Use of a zinc-chelating composition in skin care and pharmaceutical compositions or skin care products

Abstract

The embodiment of the present application discloses a use of a chelated zinc composition in skin care and a pharmaceutical composition or skin care product. In the use of a chelated zinc composition in skin care, the zinc salt composition comprises a bio-based polymer chelated zinc; the molecular weight of the bio-based polymer chelated zinc is 3-20 kDa; the mass fraction of zinc in the bio-based polymer chelated zinc is 10wt%-20wt%; and the chelation degree of zinc in the bio-based polymer chelated zinc is 75%-90%. A pharmaceutical composition or skin care product containing the chelated zinc composition is also disclosed, wherein the chelated zinc composition comprises a bio-based polymer chelated zinc. The bio-based polymer chelated zinc can increase the anti-inflammatory and whitening effects on the basis of the moisturizing property of the bio-based polymer; and the relative stability of the chelate bond can effectively improve the efficacy and durability of the bio-based polymer chelated zinc compared with elemental zinc, zinc oxide and zinc salt.

Description

Technical Field

[0001] This invention relates to the field of daily chemical product application technology, and in particular to the use of a chelated zinc composition in skin care and pharmaceutical compositions or skin care products. Background Technology

[0002] Polyaspartic acid and its sodium salt are homopolymeric amino acids whose backbone is composed of aspartic acid residues, exhibiting excellent biodegradability and biocompatibility. Traditionally, polyaspartic acid is prepared by using aspartic acid, maleic anhydride, maleic acid, maleamide, or fumaric acid as raw materials, and obtaining a water-insoluble polymerization intermediate, polysuccinimide, through different processes, followed by hydrolysis of polysuccinimide in an alkaline aqueous solution.

[0003] Because polyaspartic acid and its sodium salt have a large number of carboxyl or sodium carboxylate side chains, their properties are similar to those of polyglutamic acid or hyaluronic acid. Therefore, they have been widely recognized and used as moisturizing ingredients in moisturizing cosmetics. Existing technologies also provide preparation processes for sodium polyaspartic acid suitable for use as a moisturizing ingredient in cosmetics.

[0004] Although polyaspartic acid and its sodium salt exhibit excellent moisturizing properties, their functions are relatively limited. Therefore, studies have been reported on modifying them to enhance their functionality, including: (1) grafting polysuccinimide with amine compounds and halogenated fatty acid compounds in a well-soluble organic solvent to obtain hair treatment compositions and cosmetic compositions with good hair care properties and biocompatibility. (2) using aspartic acid as a raw material, through a multi-step reaction including thermal polycondensation to obtain polysuccinimide, heated ring-opening grafting of alkyl primary amines, and carbodiimide grafting of lysine, a lysine-polyaspartic acid derivative with amphoteric molecules is obtained, which can increase skin permeability and promote collagen production.

[0005] On the other hand, zinc, zinc oxide, and zinc ions can penetrate microbial cell membranes and interfere with their enzyme activity and metabolism. They also inhibit 5-α reductase activity, thus reducing excessive sebum secretion. Therefore, they are often used in cosmetics as antibacterial, anti-inflammatory, and oil-controlling ingredients. Salts or chelates formed by ionic or chelate bonds are the main way zinc is used in cosmetics.

[0006] Based on the above, polyaspartic acid, due to the large number of carboxyl groups in its side chains, can relatively easily form chelates with metal ions, making it suitable for preparing polyaspartic acid chelated zinc with zinc ions. However, in existing publicly available technologies, polyaspartic acid zinc is generally used in agriculture as a zinc supplement and fertilizer synergist, and its application in the cosmetics field has not yet been observed. Summary of the Invention

[0007] The purpose of this invention is to provide the use of a chelated zinc composition in skin care and a pharmaceutical composition or skin care product to solve at least one of the above-mentioned technical problems. Polyaspartic acid chelated zinc can increase anti-inflammatory and whitening effects on the basis of the moisturizing properties of polyaspartic acid; and compared with elemental zinc, zinc oxide and zinc salts, the relative stability of its chelate bond effectively improves the longevity of its effects.

[0008] The embodiments of the present invention are implemented as follows:

[0009] Use of a chelated zinc composition in skin care products, said chelated zinc composition comprising polyaspartic acid chelated zinc.

[0010] In a preferred embodiment of the present invention, the molecular weight of the polyaspartic acid chelated zinc described in the above-mentioned uses is calculated based on the average molecular weight of polyaspartic acid, and its range is 3 to 20 kDa.

[0011] The technical advantages are as follows: the water-retention performance of the product is determined by polyaspartic acid; if the molecular weight is too small, the water-retention performance will decrease. The anti-inflammatory and whitening effects of the product are provided by zinc ions; if the molecular weight is too large, the polyaspartic acid molecular chains will be more tightly wound, increasing the stability of the chelate structure and ultimately leading to a poorer anti-inflammatory and whitening effect. In a preferred embodiment of the invention, the mass fraction of zinc in the polyaspartic acid chelated zinc used in the above applications is between 10 wt% and 20 wt%.

[0012] The technical effect is that the zinc content and zinc chelation degree are determined by the preparation process. The theoretical values ​​and actual process conditions determine that the zinc content and zinc chelation degree of chelated zinc obtained from polyaspartic acid of different molecular weights are within this range.

[0013] In a preferred embodiment of the present invention, the degree of zinc chelation in the polyaspartic acid chelated zinc described in the above-mentioned uses is 75% to 90%.

[0014] The technical effect is that the zinc content and zinc chelation degree are determined by the preparation process. The theoretical values ​​and actual process conditions determine that the zinc content and zinc chelation degree of chelated zinc obtained from polyaspartic acid of different molecular weights are within this range.

[0015] The use of a chelated zinc composition in the preparation of facial masks, hand care products, sunscreen products, skin-refreshing products, antifreeze products, anti-dandruff products, moisturizing products, anti-inflammatory products, whitening products, and whitening and darkening products for pigmentation, wherein the chelated zinc composition comprises polyaspartic acid chelated zinc.

[0016] In a preferred embodiment of the present invention, the molecular weight of the polyaspartic acid chelated zinc described in the above-mentioned uses is calculated based on the average molecular weight of polyaspartic acid, and its range is 3 to 20 kDa.

[0017] The technical effects are as follows: the water retention performance of the product is determined by polyaspartic acid. If the molecular weight is too small, the water retention performance of the product will decrease. The anti-inflammatory and whitening effect of the product is provided by zinc ions. If the molecular weight is too large, the polyaspartic acid molecular chains will be relatively tightly wrapped, the stability of the chelation structure will be enhanced, and the anti-inflammatory and whitening effect will eventually be worse.

[0018] In a preferred embodiment of the present invention, the zinc mass fraction in the polyaspartic acid chelated zinc used in the above-described applications is between 0.1 wt% and 5 wt%.

[0019] The technical effect is that the zinc content and zinc chelation degree are determined by the preparation process. The theoretical values ​​and actual process conditions determine that the zinc content and zinc chelation degree of chelated zinc obtained from polyaspartic acid of different molecular weights are within this range.

[0020] A pharmaceutical composition or skin care product containing a chelated zinc composition, the chelated zinc composition comprising polyaspartic acid chelated zinc, wherein the polyaspartic acid chelated zinc is as described above.

[0021] In a preferred embodiment of the present invention, the dosage form of the above-mentioned pharmaceutical composition or skin care product includes an aqueous solution, an aerosol, a spray, an emulsion, a cream, a gel, or a lyophilized powder.

[0022] The skincare products include facial cleansers, toners, serums, lotions, or creams.

[0023] In a preferred embodiment of the present invention, the above-mentioned pharmaceutical composition or skin care product further includes one or more of the following: thickener, solubilizer, cosolvent, stabilizer, softener, aerosol solvent, preservative, surfactant, controlled-release agent, sustained-release agent, fragrance, colorant, penetration enhancer, moisturizer, emulsifier, shaping agent, or pearlescent agent.

[0024] In some embodiments of the present invention, the efficacy of the polyaspartic acid chelated zinc was analyzed and compared using biochemical experiments, human trials, and other methods.

[0025] The beneficial effects of the embodiments of the present invention are:

[0026] The polyaspartic acid chelated zinc of this invention not only has excellent water retention and moisturizing properties compared to polyaspartic acid, but also has better whitening effects and antibacterial and anti-inflammatory effects, making it applicable to a wider range of fields. The chelated zinc of this invention uses polyaspartic acid as a chelating agent, which not only has high biocompatibility and low skin irritation, but also has relatively stable chelating bonds compared to elemental zinc, zinc oxide, and zinc salts, giving it long-lasting efficacy. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the molecular structure of the polyaspartic acid chelated zinc of the present invention;

[0029] Figure 2 This is a schematic diagram of the molecular structure of aspartic acid in this invention;

[0030] Figure 3 This is a schematic diagram of the molecular structure of polyaspartic acid according to the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention easier to understand, the invention will be further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other. Specific experimental methods not mentioned in the following embodiments are generally performed according to conventional experimental methods.

[0032] The "polyaspartic acid chelated zinc" of this invention can also be called "polyaspartic acid chelated zinc" or "polyaspartic acid chelated zinc".

[0033] Use of a chelated zinc composition in skin care products, said chelated zinc composition comprising polyaspartic acid chelated zinc.

[0034] Among them, the molecular structure of aspartic acid is as follows Figure 2 As shown.

[0035] An amide bond is formed by the dehydration of the carboxyl group of one aspartic acid molecule and the amino group of another aspartic acid molecule, allowing two aspartic acid molecules to combine into one. Repeating this reaction with multiple aspartic acid molecules yields long-chain polyaspartic acid molecules. The molecular structure of polyaspartic acid is shown below. Figure 3 As shown. Because the aspartic acid molecule contains two carboxyl groups, the aspartic acid repeating units on the polyaspartic acid backbone can have two structures.

[0036] Because polyaspartic acid has a large number of carboxyl groups on its side chains, it has the potential to form chelate structures with metal ions. In the presence of exogenous ammonia, amino, or ammonium ions, polyaspartic acid can form relatively stable six-coordinate chelate structures with zinc ions, such as... Figure 1 As shown.

[0037] In a preferred embodiment of the present invention, the molecular weight of the polyaspartic acid chelated zinc described in the above-mentioned uses is calculated based on the average molecular weight of polyaspartic acid, and its range is 3 to 20 kDa.

[0038] The technical effects are as follows: the water retention performance of the product is determined by polyaspartic acid. If the molecular weight is too small, the water retention performance of the product will decrease. The anti-inflammatory and whitening effect of the product is provided by zinc ions. If the molecular weight is too large, the polyaspartic acid molecular chains will be relatively tightly wrapped, the stability of the chelation structure will be enhanced, and the anti-inflammatory and whitening effect will eventually be worse.

[0039] In a preferred embodiment of the present invention, the zinc mass fraction in the polyaspartic acid chelated zinc used in the above-mentioned applications is 10wt% to 20wt%.

[0040] The technical effect is that the zinc content and zinc chelation degree are determined by the preparation process. The theoretical values ​​and actual process conditions determine that the zinc content and zinc chelation degree of chelated zinc obtained from polyaspartic acid of different molecular weights are within this range.

[0041] In a preferred embodiment of the present invention, the degree of zinc chelation in the polyaspartic acid chelated zinc described in the above-mentioned uses is 75% to 90%.

[0042] The technical effect is that the zinc content and zinc chelation degree are determined by the preparation process. The theoretical values ​​and actual process conditions determine that the zinc content and zinc chelation degree of chelated zinc obtained from polyaspartic acid of different molecular weights are within this range.

[0043] The use of a chelated zinc composition in the preparation of facial masks, hand care products, sunscreen products, skin-refreshing products, antifreeze products, anti-dandruff products, moisturizing products, anti-inflammatory products, whitening products, and whitening and darkening products for pigmentation, wherein the chelated zinc composition comprises polyaspartic acid chelated zinc.

[0044] In a preferred embodiment of the present invention, the molecular weight of the polyaspartic acid chelated zinc described in the above-mentioned uses is calculated based on the average molecular weight of polyaspartic acid, and its range is 3 to 20 kDa.

[0045] The technical effects are as follows: the water retention performance of the product is determined by polyaspartic acid. If the molecular weight is too small, the water retention performance of the product will decrease. The anti-inflammatory and whitening effect of the product is provided by zinc ions. If the molecular weight is too large, the polyaspartic acid molecular chains will be relatively tightly wrapped, the stability of the chelation structure will be enhanced, and the anti-inflammatory and whitening effect will eventually be worse.

[0046] In a preferred embodiment of the present invention, the zinc mass fraction in the polyaspartic acid chelated zinc used in the above-described applications is between 0.1 wt% and 5 wt%.

[0047] The technical effect is that the zinc content and zinc chelation degree are determined by the preparation process. The theoretical values ​​and actual process conditions determine that the zinc content and zinc chelation degree of chelated zinc obtained from polyaspartic acid of different molecular weights are within this range.

[0048] A pharmaceutical composition or skin care product containing a chelated zinc composition, the chelated zinc composition comprising polyaspartic acid chelated zinc, wherein the polyaspartic acid chelated zinc is as described above.

[0049] In a preferred embodiment of the present invention, the dosage form of the above-mentioned pharmaceutical composition or skin care product includes an aqueous solution, an aerosol, a spray, an emulsion, a cream, a gel, or a lyophilized powder.

[0050] The skincare products include facial cleansers, toners, serums, lotions, or creams.

[0051] In a preferred embodiment of the present invention, the above-mentioned pharmaceutical composition or skin care product further includes one or more of the following: thickener, solubilizer, cosolvent, stabilizer, softener, aerosol solvent, preservative, surfactant, controlled-release agent, sustained-release agent, fragrance, colorant, penetration enhancer, moisturizer, emulsifier, shaping agent, or pearlescent agent.

[0052] In some embodiments of the present invention, the efficacy of the polyaspartic acid chelated zinc was analyzed and compared using biochemical experiments, human trials, and other methods.

[0053] The first embodiment of the present invention provides the preparation of an experimental sample of polyaspartic acid chelated zinc, comprising:

[0054] Preparation of polyaspartic acid chelated zinc: 1.5 L of deionized water was added to a 5 L reactor, followed by the addition of 0.5 kg ammonium sulfate, 0.7 L ammonia (25%), and 0.3 kg zinc oxide under stirring, ensuring complete dissolution and uniform mixing. The reaction system was heated to 60 °C, and 1 kg of polysuccinimide with an average molecular weight of 8 kDa or 50 kDa was added. The mixture was reacted at 60 °C with stirring for 4 h to obtain a clear, transparent, reddish-brown liquid. The product was filtered through a fiber membrane with a molecular weight cutoff of 3000 to remove residual salts, and then spray-dried at 180 °C to obtain a brownish-yellow powder.

[0055] Selection of experimental samples for anti-inflammatory and whitening efficacy evaluation: The polyaspartic acid chelated zinc obtained above was used as an example, and zinc aspartate and sodium polyaspartate were used as comparative examples. The indicators are shown in Table 1.

[0056] Table 1. Indicators of polyaspartic acid chelated zinc and comparative ratios

[0057]

[0058] The zinc content was tested by dissolving the sample in pure water to prepare a solution of a certain concentration, and then measuring the zinc content using a Thermo Fisher iCAP™PRO ICP-OES inductively coupled plasma atomic emission spectrometer. The zinc chelation degree was tested using EDTA titration.

[0059] The experimental samples were dissolved in deionized water to prepare solutions of different concentrations. The composition of the experimental samples is shown in Table 2.

[0060] Table 2 Composition of experimental samples

[0061]

[0062] The second embodiment of the present invention provides a method for testing the anti-inflammatory effect of polyaspartic acid chelated zinc. Hyaluronidase is involved in type I hypersensitivity reactions and is strongly correlated with inflammation and allergies. Studies have reported that various drugs that release histamine from mast cells can regulate hyaluronidase activity, and some anti-allergy drugs have strong inhibitory effects on hyaluronidase activity. Therefore, the inhibition of hyaluronidase activity is used as an indicator for studying anti-allergic effects.

[0063] Test methods for the anti-inflammatory effects of polyaspartic acid chelated zinc include:

[0064] The solution prepared in the first example was used as the test sample to detect its effect on the inhibition rate of hyaluronidase.

[0065] (1) Prepare the test solution according to the components shown in Table 3.

[0066] Table 3 Components of the solution to be tested

[0067]

[0068] (2) After keeping the above solutions at 37 °C for 20 min, add 0.1 mL of 2.5 mol / L CaCl2 solution to each solution. After keeping the solutions at 37 °C for 20 min, add 0.5 mL of 0.5 mg / mL sodium hyaluronate solution to A and C respectively, and add 0.5 mL of pH 5.6 acetate buffer solution to B and D respectively.

[0069] (3) After keeping the above solutions at 37 °C for 40 min, place them at room temperature (25 °C) for 10 min, and then add 0.5 mL of pure water and 0.1 mL of 5 mol / L NaOH solution to each solution respectively; at the same time, mix 50 mL of 10 mol / L sodium carbonate solution and 3.5 mL of acetylacetone evenly, and then add 0.5 mL to each of the above solutions respectively.

[0070] (4) Place each of the above solutions in a boiling water bath for 15 min, then in an ice bath for 10 min, and then let them stand at room temperature (25 °C) for 10 min. Add 1 mL of P-DAB colorimetric reagent prepared by dissolving 0.8 g of p-dimethylaminobenzaldehyde in 15 mL of concentrated hydrochloric acid and 15 mL of anhydrous ethanol to each solution.

[0071] (5) After shaking the above solution thoroughly, add anhydrous ethanol to make up the solution volume to 8 mL; after standing at room temperature (25 °C) for 30 min, use a UV spectrophotometer to detect the absorbance at 530 nm.

[0072] The method for calculating the hyaluronidase inhibition rate is as follows:

[0073] .

[0074] Where: A is the UV absorbance of solution A (i.e., sample, hyaluronidase, sodium hyaluronate solution); B is the UV absorbance of solution B (i.e., sample, acetate buffer); C is the UV absorbance of solution C (i.e., hyaluronidase, sodium hyaluronate solution); and D is the UV absorbance of solution D (i.e., acetate buffer).

[0075] Following the above method, the hyaluronidase inhibition rate of each sample solution prepared in Example 1 was detected, with acetate buffer as a blank control. The results are shown in Table 4.

[0076] Table 4 Results of hyaluronidase inhibition rate detection

[0077]

[0078] As shown in Table 4, all sample solutions exhibited hyaluronidase inhibition. Specifically, the hyaluronidase inhibition rates of polyaspartic acid chelated zinc at different concentrations and molecular weights were higher than those of sodium polyaspartate, indicating that zinc significantly promotes the improvement of hyaluronidase inhibition. At the same concentration, the hyaluronidase inhibition rate of polyaspartic acid chelated zinc was higher than that of zinc aspartate, suggesting that using polymeric polyaspartic acid as a carrier enhances zinc utilization more effectively than using monomeric aspartic acid. Furthermore, at the same concentration, the hyaluronidase inhibition rate varied depending on the molecular weight of polyaspartic acid chelated zinc; lower molecular weight polyaspartic acid chelated zinc exhibited a higher hyaluronidase inhibition rate. Therefore, polyaspartic acid chelated zinc significantly enhances the hyaluronidase inhibition rate and possesses good anti-inflammatory effects.

[0079] The third embodiment of this invention provides a method for testing the skin-whitening effect of polyaspartic acid chelated zinc. Tyrosinase is the rate-limiting enzyme in melanin synthesis. The depth of human epidermal pigmentation and pigmentation disorders are related to the activity of tyrosinase in the body; the higher the activity and the higher the content, the easier it is to form melanin. During metabolism, L-tyrosine can be converted into dopa under the action of tyrosinase, and dopa can then be converted into dopaquinone under the further catalysis of tyrosinase. Since dopaquinone has a maximum absorption peak at a wavelength of 475 nm, the absorption rate of the product dopaquinone can be measured to characterize the inhibition efficiency of the sample against tyrosine and to demonstrate its skin-whitening effect.

[0080] Test methods for assessing the skin-whitening effect of polyaspartic acid chelated zinc include:

[0081] The solution prepared in the first example was used as the test sample to detect its effect on the inhibition rate of tyrosinase.

[0082] (1) Prepare the test solution according to the components shown in Table 5.

[0083] Table 5. Proportions of the test solutions

[0084]

[0085] (2) After heating each solution in a water bath at 37°C for 10 min, the absorbance at 475 nm was measured using a UV spectrophotometer.

[0086] The method for calculating the hyaluronidase inhibition rate is as follows:

[0087]

[0088] Where: C1 is the absorbance of the tyrosine solution; C2 is the absorbance of the tyrosinase and the tyrosine solution; T1 is the absorbance of the sample and the tyrosine solution; T2 is the absorbance of the sample, the tyrosinase, and the tyrosine solution.

[0089] Following the above method, the tyrosinase inhibition rate of each sample solution prepared in Example 1 was detected, with phosphate buffer as a blank control. The results are shown in Table 6.

[0090] Table 6 Tyrosinase Inhibition Rate

[0091]

[0092] As can be seen, all sample solutions exhibited tyrosinase inhibition. Specifically, the tyrosinase inhibition rates of polyaspartic acid chelated zinc at different concentrations and molecular weights were higher than those of sodium polyaspartate, indicating that zinc significantly promotes the improvement of tyrosinase inhibition. At the same concentration, the tyrosinase inhibition rate of polyaspartic acid chelated zinc was higher than that of zinc aspartate, suggesting that using polymeric polyaspartic acid as a carrier enhances zinc utilization more effectively than using monomeric aspartic acid. Furthermore, at the same concentration, the tyrosinase inhibition rate varied depending on the molecular weight of polyaspartic acid chelated zinc; that is, polyaspartic acid chelated zinc with a relatively lower molecular weight exhibited a higher hyaluronidase inhibition rate. Therefore, polyaspartic acid chelated zinc significantly enhances the tyrosinase inhibition rate and possesses good whitening effects.

[0093] The fourth embodiment of the present invention provides an evaluation experiment on the moisturizing efficacy of polyaspartic acid chelated zinc in human skin. Samples No. 3 and No. 4, which showed good inhibition rates of hyaluronidase and tyrosinase in the samples prepared in Example 1, were selected. Samples No. 7, No. 9, and No. 12, with a concentration of 2 wt%, were used as comparative examples, and pure water was used as a control. A total of 6 groups of samples were evaluated for their moisturizing efficacy in human skin.

[0094] (1) Skin moisture loss test

[0095] Thirteen female volunteers aged 20-59 were selected as subjects, and six 4×3 cm test areas were randomly divided on the inner side of both forearms of the subjects. A single sample was administered to the subjects on-site by technicians at a dosage of 2 mg / cm². 2 The test temperature was 22±1 ℃, and the test humidity was 50±5%. Before sample use, and 2 h, 4 h, and 8 h after sample use, each test area was tested using a skin moisture loss meter. Each test area was tested 5 times, and the average value was taken. The average values ​​measured for the same sample test area from each subject were calculated, and the test results are shown in Table 7.

[0096] Table 7 Results of Skin Moisture Loss Test

[0097]

[0098] *Based on Dunnett's test value, "+" indicates a significant difference (ρ≤0.05), and "--" indicates a non-significant difference (ρ>0.05).

[0099] As shown in Table 7, compared with the blank sample, polyaspartic acid chelated zinc (samples 3, 4, and 7) and polyaspartic acid sodium (sample 12) can significantly reduce skin moisture loss, and the performance difference between the two is not significant; zinc aspartate has a small effect on skin moisture loss and there is no significant difference from the blank sample.

[0100] The Dunnett test, a method for comparing means in analysis of variance (ANOVA), is used in the efficacy evaluation of cosmetic experiments. Since most experiments require statistical analysis, ANOVA is introduced to perform significance analysis based on variance, thus verifying the reliability of the experimental data. If the calculated result ρ ≤ 0.05, the comparison between the two groups of data is considered significant; if ρ > 0.05, the comparison between the two groups of data is considered non-significant, meaning that although the experimental values ​​are different, there is no statistically significant difference.

[0101] (2) Skin moisture content test

[0102] Twenty-four female volunteers aged 20-59 were selected as subjects, and six 4×3 cm test areas were randomly divided on the inner side of both forearms of the subjects. A single sample was administered to the subjects on-site by technicians at a dosage of 2 mg / cm². 2 The test temperature was 22±1 ℃, and the test humidity was 50±5%. Skin moisture content was measured in each test area using a skin moisture meter before sample use and at 2 h, 4 h, and 8 h after sample use. Each test area was tested 5 times, and the average value was taken. The average values ​​measured in the same sample test area for each subject were calculated, and the results are shown in Table 8.

[0103] Table 8 Results of Skin Moisture Content Test

[0104]

[0105] *Based on the t-test values, "+" indicates a significant difference (ρ≤0.05), and "--" indicates a non-significant difference (ρ>0.05).

[0106] The fifth embodiment of the present invention provides an evaluation experiment on the skin whitening effect of polyaspartic acid chelated zinc on human skin.

[0107] Among the samples prepared in Example 1, samples No. 3, No. 9 and No. 12, each with a concentration of 2 wt%, were selected. Sample No. 3 (polyaspartic acid chelated zinc) was used as the test sample, and samples No. 9 (zinc aspartate) and No. 12 (sodium aspartate) were used as comparative examples to evaluate the skin whitening effect on human skin.

[0108] Thirty-three female volunteers aged 20-62 years were selected as subjects and randomly divided into three groups, using samples No. 3, 9, and 12 as described above, respectively. The method of application was to apply the sample evenly to the face twice daily, morning and evening, and massage gently with the palms for 3 minutes, starting from day 1 until the end of the efficacy evaluation experiment. Data on skin melanin index (MI), VISA L* value, VISA a* value, and VISA ITA° value were collected from subjects on days 0 (D0), 14 (D14), 28 (D28), and 56 (D56). Data collection involved subjects cleansing their faces with a facial cleanser, drying their skin with a tissue, and sitting quietly for 20 minutes in an indoor environment with a temperature of 22±1 ℃ and humidity of 50±5%. The corresponding indicators were then measured using appropriate instruments.

[0109] The t-test is a method for comparing means in analysis of variance. In the efficacy evaluation of cosmetic experiments, since most experiments require statistical analysis, the mathematical method of analysis of variance is introduced to perform significance analysis based on variance to test the reliability of the experimental data. If the calculated result ρ ≤ 0.05, the comparison between the two groups of data is considered significant; if ρ > 0.05, the comparison between the two groups of data is considered non-significant, meaning that although the experimental values ​​are different, there is no statistically significant difference.

[0110] (1) Skin melanin index (MI) test

[0111] Melanin in human skin is synthesized by skin melanocytes through a series of reactions, and its content and distribution result in a variety of skin colors. The melanin index (MI) characterizes the skin's melanin content, ranging from 0 to 999. A lower MI indicates less melanin in the skin, resulting in a lighter skin tone. Therefore, the melanin index (MI) is one of the main indicators reflecting changes in skin color. Using the Mexameter skin melanin and hemoglobin analyzer, the MI of each subject was measured at D0, D14, D28, and D56. The results are shown in Table 9.

[0112] Table 9 Results of Skin Melanin Index (MI) Detection

[0113]

[0114] *Based on the t-test values, "+" indicates a significant difference (ρ≤0.05), and "--" indicates a non-significant difference (ρ>0.05).

[0115] It is evident that after a period of testing, the skin melanin index (MI) in the tested areas of all three samples decreased significantly compared to the baseline value, and the magnitude of the decrease increased with the extension of the testing time. Among them, sample No. 3 showed the largest decrease, indicating that polyaspartic acid chelated zinc has a better effect on the skin melanin index (MI) than the control group.

[0116] (2) VISA L* value test

[0117] The skin brightness L* value is used to characterize the brightness of the skin, that is, the whiteness or blackness of the skin; the higher the value, the whiter the skin. The L* value of each subject's test area was collected at D0, D14, D28, and D56 using the VISIA facial image analyzer, and the results are shown in Table 10.

[0118] Table 10 VISA L* Value Detection Results

[0119]

[0120] *Based on the t-test values, "+" indicates a significant difference (ρ≤0.05), and "--" indicates a non-significant difference (ρ>0.05).

[0121] It is evident that after a period of testing, the VISA L* values ​​in the tested areas of all three samples significantly increased compared to baseline values, and the increase in magnitude increased with the duration of the test. Sample No. 3 showed the greatest increase, indicating that polyaspartic acid chelated zinc has a better effect on skin VISA L* values ​​than the control group.

[0122] (3) VISA a* value test

[0123] The skin redness a* value is used to characterize the redness of the skin; the higher the value, the redder the skin. Using the VISIA facial image analyzer, the a* values ​​of each subject's test sites were collected at D0, D14, D28, and D56. The results are shown in Table 11.

[0124] Table 11 VISA a* value test results

[0125]

[0126] *Based on the t-test values, "+" indicates a significant difference (ρ≤0.05), and "--" indicates a non-significant difference (ρ>0.05).

[0127] It is evident that after a period of testing, the VISA a* values ​​in the tested areas of all three samples significantly decreased compared to baseline values, and the magnitude of the decrease increased with the extension of the testing time. Among them, sample 3 showed the largest decrease, indicating that polyaspartic acid chelated zinc has a better effect on skin VISA a* values ​​than the control group.

[0128] (4) VISA ITA° value test

[0129] The ITA° value characterizes the whiteness of the skin; the higher the value, the whiter the skin. Using the VISIA facial image analyzer, ITA° values ​​were collected for each subject's test areas at D0, D14, D28, and D56. The results are shown in Table 12.

[0130] Table 12 VISA ITA° Value Detection Results

[0131]

[0132] *Based on the t-test values, "+" indicates a significant difference (ρ≤0.05), and "--" indicates a non-significant difference (ρ>0.05).

[0133] It is evident that after a period of testing, the VISA ITA° values ​​in the tested areas of all three samples significantly increased compared to baseline values, and the increase in magnitude increased with the extension of testing time. Among them, sample 3 showed the greatest increase, indicating that polyaspartic acid chelated zinc has a better effect on skin VISA ITA° values ​​than the control group.

[0134] Based on the results of the skin melanin index (MI), VISA L* value, VISA a* value, and VISA ITA° value from the above human skin whitening efficacy evaluation experiment, it can be concluded that polyaspartic acid chelated zinc has a better skin whitening effect than zinc aspartate and sodium polyaspartate at the same concentration.

[0135] The sixth embodiment of the present invention provides a skin care product formulation with polyaspartic acid chelated zinc as one of its components.

[0136] Polyaspartic acid chelated zinc with an average molecular weight of 8 kDa was used as a component in facial cleanser, shampoo, soap, and laundry detergent, respectively, with the following formulations:

[0137] (1) Facial cleanser: Its components and proportions are shown in Table 13.

[0138] Table 13 Facial Cleanser Formula

[0139]

[0140] (2) Toner: Its components and proportions are shown in Table 14.

[0141] Table 14 Toner Formula

[0142]

[0143] (3) Essence: Its components and proportions are shown in Table 15.

[0144] Table 15 Serum Formula

[0145]

[0146] (3) Face cream: Its components and proportions are shown in Table 16.

[0147] Table 16 Face Cream Formula

[0148]

[0149] The embodiments of the present invention aim to protect the use of a chelated zinc composition in skin care and pharmaceutical compositions or skin care products, and have the following effects:

[0150] 1. The polyaspartic acid chelated zinc of the present invention, compared with polyaspartic acid, not only has excellent water retention and moisturizing properties, but also has better whitening effect, and also has antibacterial and anti-inflammatory effects, making it more widely applicable.

[0151] 2. The chelated zinc of the present invention uses polyaspartic acid as a chelating agent, which not only has high biocompatibility and low skin irritation, but also has a relatively stable chelating bond compared to elemental zinc, zinc oxide and zinc salts, giving it long-lasting efficacy.

[0152] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. The use of a chelated zinc composition in the preparation of moisturizing products, anti-inflammatory products, and whitening products, characterized in that, The chelated zinc composition is polyaspartic acid chelated zinc, and the molecular weight of the polyaspartic acid chelated zinc is calculated based on the average molecular weight of polyaspartic acid, ranging from 8 kDa to 20 kDa.

2. The use according to claim 1, characterized in that, The zinc content in the polyaspartic acid chelated zinc is between 10 wt% and 20 wt%.

3. The use according to claim 2, characterized in that, The zinc chelation degree in the polyaspartic acid chelated zinc is 75% to 90%.

4. A pharmaceutical composition or skin care product, characterized in that, The pharmaceutical composition or skin care product contains a chelated zinc composition, wherein the chelated zinc composition is polyaspartic acid chelated zinc, and the polyaspartic acid chelated zinc is the polyaspartic acid chelated zinc as described in any one of claims 1-3.

5. The pharmaceutical composition or skin care product according to claim 4, characterized in that, The dosage forms of the pharmaceutical composition include aqueous solutions, aerosols, sprays, emulsions, ointments, gels, or lyophilized powders; The skincare products include facial cleansers, toners, serums, lotions, or creams.

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