Water-soluble whitening composition with good light stability and preparation and application thereof

Abstract

The invention relates to a water-soluble whitening composition with good light stability as well as preparation and application of the water-soluble whitening composition. The composition is prepared from the following raw material components in parts by weight: 2.5 to 7.5 parts of phenylethyl resorcinol, 80 to 95 parts of a water-based solvent, 0.005 to 1 part of a pH regulator, 1 to 5 parts of a light protective agent, 1 to 5 parts of diglucosyl gallic acid and 0.1 to 1 part of sodium pyrosulfite. Compared with the prior art, the whitening composition disclosed by the invention can be basically not changed under daily irradiation, and can provide a lasting protection effect for phenylethyl resorcinol when being used in products for whitening and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of cosmetics and relates to a water-soluble whitening composition with good light stability and a preparation method and application thereof. Background Art

[0002] As people's living standards improve, they pay more and more attention to adverse skin problems such as dull skin, pigmentation, and spots. Improving skin color has become an area that contemporary people pay more and more attention to, and the research and development of skin care products with whitening effects has also received much attention.

[0003] Phenylethyl Resorcinol (PR) is an organic compound commonly used as a whitening ingredient in cosmetics. It reduces the production of melanin by inhibiting the activity of tyrosinase, thereby achieving a whitening effect. In cosmetics, PR is mainly used to brighten the skin, reduce pigmentation, and inhibit the activity of melanocytes. However, PR is unstable under conditions such as light and is easily oxidized and discolored, which has become a major factor limiting its further application.

[0004] For example, Chinese patent CN202211286669.2 discloses a whitening composite microemulsion cosmetic intermediate and its application, wherein the whitening composite microemulsion cosmetic intermediate includes the following components by weight: PPG-6 decyl tetradecanol polyether-3022-25 parts, 1,2-hexanediol 20-30 parts, 4-7.5 parts of rosewood bark extract, 8-12 parts of phenethyl resorcinol, 13-22 parts of isononanoate and 2-6 parts of polyethylene glycol-8. This patent also does not consider the stability of phenethyl resorcinol under light, and cannot guarantee that the product will not change during storage. Summary of the invention

[0005] The purpose of the present invention is to provide a water-soluble whitening composition with good photostability and its preparation and application, which can remain basically unchanged under daily irradiation and can provide a lasting protective effect for phenylethyl resorcinol when used in whitening products.

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

[0007] In the first aspect, the present invention provides a water-soluble whitening composition with good light stability, comprising the following raw material components in parts by weight: 2.5 to 7.5 parts of phenethyl resorcinol, 0.005 to 1 part of a pH regulator, 1 to 5 parts of a light protectant, 1 to 5 parts of diglucosyl gallic acid, and 0.1 to 1 part of sodium pyrosulfite. Preferably, it also comprises 80 to 95 parts of an aqueous solvent.

[0008] Furthermore, the aqueous solvent is prepared by mixing 1,3-propylene glycol and water in a mass ratio of (30-60): (40-60).

[0009] Furthermore, the pH regulator is lactobionic acid.

[0010] Furthermore, the light protectant is glucosylrutin.

[0011] In a second aspect, the present invention provides a method for preparing a water-soluble whitening composition with good light stability, firstly weighing phenylethyl resorcinol and dissolving it in a part of an aqueous solvent, stirring it evenly under light-proof and low-temperature conditions to obtain a phase A solution;

[0012] Mixing the pH regulator, the light protectant, the diglucosyl gallic acid and another portion of the aqueous solvent at room temperature to obtain a phase B solution;

[0013] Add the phase B solution into the phase A solution and continue stirring. Finally, add sodium metabisulfite and stir evenly at room temperature in the dark.

[0014] Furthermore, the preparation of the phase A solution is carried out below 40°C.

[0015] In a third aspect, the present invention provides a use of a water-soluble whitening composition with good light stability in whitening products. Specifically, the whitening products are whitening water, lotion, cream, essence, etc.

[0016] Furthermore, when the water-soluble whitening composition with good light stability is used in whitening products, the addition amount thereof is about 5-10 wt %.

[0017] Compared with the prior art, the present invention optimizes the functional auxiliary ingredients compounded with phenethyl resorcinol, and each functional auxiliary ingredient is a conventional raw material that can be used in cosmetics. The formed composition does not rely on the addition of an external stabilizer ingredient and basically does not change under the irradiation of sunlight; furthermore, when the composition is used in whitening products, it can provide a lasting protective effect for phenethyl resorcinol. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a color reference for characterizing the simulated UV stability effect of water-soluble whitening compositions at different pH values. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0020] In the following examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0021] Example:

[0022] A method for preparing a water-soluble whitening composition with good light stability comprises: firstly weighing phenylethyl resorcinol and dissolving it in 1,3-propylene glycol, stirring it evenly under light-proof and low-temperature conditions to obtain a phase A solution;

[0023] Mix pH regulator (lactose acid), light protectant (glucosylrutin), diglucosyl gallic acid and water at room temperature to obtain a phase B solution;

[0024] Add the phase B solution into the phase A solution and continue stirring. Finally, add sodium metabisulfite and stir evenly at room temperature in the dark.

[0025] The addition ratios of all raw materials in each example are shown in Table 1.

[0026] Table 1 Raw material ratio of the composition of each embodiment (the unit of each raw material is weight part)

[0027]

[0028] The performance of the water-soluble whitening compositions with good photostability prepared in the above examples was tested.

[0029] Among them, the test process of absorbance value change and ultraviolet absorption is:

[0030] Test samples were prepared according to the composition sample ratios of the embodiments in Table 1 above (numbered 1 to 9 in sequence corresponding to the embodiments).

[0031] Place equal amounts of test samples in transparent bottles and simulate sunlight (light source CEL-S500, light intensity 100mW / cm 2 ) for 0 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, and 24 h respectively. The samples were diluted 100 times with anhydrous ethanol and calibrated with anhydrous ethanol as the blank control sample (calibration with blank samples can avoid the influence of the matrix). The ultraviolet absorption of the samples before and after illumination was measured with an enzyme marker, and the changes in absorbance values ​​were recorded.

[0032] The absorbance value at the maximum absorption peak of each test sample (i.e., photoprotectant) is taken for calculation. When testing the combination of photoprotectants, the absorption curve in the range of 290-400nm is scanned by an ultraviolet spectrophotometer, and the absorbance value at the maximum absorption is selected from the absorption curve. The initial absorbance value, i.e., the absorbance value before irradiation, is recorded as A0, and the absorbance value after irradiation is recorded as A1. The calculation method of the absorbance reduction rate ΔA after different irradiation times is as follows:

[0033] ΔA=|1-A1 / A0|*100%. The larger the ΔA, the more light changes there are and the worse the light stability is.

[0034] The test results of the above groups of test samples are shown in Table 2 below.

[0035] Table 2 Performance results of each test sample

[0036]

[0037] Preferably, after 24 hours of sunlight exposure, the absorbance value change is less than 10% of the photoprotectant.

[0038] When a single light protectant is used, the absorbance change rate after adding 1.2% glucosyl rutin and 24 hours of sunlight irradiation is 3.97%, and the absorbance change rates after adding 5% diglucosyl gallic acid and 0.3% sodium metabisulfite and 24 hours of sunlight irradiation are 9.98% and 8.5%, respectively. This indicates that 1.2% glucosyl rutin, 5% diglucosyl gallic acid and 0.3% sodium metabisulfite can all improve the stability of phenethyl resorcinol under light, among which 1.2% glucosyl rutin has the best stabilizing effect.

[0039] Comparing Example 2 with Example 1, it can be seen that after further introducing diglucosyl gallic acid and glucosyl rutin, although the stability is further improved, it is somewhat lower than the effect improvement brought by diglucosyl gallic acid alone; and comparing Example 4 with Example 1, the introduction of sodium pyrosulfite and glucosyl rutin has a smaller improvement in the stabilization effect than the glucosyl rutin added alone; comparing Example 7 with Example 5 and Example 3, after diglucosyl gallic acid and sodium pyrosulfite are compounded, the light stabilization effect is also increased to a certain extent compared with the diglucosyl gallic acid and sodium pyrosulfite introduced alone, but the increase is reduced.

[0040] However, as in Example 8, when a combined light protectant is used, the absorbance change rate after adding 5% diglucosyl gallic acid + 1.2% glucosyl rutin + 0.3% sodium metabisulfite for 24 hours of sunlight irradiation is 1.24%, which has the best protective effect on phenylethyl resorcinol, overcoming the adverse effects of sodium metabisulfite and glucosyl rutin when compounded, and compared with the two-by-two compounding schemes of Examples 2, 4, 7, 10 to 12, there is also a significant improvement.

[0041] Therefore, when the composition of the present invention is used in whitening products, such as the preparation of whitening lotions, it is introduced in an amount of 5-10 wt % to replace the original single whitening ingredient phenylethyl resorcinol. In this way, when exposed to subsequent sunlight, the light stability of phenylethyl resorcinol can be effectively improved, thereby providing long-lasting ultraviolet protection, etc.

[0042] In addition, based on the formula of Example 8, the pH was adjusted by adjusting the content of lactobionic acid, etc., to measure the simulated UV stability effect of the water-soluble whitening composition at different pH values, as shown in Table 3 below.

[0043] Table 3

[0044]

[0045]

[0046] The results of the UV stability experiment show that phenethyl resorcinol has good light stability when the pH is close to 2.5, and the overall trend is that the higher the acid value, the higher the stability under UV irradiation. However, under conditions close to neutral or above alkaline, the stability of phenethyl resorcinol is extremely poor, and it cannot be well applied in alkaline systems.

[0047] It was observed in the experiment that when the system pH is above 5.5 (the average value is taken to obtain data), the stability will gradually decrease (the speed of color change after exposure to light will be extremely accelerated). When the system pH drops below 5.5, its stability under light will begin to improve, and as the pH gradually decreases, the stability becomes better and better, and this trend reaches a plateau after 3.0, that is, the stability does not change much after the pH decreases again. Therefore, the suitable system pH value of the whitening composition of the present invention when used is in the range of 4.5-5.5.

[0048] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A water-soluble whitening composition with good photostability, characterized in that: The invention comprises the following raw material components in parts by weight: 2.5-7.5 parts of phenethyl resorcinol, 0.005-1 part of pH regulator, 1-5 parts of light protectant, 1-5 parts of diglucosyl gallic acid and 0.1-1 part of sodium pyrosulfite.

2. A water-soluble whitening composition with good photostability according to claim 1, characterized in that: It also includes 80 to 95 parts of an aqueous solvent.

3. A water-soluble whitening composition with good photostability according to claim 2, characterized in that: The aqueous solvent is prepared by mixing 1,3-propylene glycol and water in a mass ratio of (30-60): (40-60).

4. A water-soluble whitening composition with good photostability according to claim 1, characterized in that: The pH adjuster is lactobionic acid.

5. A water-soluble whitening composition with good photostability according to claim 1, characterized in that: The photoprotectant is glucosylrutin.

6. The method for preparing the water-soluble whitening composition with good photostability according to any one of claims 1 to 5, characterized in that: The following steps are involved: First, weigh phenethyl resorcinol and dissolve it in part of the aqueous solvent, stir it evenly under light-proof and low-temperature conditions to obtain a phase A solution; Mixing the pH regulator, the light protectant, the diglucosyl gallic acid and another portion of the aqueous solvent at room temperature to obtain a phase B solution; Add the phase B solution into the phase A solution and continue stirring. Finally, add sodium metabisulfite and stir evenly at room temperature in the dark.

7. The method for preparing a water-soluble whitening composition with good photostability according to claim 6, characterized in that: The preparation of the phase A solution is carried out below 40°C.

8. Use of the water-soluble whitening composition with good photostability as claimed in any one of claims 1 to 5 in whitening products.

9. The use of the water-soluble whitening composition with good photostability according to claim 8, characterized in that: When the water-soluble whitening composition with good light stability is used in whitening products, the addition amount thereof is 5-10%.

10. The use of the water-soluble whitening composition with good photostability according to claim 8, characterized in that: The whitening products are whitening water, whitening lotion, whitening cream and whitening essence.

Images