be 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or any range thereof.

[0032] On the other hand, this application provides the application of the above-mentioned physical sunscreen in the preparation of sunscreen cosmetics for sensitive skin.

[0033] Furthermore, this application provides the application of the aforementioned physical sunscreen in the preparation of cosmetics for daily sun protection of the skin after microneedling procedures.

[0034] The beneficial effects of this application include, but are not limited to: 1. This invention combines titanium dioxide powder paste and zinc oxide powder paste in a specific ratio, utilizing their protective advantages in different ultraviolet bands to achieve synergistic protection against UVA and UVB; butyl octyl salicylate and oil phase further improve the wettability and spreadability of physical sunscreen particles, making the particle distribution more uniform, thereby reducing particle agglomeration, uneven application and whitening while maintaining high sun protection performance.

[0035] 2. Emulsifiers, polymethylsilsesquioxane, suspension stabilizers, thickeners, and inorganic salts jointly construct an emulsification-suspension-rheological stabilization system. The emulsifier maintains the stability of the oil-water interface, the suspension stabilizer and polymethylsilsesquioxane inhibit the sedimentation of physical sunscreen particles, and the thickener and inorganic salts adjust the viscosity and thixotropic properties of the system. This improves the dispersion stability of high-content physical sunscreen powder and reduces the spreadability, greasiness, and heaviness of the sunscreen emulsion.

[0036] 3. The film-forming agent, oil phase, and polymethylsilsesquioxane synergistically form a uniform and continuous composite sunscreen film with physical sunscreen particles, enhancing the adhesion of sunscreen particles to the skin surface and reducing their detachment due to water, sweat, or friction, thereby improving the water resistance, friction resistance, and sun protection durability of the sunscreen lotion; this composite film can also reduce the migration of sunscreen particles on the skin surface, which helps to reduce the risk of them entering areas with damaged skin barriers.

[0037] 4. This invention employs a phase-separated preparation and staged emulsification process. First, an emulsifier phase, an oil phase containing physical sunscreen agents, and an aqueous phase are prepared separately at 70–80°C. Then, homogenization is used to fully combine the physical sunscreen agents, film-forming agents, and emulsion system, reducing particle agglomeration and improving the uniformity of the emulsion system. The active ingredient is added after the emulsion cools down to 40–50°C to reduce the inactivation of the active ingredient due to heat.

[0038] 5. Stearyl glycyrrhetinic acid and a small amount of free glycyrrhetinic acid are loaded onto the hydrophobic and interfacial regions of the phospholipid bilayer, respectively. Cholesterol improves the film density, reducing crystallization, aggregation, and leakage of active ingredients, and enhancing their dispersion stability. Free glycyrrhetinic acid exerts a soothing effect quickly, while stearyl glycyrrhetinic acid is slowly released via liposomes, creating an immediate and continuous soothing effect. At the same time, liposome encapsulation reduces the interference of active ingredients on the dispersion and film-forming process of physical sunscreens. Combined with other active ingredients and a cooling addition process, the product's gentleness is improved while maintaining the integrity of the sunscreen film, making it particularly suitable for sensitive skin and skin after microneedling. Detailed Implementation

[0039] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0040] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0041] In this invention, both titanium dioxide slurry and zinc oxide slurry have a kinematic viscosity of 6 mm at 25°C. 2 Polydimethylsiloxane was used as the dispersion medium. Rutile titanium dioxide was first inorganically coated with aluminum hydroxide, and then hydrophobically treated with triethoxyoctylsilane; hexagonal wurtzite zinc oxide was also hydrophobically treated with triethoxyoctylsilane. The hydrophobically treated powder was added to polydimethylsiloxane containing 2% polyhydroxystearic acid, dispersed at 2500 r / min for 25 min, and ground to obtain titanium dioxide slurry with a titanium dioxide content of 50% and a D50 of 200 nm, and zinc oxide slurry with a zinc oxide content of 50% and a D50 of 250 nm, respectively.

[0042] The method for preparing the physical sunscreen lotion of the present invention includes the following steps: (1) Heat and stir the emulsifier at 75°C until homogeneous to obtain phase A; (2) Mix the oil phase, polymethylsilsesquioxane, suspension stabilizer and physical sunscreen powder, heat and stir at 75°C to obtain phase B; add phase A to phase B and stir to obtain phase AB. (3) Mix the film-forming agent and butyl octyl salicylate evenly to obtain phase D; add phase D to phase AB, homogenize at 2500 rpm for 5 min, heat to 75℃, stir evenly to obtain phase ABD; (4) Mix water, humectant, thickener, chelating agent and inorganic salt, heat and stir at 75°C to obtain phase C; (5) Add phase C to phase ABD, stir and homogenize at 2500 rpm for 5 min to obtain phase ABCD; (6) Mix the active ingredients evenly to obtain phase E, and use the preservative as phase F; cool phase ABCD to 45°C, add phase E and phase F, stir evenly to obtain phase ABCDEF, discharge the material, and obtain physical sunscreen emulsion; The preparation method of stearyl glycyrrhetinic acid liposome dispersion includes the following steps: S1. Add 6g phosphatidylcholine, 1g cholesterol and 1.8g stearyl glycyrrhetinic acid ester to 100mL ethanol and sonicate in a water bath at 40℃ for 8min to obtain a drug-loaded lipid solution. S2. The drug-loaded lipid solution was rotary evaporated at 45℃, gauge pressure -0.08MPa, and 60r / min to remove ethanol, so that phosphatidylcholine, cholesterol, and stearyl glycyrrhetinic acid ester formed a drug-loaded lipid film on the inner wall of the rotary evaporation container. The drug-loaded lipid film was vacuum dried at 45℃ for 4h to further remove residual ethanol. S3. Mix 72.96g of water and 18.24g of 1,3-butanediol to obtain a hydration solution. Preheat the hydration solution to 50℃ and add it to the drug-loaded lipid film. Hydrate for 40 min and then sonicate in a water bath for 15 min to obtain a stearyl glycyrrhetinic acid liposome dispersion with a mass percentage of 1.8%.

[0043] The average particle size of the obtained stearyl glycyrrhetinic acid liposomes was determined to be 195 nm, and the encapsulation efficiency of stearyl glycyrrhetinic acid liposomes was 86.5%.

[0044] The physical sunscreens used in the following experimental examples were prepared according to the above-described preparation method, and the differences from the preparation conditions described above have been listed in Examples 1-18. These experimental examples can provide a reference for those skilled in the art to implement the invention or verify its effects. These examples do not limit the scope of the claims.

[0045] I. Screening the type and amount of emulsifier added 1. The group allocation examples in Examples 1-7 are shown in Table 1 below: Table 1 Material composition of Examples 1-7

[0046] 2. Stability Test Accelerated stability tests were conducted on samples at 50°C and 4°C for 30 days. Preliminary stability was determined by sensory evaluation (emulsion color, presence of stratification). Centrifugal stability: The product was placed in a centrifuge (centrifugation test conditions: 2000 r / min, 30 min). The product was then observed. If stratification occurred, the product was considered unstable; otherwise, it was considered centrifugally stable.

[0047] Table 2 Test Results for Each Group

[0048] According to the results in Table 2, Example 1 passed all accelerated stability tests and remained stable without stratification after centrifugation, showing high stability, while other examples had some failures.

[0049] II. Screening the types and amounts of film-forming agents 1. The group allocation examples in Examples 8-12 are shown in Table 3 below: Table 3 Material composition of Examples 1 and 8-12

[0050] 2. Anti-scratching test Test method: Take an equal area from the front of the arm, locate the four corners, and use the sunscreen prepared in Examples 1 and 8-12 at a concentration of 2 mg / cm². 2 Apply the appropriate dosage evenly to the target area and allow it to form a film within 20 minutes. Measure the skin brightness (L0 value) using a Dermalab skin analyzer. Wipe the area back and forth three times with a tissue and measure the skin brightness (L1 value) again. The rate of change in the L value determines the anti-scratching effect; a smaller rate of change indicates better anti-scratching performance. L-value change rate = (L1 - L0 / L1) 100% Table 4 Test Results for Each Group

[0051] As shown in Table 4, the L-value change rate of Example 1 was only 0.15%, indicating that only a very small amount of the sample was rubbed off by the paper towel during the anti-scratch test. Therefore, the L-value change rate was low, and the sample achieved a good anti-scratch effect. The L-value change rates of the other examples were all higher than those of Example 1, indicating that their anti-scratch effects were lower than those of Example 1.

[0052] III. Screening the types and amounts of active ingredients 1. The group allocation examples in Examples 13-16 are shown in Table 5 below: Table 5. Composition of substances in Examples 1, 13-16

[0053] 2. Test on protection against light damage The effect of the product on preventing photodamage was investigated using the zebrafish embryo photodamage neutrophil inhibition test method. The specific test method is as follows.

[0054] Application 0.3J / cm 2 The UVB irradiation model was tested. Twenty-four 3-day-old zebrafish embryos were exposed to 0.1% of different sample solutions from various embodiments at the test concentration. A model control group and a blank control group were also set up. After 1 hour of exposure, 0.3 J / cm² irradiation was applied. 2 The fish embryos were irradiated with UVB to create a model. After changing the solution, the embryos were cultured for 24 hours and then fixed and stained with Sudan Black. The number of neutrophils in the terminal region of the caudal fin was counted and statistically analyzed. The results are shown in Table 6 below.

[0055] Table 6 Test Results for Each Group

[0056] As shown in Table 6, Example 1 exhibited a 48.60% inhibition rate against neutrophils in zebrafish embryos at a test concentration of 0.1%, significantly higher than other examples. This indicates that the combination and concentration of active ingredients in Example 1 can significantly inhibit neutrophil aggregation in zebrafish embryos induced by UVB irradiation, demonstrating a protective effect against photodamage.

[0057] IV. Liposome Action Test 1. The group assignments in Comparative Examples 1-2 are shown in Table 7 below: Table 7 Material composition of Example 1 and Comparative Examples 1-2

[0058] 2. Accelerated stability test Example 1 and Comparative Example 1 were stored at 50°C for 30 days, respectively. After being restored to room temperature, the samples were observed to see if crystallization, layering, or water precipitation occurred. The crystal precipitation was observed using a polarizing microscope. The content of stearyl glycyrrhetinic acid ester before and after storage was determined by high performance liquid chromatography.

[0059] 3. Skin penetration test The Franz diffusion cell was used for testing. Ex vivo pigskin was fixed in the diffusion cell with the keratin layer facing the supply cell; the effective diffusion area was 3.14 cm². 2Add approximately 8 mL of phosphate buffer containing 20% ​​ethanol and 0.5% polysorbate-80 to the receiving chamber.

[0060] 0.1 g of each of Example 1 and Comparative Example 1 was uniformly coated onto the surface of pigskin and tested at 32.5℃ and 250 r / min for 24 h. All the receiving liquid was collected, and the content of stearyl glycyrrhetinic acid ester was determined by high performance liquid chromatography.

[0061] 4. Light damage protection test Twenty-four 3-day-old zebrafish embryos were taken from each group and exposed to sample dispersions of Example 1, Comparative Example 1, and Comparative Example 2 at a mass concentration of 0.1%. A blank control group and a UVB model control group were also set up.

[0062] One hour after exposure, at 0.3 J / cm 2 The samples were irradiated with UVB, then the dispersion was replaced and the samples were cultured for 24 h. Zebrafish embryos were fixed and stained with Sudan Black, and the number of neutrophils in the caudal fin terminal region was counted.

[0063] The test results are shown in Table 8 below: Table 8 Test results of Example 1 and Comparative Examples 1-2

[0064] As shown in Table 8, no crystallization occurred in Example 1 after storage at 50°C for 30 days, and the retention rate of stearyl glycyrrhetinic acid ester content was higher than that in Comparative Example 1, indicating that liposome encapsulation can reduce the crystallization and content loss of stearyl glycyrrhetinic acid ester in sunscreen. The 24-hour cumulative transmittance of Example 1 was lower than that of Comparative Example 1, indicating that liposome encapsulation can reduce the proportion of stearyl glycyrrhetinic acid ester migrating into the skin in a short period of time. The neutrophil inhibition rate of Example 1 was higher than that of Comparative Examples 1 and 2, indicating that liposome encapsulation is beneficial to maintaining the photoprotective effect of stearyl glycyrrhetinic acid ester, and this effect is not solely produced by the blank liposome carrier.

[0065] V. Effect Testing Based on the screening of emulsifiers, film-forming agents, and active ingredients according to their types, concentrations, and dosages, the final emulsifiers selected were cetyl PEG / PPG-10 / 1 polymethylsiloxane 1.5% and PEG-10 polydimethylsiloxane 2.5%; the film-forming agents were TEGO® SP 13Sun Up 1% and KP545 1%; and the active ingredient combination was QUERCUS SUBER bark extract 0.5%, stearyl glycyrrhetinic acid liposome dispersion 0.1%, and Bacillus fermentation product 0.5%. Example 1 was prepared as the final formulation. After preparing the sample according to the process conditions, the efficacy of Example 1 was evaluated and compared with Examples 17-18 without the addition of film-forming agents / active ingredients.

[0066] 1. The group allocation examples in Examples 17-18 are shown in Table 9 below: Table 9 Composition of Components in Examples 1 and 17-18

[0067] ①SPF value: Tested according to the specific requirements of the "Cosmetic Safety Technical Specifications" (2015 edition). Subjects were placed in a prone position, and their backs were irradiated. The minimum erythema dose (MED) of the subject's skin to ultraviolet radiation was predicted 24 hours prior to the test, and the ultraviolet radiation dose was adjusted based on the prediction result for testing the analyte. On the day of the test, a spot no less than 30cm long was first selected on the subject's back. 2 For normal skin areas, apply (2.00 + 0.05) mg / cm². 2 Apply the test substance or control evenly to the above-mentioned area, then select the irradiation dose according to the specifications, and irradiate under three conditions: 1. No test substance applied to the subject's skin; 2. Control substance applied; 3. Test substance applied. Observe the experimental results after 24 hours and record the MED value under each of the three conditions. SPF value calculation method: The SPF value of the test substance or control substance protecting a single subject is expressed by the following formula: SPF = MED value of protected skin / MED value of unprotected skin ②PA value: Tested according to the specific requirements of the "Cosmetic Safety Technical Specifications" (2015 edition). The subject lies prone, and their back is irradiated. The minimum melanization potential (MPPD) of the subject's skin to ultraviolet radiation is predicted 24 hours prior to the test, and the ultraviolet radiation dose is adjusted based on the prediction result for testing the analyte. The test begins by selecting a spot at least 30cm long on the subject's back. 2 For normal skin areas, administer (2.00 + 0.05) mg / cm². 2 Apply the test substance or control evenly to the above-mentioned area; then select the UVA irradiation dose according to the specifications, and irradiate under three conditions: 1. No test substance applied to the subject's skin; 2. Control applied; 3. Test substance applied. Observe the experimental results after 2-4 hours and record the MPPD values ​​under each of the three conditions. PA value calculation method: The PA value of the test substance or control for protecting a single subject is expressed by the following formula: PA = MPPD value of protected skin / MPPD value of unprotected skin The SPF and PA values ​​of Examples 1 and 17 were tested according to the above method, and the test results are shown in Table 10 below: Table 10 Test Results for Each Group

[0068] According to the results in Table 10, the SPF and PA values ​​of Example 1 are higher than those of Example 17, indicating that the addition of film-forming agents and active ingredients can effectively improve the sun protection effect of sunscreen products.

[0069] 2. Skin permeability test To evaluate the transdermal absorption capacity of titanium dioxide, a sunscreen agent in physical sunscreen formulations, and to investigate the effect of the addition of film-forming agents on its transdermal behavior, the transdermal behavior of ethylhexyl methoxycinnamate, a chemical sunscreen agent, was also evaluated under the same experimental conditions and compared with that of physical sunscreens. Therefore, skin permeability tests were conducted to compare the transdermal absorption of the two types of sunscreens and to explore their safety.

[0070] The specific experimental method is as follows: ① Fill the receiving chamber of the Franz diffusion cell with the appropriate receiving solution (approximately 8 mL), place the rotor inside, and ensure there are no air bubbles. Lay the treated pigskin keratin layer side up flat on the receiving cell, place the pad on top of the pigskin, place the supply cell on top of the pad, and secure the upper and lower cells with clamps.

[0071] ② Apply physical / chemical sunscreen evenly to the pigskin area circled by the pad (0.1g, fixed amount for parallel groups), effective diffusion area 3.14cm. 2 The supply tank was sealed with sealing film and placed in a transdermal diffusion apparatus. Skin without sunscreen was used as a blank control. The temperature was set at 32.5℃, the rotation speed at 250 rpm, and the mixture was stirred for 24 hours. At the 24-hour endpoint, all the receiving liquid was collected as the final sample.

[0072] ③ Sample testing Determination method for titanium dioxide content in physical sunscreens: Refer to Chapter 4, Section 5.3, Titanium Dioxide, of the 2015 edition of the "Cosmetic Safety Technical Specifications". Method for determining OMC content in chemical sunscreens: Refer to Chapter 4, Section 5.8 of the 2015 edition of the "Cosmetic Safety Technical Specifications" for the detection methods of 22 sunscreen agents, including 3-benzyl camphor. ④ Calculate the cumulative transdermal dose of titanium dioxide or OMC using the following formula.

[0073]

[0074] Among them, C t C represents the concentration of the chemical sunscreen agent measured at the t-th sampling point; i V represents the concentration of the chemical sunscreen agent measured at the (t-1)th sampling point; t and V i These represent the receiving chamber and the sampling volume, respectively; A represents the effective skin penetration area.

[0075] The cumulative permeation of Examples 1 and 18 was tested using the method described above, and the test results are shown in Table 11 below: Table 11 Test Results for Each Group

[0076] According to the results in Table 11, the cumulative penetration of OMC in the chemical sunscreen formula reached 258.7 μg / cm³. 2 The results indicate that it can penetrate the skin barrier, posing a certain risk; while the cumulative penetration amount in Example 1 is below the detection limit, indicating that titanium dioxide has not penetrated the skin or has only a very small amount; and in Example 18, where no film-forming agent was added, trace amounts of titanium dioxide were still detected through the skin, indicating that the addition of a film-forming agent further reduced the transdermal penetration of the sunscreen and improved the safety of the product.

[0077] 3. Post-medical aesthetic trial feedback Ten subjects were divided into two groups after undergoing full-face nano-microneedling. One group used a regular chemical sunscreen lotion, and the other group used a physical sunscreen lotion prepared in Example 1. The lotion was applied immediately after the procedure and used every morning after returning home.

[0078] The testing time points were: before use, 10 days after use, and 16 days after use. The ambient temperature was (21±1)℃; relative humidity was 40%~60%, and measurements were avoided in direct sunlight. Testing conditions remained consistent throughout the testing process, including lighting conditions, instrument parameter settings, image acquisition and positioning methods, image analysis software version and parameter settings, testing area, and the capabilities of the testing personnel. Subjects needed to remain stable under the above environmental conditions for at least 30 minutes before evaluation and testing. For a series of tests, the environment should be kept as consistent as possible.

[0079] Skin redness test: before product use, 10 days after product use, and 16 days after product use. Images of the subject's face were captured using VISIA-CR from the front, left side, and right side.

[0080] Skin TEWL testing: before use, on day 10 after use, and on day 16 after use. Data was collected from subjects using the Dermalab skin analyzer in each round.

[0081] Table 12 Skin red area and Tewling Value at Different Time Points

[0082] Human testing results show that the area of ​​redness on the skin using the physical sunscreen lotion prepared in Example 1 was significantly reduced on both days 10 and 16 after product use, demonstrating better results than the use of ordinary chemical sunscreen lotion. The barrier health of the skin using the physical sunscreen lotion prepared in Example 1 was also significantly improved on both days 10 and 16 after product use, again showing better results than the use of ordinary chemical sunscreen lotion. This indicates that the physical sunscreen lotion prepared in Example 1 can improve facial redness and barrier damage after microneedling procedures, making it suitable for use after cosmetic procedures.

[0083] In summary, the physical sunscreen lotion meets at least one of the following performance requirements: (1) It does not separate into layers after being placed at 50℃ for 30 days; (2) No stratification occurred after centrifugation at 2000 r / min for 30 min; (3) According to 2mg / cm 2 After the amount of disinfectant forms a film on the skin surface, and after wiping it back and forth three times with a tissue, the change rate of the skin brightness L value before and after wiping does not exceed 0.5%; (4) The sun protection factor (SPF) is not less than 50 and the UVA protection factor is not less than 8; (5) When the cumulative transdermal dose over 24 hours was measured using a skin diffusion cell, the titanium content in the receiving solution was below the detection limit.

[0084] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A physical sunscreen lotion, characterized in that, By weight, it comprises the following components: 45-55 parts physical sunscreen powder, 1.5-5 parts emulsifier, 1.5-2.5 parts film-forming agent, 8-15 parts oil phase, 0.5-3 parts polymethylsilsesquioxane, 1-4 parts suspension stabilizer, 1-3 parts butyl octyl salicylate, 4-10 parts moisturizer, 0.1-1.2 parts active ingredient, 0.03-0.10 parts thickener, 0.02-0.10 parts chelating agent, 0.5-1.5 parts inorganic salt, 0.3-0.8 parts preservative, and the balance being water.

2. The physical sunscreen lotion according to claim 1, characterized in that, The physical sunscreen powder paste includes titanium dioxide powder paste and zinc oxide powder paste, and the mass ratio of titanium dioxide powder paste to zinc oxide powder paste is (0.6~0.8):

1.

3. The physical sunscreen lotion according to claim 1, characterized in that, The emulsifier is selected from one or more of polyglycerol-4 diisostearate / polyhydroxystearate / sebacate, lauryl PEG-9 polydimethylsiloxane-ethyl polydimethylsiloxane, cetyl PEG / PPG-10 / 1 polymethylsiloxane, and PEG-10 polydimethylsiloxane; And / or, the film-forming agent is selected from one or more of KP545, KP7312J, SUNUP, 4003, acrylate copolymers and VP / eicosene copolymers; And / or, the oil phase is selected from those with a viscosity of 2 mm. 2 / s of polydimethylsiloxane, viscosity 6mm 2 / s of polydimethylsiloxane, with a viscosity of 350 mm. 2 / s contains one or more of polydimethylsiloxane, dioctyl carbonate, and caprylic / capric triglyceride.

4. The physical sunscreen lotion according to claim 1, characterized in that, The active ingredient is selected from one or more of the following: European cork oak bark extract, stearyl glycyrrhetinic acid liposome dispersion, Bacillus fermentation product, Otamine 10W, and bisabolol.

5. The physical sunscreen lotion according to claim 1, characterized in that, The suspension stabilizer includes one or more of cyclopentadimethylsiloxane, lithium distearate dimethylammonium montmorillonite, and propylene glycol carbonate. And / or, the moisturizer includes glycerin and 1,3-butanediol; And / or, the thickener is xanthan gum; And / or, the chelating agent is disodium EDTA; And / or, the inorganic salt is sodium chloride.

6. A method for preparing the physical sunscreen lotion according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Heat and stir the emulsifier at 70-80℃ to obtain phase A; (2) Mix the oil phase, polymethylsilsesquioxane, suspension stabilizer and physical sunscreen powder, heat and stir at 70-80℃ to obtain phase B; add phase A to phase B and stir to obtain phase AB. (3) Mix the film-forming agent and butyl octyl salicylate evenly to obtain phase D; add phase D to phase AB, homogenize at 2000-3000 rpm for 3-8 min, heat to 70-80℃, stir evenly to obtain phase ABD; (4) Mix water, humectant, thickener, chelating agent and inorganic salt, heat and stir evenly at 70-80℃ to obtain phase C; (5) Add phase C to phase ABD, stir and homogenize at 2000-3000 rpm for 3-8 min to obtain phase ABCD; (6) Mix the active ingredients evenly to obtain phase E, and use the preservative as phase F; cool phase ABCD to 40-50℃, add phase E and phase F, stir evenly to obtain phase ABCDEF, discharge the material, and obtain physical sunscreen emulsion.

7. The method according to claim 6, characterized in that, The active ingredient includes a stearyl glycyrrhetinic acid liposome dispersion; The method for preparing the stearyl glycyrrhetinic acid liposome dispersion includes the following steps: S1. Phosphatidylcholine, cholesterol, and stearyl glycyrrhetinic acid ester are added to an organic solvent and sonicated in a water bath for 5-10 min to obtain a drug-loaded lipid solution. S2. The drug-loaded lipid solution is subjected to rotary evaporation to remove organic solvents, so that phosphatidylcholine, cholesterol and stearyl glycyrrhetinic acid form a drug-loaded lipid film on the inner wall of the rotary evaporation container, and the drug-loaded lipid film is vacuum dried. S3. Mix water and 1,3-butanediol to obtain an hydrated solution. Preheat the hydrated solution to 45-55°C and add it to the drug-loaded lipid film. Hydrate for 20-60 min, then sonicate in a water bath for 10-20 min to obtain a stearyl glycyrrhetinic acid liposome dispersion.

8. The method according to claim 7, characterized in that, The mass ratio of phosphatidylcholine to cholesterol is (3-8):

1.

9. The method according to claim 7, characterized in that, The stearyl glycyrrhetinic acid liposome dispersion contains 1.5% to 2.0% stearyl glycyrrhetinic acid by mass.

10. The use of the physical sunscreen emulsion according to any one of claims 1 to 5 in the preparation of sunscreen cosmetics for sensitive skin or daily sun protection cosmetics for skin after microneedling.

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