A kind of whitening and freckle-removing essence and its preparation method

Abstract

The present invention relates to the technical field of cosmetics, and discloses a whitening and freckle-removing essence and a preparation method thereof. The whitening and freckle-removing essence is formed by mixing additives such as nicotinamide, EDTA, L-lactic acid, citric acid, baicalein inclusion complex, etc. The baicalein inclusion complex has a coated structure. Since the skin surface carries a negative charge and the coating layer of the baicalein inclusion complex contains chitosan, it can be adsorbed on the skin surface through electrostatic action, producing a sustained-release effect, and then targeted release, so as to improve the whitening effect of the essence. In addition, after being encapsulated, baicalein can have good compatibility with other substances in the formula. Moreover, the linolenic fatty acid chain in the structure of the chitosan derivative has excellent antioxidant, anti-inflammatory and other effects, which can reduce the phenomenon of scar formation on the skin due to inflammation.

Description

Technical Field

[0001] The present invention relates to the technical field of cosmetics, and particularly relates to a whitening and freckle-removing essence and a preparation method thereof. Background Art

[0002] In the pursuit of beauty and confidence, the purity and flawlessness of the skin have always been the aspiration of many beauty lovers. In recent years, although the living standards have been continuously improved, the living environment of humans has gradually deteriorated, which easily causes skin problems such as allergies and erythema. Moreover, modern people have poor work and rest regularity and poor mental state, which will also cause endocrine disorders, resulting in skin redness and directly causing dull skin color and other phenomena. These skin problems have a great impact on emotions, and poor emotions will further deteriorate the mental state, thus forming a vicious cycle. Therefore, cosmetic products with whitening and freckle-removing effects have gradually emerged. As the leader among such products, essence has become the secret weapon for many people to improve skin color, fade spots, and enhance the overall brightness of the skin with its high efficiency and precision.

[0003] Melanin is the main factor determining skin color, and tyrosinase is considered the decisive rate-limiting enzyme in melanocyte synthesis and pigmentation. Therefore, inhibiting the activity of tyrosinase plays an important role in skin whitening. Currently, the whitening products on the market are basically formulated in this way.

[0004] At present, many substances that can inhibit the activity of tyrosinase have been discovered. Among them, flavonoids can inhibit the activity of tyrosinase by changing its conformation, so they are widely used in cosmetics. Baicalein is a very representative flavonoid with excellent melanin inhibition effect, and it also has anti-inflammatory and antibacterial effects, etc. It can be used as a whitening additive in cosmetics. However, it is easily oxidized and has poor water solubility, making it difficult to effectively match with the gas components in the essence, resulting in difficulty in effectively exerting its effects. Therefore, there are still deficiencies in its practical application. Summary of the Invention

[0005] In order to solve the problems mentioned in the background art, the purpose of the present invention is to provide a whitening and freckle-removing essence and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A preparation method of a whitening and freckle-removing essence. The essence comprises the following raw materials in parts by mass: 0.5 - 1 part of niacinamide, 0.1 - 0.3 part of EDTA, 0.2 - 0.4 part of L-lactic acid, 0.2 - 0.4 part of citric acid, 0.5 - 1.5 parts of 3-o-ethyl ascorbic acid, 1 - 2 parts of baicalin inclusion complex, 4 - 8 parts of glycerol, 0.3 - 0.5 part of xanthan gum, 0.1 - 0.4 part of Pulsatilla chinensis extract, and 30 - 45 parts of water;

[0008] The preparation method comprises the following steps:

[0009] Step S1: Weigh each raw material according to the parts by mass and set aside;

[0010] Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerol to water, control the temperature at 60 - 70°C, stir and mix evenly to obtain a precursor solution;

[0011] Step S3: Lower the temperature to 40 - 50°C. Under continuous stirring, add the baicalin inclusion complex and Pulsatilla chinensis extract to the precursor solution. After adding, continue to stir and mix evenly. Then add xanthan gum and mix at a rotation speed of 200 - 300 r / min for 20 - 30 min. Cool down and discharge to obtain the whitening and freckle-removing essence.

[0012] As a further scheme of the present invention, the preparation method of the baicalin inclusion complex comprises the following steps:

[0013] The first step: Mix liquid oil and baicalin, stir evenly, control the temperature at 45 - 55°C, mechanically stir for 3 - 5 min, then cool to room temperature and continue to stir and mix for 20 - 40 min. Then add an emulsifier to the formed mixture. After adding, shear and emulsify at a rotation speed of 2000 - 3000 r / min for 5 - 10 min to form an emulsified suspension;

[0014] The second step: Mix chitosan derivative with an ethanol aqueous solution with a volume fraction of 60 - 70%, stir until a uniform mixture is formed, then pour it into pure water according to a volume ratio of 1:4 - 5 to prepare a liquid-phase material. Then, add the emulsified suspension to the liquid-phase material. After adding, let it stand for 20 - 30 min, finally mechanically stir for 10 - 20 min, and then perform freeze-drying treatment to obtain the baicalin inclusion complex.

[0015] Specifically, in the above technical solution, first, baicalein is dissolved using a liquid oil, and then an emulsifier is added and high-speed stirring is carried out for emulsification to form nanoscale baicalein oil droplets, that is, an emulsified oil droplet suspension. In the second step, due to the long fatty chains in the structure of the chitosan derivative, its solubility in aqueous solution is poor. Therefore, an ethanol aqueous solution is used as a dispersant to disperse the chitosan derivative to form a mixed solution. Then, by quickly pouring the mixed solution into water with a high multiple volume, the water content in the system increases sharply at this time, and the solvent changes from a benign state to a poor state, causing the hydrophobic fatty chains in the molecular chain of the chitosan derivative to spontaneously contract inward and the hydrophilic chain segments such as hydroxyl groups to expand outward. Therefore, a cavity structure with hydrophilic outside and hydrophobic inside can be spontaneously formed to obtain a liquid-phase material. At this time, the emulsified suspension is added to the liquid-phase material, and the lipophilic emulsified droplets will spontaneously enter the cavity structure and be wrapped inside the cavity. Through freeze-drying treatment, a chitosan-coated baicalein powder, that is, baicalein-embedded powder, can be formed.

[0016] As a further aspect of the present invention, the liquid oil is octyldodecanol or glyceryl trioctanoate.

[0017] As a further aspect of the present invention, the mass ratio of the liquid oil to baicalein is 1:0.1 - 0.15.

[0018] As a further aspect of the present invention, the emulsifier is glyceryl stearate or cetearyl alcohol.

[0019] As a further aspect of the present invention, the preparation method of the chitosan derivative is as follows:

[0020] Chitosan is mixed with an acetic acid solution with a volume fraction of 1 - 3%, stirred until completely dissolved, sodium linoleate is added, and dicyclohexylcarbodiimide and 4-dimethylaminopyridine are added under stirring conditions. After adding, keep stirring for 2 - 3 h, discharge, and after purification treatment, the chitosan derivative can be obtained.

[0021] Specifically, using sodium linoleate as a modifier and dicyclohexylcarbodiimide and 4-dimethylaminopyridine as promoters to modify chitosan, thereby introducing long hydrophobic fatty chains into the structure of chitosan to obtain the chitosan derivative.

[0022] As a further aspect of the present invention, the mass ratio of chitosan to sodium linoleate is 1:0.1 - 0.2.

[0023] As a further aspect of the present invention, the mass fraction of the mixed solution is 5 - 15%.

[0024] As a further aspect of the present invention, the volume ratio of the emulsified suspension to the liquid-phase material is 1:8 - 12.

[0025] A whitening and freckle-removing essence is prepared by the above-mentioned preparation method.

[0026] Advantages of the present invention:

[0027] (1) By adding L-lactic acid to the formula as an exfoliant, the present invention can not only remove melanin particles on the skin surface and reduce scars by removing skin impurities, but also improve the skin's absorption capacity, making it easier for active substances to penetrate into the interior through the skin, resulting in good nursing effects. The baicalein inclusion complex in the formula has a coated structure. Since the skin surface carries a negative charge and the coating layer of the baicalein inclusion complex contains chitosan, it can be adsorbed on the skin surface through electrostatic interaction. Along with the evaporation of the moisture in the essence, the emulsified oil droplets of the encapsulated baicalein will be gradually released under the pressure difference. Due to the natural hydrophobic and lipophilic properties of cell membranes, along with the improvement of the skin's absorption capacity, the emulsified oil droplets of baicalein can penetrate the stratum corneum well and gradually enter the interior of the skin, releasing baicalein inside the skin. Through this sustained-release effect, not only can the oxidation of baicalein be avoided, but also the utilization rate and absorption rate of baicalein can be increased, achieving the effect of targeted release, thereby effectively inhibiting the activity of tyrosinase, reducing the generation of melanin, and further playing the role of fading freckles and enhancing the whitening effect of the essence.

[0028] (2) Through a special preparation process, the hydrophilic groups of the chitosan derivative in the coating layer of the baicalein inclusion complex are arranged outward in the present invention. Therefore, the baicalein inclusion complex has good hydrophilicity, which can improve the compatibility of baicalein with other substances in the formula. Moreover, the linseed fatty acid chain in the chitosan derivative structure has excellent antioxidant, anti-inflammatory and other effects, which can reduce the phenomenon of scar formation on the skin due to inflammation.

[0029] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. Detailed implementation manners

[0030] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0031] Example 1

[0032] A whitening and freckle-removing essence, comprising the following raw materials in parts by mass: 0.5 part of niacinamide, 0.1 part of EDTA, 0.2 part of L-lactic acid, 0.2 part of citric acid, 0.5 part of 3-o-ethyl ascorbic acid, 1 part of baicalein inclusion complex, 4 parts of glycerol, 0.3 part of xanthan gum, 0.1 part of Pulsatilla chinensis extract, 30 parts of water;

[0033] The preparation method of the whitening and freckle-removing essence includes the following steps:

[0034] Step S1: Weigh each raw material according to the mass fraction and set aside.

[0035] Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerol into water, control the temperature at 65 °C, stir and mix evenly to obtain a precursor solution.

[0036] Step S3: Lower the temperature to 45 °C. Under continuous stirring, add baicalein inclusion complex and Pulsatilla chinensis extract to the precursor solution. After adding, continue to stir and mix evenly, then add xanthan gum, and mix at a rotation speed of 200 r / min for 30 min. Cool down and discharge to obtain the whitening and freckle-removing essence.

[0037] Example 2

[0038] A whitening and freckle-removing essence, comprising the following raw materials in mass fractions: 0.6 part of niacinamide, 0.2 part of EDTA, 0.3 part of L-lactic acid, 0.3 part of citric acid, 1 part of 3-o-ethyl ascorbic acid, 1.8 parts of baicalein inclusion complex, 6 parts of glycerol, 0.4 part of xanthan gum, 0.2 part of Pulsatilla chinensis extract, 35 parts of water;

[0039] The preparation method of the whitening and freckle-removing essence includes the following steps:

[0040] Step S1: Weigh each raw material according to the mass fraction and set aside.

[0041] Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerol into water, control the temperature at 65 °C, stir and mix evenly to obtain a precursor solution.

[0042] Step S3: Lower the temperature to 45 °C. Under continuous stirring, add baicalein inclusion complex and Pulsatilla chinensis extract to the precursor solution. After adding, continue to stir and mix evenly, then add xanthan gum, and mix at a rotation speed of 300 r / min for 25 min. Cool down and discharge to obtain the whitening and freckle-removing essence.

[0043] Example 3

[0044] A whitening and freckle-removing essence, comprising the following raw materials in mass fractions: 1 part of niacinamide, 0.3 part of EDTA, 0.4 part of L-lactic acid, 0.4 part of citric acid, 1.5 parts of 3-o-ethyl ascorbic acid, 2 parts of baicalein inclusion complex, 8 parts of glycerol, 0.5 part of xanthan gum, 0.4 part of Pulsatilla chinensis extract, 45 parts of water;

[0045] The preparation method of the whitening and freckle-removing essence includes the following steps:

[0046] Step S1: Weigh each raw material according to the mass parts and set aside.

[0047] Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerol into water, control the temperature at 65°C, stir and mix evenly to obtain a precursor solution.

[0048] Step S3: Lower the temperature to 45°C. Under continuous stirring, add baicalein inclusion complex and pulsatilla chinensis extract to the precursor solution. After adding, continue to stir and mix evenly. Then add xanthan gum and mix at a rotation speed of 300 r / min for 20 min. Cool down and discharge to obtain the whitening and freckle-removing essence.

[0049] The baicalein inclusion complex in the above examples is prepared by the following method:

[0050] The preparation method of the baicalein inclusion complex includes the following steps:

[0051] The first step: Mix 1.2 g of chitosan with 100 mL of acetic acid solution with a volume fraction of 2%. After stirring until completely dissolved, add 0.15 g of sodium linoleate, and add 0.03 g of dicyclohexylcarbodiimide and 0.01 g of 4-dimethylaminopyridine under stirring. After adding, keep stirring at a constant temperature for 3 h, discharge, dialyze for 3 days, then freeze and solidify in an environment at -10°C, and finally dry completely in a freeze dryer at -50°C to obtain a chitosan derivative with a yield of 85.1%.

[0052] Use acid-base titration to test the amino group content of chitosan and chitosan derivative. The specific operation method is as follows, taking chitosan derivative as an example:

[0053] Take 0.3 g of chitosan derivative sample, stir and mix it with 50 mL of 0.1 mol / L HCl standard solution to form a mixed solution. After standing at 40°C for 2 h, take 10 mL and transfer it to another container. Then add 10 mL of deionized water and one drop of phenolphthalein indicator, shake well, and titrate with 0.1 mol / L sodium hydroxide standard solution until the color changes. Stop titration and record the consumption of sodium hydroxide standard solution T (mL). Calculate the amino group content of the sample using the formula (50×0.1 - 4×0.1×T) / 0.3. The result is 3.819 mmol / g. Conduct the same experiment with chitosan with the same parameters, and the result shows that the amino group content is 12.531 mmol / g. It can be reasonably speculated that the amino group of chitosan undergoes condensation with sodium linoleate during this process, resulting in consumption.

[0054] Step 2: Mix 1.5 g of octyldodecanol with 0.2 g of baicalein. After stirring evenly, control the temperature at 50 °C and stir mechanically for 5 min. Then cool to room temperature and continue stirring and mixing for 30 min. Then add 0.02 g of glyceryl stearate to the formed mixture. After adding, shear and emulsify at a rotation speed of 2500 r / min for 10 min to form an emulsified suspension;

[0055] Step 3: Mix the chitosan derivative with an ethanol aqueous solution with a volume fraction of 70% and stir until a homogeneous mixture with a mass fraction of 12% is formed. Then pour 50 mL of the mixture into 240 mL of pure water to prepare a liquid-phase material. Next, add 30 mL of the emulsified suspension to the formed liquid-phase material. After adding, let it stand for 30 min. Finally, stir mechanically for 15 min and then perform freeze-drying treatment to obtain the baicalein inclusion;

[0056] Comparative Example 1

[0057] A whitening and freckle-removing essence contains the following raw materials in parts by mass: 0.6 part of niacinamide, 0.2 part of EDTA, 0.3 part of L-lactic acid, 0.3 part of citric acid, 1 part of 3-o-ethyl ascorbic acid, 1.8 parts of baicalein, 6 parts of glycerol, 0.4 part of xanthan gum, 0.2 part of Pulsatilla chinensis extract, and 35 parts of water;

[0058] The preparation method of the whitening and freckle-removing essence includes the following steps:

[0059] Step S1: Weigh each raw material according to the parts by mass and set aside;

[0060] Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerol to water, control the temperature at 65 °C, stir and mix evenly to obtain a precursor solution;

[0061] Step S3: Lower the temperature to 45 °C. Under continuous stirring, add baicalein and Pulsatilla chinensis extract to the precursor solution. After adding, continue stirring and mixing evenly. Then add xanthan gum and mix at a rotation speed of 300 r / min for 25 min. Cool down and discharge to obtain the whitening and freckle-removing essence.

[0062] Comparative Example 2

[0063] A whitening and freckle-removing essence contains the following raw materials in parts by mass: 0.6 part of niacinamide, 0.2 part of EDTA, 0.3 part of L-lactic acid, 0.3 part of citric acid, 1 part of 3-o-ethyl ascorbic acid, 6 parts of glycerol, 0.4 part of xanthan gum, 0.2 part of Pulsatilla chinensis extract, and 35 parts of water;

[0064] The preparation method of the whitening and freckle-removing essence includes the following steps:

[0065] Step S1: Weigh each raw material according to the mass parts and set aside for later use;

[0066] Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerin to water, control the temperature at 65 °C, stir and mix evenly to obtain a precursor solution;

[0067] Step S3: Lower the temperature to 45 °C. Under continuous stirring, add the Pulsatilla chinensis extract to the precursor solution. After adding, continue to stir and mix evenly. Then add xanthan gum and mix at a rotation speed of 300 r / min for 25 min. Cool down and discharge to obtain the whitening and freckle-removing essence.

[0068] Test Example

[0069] a. Conduct a skin irritation experiment on the essence in Examples 1 - 3 and Comparative Examples 1 - 2. The specific operation of the experiment is as follows: Take 50 healthy female New Zealand rabbits with a body weight of about 2 ± 0.2 kg, divide them into 5 groups evenly, with 10 rabbits in each group on average, and name them Example 1 group, Example 2 group, Example 3 group, Comparative Example 1 group, and Comparative Example 2 group respectively. Scrape the back hair on both sides of the spine of the New Zealand rabbits to form an area of 4 cm × 4 cm without damaging the epidermis. Apply the corresponding group's essence to the shaved area of the back hair of each group of New Zealand rabbits. The application amount is 0.5 mL. After application, cover with a gauze and fix it. Remove the gauze after 1 h, wash it, and conduct the experiment continuously for 3 days with the same experimental steps, 3 times in the morning, noon, and evening each day. After the last experiment, observe whether the tested New Zealand rabbits in each group show symptoms such as swelling, erythema, erosion, eschar, etc. If corresponding symptoms appear, record the number. The test results are shown in Table 1:

[0070] Table 1 - Results of the irritation experiment

[0071]

[0072]

[0073] b. Select B16F10 murine melanoma cells, which are basically the same as the normal melanin synthesis function of the human body, to test the whitening effect of the essence. Inoculate them in a fetal bovine serum medium with a volume fraction of 10%, and culture them at 37°C. Digest and passage them every other day with trypsin with a mass fraction of 0.25%. Take the second-generation melanoma cells, place them in a 12-well plate at an inoculation density of 100 cells / mL, incubate overnight, and perform a medium change operation. Then, add 2 mL of the essence in each example and comparative example to the well plate respectively. At the same time, set a control group without any treatment. After adding, continue to culture in an environment of 37°C for 3 days. Skim off the supernatant, wash with 1 mL of PBS buffer, then add 100 μL of trypsin, digest for 10 min, add PBS buffer to stop digestion, remove the supernatant, then add Triton X-100 with a mass fraction of 0.1% to each well, shake well, store in an environment of -20°C for 20 min, then place at a temperature of 5°C for 30 min, remove the supernatant again, and finally add a sodium hydroxide dimethyl sulfoxide solution with a mass fraction of 1%, incubate at 80°C for 3 h. Place the supernatant in a 96-well plate, and use an enzyme-linked immunosorbent assay (ELISA) reader to read the absorbance value at a wavelength of 490 nm. By comparing with the control group, calculate the melanin reduction rate, and record the results in Table 2:

[0074] Group Melanin reduction rate / % Example 1 group 86.91 Example 2 group 87.10 Example 3 group 87.03 Comparative Example 1 group 67.15 Example 2 group 38.86

[0075] From the test results shown in Table 1, the essences in the examples and comparative examples of the present invention have no obvious irritation, and can effectively avoid the problems caused by skin irritation and inflammation.

[0076] In addition, it can be analyzed from the test data in Table 2 that the essence prepared with baicalein inclusion complex as the raw material has significantly better whitening effect, and the melanin reduction rate is above 85%. However, for the essence directly prepared with baicalein as the raw material, due to poor compatibility and low percutaneous penetration rate, the effect is significantly worse. However, compared with the essence without baicalein, it still has an objective whitening effect.

[0077] In this article, specific examples are used to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The protection scope of the present invention patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements approximately the same as the literal expression of the claims, or if they include equivalent structural elements that have no substantial difference from the literal expression of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A preparation method of a whitening and freckle-removing essence, characterized in that The essence contains the following raw materials in parts by mass: 0.5 - 1 part of niacinamide, 0.1 - 0.3 part of EDTA, 0.2 - 0.4 part of L-lactic acid, 0.2 - 0.4 part of citric acid, 0.5 - 1.5 parts of 3-o-ethyl ascorbic acid, 1 - 2 parts of baicalin inclusion complex, 4 - 8 parts of glycerol, 0.3 - 0.5 part of xanthan gum, 0.1 - 0.4 part of pulsatilla chinensis extract, and 30 - 45 parts of water; The preparation method includes the following steps: Step S1: Weigh each raw material according to the parts by mass and set aside; Step S2: First, add niacinamide, EDTA, L-lactic acid, citric acid, 3-o-ethyl ascorbic acid, and glycerol to water, control the temperature at 60 - 70 °C, stir and mix evenly to obtain a precursor solution; Step S3: Lower the temperature to 40 - 50 °C. Under continuous stirring, add the baicalin inclusion complex and pulsatilla chinensis extract to the precursor solution. After adding, continue to stir and mix evenly. Then add xanthan gum and mix at a rotation speed of 200 - 300 r / min for 20 - 30 min. Cool down and discharge to obtain the whitening and freckle-removing essence; The preparation method of the baicalin inclusion complex includes the following steps: The first step: Mix the liquid oil and baicalin, stir evenly, control the temperature at 45 - 55 °C, mechanically stir for 3 - 5 min, then cool to room temperature and continue to stir and mix for 20 - 40 min. Then add an emulsifier to the formed mixture. After adding, shear and emulsify at a rotation speed of 2000 - 3000 r / min for 5 - 10 min to form an emulsified suspension; The second step: Mix the chitosan derivative with an ethanol aqueous solution with a volume fraction of 60 - 70%, stir until a uniform mixture is formed, and then pour it into pure water according to a volume ratio of 1:4 - 5 to prepare a liquid-phase material. Then, add the emulsified suspension to the liquid-phase material. After adding, let it stand for 20 - 30 min, finally mechanically stir for 10 - 20 min, and then perform freeze-drying treatment to obtain the baicalin inclusion complex; The preparation method of the chitosan derivative is as follows: Mix chitosan with an acetic acid solution with a volume fraction of 1 - 3%, stir until completely dissolved, add sodium linolenate, and add dicyclohexylcarbodiimide and 4-dimethylaminopyridine under stirring conditions. After adding, keep stirring for 2 - 3 h, discharge, and perform purification treatment to obtain the chitosan derivative.

2. The preparation method of a whitening and freckle-removing essence according to claim 1, characterized in that, In the first step, the liquid oil is octyldodecanol or glyceryl trioctanoate.

3. The preparation method of a whitening and freckle-removing essence according to claim 1, characterized in that, In the first step, the mass ratio of the liquid oil to baicalin is 1:0.1 - 0.

15.

4. The preparation method of a whitening and freckle-removing essence according to claim 1, wherein, In the first step, the emulsifier is glyceryl stearate or cetearyl alcohol.

5. The preparation method of a whitening and freckle-removing essence according to claim 1, characterized in that, The mass ratio of chitosan to sodium linolenate is 1:0.1 - 0.

2.

6. The preparation method of a whitening and freckle-removing essence according to claim 1, characterized in that, In the second step, the mass fraction of the mixture is 5 - 15%.

7. The preparation method of a whitening and freckle-removing essence according to claim 1, characterized in that, In the second step, the volume ratio of the emulsified suspension to the liquid-phase material is 1:8 - 12.

8. A whitening and freckle-removing essence, characterized in that, Prepared by the preparation method as described in claim 1.

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