A lactic acid low-irritation composition and a method for preparing the same

Abstract

The present application provides a low-irritation composition containing lactic acid, which contains a supramolecular complex formed by lactic acid and a beta-glucan solution; and a preparation method of the low-irritation composition containing lactic acid, which comprises: mixing a beta-glucan solution with lactic acid, stirring to obtain a mixture, and then reacting the mixture at a temperature of 110-121 DEG C and a relative pressure of 0.04-0.1 MPa to obtain a composition containing a supramolecular complex formed by lactic acid and the beta-glucan solution. In the present application, lactic acid and the beta-glucan solution are reacted at a certain temperature and pressure to form a supramolecular complex, which not only reduces the stinging reaction of free lactic acid on the skin, but also enhances the stability of beta-glucan in the composition, solving the problem of poor stability of beta-glucan solution as a moisturizing raw material. Therefore, the composition containing the supramolecular complex can be used as a skin care product moisturizing raw material and applied to various dosage forms of skin care products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of skin care products, and particularly relates to a low-irritation composition containing lactic acid and a preparation method thereof. BACKGROUND

[0002] Lactic acid is a component of skin natural moisturizing factor NMF, is an alpha-hydroxy acid, is a skin care product functional material, has the effects of moisturizing and renewing keratin, and is widely used in skin care products. However, lactic acid, due to its molecular properties, when acting on sensitive skin, can cause a stinging sensation on sensitive skin.

[0003] As a skin care product functional material, beta-glucan has excellent moisturizing and repairing effects, and is widely used in the skin care industry. The properties of beta-glucan mainly depend on the following aspects: 1) composition of beta-glucan (type and proportion of beta-glucan linkage); 2) three-dimensional structure of beta-glucan molecules; 3) hydrophilic groups on the outside of the polyglucose structure. Due to its own molecular properties, beta-glucan solution has the properties of a colloidal solution and is very unstable, and is easy to precipitate flocculation. When added to water-based products, due to the stability problem, flocculation and precipitation are also easy to occur, affecting the appearance and use of the product. Moreover, the beta-glucan material used in the skin care industry is usually in the form of a beta-glucan solution. Due to its unstable nature, its use is limited to some extent.

[0004] Therefore, in the development of moisturizing and keratin regulating products, how to maximize the effects of lactic acid and beta-glucan, reduce the adverse irritation of lactic acid, and solve the stability problem of beta-glucan is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0005] The present application provides a low-irritation composition containing lactic acid, which contains a supramolecular complex formed by lactic acid and a beta-glucan solution. The formation of the supramolecular complex can make the composition have excellent stability and reduce the stinging reaction of lactic acid on the skin.

[0006] Another object of the present application is to provide a preparation method of a low-irritation composition containing lactic acid.

[0007] To achieve the above object, the present application provides a low-irritation composition containing lactic acid, which contains a supramolecular complex formed by lactic acid and a beta-glucan solution.

[0008] Preferably, the mass ratio of the beta-glucan solution to lactic acid is 45-55:45-55.

[0009] Preferably, the content of beta-glucan in the beta-glucan solution is 0.01-2%.

[0010] Preferably, the composition of the present application further comprises carbomer, low carbon alcohol, polyethylene glycol and water, the mass percentage of each component in the composition is 0.01%-3% of carbomer, 0.1%-10% of low carbon alcohol, 0.01%-10% of polyethylene glycol, 0.001%-90% of the supramolecular complex formed by the β-glucan solution and lactic acid, and the balance is water.

[0011] Preferably, the low carbon alcohol is any one or more than one of glycerol, 1,3 butanediol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,2 hexanediol, and pentanediol.

[0012] Preferably, the composition further comprises an auxiliary agent, the mass percentage of the auxiliary agent in the composition is 0.1%-5%, and the auxiliary agent comprises any one or more than one of bis-PEG-18 methyl ether dimethyl silane, sodium polyacryloyl dimethyl taurate, xanthan gum, hydroxyethyl cellulose, polyacrylate crosspolymer-6, ammonium polyacryloyl dimethyl taurate, polyacrylamide, and SEPIGEL 305 emulsifier.

[0013] To achieve the above-mentioned purpose, the present application further provides a preparation method of the above-mentioned composition. The low-irritation composition containing lactic acid is prepared by the following method: mixing the β-glucan solution with lactic acid, stirring uniformly to obtain a mixture, and then reacting the mixture at a temperature of 110°C-121°C and a relative pressure of 0.04-0.1 Mpa, to obtain the composition containing the supramolecular complex formed by lactic acid and the β-glucan solution.

[0014] The preparation method of the present application further comprises the step of adding carbomer, low carbon alcohol, polyethylene glycol and water to the composition containing the supramolecular complex formed by lactic acid and the β-glucan solution.

[0015] The preparation method of the present application further comprises the step of adding an auxiliary agent to the composition containing the supramolecular complex formed by lactic acid and the β-glucan solution, and the auxiliary agent comprises any one or more than one of bis-PEG-18 methyl ether dimethyl silane, sodium polyacryloyl dimethyl taurate, xanthan gum, hydroxyethyl cellulose, polyacrylate crosspolymer-6, ammonium polyacryloyl dimethyl taurate, polyacrylamide, and SEPIGEL 305 emulsifier.

[0016] The preparation method of the present application further comprises the step of heating the auxiliary agent to 70-80°C to be miscible before adding the auxiliary agent, and then cooling to 20-35°C before adding.

[0017] The auxiliary agent can be added at room temperature or can be heated to be miscible before adding. The latter adding method can accelerate the preparation process of the composition.

[0018] The present application has the following advantages:

[0019] In the present application, lactic acid and β-glucan solution are reacted at a certain temperature and pressure to form a supramolecular complex. This not only reduces the stinging reaction of free lactic acid on the skin, but also enhances the stability of β-glucan in the composition, solving the problem of poor stability of β-glucan solution as a moisturizing raw material. Therefore, the composition containing the supramolecular complex can be used as a raw material for skin care, skin renewal, and repair in various dosage forms of skin care products. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a surface electrostatic potential contour plot of the lactic acid molecule and the β-glucan molecule.

[0021] Figure 2 is a surface electrostatic potential intermolecular penetration plot of the lactic acid molecule and the β-glucan molecule. DETAILED DESCRIPTION

[0022] The present application will be described in detail below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above content of the present application.

[0023] The present inventors studied the weak interaction between lactic acid and β-glucan through density functional theory (DFT). Specifically, the weak interaction between the two molecules was analyzed by an independent gradient model based on Hirshfeld partition (IGMH), and it was found that the main weak interaction was hydrogen bonding and van der Waals interaction. The three hydrogen bonds from top to bottom have bond lengths of: These bond lengths are all within the range of O-H…O hydrogen bond length.

[0024] Figure 1 is a surface electrostatic potential contour plot of the lactic acid molecule and the β-glucan molecule. Figure 2 is a surface electrostatic potential intermolecular penetration plot of the lactic acid molecule and the β-glucan molecule. Through analysis of Figure 1 and Figure 2 , it was found that in the region where hydrogen bonds are formed, the van der Waals surface penetration is very obvious, with red and blue interpenetration, reflecting the complementary characteristics of electrostatic potential, and also reflecting the nature of electrostatic attraction interaction of hydrogen bonds.

[0025] By the above density functional theory calculation, the following conclusions can be drawn: there is an intermolecular force between the lactic acid molecules and the β-glucan molecules, and the intermolecular force is formed by hydrogen bond interaction, and the interaction size is-25.73 kcal / mol. It is found that in the region forming the hydrogen bond, the van der Waals surface penetration is obvious, which can reflect that the lactic acid molecules are firmly adsorbed by the electrostatic interaction, that is, the lactic acid molecules and the β-glucan molecules form a supramolecular complex structure.

[0026] EMBODIMENT

[0027] Raw materials:

[0028] β-glucan solution: the content of β-glucan is 0.01%, 0.5%, 1%, and 2% (mass fraction), respectively, and the β-glucan is dissolved in water to obtain a solution.

[0029] Maltodextrin solution: the addition amount of maltodextrin is 1% (mass fraction), and the maltodextrin is dissolved in water to obtain a solution.

[0030] EMBODIMENT 1

[0031] β-glucan solution (content of 1%) 55 g, lactic acid 45 g, stirring for 5 min, mixing uniformly, placing in a steam pressure pot, heating to 110℃, pressurizing to about 0.04 Mpa (relative pressure), keeping warm and pressurizing for 10 min, then cooling and taking out, to obtain a solution 1 containing supramolecular complex.

[0032] EMBODIMENT 2

[0033] β-glucan solution (content of 1%) 45 g, lactic acid 55 g, stirring for 10 min, mixing uniformly, placing in a steam pressure pot, heating to 121℃, pressurizing to about 0.10 Mpa (relative pressure), keeping warm and pressurizing for 20 min, then cooling and taking out, to obtain a solution 2 containing supramolecular complex.

[0034] COMPARATIVE EXAMPLE 1

[0035] β-glucan solution (content of 1%) 55 g, lactic acid 45 g, stirring for 5 min at room temperature, mixing uniformly, heating to 100℃ and boiling, boiling under normal pressure for 10 min, then cooling and taking out, to obtain a composition D1.

[0036] COMPARATIVE EXAMPLE 2

[0037] Maltodextrin solution 55 g, lactic acid 45 g, stirring for 5 min at room temperature, mixing uniformly, placing in a steam pressure pot, heating to 110℃, pressurizing to about 0.06 Mpa (relative pressure), keeping warm and pressurizing for 10 min, then cooling and taking out, to obtain a composition D2.

[0038] COMPARATIVE EXAMPLE 3

[0039] The β-glucan solution (1% content) 55 g, glycolic acid 45 g, stirred at room temperature for 5 min, mixed uniformly, placed in a steam pressure cooker, heated to 110°C, pressurized to about 0.06 Mpa (relative pressure), kept warm and pressurized for 10 min, then cooled and removed, to obtain composition D3.

[0040] Examples 3-6

[0041] The solution 1 containing supramolecular complex prepared in Example 1, polyethylene glycol, glycerol, carbomer and water were mixed to obtain a composition, the amounts of the components are shown in Table 6.

[0042] Table 1 Amounts of raw materials for compositions in Examples 3-6 (parts by weight)

[0043]

[0044] Comparative Examples 4-6

[0045] The composition D1, composition D2 or composition D3 prepared in Comparative Examples 1-3, polyethylene glycol, glycerol, carbomer and water were mixed to obtain a composition, the amounts of the components are shown in Table 7.

[0046] Table 2 Amounts of raw materials for compositions in Comparative Examples 4-6 (parts by weight)

[0047] Composition D1 Composition D2 Composition D3 Polyethylene glycol Glycerol Carbomer Water Comparative Example 4 50 0 0 1 10 1 38 Comparative Example 5 0 50 0 1 10 1 38 Comparative Example 6 0 0 50 1 10 1 38

[0048] Example 7

[0049] A low-irritation composition containing lactic acid, comprising the following components: solution containing supramolecular complex 150 parts, polyethylene glycol 1 part, glycerol 10 parts, carbomer 1 part, polyacryloyldimethyltaurine sodium 0.5 part, xanthan gum 0.5 part, hydroxyethyl cellulose 0.3 part, polyacrylate cross-linked polymer-6 1 part, polyacryloyldimethylammonium taurate 2 parts, water 33.7 parts.

[0050] Example 8

[0051] A low-irritation composition containing lactic acid, comprising the following components: solution containing supramolecular complex 150 parts, polyethylene glycol 1 part, glycerol 10 parts, carbomer 1 part, methyl ether dimethyl silane 0.1 part, SEPIGEL 30 0.1 part, xanthan gum 0.2 part, hydroxyethyl cellulose 0.1 part, polyacrylate cross-linked polymer-6 0.1 part, polyacryloyldimethylammonium taurate 0.2 part, water 37.2 parts.

[0052] Example 9

[0053] A low-irritant composition containing lactic acid, comprising the following components: solution containing supramolecular complex 150 parts, polyethylene glycol 1 part, glycerin 10 parts, carbomer 1 part, SEPIGEL 305 50.5 parts, xanthan gum 0.2 parts, polyacryloyldimethylammonium taurate 0.1 part, water 37.2 parts. SEPIGEL 305 emulsifier is available from SEPPIC (France) Co., Ltd.

[0054] Test Example

[0055] The products prepared in the above examples and comparative examples were subjected to performance tests.

[0056] 1. Viscosity measurement

[0057] The products obtained in the above examples and comparative examples were subjected to viscosity tests. The viscosity of all samples in Table 3 below was tested using an NDJ-8 digital viscometer, and the possibility of forming supramolecular complexes according to the technical solutions of the present application was evaluated by comparing the viscosity values.

[0058] Viscosity test results of each sample in Table 3

[0059] Sample Viscosity (mP-s) Example 1 12.50 Example 2 11.72 Comparative Example 1 9.48 Comparative Example 2 10.25 Comparative Example 3 9.61

[0060] As can be seen from Table 3, the viscosity of solution 1 containing supramolecular complexes and solution 2 containing supramolecular complexes is significantly higher than that of composition D1, composition D2 and composition D3, indicating that the reaction conditions and raw materials provided by the present application are more conducive to the formation of high-viscosity supramolecular complexes.

[0061] A β-glucan solution with a concentration of 0.01%, 0.5% and 2% respectively was prepared according to the preparation method of Example 1, and the obtained product was subjected to viscosity test, the viscosity value was comparable to that of Example 1, indicating that high-viscosity supramolecular complexes can also be formed.

[0062] 2. Zeta potential measurement

[0063] Zeta potential is a measure of the strength of the mutual repulsion or attraction between particles. The smaller the molecules or dispersed particles, the higher the absolute value (positive or negative) of the Zeta potential, and the more stable the system, i.e. the dissolution or dispersion can resist aggregation. The correspondence between the size of the Zeta potential value and the stability of the colloid is shown in Table 4.

[0064] Table 4

[0065] Zeta potential (mV) Colloidal stability 0 to ± 5 Fast coagulation or flocculation ± 10 to ± 30 Start to become unstable ± 30 to ± 40 Stability generally ± 40 to ± 60 Better stability More than ± 61 Excellent stability

[0066] Zeta potential test was performed on the products obtained in the above examples and comparative examples, and on the β-glucan solution and the maltodextrin solution. A nanoparticle size and Zeta potential analyzer (Malvern Zetasizer Nano ZS90) was used. After the sample to be tested was prepared, it was allowed to stand for 1 h before Zeta potential test. An AQ-961 palladium electrode was used for measurement, and the Zeta potential value was directly recorded.

[0067] The Zeta potential test results are shown in Table 5.

[0068] Zeta potential test results of each sample in Table 5

[0069]

[0070]

[0071] As can be seen from Table 5, the absolute values of the Zeta potentials of the solution 1 containing the supramolecular complex and the solution 2 containing the supramolecular complex are higher than that of the β-glucan solution. The Zeta potential value of the composition of Comparative Example 1 is not much different from that of the β-glucan solution, indicating that β-glucan and lactic acid cannot generate a substance that can make the system more stable under specific conditions. The Zeta potential value of the composition of Comparative Example 2 is not much different from that of the maltodextrin solution, indicating that maltodextrin and lactic acid cannot generate a substance that can make the system more stable. The Zeta potential value of the composition of Comparative Example 3 is not much different from that of the β-glucan solution, indicating that β-glucan and glycolic acid cannot generate a substance that can make the system more stable. As can be seen from Examples 4-9, the addition of other specific adjuvants in the composition can further improve the stability of the system.

[0072] 3. Lactic acid stinging test

[0073] A single-center, randomized, self-controlled method was used to evaluate the stinging sensation at 2 min, 3 min, 5 min, and 8 min after applying the diluted products of examples and comparative examples to the nasolabial groove. Qualified subjects were selected according to the inclusion and exclusion criteria, and 12 people were enrolled in each product group to ensure that the final number of effective subjects in each group was not less than 12 people / group.

[0074] The products obtained in the examples and comparative examples were diluted to a lactic acid solution containing 10% by mass. The sample configuration concentration is shown in Table 6.

[0075] Table 6 Sample configuration information for lactic acid stinging test

[0076]

[0077]

[0078] The inclusion criteria of the subjects are:

[0079] 1. Healthy subjects aged 18-60 years old, both male and female;

[0080] 2. Subjects with a total score of 3 or more in the lactic acid pricking test are positive for lactic acid pricking reaction;

[0081] 3. Subjects who can not use other anti-allergic drugs during the entire observation period of the test;

[0082] 4. Subjects who guarantee not to change the usage habit of existing skin care products during the test period;

[0083] 5. Subjects who do not participate in other facial tests during the test period; subjects who cannot perform long-term sun exposure, outdoor sports, swimming, travel, etc.

[0084] 6. Subjects who are aware of the project, are willing and able to comply with all test requirements, accept skin examination, agree and accept subsequent series of examinations.

[0085] The exclusion criteria of the subjects are:

[0086] 1. Female subjects who are pregnant, lactating or planning to become pregnant during the test period;

[0087] 2. Subjects who are known to be allergic to the product;

[0088] 3. Subjects with highly sensitive constitution;

[0089] 4. Subjects with immune deficiency or autoimmune disease;

[0090] 5. Subjects with insulin-dependent diabetes;

[0091] 6. Subjects with diseases such as dermatitis on the test site that may affect the judgment of the test results;

[0092] 7. Subjects who have used antihistamines in the past week or immunosuppressants in the past month;

[0093] 8. Subjects who have participated in a drug clinical trial within the past month or have taken oral hormone drugs that may affect the results;

[0094] 9. Subjects who are receiving dermatological treatment, or have taken hydroxy acid, whitening and anti-aging drugs that may affect the test results within the past month;

[0095] 10. Subjects with large areas of skin markings, scratches, vitiligo, pigmented nevi, keloid scars, etc. on the test area that may affect the test results;

[0096] 11. Non-volunteers or subjects who cannot complete the specified content according to the test requirements;

[0097] 12. The investigator considers other subjects unsuitable for the study.

[0098] Test method:

[0099] The point of inquiry score, respectively in 2min, 3min, 5min, 8min, ask the subject symptoms, according to 0-3 points method to perform the pricking pain score.

[0100] The test results are shown in Table 7 as follows:

[0101] Table 7 The pricking pain score results average (n=12) of the volunteers after applying the samples

[0102] Sample 2 min 3 min 5 min 8 min Lactic acid 1.8 2.1 2.4 2.4 Example 1 1.5 1.6 1.9 2.1 Example 2 1.3 1.4 1.8 2.1 Comparative Example 1 1.8 2.0 2.0 2.1 Comparative Example 2 1.6 1.7 2.0 2.0 Example 5 1.0 1.0 1.1 1.2 Example 6 1.1 1.1 1.2 1.3 Comparative Example 4 1.7 2.0 2.1 2.1 Comparative Example 5 1.5 1.5 1.9 2.0 Example 7 0.7 0.8 1.0 1.1 Example 8 0.8 0.8 0.9 1.0 Example 9 0.9 1.0 1.0 1.1

[0103] The results of the lactic acid pricking pain experiment of each sample show that the lactic acid pricking pain effect on the skin can be effectively reduced by the examples 1, 2, 5, 6, 7, 8 and 9 of the present application. The example 1 is better than the comparative example 1, which shows that the heat and pressure preservation process adopted in the technical scheme of the present application can effectively reduce the pricking pain effect of lactic acid on the skin. The comparative example 2 uses malt dextrin instead of dextran, and the pricking pain effect of lactic acid on the skin is basically not reduced, which shows that the dextran solution in the technical scheme of the present application has certain specificity in reducing the pricking pain effect of lactic acid on the skin. The effects of the examples 7, 8 and 9 are better than that of the example 5, which shows that the addition of the auxiliary agent is more beneficial to the product in reducing the pricking pain effect.

[0104] In the preparation of the composition of the solution containing the supramolecular complex, the content of the solution containing the supramolecular complex can also be 0.001%, 0.005%, 0.1%, 0.5%, 5%, 20%, 70%, and when the Zeta potential measurement and the lactic acid pricking pain test are performed on the corresponding composition, the effects are consistent with those achieved by the examples, and the stability of the system can also be improved and the pricking pain effect can also be reduced.

[0105] In the preparation of the composition, the low-carbon alcohol can also be selected from 1, 3 butanediol, propylene glycol, 1, 3-propylene glycol, dipropylene glycol, 1, 2 hexanediol or pentanediol, and the effects of various experiments are equivalent to those when glycerol is selected. In order to save space, no longer tedious.

[0106] Of course, the present application can also have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A low-irritation composition comprising lactic acid, characterized in that, The composition contains a supramolecular complex formed by lactic acid and a β-glucan solution; The low-irritation composition containing lactic acid is prepared by mixing a β-glucan solution with lactic acid, stirring the mixture to uniformity, and then reacting the mixture at a temperature of 110-121°C and a relative pressure of 0.04-0.1 MPa. The mass ratio of the β-glucan solution to lactic acid is 45-55:45-55, and the content of β-glucan in the β-glucan solution is 0.01-2%.

2. The composition of claim 1, wherein, The composition also contains carbomer, a low-carbon alcohol, polyethylene glycol, and water, and the mass percentages of the respective components in the composition are 0.01-3% carbomer, 0.1-10% low-carbon alcohol, 0.01-10% polyethylene glycol, 0.001-90% supramolecular complex formed by a β-glucan solution and lactic acid, and the balance water.

3. The composition of claim 2, wherein, The low-carbon alcohol is any one or more of glycerol, 1,3-butanediol, propylene glycol, dipropylene glycol, 1,2-hexanediol, and pentanediol.

4. The composition of claim 1, wherein, The composition also contains an auxiliary agent, and the mass percentage of the auxiliary agent in the composition is 0.1-5%, the auxiliary agent including any one or more of bis-PEG-18 methyl ether dimethyl silane, sodium polyacryloyl dimethyl taurate, xanthan gum, hydroxyethyl cellulose, polyacrylate crosspolymer-6, ammonium polyacryloyl dimethyl taurate, polyacrylamide, and SEPIGEL 305 emulsifier.

5. Process for the preparation of a composition according to any one of claims 1 to 4, characterized in that, The low-irritation composition containing lactic acid is prepared by mixing a β-glucan solution with lactic acid, stirring the mixture to uniformity, and then reacting the mixture at a temperature of 110-121°C and a relative pressure of 0.04-0.1 MPa, to obtain a composition containing a supramolecular complex formed by lactic acid and a β-glucan solution.

6. The production method according to claim 5, wherein The method also includes the step of adding carbomer, a low-carbon alcohol, polyethylene glycol, and water to the composition containing a supramolecular complex formed by lactic acid and a β-glucan solution.

7. The production method according to claim 6, wherein The method also includes the step of adding an auxiliary agent to the composition containing a supramolecular complex formed by lactic acid and a β-glucan solution, the auxiliary agent including any one or more of bis-PEG-18 methyl ether dimethyl silane, sodium polyacryloyl dimethyl taurate, xanthan gum, hydroxyethyl cellulose, polyacrylate crosspolymer-6, ammonium polyacryloyl dimethyl taurate, polyacrylamide, and SEPIGEL 305 emulsifier.

8. The production method according to claim 7, characterized by, The preparation method also includes the step of heating the auxiliary agent to 70-80°C to make it miscible, and then cooling it to 20-35°C before adding it.

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