A w / o / w composition and a process for its preparation

Abstract

The application discloses a W / O / W composition and a preparation method thereof, and belongs to the technical field of cosmetics. The W / O / W composition comprises the following components in percentage by weight: 0.5-2% of lipophilic surfactant, 1-5% of hydrophilic surfactant, 5-20% of oil phase, 0.5-2% of cholesterols and / or sterol derivatives, 5-20% of polyhydric alcohol and 0.1-2% of thickening agent. Based on the long-term stability of multiple emulsions, the application adds cholesterols and / or sterol derivatives to obtain a W / O / W composition which is long-term stable and has excellent skin feeling. In addition, the preparation method of the W / O / W composition is less than 40 DEG C, which can reduce the production energy consumption and the risk of inactivation of temperature-sensitive active ingredients.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cosmetics, and particularly relates to a W / O / W composition and a preparation method thereof. BACKGROUND

[0002] Multiple emulsions are multilayer emulsions formed by dispersing one emulsion in another continuous phase. Currently, there are two common types of multiple emulsions, namely water-in-oil-in-water (W / O / W) and oil-in-water-in-oil (O / W / O). Because multiple emulsions have the advantages of traditional water-in-oil and oil-in-water emulsions in terms of performance, they can simultaneously load water-soluble and oil-soluble active substances, and have multiple protection and certain sustained release effects on the active substances loaded in the inner phase, so they have attracted widespread attention in the field of cosmetics.

[0003] However, the complex structure of "two membranes and three phases" in multiple emulsions makes the multiple phase interface have high interfacial energy, so there are many unstable factors, which makes it difficult to obtain long-term stable multiple emulsions. The long-term stability problem of multiple emulsions has become the biggest obstacle to their application in the field of cosmetics.

[0004] Chinese Patent CN110638666B discloses a W / O / W type multiple emulsion and a preparation method thereof. The preparation temperature of the multiple emulsion is 70-95℃. Chinese Patent CN104135999B discloses a W / O / W type emulsion with time stability and a manufacturing method thereof. The W / O / W type emulsion is prepared by a two-step method, the first step is emulsified at 75-85℃, and the second step is emulsified at 10-50℃. The preparation temperature of the above emulsions is above 50℃, which is not conducive to the addition of temperature-sensitive active substances.

[0005] Based on the above problems, the present application provides a W / O / W composition and a preparation method thereof. The composition has good stability after aging test and no delamination of the material body. SUMMARY

[0006] To solve the above technical problems, the present application provides a W / O / W composition and a preparation method thereof. Specifically, the following technical solutions are included:

[0007] In a first aspect, a W / O / W composition is provided, which includes the following components by weight percentage:

[0008] 0.5-2% of lipophilic surfactant, 1-5% of hydrophilic surfactant, 5-20% of oil phase, 0.5-2% of cholesterols and / or sterol derivatives, 5-20% of polyhydric alcohol, and 0.1-2% of thickening agent.

[0009] The cholesterols and / or sterol derivatives are one or more of cholesterols, phytosteryl macadamia nut oilate, phytosteryl oleate, and phytosteryl / octyldodecyl lauroyl glutamate.

[0010] Further, the lipophilic surfactant is polyglycerol fatty acid ester, and the HLB value of the polyglycerol fatty acid ester is ≤5.

[0011] Further, the polyglycerol fatty acid ester includes one or more of polyglyceryl-6 polyricinoleate, polyglyceryl-3 polyricinoleate, glyceryl stearate, polyglyceryl-2 isostearate, polyglyceryl-4 diisostearate / polyhydroxystearate / decanediol.

[0012] Further, the weight ratio of the lipophilic surfactant to cholesterols and / or sterol derivatives is 1:(0.5-2).

[0013] Further, the hydrophilic surfactant consists of methyl stearoyl taurate and Tween 80.

[0014] Preferably, the methyl stearoyl taurate is sodium methyl stearoyl taurate.

[0015] Preferably, the Tween 80 is polysorbate-80.

[0016] Further, the oil phase is one or more of squalane, hydrogenated polyisobutene, cetyl alcohol ethylhexanoate, dimethicone, isopropyl myristate, ethylhexyl palmitate, isononyl isononanoate.

[0017] Preferably, the oil phase has a polar index IOB value ≤0.2.

[0018] Further, the polyol is one or more of glycerin, butylene glycol, propylene glycol, dipropylene glycol, sorbitol, polyethylene glycol-32.

[0019] Further, the thickening agent is one or more of NaCl, MgSO4, xanthan gum, hydroxyethylcellulose and derivatives, gum arabic, acrylates / C10-30 alkyl acrylate crosspolymer, polyacrylate crosspolymer-6.

[0020] Preferably, the thickening agent includes W / O primary emulsion thickening agent and multiple emulsion thickening agent, the W / O primary emulsion thickening agent is one or more of NaCl, MgSO4; the multiple emulsion thickening agent is one or more of xanthan gum, hydroxyethylcellulose and derivatives, gum arabic, acrylates / C10-30 alkyl acrylate crosspolymer, polyacrylate crosspolymer-6.

[0021] Further, the W / O / W composition further includes a preservative, the weight percentage of the preservative in the W / O / W composition is 0.1-1%; the preservative includes one or more of methylparaben, phenoxyethanol, ethylhexylglycerin.

[0022] Preferably, the W / O / W composition comprises the following components by weight percentage: 0.5-2% lipophilic surfactant, 1-5% hydrophilic surfactant, 5-20% oil phase, 0.5-2% cholesterol and / or sterol derivatives, 5-20% polyol, 0.1-2% thickener, 0.1-1% preservative, and the balance being water.

[0023] In a second aspect, a method for preparing the W / O / W composition as described in the first aspect is provided, comprising the following steps:

[0024] 1) Weigh out the lipophilic surfactant, hydrophilic surfactant, oil phase, cholesterol and / or sterol derivatives, polyol, thickener and water according to the weight percentage of each component; wherein, the polyol includes a first part polyol and a second part polyol, the water includes a first part water and a second part water, and the thickener includes W / O thickener and double emulsion thickener.

[0025] 2) Mix the lipophilic surfactant, cholesterol and / or sterol derivatives evenly at 85-90℃ and keep warm for 10-15 minutes, then cool down to 35-40℃ and set aside for use.

[0026] 3) Add the oil phase to the component obtained in step 2) and mix well, then set aside for later use;

[0027] 4) Mix the W / O thickener, the first polyol and the first water evenly to obtain the inner aqueous phase. Add the inner aqueous phase to the components obtained in step 3) at a stirring speed of 350 rpm under the condition of below 40°C and mix evenly. Then, homogenize at a stirring speed of 6000 rpm for 1-2 minutes to form a W / O emulsion for later use.

[0028] 5) Mix the hydrophilic surfactant, the second part of polyol, the re-emulsion thickener, and the second part of water at 60-80℃ to obtain the external aqueous phase, and set aside for later use;

[0029] 6) Add the W / O emulsion obtained in step 4) to the external aqueous phase obtained in step 5) at a stirring speed of 200 rpm, disperse and mix evenly, and then homogenize at a stirring speed of 3000 rpm for 2-3 minutes to obtain the W / O / W composition.

[0030] This invention provides a W / O / W composition and its preparation method. Addressing the long-term stability issues of multiple emulsions, this invention achieves a long-term stable W / O / W composition with excellent skin feel by adding cholesterol and / or sterol derivatives. Furthermore, the preparation method of this invention's W / O / W composition is performed at temperatures below 40°C, reducing production energy consumption and the risk of inactivation of temperature-sensitive active ingredients. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 Microscopic images (200X) of the W / O / W composition of Example 1 of the present invention;

[0033] Figure 2 Microscopic images (500X) of the W / O / W composition of Example 1 of the present invention;

[0034] Figure 3 Images of the W / O / W composition of Example 2 of this invention after rapid centrifugation at LUM GmbH;

[0035] Figure 4 The transmittance spectrum of the W / O / W composition of Example 2 of this invention, obtained by rapid centrifugation test by LUM GmbH.

[0036] Figure 5 The image (200X) shows the W / O / W composition of Example 2 of the present invention after being placed at room temperature for 30 days for constant temperature testing.

[0037] Figure 6 Microscopic images (200X) of the W / O / W composition of Example 2 of the present invention after being placed at a constant temperature of 48°C for 30 days;

[0038] Figure 7 Microscopic images (200X) of the W / O / W composition of Example 2 of the present invention after being subjected to a thermal cycle of 45°C to -15°C for 5 times;

[0039] Figure 8 The results of the stratum corneum moisture content test for the W / O / W composition of Example 4 of the present invention were obtained through a moisturizing efficacy test.

[0040] Figure 9 The results of the epidermal moisture content test for the W / O / W composition of Example 4 of the present invention were obtained through a moisturizing efficacy test.

[0041] Figure 10 The results of the transdermal water loss test are for the W / O / W composition of Example 4 of the present invention, which is tested for its moisturizing efficacy. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0044] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0045] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0046] To better understand the technical content of the present invention, the technical solution of the present invention will be further introduced and explained below with reference to specific embodiments.

[0047] Preparation method of W / O / W composition:

[0048] Includes the following steps:

[0049] 1) Weigh out the following components according to their weight percentages: lipophilic surfactant, hydrophilic surfactant, oil phase, cholesterol and / or sterol derivatives, polyol, thickener, water, and preservative (if any); wherein the polyol comprises a first part polyol and a second part polyol, the water comprises a first part water and a second part water, and the thickener comprises a W / O thickener and a double emulsion thickener.

[0050] 2) Mix the lipophilic surfactant, cholesterol and / or sterol derivatives evenly at 85-90℃ and keep warm for 10-15 minutes, then cool down to 35-40℃ and set aside for use.

[0051] 3) Add the oil phase to the component obtained in step 2) and mix well, then set aside for later use;

[0052] 4) Mix the W / O thickener, the first polyol and the first water evenly to obtain the inner aqueous phase. Add the inner aqueous phase to the components obtained in step 3) at a stirring speed of 350 rpm under the condition of below 40°C and mix evenly. Then, homogenize at a stirring speed of 6000 rpm for 1-2 minutes to form a W / O emulsion for later use.

[0053] 5) Mix the hydrophilic surfactant, the second part of polyol, the thickener for re-emulsion, and the second part of water at 60-80℃ to obtain the external aqueous phase. After cooling to below 40℃, add the preservative (if any) and mix well. Set aside for use.

[0054] 6) Add the W / O emulsion obtained in step 4) to the external aqueous phase obtained in step 5) after adding preservatives (if any) at a stirring speed of 200 rpm, disperse and mix evenly, and then homogenize at a stirring speed of 3000 rpm for 2-3 minutes to obtain the W / O / W composition.

[0055] Performance testing methods

[0056] 1) Structural evaluation of W / O / W compositions

[0057] This invention utilizes a polarizing microscope to observe and characterize the structure of W / O / W compositions, allowing for particle size assessment of the W / O / W compositions based on the micrographs.

[0058] 2) Stability evaluation of W / O / W compositions

[0059] The stability of the W / O / W composition of the present invention was tested by high temperature and thermal cycling aging, LUM GmbH ( 611.3-137) Evaluation was performed using rapid centrifugation test. The appearance, odor, and layering of the sample before and after the test were observed to determine its stability.

[0060] Test conditions: The samples were placed at room temperature (25℃) for 30 days, at 48℃ for 30 days, and subjected to 5 cycles of hot and cold cycling from 45℃ to -15℃ (each cycle consisted of 12 hours at 45℃, 12 hours at room temperature, 12 hours at -15℃, and 12 hours at room temperature). The samples were then subjected to rapid centrifugation at LUM GmbH (45℃, 4000 r / min, 5 hours).

[0061] Evaluation criteria:

[0062] Stratified evaluation: ○ No stratification, × stratification.

[0063] Appearance evaluation: ○ No change, △ Slight change (viscosity thins), × Change (layering, demulsification, phase inversion, etc.).

[0064] Odor evaluation: ○ No change, × Change (abnormal odor: such as oxidized oil smell, etc.)

[0065] 3) Evaluation of the encapsulation efficiency of W / O emulsion in W / O / W compositions

[0066] To confirm the encapsulation rate and stability of the W / O emulsion in the W / O / W composition prepared by the present invention, the present invention detects the change in the conductivity of the W / O / W composition to confirm the leakage of NaCl in the inner aqueous phase, thereby evaluating the encapsulation rate and stability of the W / O emulsion in the W / O / W composition.

[0067] Test method: Take 10g of each of the W / O / W composition samples that have been placed at 45℃ for 3 months, at -15℃ for 3 months, and at room temperature (25℃) for 24 hours, respectively, dilute them with pure water to 100g and mix well, and measure the conductivity using FiveEasyPlus. Then, plot a standard curve using the conductivity of different concentrations of NaCl in the inner aqueous phase to determine the encapsulation rate of W / O emulsion in the W / O / W composition.

[0068] Package rate (%) = (1 - υ1 / υ2) × 100%

[0069] In the formula: υ1 is the conductivity of the W / O / W composition; υ2 is a standard curve plotted using the conductivity of different concentrations of NaCl in the aqueous phase.

[0070] 4) Evaluation of the application of W / O / W compositions

[0071] The W / O / W composition of this invention belongs to the field of cosmetic technology and should be significantly different from related technologies in the petroleum and pharmaceutical fields. Therefore, the W / O / W composition of this invention should not only have long-term stable effects, but also provide a good user experience and moisturizing effects.

[0072] Based on this, the application evaluation of the skin feel and moisturizing efficacy of the W / O / W composition of the present invention, as well as the application evaluation of the combination of active ingredients, are conducted to verify the user experience and moisturizing effects of the W / O / W composition in application. The specific implementation method is as follows:

[0073] ① Evaluation of skin feel and moisturizing effects

[0074] This invention uses a volunteer sample trial method and a questionnaire to collect volunteers' satisfaction ratings on the skin feel of the product in terms of stickiness, richness, and spreadability, as well as their evaluation of moisturizing efficacy.

[0075] Evaluation method:

[0076] Skin feel evaluation method: Twenty healthy adult subjects aged 18-60 years were selected. Equal amounts of the W / O / W composition and a commercially available sample were applied simultaneously to the same area of ​​the inner arm. Satisfaction with the skin feel was evaluated based on the initial stickiness and fullness felt after product use, as well as the spreadability felt from the middle to the final stage.

[0077] The evaluation criteria are as follows:

[0078] Stickiness: ◎Excellent, ○Good, △Average, ×Poor

[0079] Sense of abundance: ◎Excellent, ○Good, △Average, ×Poor

[0080] Extensibility: ◎Excellent, ○Good, △Average, ×Poor

[0081] Overall satisfaction: ○ Satisfied, × Dissatisfied

[0082] Moisturizing efficacy evaluation method: Ten healthy adult subjects aged 18-60 years were selected. The moisturizing effect of the W / O / W composition and the commercially available sample was evaluated according to the method of the Guideline for Evaluation of Moisturizing Efficacy of Cosmetics (QB / T 4256-2011). The stratum corneum moisture content, epidermal moisture content and transepidermal water loss value of the skin in the test area and the control area were measured at 1h, 2h and 4h and compared.

[0083] ② Evaluation of the application of active ingredient combinations

[0084] The active ingredients described in this invention are not limited and can be water-soluble or oil-soluble. For example, water-soluble active ingredients may be one or more of the following: nicotinamide, 3-o-ethyl ascorbic acid, tranexamic acid, glyceryl glucoside, arginine / lysine polypeptide, and ascorbate glucoside; oil-soluble active ingredients may be one or more of the following: ubiquinone, astaxanthin, ascorbate tetraisopalmitate, licorice root extract, and phenylethyl resorcinol.

[0085] Studies have shown that tranexamic acid and ascorbic acid have a good synergistic effect in improving melasma (IrajiFaribaNasimi MojtabaAsilian AliFaghihi GitaMozafarpoor SamanehHafeziHossein. Efficacy of mesotherapy with tranexamic acid and ascorbic acid with and without glutathione in treatment of melasma: A split face comparative trial[J]. Journal of cosmetic dermatology, 2019, 18(5).). However, when tranexamic acid and ascorbic acid coexist, the two undergo a Maillard reaction, resulting in discoloration. This invention proposes to separate tranexamic acid and 3-o-ethyl ascorbic acid by compounding them (based on the physical properties of tranexamic acid and 3-o-ethyl ascorbic acid, 3-o-ethyl ascorbic acid is encapsulated in the inner aqueous phase, while tranexamic acid is added to the outer aqueous phase, and the special "two-membrane three-phase" structure of the W / O / W composition is used to separate them), and to evaluate the color change and stability of the active ingredient by measuring the transmittance of the sample before and after high-temperature testing.

[0086] Test conditions: The sample was placed at a constant temperature of 50℃ for 2 weeks.

[0087] Test method: Take 10g of each of the W / O / W samples placed at 50℃ for 2 weeks and at room temperature (25℃) for 24 hours, add pure water to dilute to 100g, and use ultrasonic disruption and mixing. After centrifugation at 4000r / min for 30min using a centrifuge (Feige brand, TDL-50B), take 2-5mL of the supernatant. Finally, use a UV-Vis spectrophotometer (Shanghai Meipuda Instrument Co., Ltd.) to measure the transmittance of the supernatant of the sample.

[0088] Example

[0089] The W / O / W compositions of Examples 1-3 and Comparative Examples 1-3 were prepared according to the raw materials and their weight percentage content in Table 1.

[0090] Table 1. Raw materials and content of W / O / W compositions in Examples 1-3 and Comparative Examples 1-3

[0091]

[0092]

[0093]

[0094] The W / O / W compositions of Comparative Examples 4-7 were prepared according to the raw materials and their weight percentage content in Table 2.

[0095] Table 2. Raw materials and content of W / O / W compositions in Comparative Examples 4-7

[0096]

[0097]

[0098] The preparation methods of Examples 1-3 and Comparative Examples 1-7 include the following steps:

[0099] 1) Weigh out the following components according to their weight percentages: lipophilic surfactant, hydrophilic surfactant, oil phase, cholesterol and / or sterol derivatives, polyol, thickener, water, and preservative; wherein the polyol includes a first part polyol and a second part polyol, the water includes a first part water and a second part water, and the thickener includes a W / O thickener and a double emulsion thickener.

[0100] 2) Mix the lipophilic surfactant, cholesterol and / or sterol derivatives (phase A) at 90°C and keep warm for 10 min, then cool to 40°C for later use;

[0101] 3) Add the oil phase (B phase) to the component obtained in step 2) and mix well, then set aside for later use;

[0102] 4) Mix the W / O thickener, the first polyol and the first water (C phase) evenly to obtain the inner aqueous phase. Add the inner aqueous phase to the components obtained in step 3) at a stirring speed of 350 rpm under the condition of below 40°C and mix evenly. Then, homogenize at a stirring speed of 6000 rpm for 1 min to form a W / O emulsion for later use.

[0103] 5) Mix the hydrophilic surfactant, the second part of polyol, the thickener, and the second part of water (D phase) at 80°C to obtain the external aqueous phase. After cooling to below 40°C, add the preservative (E phase) and mix well. Set aside for use.

[0104] 6) Add the W / O emulsion obtained in step 4) to the aqueous phase with added preservatives obtained in step 5) at a stirring speed of 200 rpm, disperse and mix evenly, and then homogenize at a stirring speed of 3000 rpm for 2 min to obtain the W / O / W composition.

[0105] The W / O / W composition of Example 1 was subjected to W / O / W composition structure evaluation tests. Figure 1 These are micrographs (200X) of the W / O / W composition of Example 1 of the present invention. Figure 2 Micrograph (500X) of the W / O / W composition of Example 1 of the present invention.Figure 1 and Figure 2 As can be seen from the above, the W / O / W composition of Example 1 of the present invention is a W / O / W structural composition comprising an inner aqueous phase, an oil phase, and an outer aqueous phase. According to... Figure 2 The particle size of the W / O / W composition of Example 1 was evaluated, and the multiple droplet particle size of the W / O / W composition of Example 1 of the present invention was ≤30μm.

[0106] The appearance, droplet structure distribution, and particle size changes of the W / O / W composition of Example 2 before and after the stability evaluation test were observed using a polarizing microscope. Figure 3 Images of the W / O / W composition of Example 2 of this invention after rapid centrifugation at LUM GmbH. Figure 3 As can be seen from the results, the W / O / W composition of Example 2 did not exhibit any stratification after rapid centrifugation at LUM GmbH.

[0107] Figure 4 The image shows the transmittance spectrum of the W / O / W composition of Example 2 of this invention after rapid centrifugation at LUM GmbH. As can be seen from the curve changes in the image, the transmittance of the W / O / W composition of Example 2 of this invention did not change significantly after rapid centrifugation at 45°C, 4000 r / min and 5 h, indicating that the W / O / W composition of Example 2 has good stability.

[0108] Figure 5 The image shown is a micrograph (200X) of the W / O / W composition of Example 2 of this invention after being kept at room temperature for 30 days. Figure 6 The image shown is a micrograph (200X) of the W / O / W composition of Example 2 of the present invention after being placed at a constant temperature of 48°C for 30 days. Figure 7 The image (200X) shows the W / O / W composition of Example 2 of this invention after being subjected to a thermal cycle of 45°C to -15°C for 5 times. Figures 5-7 It can be seen that the droplet structure distribution and particle size of the W / O / W composition sample in Example 2 of the present invention did not change significantly, which confirms that the multiple structures of the W / O / W composition in Example 2 of the present invention have long-term stability.

[0109] I. The Influence of Cholesterol and / or Sterol Derivatives on Stability

[0110] Stability evaluation tests were conducted on the W / O / W compositions of Examples 1-3 and Comparative Examples 1-3, and the test results are shown in Table 3 below:

[0111] Table 3. Stability evaluation test results of the W / O / W compositions of Examples 1-3 and Comparative Examples 1-3.

[0112]

[0113] As shown in Table 3, the W / O / W compositions of Examples 1-3 of this invention passed the stability evaluation test. The difference between Comparative Example 1 and the W / O / W composition of Example 1 is that Comparative Example 1 did not contain cholesterol and / or sterol derivatives; all other conditions were the same. The difference between Comparative Example 2 and the W / O / W composition of Example 1 is that Comparative Example 2 used phytosterol / isostearyl / cetearyl / stearyl / behenol dimer linoleate instead of phytosterol macadamia oleate in Example 1; all other conditions were the same. The difference between Comparative Example 3 and Example 1 is that carnauba wax was used instead of phytosterol macadamia oleate in Example 1; all other conditions were the same. The W / O / W compositions of Comparative Examples 1-3 failed the stability evaluation test. Therefore, it is evident that the addition of cholesterol and / or sterol derivatives in this invention is beneficial for increasing the stability of the W / O / W compositions.

[0114] II. The effect of the weight ratio of lipophilic surfactants to cholesterol and / or sterol derivatives on stability

[0115] Stability evaluation tests were conducted on the W / O / W compositions of Example 1 and Comparative Examples 4-5. The test results are shown in Table 4 below:

[0116] Table 4. Stability evaluation test results of the W / O / W compositions in Examples 1 and Comparative Examples 4-5.

[0117]

[0118] As shown in Table 4, the difference between Comparative Example 4 and the W / O / W composition of Example 1 lies in the weight ratio of the lipophilic surfactant to cholesterol and / or sterol derivatives, which is outside the 1:(0.5-2) range limited by this invention. All other conditions are the same. The W / O / W composition of Comparative Example 4 exhibits decreased high-temperature and cycling stability, but its stability evaluation test results are superior to those of the W / O / W composition of Comparative Example 1.

[0119] The difference between Comparative Example 5 and the W / O / W composition of Example 1 is that the weight ratio of the lipophilic surfactant to cholesterol and / or sterol derivatives is not within the 1:(0.5-2) range limited by this invention; all other conditions are the same. The W / O / W composition of Comparative Example 5 exhibits good high-temperature stability, but demulsification occurs during cycling, indicating that the addition of excessive cholesterol and / or sterol derivatives reduces low-temperature freezing stability.

[0120] III. The Influence of the Type of Lipophilic Surfactant (HLB Value) on Stability

[0121] The stability evaluation tests were conducted on the W / O / W compositions of Example 2 and Comparative Example 6, and the test results are shown in Table 5 below:

[0122] Table 5. Stability evaluation test results of the W / O / W compositions of Example 2 and Comparative Example 6.

[0123]

[0124] As shown in Table 5, the difference between Comparative Example 6 and Example 2's W / O / W composition is the use of polyglycerol-3 diisostearate (HLB = 5.5) instead of polyglycerol-6 polyricinoleate (HLB = 3.2), while all other conditions remain the same. Comparative Example 6's W / O / W composition failed to form a stable W / O / W composition. This indicates that a lower HLB value of the lipophilic surfactant is more conducive to forming a stable W / O / W composition. Preferably, the HLB value of the lipophilic surfactant in the W / O / W composition of this invention is ≤5.

[0125] IV. The Influence of Oil Phase Type (IOB Value) on Stability

[0126] The stability evaluation tests were conducted on the W / O / W compositions of Example 2 and Comparative Example 7, and the test results are shown in Table 6 below:

[0127] Table 6. Stability evaluation results of the W / O / W compositions of Example 2 and Comparative Example 7.

[0128]

[0129] As shown in Table 6, the difference between Comparative Example 7 and the W / O / W composition of Example 2 is that glyceryl tri(ethylhexanoate) (IOB = 3.6) was used instead of isononyl isononanoate (IOB = 0.2), while all other conditions remained the same. The W / O / W composition of Comparative Example 7 failed the stability evaluation test. This indicates that a higher IOB value in the oil phase is detrimental to the stability of the W / O / W composition, especially its high-temperature aging stability. Therefore, the IOB value of the oil phase in the W / O / W composition of the present invention is preferably ≤0.2.

[0130] V. Evaluation Test of Aqueous Phase Encapsulation Rate in W / O / W Compositions

[0131] The encapsulation efficiency of the W / O emulsions in Examples 1-3, Comparative Examples 1, and Comparative Examples 4-5 was evaluated, and the test results are shown in Table 7 below:

[0132] Table 7. Evaluation results of W / O emulsion encapsulation rate in W / O / W compositions of Examples 1-3, Comparative Examples 1, and Comparative Examples 4-5.

[0133]

[0134] As shown in Table 7, the encapsulation rate of the W / O / W compositions in Examples 1-3 was approximately 50-60%, and the conductivity at both high and low temperatures showed no significant change after 3 months, proving that the NaCl electrolyte encapsulated in the inner aqueous phase did not leak. However, the encapsulation rate of the W / O / W composition sample in Comparative Example 1 (without added cholesterol and / or sterol derivatives) decreased significantly after high and low temperature tests. When the weight ratio of the lipophilic surfactant to cholesterol and / or sterol derivatives was small, the W / O / W composition prepared (Comparative Example 4) showed a significantly smaller decrease in encapsulation rate after high and low temperature tests compared to the W / O / W composition in Comparative Example 1. This indicates that the addition of cholesterol and / or sterol derivatives to the W / O primary emulsion significantly improved the encapsulation stability of the inner aqueous phase in the W / O / W composition. When the weight ratio of the lipophilic surfactant to cholesterol and / or sterol derivatives is high, the resulting W / O / W composition (Comparative Example 5) shows no significant change in encapsulation rate after high-temperature testing, but the encapsulation rate decreases to 6.1% after low-temperature testing. This demonstrates that excessively high amounts of cholesterol and / or sterol derivatives are detrimental to the low-temperature stability of the W / O / W composition. Therefore, the W / O / W compositions of the embodiments of this invention exhibit long-term stability in terms of appearance, multiple structures, and W / O emulsion encapsulation.

[0135] VI. Evaluation of the skin feel and moisturizing effect of W / O / W compositions

[0136] Table 8. Raw materials and content of the W / O / W composition in Example 4

[0137]

[0138]

[0139] Note: Glyceryl glucoside was purchased from bitop AG, Portulaca oleracea extract was purchased from HYUNDAI BIOLAND CO.,LTD., and Artemia worm extract was purchased from Ashland LLC.

[0140] The W / O / W composition of Example 4 was prepared according to the raw materials and their weight percentage content in Table 8. The preparation method of the W / O / W composition of Example 4 was the same as that of Example 2.

[0141] Among them, the commercially available samples are a certain brand's (W1 / O1+O2) / W2 products, purchased from offline counters.

[0142] Application evaluation tests on skin feel and moisturizing efficacy were conducted on Example 4 and the commercially available sample. The skin feel evaluation test results for Example 4 and the commercially available sample are shown in Table 9 below:

[0143] Table 9. Skin feel evaluation test results of commercially available samples in Example 4.

[0144]

[0145]

[0146] The test results in Table 9 show that both Example 4 and the commercially available sample have good skin feel satisfaction. Example 4 exhibits better stickiness and spreadability, while the commercially available sample has a better fullness. This indicates that, compared with other W / O / W products, the W / O / W composition of the present invention not only has a good skin feel but also possesses certain advantages and characteristics. Therefore, based on the skin feel experience, the W / O / W composition of the present invention has good application prospects in the cosmetics field.

[0147] The results of the moisturizing efficacy evaluation test of Example 4 and commercially available samples are as follows: Figures 8-10 As shown, where, Figure 8 The results of the stratum corneum moisture content test for the W / O / W composition of Example 4 of the present invention were obtained through a moisturizing efficacy test. Figure 9 The results of the epidermal moisture content test for the W / O / W composition of Example 4 of the present invention were obtained through a moisturizing efficacy test. Figure 10 The results of the transdermal water loss test are for the W / O / W composition of Example 4 of the present invention, which is tested for its moisturizing efficacy.

[0148] Depend on Figures 8-10 Test results show that, after 4 hours of moisturizing efficacy testing, Example 4 outperformed commercially available samples in maintaining the moisture content of the stratum corneum and epidermis. Furthermore, after 2-4 hours, Example 4 also showed superior performance in reducing transepidermal water loss compared to commercially available samples. This indicates that although the W / O / W composition of this invention and commercially available samples both belong to the category of products containing multiple W / O / W structures, the W / O / W composition of this invention possesses superior moisturizing efficacy. Therefore, based on its moisturizing efficacy, the W / O / W composition of this invention has broad application prospects in the cosmetics field.

[0149] VII. Application Evaluation of W / O / W Combinations of Active Ingredients

[0150] The W / O / W composition of Example 5 was prepared according to the raw materials and their weight percentage content in Table 10. The preparation method of the W / O / W composition of Example 5 was the same as that of Example 2.

[0151] Table 10. Raw materials and content of the W / O / W composition in Example 5

[0152]

[0153]

[0154] Note: 3-o-ethyl ascorbic acid was purchased from Yantai Dongfang Chemical Co., Ltd., and tranexamic acid was purchased from Hunan Dongting Pharmaceutical Co., Ltd.

[0155] Comparative Example 8

[0156] The component content of Comparative Example 8 is the same as that of Example 5, but the preparation method is different. The specific preparation steps are as follows:

[0157] 1) Mix phase A thoroughly at 90°C, cool to 40°C, add phase B and mix thoroughly before use;

[0158] 2) Heat phases C, D, and E to 80°C and mix them thoroughly, then cool them down to 40°C and set aside for later use;

[0159] 3) Add the product obtained in step 1) to the product obtained in step 2) and mix well. Homogenize at 3000 rpm for 2 minutes.

[0160] 4) After mixing C1 and E1 phases evenly, add them to the product obtained in step 3) and mix evenly to obtain an O / W emulsion.

[0161] Application evaluation tests were conducted on the active ingredient combinations of Example 5 and Comparative Example 8, and the test results are shown in Table 11:

[0162] Table 11. Test results of the combined application of active ingredients in Example 5 and Comparative Example 8.

[0163]

[0164] As shown in Table 11, after two weeks of high-temperature testing at 50°C, the transmittance of the underlying liquid of the W / O / W composition in Example 5 decreased from 82% to 52.9%, while the transmittance of the underlying liquid of the O / W emulsion in Comparative Example 8 decreased from 79.5% to 29.9%. This indicates that the W / O / W composition of this invention increases the stability of the 3-o-ethyl ascorbic acid active ingredient. Specifically, in Example 5, by separating 3-o-ethyl ascorbic acid and tranexamic acid using the "two-membrane three-phase" structure of the W / O / W composition, the Maillard reaction between 3-o-ethyl ascorbic acid and tranexamic acid is inhibited, thereby increasing the stability of the active ingredients. Therefore, based on the stable encapsulation of the active ingredient, the W / O / W composition of this invention has good application prospects in the cosmetics field.

[0165] In summary, this invention provides a W / O / W composition and its preparation method. The resulting W / O / W composition exhibits a good skin feel and stable encapsulation effect on the aqueous active ingredients. By adding cholesterol and / or sterol derivatives, this invention achieves a long-term stable W / O / W composition with excellent skin feel. Furthermore, the preparation method of this invention uses a temperature below 40°C, which reduces production energy consumption and the risk of inactivation of temperature-sensitive active ingredients.

[0166] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A W / O / W composition, characterized in that, Includes the following components by weight percentage: 0.5-2% lipophilic surfactant, 1-5% hydrophilic surfactant, 5-20% oil phase, 0.5-2% cholesterol and / or sterol derivatives, 5-20% polyol, and 0.1-2% thickener; The cholesterol and / or sterol derivatives mentioned are one or more of cholesterol, phytosterol macadamia oleate, phytosterol oleate, and phytosterol / octyldodecyl lauroyl glutamate. The lipophilic surfactant is a polyglycerol fatty acid ester, and the HLB value of the polyglycerol fatty acid ester is ≤5; The polyglycerol fatty acid esters include one or more of polyglycerol-6 polyricinoleate, glycerol stearate, polyglycerol-2 isostearate, and polyglycerol-4 diisostearate / polyhydroxystearate / sepiacetate; The weight ratio of the lipophilic surfactant to cholesterol and / or sterol derivatives is 1:(0.5-2); The hydrophilic surfactant is composed of methylstearoyl taurate and Tween 80; The oil phase is one or more of squalane, hydrogenated polyisobutylene, cetyl ethylhexanoate, polydimethylsiloxane, isopropyl myristate, ethylhexyl palmitate, and isononyl isononanoate; the polarity index (IOB) of the oil phase is ≤0.

2.

2. The W / O / W composition as claimed in claim 1, characterized in that, The polyol is one or more of glycerol, butylene glycol, propylene glycol, dipropylene glycol, sorbitol, and polyethylene glycol-32.

3. The W / O / W composition as described in claim 2, characterized in that, The thickener is one or more of NaCl, MgSO4, xanthan gum, hydroxyethyl cellulose and its derivatives, gum arabic, acrylate / C10-30 alkanol acrylate crosspolymer, and polyacrylate crosspolymer-6.

4. The W / O / W composition as described in claim 3, characterized in that, It also includes a preservative, which is present in the W / O / W composition at a weight percentage of 0.1-1%; the preservative includes one or more of methylparaben, phenoxyethanol, and ethylhexylglycerin.

5. The method for preparing the W / O / W composition according to any one of claims 1-4, characterized in that, Includes the following steps: 1) Weigh out the lipophilic surfactant, hydrophilic surfactant, oil phase, cholesterol and / or sterol derivatives, polyol, thickener and water according to the weight percentage of each component; wherein, the polyol includes a first part polyol and a second part polyol, the water includes a first part water and a second part water, and the thickener includes W / O thickener and double emulsion thickener. 2) Mix the lipophilic surfactant, cholesterol and / or sterol derivatives evenly at 85-90℃ and keep warm for 10-15 minutes, then cool down to 35-40℃ and set aside for use. 3) Add the oil phase to the component obtained in step 2) and mix well, then set aside for later use; 4) Mix the W / O thickener, the first polyol and the first water evenly to obtain the inner aqueous phase. Add the inner aqueous phase to the components obtained in step 3) at a stirring speed of 350 rpm under the condition of below 40°C and mix evenly. Then, homogenize at a stirring speed of 6000 rpm for 1-2 minutes to form a W / O emulsion for later use. 5) Mix the hydrophilic surfactant, the second part of polyol, the re-emulsion thickener, and the second part of water at 60-80℃ to obtain the external aqueous phase, and set aside for later use; 6) Add the W / O emulsion obtained in step 4) to the external aqueous phase obtained in step 5) at a stirring speed of 200 rpm, disperse and mix evenly, and then homogenize at a stirring speed of 3000 rpm for 2-3 minutes to obtain the W / O / W composition.

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