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

Abstract

The present application relates to a kind of water-soluble whitening composition with good light stability and its preparation and application, the composition includes the following weight parts of raw material component: phenethyl resorcinol 2.5~7.5 parts, aqueous solvent 80~95 parts, pH regulator 0.005~1 part, light protection agent 1~5 parts, diglucosyl gallate 1~5 parts, sodium metabisulfite 0.1~1 part.Compared with prior art, the whitening composition of the present application can be substantially unchanged under daily irradiation, when used in whitening products etc., can provide long-lasting protection for phenethyl resorcinol.

Description

Technical Field

[0001] This invention belongs to the field of cosmetic technology and relates to a water-soluble whitening composition with good photostability, its preparation and application. Background Technology

[0002] As people's living standards improve, they are paying more and more attention to skin problems such as dullness, pigmentation, and blemishes. Improving skin tone has become an increasingly important area for modern people, 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 skin-whitening ingredient in cosmetics. It reduces melanin production by inhibiting the activity of tyrosinase, thus achieving a skin-whitening effect. In cosmetics, PR is mainly used to brighten skin tone, reduce pigmentation, and inhibit the activity of melanocytes. However, PR is unstable under conditions such as light exposure and is easily oxidized and discolored, which are major factors limiting its further application.

[0004] For example, Chinese patent CN202211286669.2 discloses a whitening composite microemulsion cosmetic intermediate and its application. This whitening composite microemulsion cosmetic intermediate comprises the following components in parts by weight: 25 parts PPG-6 decyltetradecyl alcohol polyether-3022, 20-30 parts 1,2-hexanediol, 4-7.5 parts Dalbergia odorifera bark extract, 8-12 parts phenylethyl resorcinol, 13-22 parts isononyl isononanoate, and 2-6 parts polyethylene glycol-8. This patent also does not consider the stability of phenylethyl resorcinol under light exposure, and therefore cannot guarantee that the product will not change during storage. Summary of the Invention

[0005] The purpose of this invention is to provide a water-soluble whitening composition with good photostability, its preparation and application, which remains essentially unchanged under daily irradiation and can provide long-lasting protection for phenylethyl resorcinol when used in whitening and other products.

[0006] The objective of this invention can be achieved through the following technical solutions:

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

[0008] Furthermore, the aqueous solvent is a mixture of 1,3-propanediol and water in a mass ratio of (30-60):(40-60).

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

[0010] Furthermore, the photoprotectant is glucosylrutin.

[0011] In a second aspect, the present invention provides a method for preparing a water-soluble whitening composition with good photostability, wherein phenylethyl resorcinol is first weighed and dissolved in a portion of an aqueous solvent, and stirred evenly under light-protected and low-temperature conditions to obtain a phase A solution;

[0012] The pH adjuster, photoprotectant, diglucosyl gallic acid, and another portion of aqueous solvent were mixed evenly at room temperature to obtain phase B solution;

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

[0014] Furthermore, the preparation of phase A solution was carried out at a temperature below 40°C.

[0015] In a third aspect, the present invention provides the application of a water-soluble whitening composition with good photostability in whitening products. Specifically, the whitening products include whitening lotions, emulsions, creams, serums, etc.

[0016] Furthermore, when a water-soluble whitening composition with good photostability is used in whitening products, its addition amount is approximately 5-10 wt%.

[0017] Compared with the prior art, the present invention optimizes the functional auxiliary ingredients compounded with phenylethyl resorcinol. Each functional auxiliary ingredient is a conventional raw material that can be used in cosmetics. The resulting composition does not rely on external stabilizers and remains essentially unchanged under sunlight. Furthermore, when this composition is applied to whitening products, it can provide a long-lasting protective effect for phenylethyl resorcinol. Attached Figure Description

[0018] Figure 1 A colorimetric reference for characterizing the simulated UV stability of water-soluble whitening compositions at different pH values. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0020] In the following embodiments, unless otherwise specified, the 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 photostability: First, phenylethyl resorcinol is weighed and dissolved in 1,3-propanediol, and stirred evenly under light-protected and low-temperature conditions to obtain phase A solution;

[0023] The pH adjuster (lactobionic acid), photoprotectant (glucosylrutin), disaccharosyl gallic acid, and water were mixed evenly at room temperature to obtain phase B solution;

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

[0025] The proportions of all raw materials added in each embodiment are shown in Table 1.

[0026] Table 1 shows the raw material ratios of the compositions in each embodiment (each raw material is in parts by weight).

[0027]

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

[0029] The testing process for changes in absorbance and ultraviolet absorption is as follows:

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

[0031] Equal amounts of test samples were placed in a transparent bottle to simulate sunlight (light source CEL-S500, light intensity 100mW / cm²). 2 The samples were exposed to light for 0h, 2h, 4h, 6h, 8h, 10h, 12h, and 24h respectively. The samples were diluted 100 times with anhydrous ethanol and anhydrous ethanol was used as a blank control (the use of blank samples for calibration can avoid the influence of the matrix). The UV absorption of the samples before and after light exposure was measured using an ELISA reader, and the changes in absorbance values ​​were recorded.

[0032] The absorbance values ​​at the maximum absorption peak of each test sample (i.e., photoprotectant) were used for calculation. When testing combinations of photoprotectants, an absorption curve in the 290-400 nm range was scanned using a UV spectrophotometer, and the absorbance value at the maximum absorption point was selected. The initial absorbance value before irradiation was recorded as A0, and the absorbance value after irradiation was recorded as A1. The method for calculating the absorbance reduction rate ΔA after different irradiation times is as follows:

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

[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] The preferred photoprotectant is one whose absorbance value changes by less than 10% after 24 hours of sunlight exposure.

[0038] When using single-photoprotectant, the absorbance value change rate after 24 hours of sunlight irradiation was 3.97% for 1.2% glucosylrutin, and 9.98% and 8.5% for 5% disaccharidated gallic acid and 0.3% sodium metabisulfite, respectively. This indicates that 1.2% glucosylrutin, 5% disaccharidated gallic acid, and 0.3% sodium metabisulfite can all improve the stability of phenylethyl resorcinol under light irradiation, with 1.2% glucosylrutin showing the best stabilizing effect.

[0039] Comparing Example 2 and Example 1, it can be seen that when diglucosyl gallic acid and glucosyl rutin are further introduced into a compound, although the stability is further improved, the improvement is somewhat lower than that brought by diglucosyl gallic acid alone. Comparing Example 4 and Example 1, the introduction of sodium metabisulfite and glucosyl rutin shows a slight improvement in stability compared to glucosyl rutin alone. Comparing Example 7 and Examples 5 and 3, the combination of diglucosyl gallic acid and sodium metabisulfite also shows a certain increase in photostability compared to the introduction of diglucosyl gallic acid and sodium metabisulfite alone, but the increase is somewhat reduced.

[0040] However, as in Example 8, when a combination of photoprotectants is used, the absorbance value change rate after 24 hours of sunlight irradiation with 5% disaccharidated gallic acid + 1.2% glucosylrutin + 0.3% sodium metabisulfite is 1.24%, which shows the best protective effect on phenylethyl resorcinol. This overcomes the adverse effects of combining sodium metabisulfite with glucosylrutin, and also shows a significant improvement compared to the pairwise combinations in Examples 2, 4, 7, 10 to 12.

[0041] Therefore, when the composition of the present invention is applied to whitening products, such as the preparation of whitening lotions, it is introduced in the form of replacing the original single whitening ingredient phenylethyl resorcinol at an addition amount of 5-10 wt%. In this way, under subsequent sunlight exposure, the photostability of phenylethyl resorcinol can be effectively improved, thereby providing long-lasting ultraviolet protection, etc.

[0042] In addition, based on the formulation of Example 8, the pH was adjusted by adjusting the content of lactobionic acid, etc., to determine 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 UV stability test results show that phenylethyl resorcinol has good photostability at a pH close to 2.5, and the overall trend is that the higher the acid value, the higher the stability under UV irradiation. However, under near-neutral or alkaline conditions, the stability of phenylethyl resorcinol is extremely poor, and it cannot be well applied to alkaline systems.

[0047] Experiments showed that when the system pH was above 5.5 (average value), the stability gradually decreased (the discoloration rate accelerated rapidly upon exposure to light). When the system pH dropped below 5.5, its stability under light exposure began to improve, and this improvement continued as the pH decreased further. This trend then plateaued after pH 3.0, meaning that further decreases in pH did not significantly alter the stability. Therefore, the suitable system pH range for the whitening composition of this invention is 4.5-5.5.

[0048] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any 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 invention should be within the protection scope of the present invention.

Claims

1. A water-soluble whitening composition with good light stability, characterized by comprising: The good light stability water-soluble whitening composition is prepared from the following raw material components by weight: phenylethyl resorcinol 2.5-7.5 parts, pH regulator 0.005-1 part, light protection agent 1-5 parts, diglucosyl gallate 1-5 parts, sodium pyrosulfite 0.1-1 part, and water-based solvent 80-95 parts, wherein the water-based solvent is prepared from 1,3-propanediol and water in a mass ratio of (30-60):(40-60), the pH regulator is lactobionic acid, and the light protection agent is glucosyl rutin.

2. The method for preparing a water-soluble whitening composition having good light stability according to claim 1, wherein The method comprises the following steps: First, phenylethyl resorcinol is weighed and dissolved in part of the water-based solvent, and stirred uniformly under low temperature and light shielding condition to obtain phase A solution; The pH regulator, light protection agent, diglucosyl gallate and another part of the water-based solvent are mixed uniformly at normal temperature to obtain phase B solution; The phase B solution is added into the phase A solution and continuously stirred, and finally sodium pyrosulfite is added and stirred uniformly at normal temperature under light shielding condition.

3. The method for preparing a water-soluble whitening composition having good light stability according to claim 2, characterized by, The preparation of the phase A solution is carried out below 40℃.

4. Use of the good light stability water-soluble whitening composition of claim 1 in the preparation of a whitening product.

5. The use of the water-soluble whitening composition having good light stability according to claim 4, characterized by, When the good light stability water-soluble whitening composition is used in the whitening product, the added amount is 5-10%.

6. The use of the water-soluble whitening composition having good light stability according to claim 4, wherein The whitening product is whitening water, whitening milk, whitening cream, or whitening essence.

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