Multiple emulsion as well as preparation method and application thereof

Abstract

The invention discloses a multiple emulsion as well as a preparation method and application thereof. The multiple emulsion is composed of an inner water phase, an oil phase and an outer water phase, the inner water phase is composed of a whitening agent and a humectant, the oil phase is composed of vegetable oil, an antioxidant and an emulsifier, and the outer water phase is composed of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles, a penetration enhancer and a humectant. The multiple emulsion provided by the invention has good stability, antioxidant activity and moisture retention, can effectively inhibit tyrosinase activity so as to achieve the effect of whitening the skin, is non-irritant to the skin, does not destroy the micro-ecological balance of the skin, is light in skin feeling, can be used in skin care products such as essence milk, face cream, facial masks and the like, and has a very good application prospect. The method is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] The present invention relates to the technical field of whitening and moisturizing, and in particular to a multiple emulsion and a preparation method and application thereof. Background Art

[0002] The skin is the largest organ in the human body, responsible for protection, excretion, temperature regulation, and sensing external stimuli. However, long-term exposure to external stressors such as ultraviolet radiation and air pollutants can easily induce excessive free radical production, leading to increased oxidative stress, collagen degradation, and abnormal melanin deposition, ultimately causing skin aging, pigmentation, and impaired barrier function.

[0003] As people's living standards improve, skin care is gaining more and more attention. Although commercially available skin care products offer multiple benefits, including whitening, anti-aging, and repair, they still have significant flaws, specifically as follows: 1) The content of chemical additives (e.g., synthetic emulsifiers, synthetic preservatives, fluorescent agents, etc.) is high, and long-term use can easily disrupt the skin's microecological balance; 2) The system's ability to protect active ingredients is insufficient, and phase separation or degradation of active ingredients can easily occur under high temperature, freeze-thaw, or ultraviolet irradiation, resulting in poor stability and a short duration of action; 3) The formulation design ignores the skin feel (e.g., high viscosity or greasy feel), resulting in low consumer compliance. W / O / W multiple emulsions have a unique "water-oil-water" three-phase composite structure that can simultaneously encapsulate hydrophilic and hydrophobic active ingredients, and can achieve sustained release of active ingredients through the internal aqueous phase, demonstrating significant advantages in both improving the stability of active ingredients and prolonging their duration of action. However, existing W / O / W emulsion systems mostly rely on artificially synthesized surfactants to stabilize the interface, which has problems such as poor biocompatibility and high environmental burden, making it difficult to fully meet practical application requirements.

[0004] Therefore, it is of great significance to develop a multiple emulsion with good stability, high antioxidant activity, good moisturizing property, good biocompatibility, no irritation to the skin, and good skin feel. Summary of the Invention

[0005] The purpose of the present invention is to provide a multiple emulsion and a preparation method and application thereof.

[0006] The technical solution adopted by the present invention is:

[0007] A resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticle has a core-shell structure, wherein the core is phosphorylated zein nanoparticles encapsulating resveratrol, and the shell is a carboxymethyl chitosan layer.

[0008] Preferably, the mass ratio of resveratrol, phosphorylated zein, and carboxymethyl chitosan in the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles is 1:8-12:5-20.

[0009] Preferably, the particle size of the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles is 90 nm to 130 nm.

[0010] A method for preparing the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles as described above comprises the following steps:

[0011] a) adding an ethanol solution of resveratrol to an aqueous solution of phosphorylated zein, and stirring uniformly to obtain a dispersion of phosphorylated zein nanoparticles encapsulating resveratrol;

[0012] b) adding the carboxymethyl chitosan aqueous solution to the dispersion of phosphorylated zein nanoparticles encapsulating resveratrol, stirring evenly, and then separating the products to obtain resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles.

[0013] Preferably, the mass percentage of resveratrol in the resveratrol ethanol solution in step a) is 0.1% to 2.0%.

[0014] Preferably, the mass percentage of phosphorylated zein in the phosphorylated zein aqueous solution in step a) is 0.5% to 1.5%.

[0015] Preferably, the phosphorylated zein in the phosphorylated zein aqueous solution in step a) is prepared by a preparation method comprising the following steps: dissolving zein in water, adding sodium tripolyphosphate and reacting for 2 to 4 hours, dialyzing with water for 24 to 72 hours, and freeze-drying to obtain the phosphorylated zein.

[0016] Preferably, the stirring in step a) is performed at a stirring rate of 500 rpm to 700 rpm.

[0017] Preferably, the mass percentage of carboxymethyl chitosan in the carboxymethyl chitosan aqueous solution in step b) is 0.8% to 1.2%.

[0018] Preferably, the stirring in step b) is performed at a stirring rate of 500 rpm to 700 rpm.

[0019] A multiple emulsion consists of an inner aqueous phase, an oil phase and an outer aqueous phase; the inner aqueous phase comprises a whitening agent and a moisturizer; the oil phase comprises vegetable oil, an antioxidant and an emulsifier; and the outer aqueous phase comprises the above-mentioned resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles, a penetration enhancer and a moisturizer.

[0020] Preferably, the whitening agent in the inner water phase is at least one of arbutin, niacinamide, vitamin C, and tranexamic acid.

[0021] Preferably, the moisturizing agent in the inner water phase is at least one of glycerin, butylene glycol, propylene glycol, sodium hyaluronate, trehalose, and allantoin.

[0022] Preferably, the vegetable oil in the oil phase is at least one of olive oil, sunflower oil, grape seed oil, shea butter, jojoba oil, and macadamia nut oil.

[0023] Preferably, the antioxidant in the oil phase is at least one of vitamin E, phytosterol, squalane, butylated hydroxyanisole, and butylated hydroxytoluene.

[0024] Preferably, the emulsifier in the oil phase is at least one of polyglyceryl ricinoleate, cetyl alcohol, stearyl alcohol, polyglyceryl-3 diisostearate, beeswax, polyglyceryl-4 diisostearate / polyhydroxystearic acid, and polydimethylsiloxane.

[0025] Preferably, the penetration enhancer in the external aqueous phase is at least one of water-soluble azone, lauryl azone, and dimethyl isosorbide.

[0026] Preferably, the moisturizing agent in the external aqueous phase is at least one of propylene glycol, sorbitol, allantoin, glycerin and butylene glycol.

[0027] Preferably, the composition of the external aqueous phase further includes a thickener, a preservative and a flavor.

[0028] Preferably, the thickener is at least one of xanthan gum, sodium alginate, pectin, hydroxypropyl methylcellulose and bentonite.

[0029] Preferably, the preservative is at least one of phenoxyethanol, methylisothiazolinone, methylchloroisothiazolinone, benzoic acid, and sorbic acid.

[0030] Preferably, the flavor is at least one of rose flavor, lavender flavor, jasmine flavor, violet flavor, lemon flavor, green tea flavor, ocean flavor, and aloe flavor.

[0031] Preferably, the multiple emulsion is milky white and opaque.

[0032] A method for preparing the multiple emulsion as described above comprises the following steps:

[0033] 1) preparing an inner water phase, an oil phase and an outer water phase;

[0034] 2) adding the inner aqueous phase to the stirred oil phase and then subjecting it to high-speed shearing to obtain a W / O emulsion;

[0035] 3) Adding the W / O emulsion to the external aqueous phase in a stirring state and then subjecting it to high-speed shearing to obtain a multiple emulsion.

[0036] Preferably, the preparation of the inner aqueous phase in step 1) comprises the following operations: dissolving the whitening agent and the moisturizing agent in water at a temperature of 40° C. to 60° C.

[0037] Preferably, the preparation of the oil phase in step 1) comprises the following operations: dissolving an antioxidant and an emulsifier in vegetable oil at a temperature of 40° C. to 60° C.

[0038] Preferably, the preparation of the external aqueous phase in step 1) comprises the following operations: dissolving resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles, a penetration enhancer and a moisturizer in water at a temperature of 25° C. to 45° C.

[0039] Preferably, the stirring rate of step 2) is 200 rpm to 500 rpm.

[0040] Preferably, the shear rate of the high-speed shearing in step 2) is 5000 rpm to 10000 rpm.

[0041] Preferably, the stirring rate of step 3) is 200 rpm to 500 rpm.

[0042] Preferably, the shear rate of the high-speed shearing in step 3) is 5000 rpm to 10000 rpm.

[0043] A skin care product comprising the multiple emulsion.

[0044] Preferably, the skin care product is one of essence lotion, facial cream and facial mask.

[0045] The principle of the invention: Resveratrol is encapsulated with phosphorylated zein nanoparticles and then coated with carboxymethyl chitosan to form composite nanoparticles with a core-shell structure (particle size 90nm-130nm, with the phosphorylated zein nanoparticles encapsulating resveratrol as the core and the carboxymethyl chitosan layer as the shell). These composite nanoparticles are then used as nano-delivery carriers for resveratrol, effectively enhancing the solubility of the functional factor resveratrol and reducing its skin irritation. Furthermore, a W / O / W multiple emulsion delivery system using these composite nanoparticles as the sole hydrophilic emulsifier is constructed. This system can inhibit tyrosinase activity with a tyrosinase inhibition rate of up to 95%-99%, demonstrating excellent whitening efficacy.

[0046] The beneficial effects of the present invention are: the multiple emulsion of the present invention has good stability, antioxidant activity and moisturizing properties, can effectively inhibit tyrosinase activity to achieve the effect of whitening the skin, is non-irritating to the skin, does not destroy the skin's microecological balance, and has a light skin feel. It can be used in skin care products such as essence lotion, cream, and mask, and is suitable for large-scale industrial production and application.

[0047] Specifically:

[0048] 1) The multiple emulsion of the present invention uses resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles as the only hydrophilic emulsifier, which reduces the addition of chemical components and is green, safe and highly effective;

[0049] 2) The multiple emulsion of the present invention effectively improves the stability and loading capacity of active ingredients through its unique W / O / W structural design, can better protect easily degradable active ingredients (such as arbutin), improve the retention rate and retention time of active ingredients, and extend the shelf life of the product;

[0050] 3) The multiple emulsion of the present invention has good antioxidant activity and tyrosinase inhibitory activity, can effectively inhibit the production of melanin, thereby achieving the effect of whitening the skin, and is non-irritating to the skin and highly safe;

[0051] 4) The multiple emulsion of the present invention has good moisturizing properties and can form a protective film on the skin surface, thereby locking in moisture, keeping the skin moisturized, and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a physical picture of the dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles in Example 1.

[0053] Figure 2This is the SEM image of the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles in Example 1.

[0054] Figure 3 This is a physical picture of the multiple emulsion in Example 1.

[0055] Figure 4 This is a micrograph of the multiple emulsion in Example 1. DETAILED DESCRIPTION

[0056] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0057] Example 1:

[0058] A resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticle, the preparation method of which is as follows:

[0059] a) dissolving 0.01 g of resveratrol in 2 mL of anhydrous ethanol to prepare a resveratrol ethanol solution (resveratrol content is 0.5% by weight), and dissolving 0.1 g of phosphorylated zein in 20 mL of deionized water to prepare a phosphorylated zein aqueous solution (phosphorylated zein content is 0.5% by weight), then slowly adding the resveratrol ethanol solution to the stirred phosphorylated zein aqueous solution over 20 minutes at a stirring rate of 500 rpm to obtain a dispersion of phosphorylated zein nanoparticles encapsulating resveratrol;

[0060] b) dissolving 0.2 g of carboxymethyl chitosan in 20 mL of deionized water to prepare a carboxymethyl chitosan aqueous solution (the mass percentage of carboxymethyl chitosan is 1%), and then adding the carboxymethyl chitosan aqueous solution to a stirred dispersion of phosphorylated zein nanoparticles encapsulating resveratrol over 10 minutes at a stirring rate of 500 rpm. The pH of the system was then adjusted to 6.5 to obtain a dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles.

[0061] Note:

[0062] The preparation method of phosphorylated zein is as follows: 3 g of zein is dissolved in 100 mL of deionized water (the pH value of the obtained solution is 13), 3 g of sodium tripolyphosphate is added, and the mixture is reacted for 4 h, then dialyzed with deionized water for 48 h, and freeze-dried to obtain phosphorylated zein.

[0063] The actual picture of the dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles in this example is as follows: Figure 1 shown.

[0064] Depend on Figure 1 It can be seen that the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles are uniformly dispersed as a whole, and the dispersion presents a white opalescent state.

[0065] The scanning electron microscope (SEM) image of the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles in this example is as follows: Figure 2 shown.

[0066] Depend on Figure 2 It can be seen that the sizes of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles are relatively consistent, with particle sizes ranging from 90 nm to 130 nm, and no obvious agglomeration phenomenon is observed.

[0067] A multiple emulsion, the preparation method of which is as follows:

[0068] 1) Preparation of inner water phase, oil phase and outer water phase:

[0069] Preparation of the inner aqueous phase: Dissolve 2 g of arbutin, 1 g of nicotinamide, and 3 g of glycerol in 10 mL of deionized water at 45°C to obtain the inner aqueous phase.

[0070] Preparation of the oil phase: Dissolve 1.5 g of vitamin E, 2 g of phytosterol / octyldodecanol lauroyl glutamate, 4 g of squalane, 2.5 g of polyglyceryl ricinoleate, and 1 g of polyglyceryl-4 diisostearate / polyhydroxystearic acid in 20 g of olive oil at 45°C to obtain the oil phase.

[0071] Preparation of the external aqueous phase: 30 g of the above-mentioned dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles, 1 g of water-soluble azone, 5 g of propylene glycol and 3 g of glycerol were mixed at a temperature of 30° C. to obtain an external aqueous phase;

[0072] 2) Slowly add the inner aqueous phase dropwise to the stirred oil phase at a stirring rate of 350 rpm. After the addition, high-speed shear is applied at a shear rate of 9000 rpm for 1 minute to obtain a W / O emulsion.

[0073] 3) The W / O emulsion was slowly added dropwise to the stirred external aqueous phase at a stirring rate of 200 rpm. After the addition, high-speed shearing was performed for 2 min at a shear rate of 7000 rpm. 0.1 g of xanthan gum, 0.05 g of phenoxyethanol, and 0.05 g of jasmine essence were then added. The mixture was stirred and cooled to room temperature at a stirring rate of 400 rpm to obtain a multiple emulsion.

[0074] The physical picture of the multiple emulsion in this embodiment is as follows Figure 3 As shown in the micrographs Figure 4 shown.

[0075] Depend on Figure 3 It can be seen that the multiple emulsion appears in a uniform, viscous milky white liquid state without obvious stratification.

[0076] Depend on Figure 4 It can be seen that the multiple emulsion presents a W / O / W multilayer structure, the droplet size is relatively uniform, and the proportion of the internal water phase is relatively large.

[0077] Example 2:

[0078] A multiple emulsion, the preparation method of which is as follows:

[0079] 1) Preparation of inner water phase, oil phase and outer water phase:

[0080] Preparation of the inner aqueous phase: Dissolve 2 g of arbutin, 1 g of nicotinamide, and 3 g of glycerol in 10 mL of deionized water at 45°C to obtain the inner aqueous phase.

[0081] Preparation of the oil phase: Dissolve 1.5 g of vitamin E, 2.5 g of polyglycerol ricinoleate, and 5 g of polydimethylsiloxane in 20 g of olive oil at 45°C to obtain an oil phase.

[0082] Preparation of the external aqueous phase: 36 g of the above-mentioned dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles (same as in Example 1), 1 g of water-soluble azone, 3 g of propylene glycol, 2 g of sorbitol and 0.2 g of allantoin were mixed and maintained at 30° C. to obtain the external aqueous phase;

[0083] 2) Slowly add the inner aqueous phase dropwise to the stirred oil phase at a stirring rate of 400 rpm. After the addition, high-speed shear is applied at a shear rate of 9000 rpm for 1 minute to obtain a W / O emulsion.

[0084] 3) The W / O emulsion was slowly added dropwise to the stirred external aqueous phase at a stirring rate of 400 rpm. After the addition, high-speed shearing was performed for 2 min at a shear rate of 7000 rpm. Then, 0.1 g of xanthan gum, 0.05 g of phenoxyethanol, and 0.05 g of jasmine essence were added. The mixture was stirred and cooled to room temperature at a stirring rate of 400 rpm to obtain a multiple emulsion.

[0085] Example 3:

[0086] A multiple emulsion, the preparation method of which is as follows:

[0087] 1) Preparation of inner water phase, oil phase and outer water phase:

[0088] Preparation of the inner aqueous phase: Dissolve 2 g of arbutin, 1 g of nicotinamide, and 3 g of glycerol in 10 mL of deionized water at 45°C to obtain the inner aqueous phase.

[0089] Preparation of the oil phase: Dissolve 1.5 g of vitamin E, 1 g of squalane, 2 g of polyglyceryl-3 diisostearate, and 2 g of cetyl alcohol in 20 g of olive oil at 45°C to obtain an oil phase.

[0090] Preparation of the external aqueous phase: 32 g of the above-mentioned dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles (same as in Example 1), 1 g of laurocapram, 1.5 g of butanediol, 1 g of sorbitol and 0.5 g of allantoin were mixed and the temperature was maintained at 40° C. to obtain an external aqueous phase;

[0091] 2) Slowly add the inner aqueous phase dropwise to the stirred oil phase at a stirring rate of 300 rpm. After the addition, high-speed shear is applied at a shear rate of 9000 rpm for 1 minute to obtain a W / O emulsion;

[0092] 3) The W / O emulsion was slowly added dropwise to the stirred external aqueous phase at a stirring rate of 400 rpm. After the addition, high-speed shearing was performed for 2 min at a shear rate of 7000 rpm. Then, 0.1 g of xanthan gum, 0.05 g of phenoxyethanol, and 0.05 g of jasmine essence were added. The mixture was stirred and cooled to room temperature at a stirring rate of 400 rpm to obtain a multiple emulsion.

[0093] Example 4:

[0094] A multiple emulsion, the preparation method of which is as follows:

[0095] 1) Preparation of inner water phase, oil phase and outer water phase:

[0096] Preparation of the inner aqueous phase: Dissolve 2 g of arbutin, 1 g of niacinamide, and 2 g of sodium hyaluronate in 10 mL of deionized water at 45°C to obtain the inner aqueous phase;

[0097] Preparation of the oil phase: Dissolve 1.5 g of vitamin E, 0.5 g of phytosterols, 1 g of polyglyceryl-3 diisostearate, and 3 g of polyglyceryl ricinoleate in 20 g of olive oil at 40° C. to obtain an oil phase;

[0098] Preparation of the external aqueous phase: 33 g of the above-mentioned dispersion of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles (same as in Example 1), 1 g of water-soluble copper nitrogen, 2 g of glycerol, and 0.5 g of allantoin were mixed and maintained at 45° C. to obtain the external aqueous phase;

[0099] 2) Slowly add the inner aqueous phase dropwise to the stirred oil phase at a stirring rate of 400 rpm. After the addition, high-speed shear is applied at a shear rate of 8000 rpm for 1 minute to obtain a W / O emulsion;

[0100] 3) The W / O emulsion was slowly added dropwise to the stirred external aqueous phase at a stirring rate of 400 rpm. After the addition, high-speed shearing was performed for 2 min at a shear rate of 7000 rpm. Then, 0.1 g of xanthan gum, 0.05 g of phenoxyethanol, and 0.05 g of jasmine essence were added. The mixture was stirred and cooled to room temperature at a stirring rate of 400 rpm to obtain a multiple emulsion.

[0101] Comparative Example 1:

[0102] A multiple emulsion (the inner aqueous phase does not contain a whitening agent, i.e., does not contain arbutin and niacinamide) is identical to the multiple emulsion in Example 2 except that the composition of the inner aqueous phase is adjusted to "3 g of glycerol and 10 mL of deionized water".

[0103] Comparative Example 2:

[0104] A multiple emulsion (the oil phase does not contain an antioxidant, i.e., does not contain vitamin E) is identical to the multiple emulsion in Example 2 except that the composition of the oil phase is adjusted to "2.5 g of polyglycerol ricinoleate, 5 g of polydimethylsiloxane, and 20 g of olive oil."

[0105] Comparative Example 3:

[0106] A multiple emulsion (the external aqueous phase does not contain resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles) is identical to the multiple emulsion in Example 2, except that the composition of the external aqueous phase is adjusted to "8 g of Tween 80, 1 g of water-soluble azone, 3 g of propylene glycol, 2 g of sorbitol, 0.2 g of allantoin, and 30 mL of deionized water."

[0107] Performance testing:

[0108] 1) In vitro tyrosinase inhibition activity (whitening efficacy) test of multiple emulsions:

[0109] a) adding 0.1 mL of the multiple emulsions of Examples 1 to 4 and Comparative Examples 1 to 3 to a centrifuge tube, adding 1 mL of a 0.1 g / L L-tyrosine solution, and then diluting the volume to 3.5 mL with PBS buffer, preheating the mixture at 37° C. for 10 min, and then adding 0.5 mL of a 100 U / mL tyrosinase solution. After mixing, reacting for 30 min, and then measuring the absorbance at a wavelength of 475 nm by ultraviolet spectrophotometry, the absorbance is recorded as A1;

[0110] b) adding 0.1 mL of the multiple emulsions of Examples 1 to 4 and Comparative Examples 1 to 3 to a centrifuge tube, diluting the volume to 3.5 mL with PBS buffer, and then preheating at 37° C. for 10 min, adding 0.5 mL of a 100 U / mL tyrosinase solution, mixing, and reacting for 30 min, and then measuring the absorbance at a wavelength of 475 nm by ultraviolet spectrophotometry, which is recorded as A0;

[0111] c) Add 1 mL of 0.1 g / L L-tyrosine solution to a centrifuge tube, dilute to 3.5 mL with PBS buffer, and preheat at 37°C for 10 minutes. Then add 0.5 mL of 100 U / mL tyrosinase solution, mix well, and react for 30 minutes. Measure the absorbance at 475 nm using UV spectrophotometry, which is recorded as C1.

[0112] d) Add 3.5 mL of PBS buffer to a centrifuge tube and preheat at 37°C for 10 minutes. Then add 0.5 mL of 100 U / mL tyrosinase solution, mix well, and react for 30 minutes. Measure the absorbance at 475 nm using UV spectrophotometry, which is recorded as C0.

[0113] e) Calculate the tyrosinase inhibition rate using the following formula: Tyrosinase inhibition rate (%) = [1-(A1-A0) / (C1-C0)] x 100%.

[0114] Test results:

[0115] i) The in vitro tyrosinase inhibition rates of the multiple emulsions in Examples 1 to 4 were as high as 95% to 99%, indicating that the multiple emulsions of the present invention have significant tyrosinase inhibition activity and can effectively reduce the production of melanin, thereby achieving the effect of whitening the skin;

[0116] ii) The in vitro tyrosinase inhibition rate of the multiple emulsion in Comparative Example 1 was only 30%, which was much lower than that of the multiple emulsions in Examples 1 to 4. This was because the internal aqueous phase of the multiple emulsion in Comparative Example 1 lacked whitening agents (i.e., arbutin and niacinamide), which weakened its ability to inhibit tyrosinase (whitening agents are key components that directly act on tyrosinase and can inhibit tyrosinase activity, thereby reducing melanin production).

[0117] iii) The in vitro tyrosinase inhibition rate of the multiple emulsion in Comparative Example 2 was 82%, significantly lower than that of the multiple emulsions in Examples 1 to 4. This is because the oil phase of the multiple emulsion in Comparative Example 2 lacks an antioxidant (i.e., vitamin E), which weakens its ability to inhibit tyrosinase (antioxidants can protect the whitening agent from oxidative inactivation and reduce the interference of free radicals on tyrosinase).

[0118] iv) The in vitro tyrosinase inhibition rate of the multiple emulsion in Comparative Example 3 was 75%, which was significantly lower than that of the multiple emulsions in Examples 1 to 4. This was because the external aqueous phase of the multiple emulsion in Comparative Example 3 lacked resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles, which weakened its tyrosinase inhibitory ability (resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles can improve the stability of the whitening agent and the multiple emulsion, and can also act synergistically with the whitening agent).

[0119] 2) Skin moisturizing performance test of multiple emulsions:

[0120] Test subjects: 10 volunteers aged 20 to 30 with different skin types.

[0121] Test method: The initial water content of the forearm skin of a volunteer was measured using a skin analyzer to ensure that the initial value was less than 66. Equal amounts of the multiple emulsions in Examples 1 to 4 and Comparative Examples 1 to 3 were then dropped onto the test area and massaged until absorbed. The skin water content was then measured 15 minutes, 30 minutes, 60 minutes, 120 minutes, 180 minutes, and 240 minutes after application. The increase in skin water content was then calculated (the initial value was subtracted from the test value). The test results are shown in the following table:

[0122] Table 1 Skin moisturizing performance test results of multiple emulsions

[0123] Application time 15min 30min 60min 120 minutes 180 minutes 240min Example 1 16 11 10 7 6 3 Example 2 18 14 13 12 9 4 Example 3 14 9 7 5 3 2 Example 4 15 11 9 6 4 2 Comparative Example 1 10 6 4 4 1 1 Comparative Example 2 13 11 8 4 2 1 Comparative Example 3 9 6 5 3 1 1

[0124] From Table 1 we can see that:

[0125] i) The skin moisture content of volunteers who applied the multiple emulsions of Examples 1 to 4 (particularly the multiple emulsion of Example 2) increased rapidly, and the increase in skin moisture remained at a high level within 240 minutes, indicating that the multiple emulsions of the present invention have a good moisturizing effect and can effectively lock in skin moisture and maintain the skin's hydration;

[0126] ii) The skin moisturizing performance of the multiple emulsion in Comparative Example 1 is much lower than that of the multiple emulsion in Example 2. This is because the internal aqueous phase of the multiple emulsion in Comparative Example 1 lacks whitening agents (i.e., arbutin and niacinamide), resulting in a low increase in skin moisture and difficulty in retaining moisture (arbutin and niacinamide themselves have a certain moisturizing effect);

[0127] iii) The skin moisturizing performance of the multiple emulsion in Comparative Example 2 is much lower than that of the multiple emulsion in Example 2. This is because the oil phase of the multiple emulsion in Comparative Example 2 lacks an antioxidant (i.e., vitamin E), which results in decreased stability of the multiple emulsion and accelerated water loss;

[0128] iv) The skin moisturizing performance of the multiple emulsion in Comparative Example 3 is much lower than that of the multiple emulsion in Example 2. The reason is that the external aqueous phase of the multiple emulsion in Comparative Example 3 lacks resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles, which affects the penetration of active substances in the multiple emulsion and the stability of the multiple emulsion. In addition, the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles themselves also have a certain moisturizing ability.

[0129] 3) Sensory evaluation of multiple emulsions:

[0130] Evaluation indicators: Evaluation is based on six aspects: moisturizing, glossiness, freshness, spreadability, absorbency and stickiness. The specific descriptions and scoring criteria are shown in the following table:

[0131] Table 2 Sensory evaluation indicators and scores

[0132] index describe Fraction Moisturizing After applying the sample, does the skin feel moisturized? 0 (dry) → 10 (moist) Gloss Is the skin surface shiny after applying the sample? 0 (matte) → 10 (glossy) Refreshing feeling Does the skin feel refreshed after applying the sample? 0 (greasy) → 10 (refreshing) Spreadability Is the sample easy to apply? 0 (difficult) → 10 (easy) Absorbency After applying the sample, is the skin quickly absorbed? 0 (slow) → 10 (fast) sticky feeling After applying the sample, the stickiness of the skin surface 0 (large) → 10 (small)

[0133] The sensory evaluation results of the multiple emulsion droplets in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in the following table:

[0134] Table 3 Sensory evaluation results of multiple emulsion droplets

[0135]

[0136]

[0137] From Table 3 we can see that:

[0138] i) The multiple emulsions in Examples 1 to 4 (particularly the multiple emulsion in Example 2) have a good skin feel, can effectively improve the moisturization and radiance of the skin, and do not cause excessive greasiness on the skin. They have good spreadability and absorbency, and the stickiness on the skin surface after use is relatively small;

[0139] ii) The multiple emulsion in Comparative Example 1 had lower moisturizing, glossiness, freshness, spreadability, absorbency, and stickiness scores than the multiple emulsion in Example 2. This is because the internal aqueous phase of the multiple emulsion in Comparative Example 1 lacks whitening agents (i.e., arbutin and niacinamide). Whitening agents have certain moisturizing properties, and the absence of whitening agents leads to reduced moisturizing, glossiness, etc. of the multiple emulsion.

[0140] iii) The moisturizing, glossiness, freshness, spreadability, absorbability, and stickiness scores of the multiple emulsion in Comparative Example 2 were lower than those of the multiple emulsion in Example 2. This is because the oil phase of the multiple emulsion in Comparative Example 2 lacks an antioxidant (i.e., vitamin E). Antioxidants can protect the whitening agent from oxidation and inactivation and have certain skin conditioning effects. The lack of antioxidants leads to poor moisturizing and absorbability of the multiple emulsion.

[0141] iv) The moisturizing, glossiness, refreshing feeling, spreadability, absorbability, and stickiness scores of the multiple emulsion in Comparative Example 3 were all lower than those of the multiple emulsion in Example 2. The reason is that the external aqueous phase of the multiple emulsion in Comparative Example 3 lacks resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles. While resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles can improve the stability of the multiple emulsion and have certain skin penetration promoting, antioxidant, and moisturizing effects, the absence of resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles affects the texture and stability of the multiple emulsion, ultimately resulting in reduced moisturizing, refreshing, and absorbability of the multiple emulsion.

[0142] In summary, the multiple emulsion of the present invention can not only inhibit tyrosinase activity and improve skin moisture content in a long-term manner, but also has a good skin feel and is suitable for large-scale industrial production and application.

[0143] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticle, characterized in that: It has a core-shell structure, wherein the core is phosphorylated zein nanoparticles encapsulating resveratrol, and the shell is a carboxymethyl chitosan layer.

2. The resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles according to claim 1, characterized in that: The mass ratio of resveratrol, phosphorylated zein and carboxymethyl chitosan in the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles is 1:8-12:5-20; the particle size of the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles is 90nm-130nm.

3. A method for preparing resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles according to claim 1 or 2, characterized in that: The following steps are involved: a) adding an ethanol solution of resveratrol to an aqueous solution of phosphorylated zein, and stirring uniformly to obtain a dispersion of phosphorylated zein nanoparticles encapsulating resveratrol; b) adding the carboxymethyl chitosan aqueous solution to the dispersion of phosphorylated zein nanoparticles encapsulating resveratrol, stirring evenly, and then separating the products to obtain resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles.

4. A multiple emulsion, characterized in that The invention consists of an inner aqueous phase, an oil phase and an outer aqueous phase; the inner aqueous phase comprises a whitening agent and a moisturizer; the oil phase comprises vegetable oil, an antioxidant and an emulsifier; the outer aqueous phase comprises the resveratrol-phosphorylated zein-carboxymethyl chitosan composite nanoparticles according to claim 1 or 2, a penetration enhancer and a moisturizer.

5. The multiple emulsion according to claim 4, characterized in that: The whitening agent in the inner water phase is at least one of arbutin, niacinamide, vitamin C, and tranexamic acid; the moisturizing agent in the inner water phase is at least one of glycerin, butylene glycol, propylene glycol, sodium hyaluronate, trehalose, and allantoin.

6. The multiple emulsion according to claim 4 or 5, characterized in that: The vegetable oil in the oil phase is at least one of olive oil, sunflower seed oil, grape seed oil, shea butter, jojoba oil, and macadamia nut oil; the antioxidant in the oil phase is at least one of vitamin E, phytosterols, squalane, butylated hydroxyanisole, and butylated hydroxytoluene; and the emulsifier in the oil phase is at least one of polyglyceryl ricinoleate, cetyl alcohol, stearyl alcohol, polyglyceryl-3 diisostearate, beeswax, polyglyceryl-4 diisostearate / polyhydroxystearic acid, and polydimethylsiloxane.

7. The multiple emulsion according to claim 4 or 5, characterized in that: The penetration enhancer in the external aqueous phase is at least one of water-soluble azone, lauryl azone, and dimethyl isosorbide; and the moisturizer in the external aqueous phase is at least one of propylene glycol, sorbitol, allantoin, glycerin, and butylene glycol.

8. The multiple emulsion according to claim 4 or 5, characterized in that: The composition of the external aqueous phase also includes a thickener, a preservative and a flavor; the thickener is at least one of xanthan gum, sodium alginate, pectin, hydroxypropyl methylcellulose and bentonite; the preservative is at least one of phenoxyethanol, methylisothiazolinone, methylchloroisothiazolinone, benzoic acid and sorbic acid; the flavor is at least one of rose flavor, lavender flavor, jasmine flavor, violet flavor, lemon flavor, green tea flavor, marine flavor and aloe flavor.

9. A method for preparing a multiple emulsion according to any one of claims 4 to 8, characterized in that: The following steps are involved: 1) preparing an inner water phase, an oil phase and an outer water phase; 2) adding the inner aqueous phase to the stirred oil phase and then subjecting it to high-speed shearing to obtain a W / O emulsion; 3) Adding the W / O emulsion to the external aqueous phase in a stirring state and then subjecting it to high-speed shearing to obtain a multiple emulsion.

10. A skin care product, characterized in that: The multiple emulsion according to any one of claims 4 to 8.

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