Chelated zinc composition and application thereof in wash supplies

Abstract

The invention belongs to the technical field of daily chemical product application, and discloses a chelated zinc composition and application thereof in wash supplies, the chelated zinc composition comprises polyaspartic acid chelated zinc, water and polyol, and the soluble solid content of the chelated zinc composition is 36-42%. According to the product, the anti-inflammatory and whitening effects can be improved, and compared with elemental zinc, zinc oxide and zinc salt, the effect durability of the product is effectively improved due to the relative stability of chelating bonds of the product.

Description

Technical Field

[0001] This invention belongs to the field of daily chemical product application technology, and specifically relates to a chelated zinc composition and its use in washing and care products. Background Technology

[0002] Polyaspartic acid and its sodium salt are homopolymeric amino acids whose main chain 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 then processing them through various methods to obtain a water-insoluble polymerization intermediate, polysuccinimide, which is subsequently hydrolyzed in an alkaline aqueous solution. Because polyaspartic acid and its sodium salt possess numerous carboxyl or sodium carboxylate side chains, exhibiting properties similar to polyglutamic acid or hyaluronic acid, they have gained widespread acceptance and application 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.

[0003] 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, a multi-step reaction is carried out, including thermal polycondensation to obtain polysuccinimide, heated ring-opening grafting of alkyl primary amines, and grafting lysine using the carbodiimide method, to obtain lysine-polyaspartic acid derivatives with amphoteric molecules, which can increase skin permeability and promote collagen production.

[0004] 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.

[0005] 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

[0006] (I) Purpose of the Invention

[0007] The purpose of this invention is to provide a chelated zinc composition and its use in personal care products. The chelated zinc composition includes polyaspartic acid chelated zinc and water. Polyaspartic acid chelated zinc can enhance the anti-inflammatory and whitening effects on the basis of the moisturizing properties of polyaspartic acid. Moreover, compared with elemental zinc, zinc oxide and zinc salts, the relative stability of its chelate bonds effectively improves the longevity of its effects.

[0008] (II) Technical Solution

[0009] To address the aforementioned problems, a first aspect of the present invention provides a chelated zinc composition comprising polyaspartic acid chelated zinc and water. The soluble solids content of the chelated zinc composition is 36-42%. Excessive soluble solids can lead to excessively high viscosity and ionic strength of the sample solution, thereby affecting the formulation process and resulting in low fluidity or demulsification of the washing and care products. Conversely, excessively low soluble solids indicate insufficient effective ingredients in the sample, thus affecting the various efficacy effects of the product.

[0010] Preferably, the molecular weight of the polyaspartic acid chelated zinc is 30-50 kDa, based on the average molecular weight of the polyaspartic acid. The water retention performance of the product is determined by the 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 ultimately the anti-inflammatory and whitening effect will be worse.

[0011] Preferably, the zinc mass fraction in the chelated zinc composition is between 0.4 wt% and 0.6 wt%. Preferably, the chelation degree of polyaspartic acid to zinc in the chelated zinc composition is 0.4%-0.5%. 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.

[0012] Preferably, the chelated zinc composition further comprises a polyol, wherein the polyol is one or more selected from ethylene glycol, 1,3-propanediol, glycerol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, and 1,2-hexanediol, and the mass fraction of the polyol is 6.5 to 13 wt% (the percentage in the chelated zinc composition).

[0013] A second aspect of the present invention provides the use of any of the chelated zinc compositions described above in a personal care product, the personal care product comprising the following components by weight percentage: 70%-95% main cleansing component, 7%-15% conditioning and thickening component, 1.0%-1.5% functional preservative component, and 0.6%-1.1% post-treatment component, the sum of the above components being 100%, wherein, in the functional preservative component, the chelated zinc composition accounts for 0.3% to 0.35% of the proportion in the personal care product.

[0014] Preferably, the main cleaning component comprises the following components by weight percentage: 50%–60% water, 0.05%–0.15% disodium EDTA, 0.6%–1.0% cocamide, 5%–7% cocamidopropyl betaine, 5%–7% sodium methyl cocoyl taurate, 12%–17% sodium lauryl ether sulfate, and 1%–3% sodium olefin sulfonate. Based on the total weight of the washing and care product (i.e., 100% overall), the sum of the above components is in the range of 70%–95%.

[0015] Preferably, the conditioning and thickening component comprises the following components by mass percentage: 0.08% to 0.15% of polyquaternium-67, 0.1% to 0.2% of hydroxypropyl guar gum hydroxypropyl trimethylammonium chloride, and 7% to 12% of water, with the sum of the above components in the range of 7% to 15% based on the total mass of the shampoo and conditioner product.

[0016] Preferably, the preservative component further includes the following components in weight percentage: 0.1% to 0.15% ethylhexylglycerin and 0.5% to 1% phenoxyethanol, wherein the above weight percentages are based on the total weight of the washing and care product.

[0017] Preferably, the post-conditioning component includes the following components by mass percentage: 0.4% to 0.7% sodium chloride and 0.2% to 0.4% fragrance, based on the total mass of the shampoo and conditioner (i.e., 100% overall), and the sum of the above components is in the range of 0.3% to 0.35%.

[0018] In addition, a third aspect of the present invention provides an application as described in any of the above descriptions, wherein the product form of the personal care products includes shampoo, shower gel, hand soap, conditioner, hair spray, hair treatment cream, scrub, leave-in hair care product, cream soap, bar soap, shampoo bar, hair conditioner, dry shampoo spray, and body cleansing powder.

[0019] (III) Beneficial Effects

[0020] The above-mentioned technical solution of the present invention has the following beneficial technical effects: The present invention provides a chelated zinc composition and its use in washing and care products. The soluble solids content of the chelated zinc composition is 36-42%. Compared with polyaspartic acid, the polyaspartic acid chelated zinc composition of the present invention not only has excellent water retention and moisturizing properties, but also has better whitening effect, and also has antibacterial and anti-inflammatory effects, and its application field is wider. The polyaspartic acid chelated zinc composition of the present 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 with elemental zinc, zinc oxide and zinc salts, which makes it have long-lasting efficacy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the molecular structure of the polyaspartic acid chelated zinc of the present invention;

[0022] Figure 2 This is a schematic diagram of the molecular structure of aspartic acid.

[0023] Figure 3 This is a schematic diagram of the molecular structure of polyaspartic acid according to the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0025] The chelated zinc composition provided by this invention comprises polyaspartic acid chelated zinc and water, wherein the polyaspartic acid chelated zinc has the following structure: Figure 1 As shown, combined with Figure 2 The molecular structure of aspartic acid and Figure 3 The molecular structure of polyaspartic acid is explained. Figure 2 In traditional Chinese medicine, the aspartic acid molecule is formed by the dehydration of the carboxyl group of one aspartic acid molecule and the amino group of another aspartic acid molecule to create an amide bond. This allows two aspartic acid molecules to combine into one molecule. By reacting multiple aspartic acid molecules in this manner, long-chain compounds such as... Figure 3 The polyaspartic acid molecule shown is an example of polyaspartic acid. Because the aspartic acid molecule contains two carboxyl groups, the repeating aspartic acid units on the polyaspartic acid backbone can have two structures. Due to the large number of carboxyl groups on the side chains of polyaspartic acid, it has the potential to combine with metal ions to form chelate structures. In the presence of exogenous ammonia, amino, or ammonium ions, polyaspartic acid can form a relatively stable six-coordinate chelate structure with zinc ions. The "polyaspartic acid chelated zinc" of this invention can also be called "polyaspartic acid chelated zinc" or "polyaspartic acid chelated zinc".

[0026] Example 1

[0027] (1) Preparation of polyaspartic acid chelated zinc

[0028] Add 1.5L of deionized water to a 5L reactor, then add 0.5kg of ammonium sulfate, 0.7L of ammonia (25% by mass) and 0.3kg of zinc oxide sequentially under stirring, ensuring they are fully dissolved and mixed evenly. Heat the reaction system to 60℃, then add 1kg of polysuccinimide and react at 60℃ for 4 hours with stirring to obtain a clear, transparent, reddish-brown liquid. Filter the product through a fiber membrane with a molecular weight cutoff of 3000 to remove residual salts, then spray dry at 180℃ to obtain a brownish-yellow powder, which is polyaspartic acid chelated zinc.

[0029] (2) Preparation of polyaspartic acid chelated zinc composition

[0030] The polyaspartic acid chelated zinc obtained in step (1) was dissolved in deionized water to prepare solutions with a soluble solids content of 38%. Zinc aspartate and polyaspartic acid were used as comparative examples, and the results are shown in Table 1. The zinc content was tested by dissolving the sample in pure water to prepare a solution of a certain concentration, and then using Thermo Fisher iCAP... TM Zinc content was measured using a PRO ICP-OES inductively coupled plasma atomic emission spectrometer; zinc chelation was tested using EDTA titration. The molecular weights in Table 1 are based on the average molecular weight of polyaspartic acid, which is 30 kDa.

[0031] Example 2

[0032] (1) Preparation of polyaspartic acid chelated zinc

[0033] Add 1.5L of deionized water to a 5L reactor, then add 0.7kg of ammonium sulfate, 0.5L of ammonia (25%), and 0.3kg of zinc oxide sequentially under stirring, ensuring they are fully dissolved and mixed evenly. Heat the reaction system to 50°C, then add 1kg of polysuccinimide and react at 50°C for 4 hours with stirring to obtain a clear, transparent, reddish-brown liquid. Filter the product through a fiber membrane with a molecular weight cutoff of 3000 to remove residual salts, then spray dry at 180°C to obtain a brownish-yellow powder, which is polyaspartic acid chelated zinc.

[0034] (2) Preparation of polyaspartic acid chelated zinc composition

[0035] The polyaspartic acid chelated zinc obtained in step (1) was dissolved in deionized water to prepare solutions with a soluble solids content of 40%. Zinc aspartate and polyaspartic acid were used as comparative examples, and the results are shown in Table 1. The zinc content was tested by dissolving the sample in pure water to prepare a solution of a certain concentration, and then using Thermo Fisher iCAP... TM Zinc content was measured using a PRO ICP-OES inductively coupled plasma atomic emission spectrometer; zinc chelation was tested using EDTA titration. The molecular weights in Table 1 are based on the average molecular weight of polyaspartic acid, which is 40 kDa.

[0036] Example 3

[0037] (1) Preparation of polyaspartic acid chelated zinc

[0038] Add 1.3L of deionized water to a 5L reactor, then add 0.5kg of ammonium sulfate, 0.5L of ammonia (25%), and 0.5kg of zinc oxide sequentially under stirring, ensuring they are fully dissolved and mixed evenly. Heat the reaction system to 60℃, then add 1kg of polysuccinimide and react for 6 hours under stirring at 60℃ to obtain a clear, transparent, reddish-brown liquid. Filter the product through a fiber membrane with a molecular weight cutoff of 3000 to remove residual salts, then spray dry at 180℃ to obtain a brownish-yellow powder, which is polyaspartic acid chelated zinc.

[0039] (2) Preparation of polyaspartic acid chelated zinc composition

[0040] The polyaspartic acid chelated zinc obtained in step (1) was dissolved in deionized water to prepare solutions with a soluble solids content of 36%. Zinc aspartate and polyaspartic acid were used as comparative examples, and the results are shown in Table 1. The zinc content was tested by dissolving the sample in pure water to prepare a solution of a certain concentration, and then using Thermo Fisher iCAP... TM Zinc content was measured using a PRO ICP-OES inductively coupled plasma atomic emission spectrometer; zinc chelation was tested using EDTA titration. The molecular weights in Table 1 are based on the average molecular weight of polyaspartic acid, which is 35 kDa.

[0041] Example 4

[0042] (1) Preparation of polyaspartic acid chelated zinc

[0043] Add 1.5L of deionized water to a 5L reactor, then add 0.7kg of ammonium sulfate, 0.7L of ammonia (25%), and 0.3kg of zinc oxide sequentially under stirring, ensuring they are fully dissolved and mixed evenly. Heat the reaction system to 60℃, then add 1kg of polysuccinimide and react for 5 hours under stirring at 60℃ to obtain a clear, transparent, reddish-brown liquid. Filter the product through a fiber membrane with a molecular weight cutoff of 3000 to remove residual salts, then spray dry at 180℃ to obtain a brownish-yellow powder, which is polyaspartic acid chelated zinc.

[0044] (2) Preparation of polyaspartic acid chelated zinc composition

[0045] The polyaspartic acid chelated zinc obtained in step (1) was dissolved in deionized water to prepare solutions with a soluble solids content of 42%. Zinc aspartate and polyaspartic acid were used as comparative examples, and the results are shown in Table 1. The zinc content was tested by dissolving the sample in pure water to prepare a solution of a certain concentration, and then using Thermo Fisher iCAP... TM Zinc content was measured using a PRO ICP-OES inductively coupled plasma atomic emission spectrometer; zinc chelation was tested using EDTA titration. The molecular weights in Table 1 are based on the average molecular weight of polyaspartic acid, which is 50 kDa.

[0046] Table 1. Polyaspartic acid chelated zinc compositions and comparative results

[0047]

[0048]

[0049] Example 5

[0050] This embodiment provides a formula for a shampoo and conditioner containing a polyaspartic acid chelated zinc composition as one of its components. To prepare this oil-controlling and dandruff-reducing shampoo, 56.6 wt% deionized water was first added to a mixing tank, and low-speed stirring was started. 0.1 wt% disodium EDTA was added to dissolve and form a basic aqueous phase. Then, 6.0 wt% cocamidopropyl betaine, 6.0 wt% sodium methyl cocoyl taurate, 15.0 wt% sodium lauryl ether sulfate, and 3.0 wt% sodium C14-16 olefin sulfonate were added sequentially, and the mixture was stirred at medium speed to prepare the main cleaning mixture. Separately, a small amount of water was used to disperse and dissolve 0.12 wt% polyquaternium-67 and 0.18 wt% hydroxypropyl guar gum hydroxypropyl trimethylammonium chloride to prepare a conditioning and thickening premix, which was then poured into the main cleaning mixture and stirred at medium speed until homogeneous. While stirring, 0.4 wt% chelated zinc composition (Example 2), 0.1 wt% ethylhexylglycerin, and 0.8 wt% phenoxyethanol were added and mixed thoroughly. Slowly add 0.6 wt% sodium chloride, stir at medium speed to low speed, and adjust the viscosity to the target value by salting out; add 0.3 wt% flavoring, test and adjust the pH, add deionized water to make up the volume, turn on the homogenizer and process for 5-10 minutes, and fill after the appearance, viscosity and other indicators are qualified.

[0051] The polyaspartic acid chelated zinc composition containing an average molecular weight of 40 kDa, as described in Example 2, was used as a component of the shampoo, and its formulation is shown in Table 2.

[0052] Table 2 Oil-control and anti-dandruff shampoo formulas

[0053]

[0054] Example 6

[0055] This embodiment provides a shampoo and conditioner formulation using a polyaspartic acid chelated zinc composition as one of its components. The polyaspartic acid chelated zinc composition containing an average molecular weight of 30 kDa from Example 1 is used as a component of the shampoo, and the preparation process is the same as in Example 5. The formulation is shown in Table 3.

[0056] Table 3 Oil-control and anti-dandruff shampoo formulas

[0057]

[0058]

[0059] Example 7

[0060] This embodiment provides a shampoo and conditioner formulation with a polyaspartic acid chelated zinc composition as one of its components. The polyaspartic acid chelated zinc composition containing an average molecular weight of 35 kDa from Example 3 was used as a component of the shampoo, and the preparation process was the same as in Example 5. The formulation is shown in Table 4.

[0061] Table 4 Oil-control and anti-dandruff shampoo formulas

[0062]

[0063]

[0064] Example 8

[0065] This embodiment provides a shampoo and conditioner formulation using a polyaspartic acid chelated zinc composition as one of its components. The polyaspartic acid chelated zinc composition containing an average molecular weight of 50 kDa from Example 4 is used as a component of the shampoo, and the preparation process is the same as in Example 5. The formulation is shown in Table 5.

[0066] Table 5 Oil-control and anti-dandruff shampoo formulas

[0067]

[0068]

[0069] Comparative Example 1

[0070] This comparative example provides a shampoo and conditioner formulation with zinc aspartate as one of its components. Using zinc aspartate with an average molecular weight of 0.33 kDa as a component of the shampoo from Comparative Example 1, the preparation process was the same as in Example 5, and the formulation is shown in Table 6.

[0071] Table 6 Oil-control and anti-dandruff shampoo formulas

[0072]

[0073] Comparative Example 2

[0074] This comparative example provides a shampoo and conditioner formulation with polyaspartic acid as one of its components. Using polyaspartic acid with an average molecular weight of 50 kDa from Comparative Example 2 as a component of the shampoo, the preparation process was the same as in Example 5, and its formulation is shown in Table 7.

[0075] Table 7 Oil-control and anti-dandruff shampoo formulas

[0076]

[0077] Comparative Example 3

[0078] This embodiment provides a shampoo and conditioner formulation using a polyaspartic acid chelated zinc composition as one of its components. The polyaspartic acid chelated zinc composition, with an average molecular weight of 28 kDa, a zinc content of 0.3 wt%, and a zinc chelation degree of 0.21%, is used as a component of the shampoo. The preparation process is the same as in Example 5, and its formulation is shown in Table 8.

[0079] Table 8 Oil-control and anti-dandruff shampoo formula

[0080]

[0081]

[0082] Comparative Example 4

[0083] This embodiment provides a shampoo and conditioner formulation using a polyaspartic acid chelated zinc composition as one of its components. The polyaspartic acid chelated zinc composition, with an average molecular weight of 56 kDa, a zinc content of 0.7 wt%, and a zinc chelation degree of 0.66%, is used as a component of the shampoo. The preparation process is the same as in Example 5, and its formulation is shown in Table 9.

[0084] Table 9 Oil-control and anti-dandruff shampoo formulas

[0085]

[0086]

[0087] The samples prepared in Examples 5-8 and Comparative Examples 1-4 were subjected to anti-inflammatory efficacy tests, as follows:

[0088] I. Anti-inflammatory effect test

[0089] 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. The effect of various test samples on the inhibition rate of hyaluronidase was examined.

[0090] (1) Prepare the test solution according to the components shown in Table 10.

[0091] Table 10 Components of the solution to be tested

[0092]

[0093] (2) After keeping each solution in step (1) at 37°C for 20 min, add 0.1 mL of 2.5 mol / L CaCl2 solution to each solution. After keeping the solution in 37°C for another 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.

[0094] (3) After keeping each solution in step (2) at 37°C for 40 min, place it 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.

[0095] (4) Place each solution from step (3) in a boiling water bath for 15 minutes, then in an ice bath for 10 minutes, and then let it stand at room temperature (25°C) for 10 minutes. 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.

[0096] (5) After shaking each solution in step (4) thoroughly, add anhydrous ethanol to make up the solution volume to 8 mL; after standing at room temperature (25℃) for 30 min, use a UV spectrophotometer to detect the absorbance at 530 nm.

[0097] The method for calculating the hyaluronidase inhibition rate is as follows:

[0098]

[0099] 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).

[0100] Following the above method, the hyaluronidase inhibition rate of each prepared sample solution was detected, with acetate buffer as a blank control. The results are shown in Table 11.

[0101] Table 11 Results of Hyaluronidase Inhibition Rate Detection

[0102]

[0103]

[0104] As shown in Table 11, all sample solutions exhibited hyaluronidase inhibition. The chelated zinc compositions used in Examples 5-8 showed higher hyaluronidase inhibition rates than Comparative Example 2 (sodium polyaspartate) and Comparative Example 1 (zinc aspartate), indicating that chelated zinc significantly promotes the improvement of hyaluronidase inhibition. Polyaspartic acid molecules contain numerous functional groups such as carboxyl groups, which can coordinate with zinc ions to form chelates with specific spatial structures. This coordination structure gives polyaspartic acid chelated zinc a unique three-dimensional morphology; compared to free polyaspartic acid and zinc ions, its molecular surface binding sites are more ordered and specific. When in contact with hyaluronidase, polyaspartic acid chelated zinc can bind to the enzyme's active site or key sites more precisely, thereby effectively inhibiting enzyme activity. Simultaneously, the coordination structure endows polyaspartic acid chelated zinc with high stability, making it less prone to dissociation in the physiological environment. This means it can maintain its structural integrity for a longer period, continuously interacting with hyaluronidase and maintaining its inhibitory effect on enzyme activity. While polyaspartic acid alone contains functional groups that can interact with other substances, it lacks the spatial structure optimization provided by zinc ion coordination. Its molecular structure is relatively loose and flexible, making it difficult to stably and specifically bind to the key action sites of hyaluronidase, resulting in limited inhibitory effects. Free zinc ions are in a disordered, free state in solution, and their small size makes it difficult for them to directly form stable and effective binding with hyaluronidase. They can only exert their potential effect through random collisions, thus resulting in very low inhibitory efficiency against hyaluronidase.

[0105] The differences in hyaluronidase inhibition rates between Examples 5-8 and Comparative Examples 3-4 stem from variations in the synergy of key parameters. Examples 5-8, with their moderate molecular weight of 30-50 kDa, ensured the efficient and stable participation of zinc ions in the inhibition reaction. The synergistic effect of 0.4-0.6 wt% zinc content and 0.4-0.5% chelation achieved effective zinc ion loading and controllable release, resulting in inhibition rates of 59.97%-63.72%. Comparative Example 3, with its shorter molecular weight and lower chelation, allowed zinc to easily dissociate, achieving an inhibition rate of 49.33%. Comparative Example 4, with its excessively long molecular chain and significant steric hindrance, struggled to release zinc ions, resulting in an inhibition rate of 41.52%. Both examples were significantly lower than the examples, demonstrating the rationality of the synergistic optimization of parameters in improving the inhibition effect and supporting product efficacy.

[0106] As can be seen from the above, polyaspartic acid chelated zinc has a significant effect on improving the inhibition rate of hyaluronidase and has good anti-inflammatory effects.

[0107] II. Evaluation of oil-controlling efficacy (5α-reductase inhibition rate)

[0108] 5α-reductase is a membrane protease dependent on reduced coenzyme II (NADPH) and an important enzyme in the skin that metabolizes androgens. It irreversibly converts testosterone to dihydrotestosterone (DHT), the most potent androgen, which can induce excessive sebum secretion from the sebaceous glands. Inhibiting 5α-reductase activity to reduce DHT levels can effectively alleviate excessive sebum secretion. Therefore, inhibiting 5α-reductase activity is used as an indicator in research on oil-controlling effects.

[0109] The methods for testing the 5α-reductase inhibition rate of each embodiment and comparative example include:

[0110] (1) Take out the Omnimabs Human Steroid 5Alpha Reductase (SRD5a) kit and place it at room temperature (20-25℃) for 30 min.

[0111] (2) Follow the kit operation procedure strictly and finally measure the UV absorption at 450nm.

[0112] (3) The content of 5α-reductase was obtained from the standard curve, and the inhibition rate of 5α-reductase was calculated.

[0113] The method for calculating the 5α-reductase inhibition rate is as follows:

[0114]

[0115] Where: C is the 5α-reductase content of the negative control; T is the 5α-reductase content of the sample solution.

[0116] Deionized water was used as a negative control, and 0.5 μmol dutasteride was used as a positive control. The results are shown in Table 12.

[0117] Table 12 5α-Reductase Inhibition Rate

[0118]

[0119]

[0120] As shown in Table 12, all sample solutions exhibited 5α-reductase inhibition, similar to the inhibition pattern of hyaluronidase described above. However, there were significant differences in the 5α-reductase inhibition effects between Examples 5-8 and Comparative Examples 1-4. The coordination structure of polyaspartic acid chelated zinc, through optimized molecular-enzyme binding site adaptation, synergistic inhibition of zinc ions and polyaspartic acid, strong induction of enzyme structural and functional changes, and improved bioavailability and duration of action, resulted in a significantly higher inhibition rate of 5α-reductase than that of polyaspartic acid and free zinc ions. Therefore, polyaspartic acid chelated zinc significantly enhances the 5α-reductase inhibition rate and possesses excellent oil-controlling efficacy.

[0121] This invention provides a chelated zinc composition suitable for use in the cosmetics industry and its use in personal care products, which has the following advantages:

[0122] 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.

[0123] 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.

[0124] 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. A chelated zinc composition, characterized in that, The chelated zinc composition comprises polyaspartic acid chelated zinc and water, and the soluble solids content of the chelated zinc composition is 36-42%.

2. The chelated zinc composition according to claim 1, characterized in that, The molecular weight of the polyaspartic acid chelated zinc is calculated based on the average molecular weight of polyaspartic acid, and its range is 30-50 kDa.

3. The chelated zinc composition according to claim 1, characterized in that, The zinc mass fraction in the chelated zinc composition is between 0.4 wt% and 0.6 wt%.

4. The chelated zinc composition according to claim 1, characterized in that, The chelation degree of polyaspartic acid in the chelated zinc composition is 0.4% to 0.5%.

5. The chelated zinc composition according to claim 1, characterized in that, The chelated zinc composition further comprises a polyol, which is one or more of ethylene glycol, 1,3-propanediol, glycerol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, and 1,2-hexanediol, and the mass fraction of the polyol is 6.5 to 13 wt%.

6. The use of the chelated zinc composition according to any one of claims 1 to 5 in a personal care product, characterized in that, The washing and care product comprises the following components by weight percentage: 70%-95% main cleansing component, 7%-15% conditioning and thickening component, 1.0%-1.5% functional preservative component, and 0.6%-1.1% post-conditioning component, with the sum of all components being 100%. Among the functional preservative component, the chelated zinc composition accounts for 0.3% to 0.35% of the washing and care product.

7. The use according to claim 6, characterized in that, The main cleaning component comprises the following components in weight percentage: 50%–60% water, 0.05%–0.15% disodium ethylenediaminetetraacetate, 0.6%–1.0% cocamide, 5%–7% cocamidopropyl betaine, 5%–7% sodium methyl cocoyl taurate, 12%–17% sodium lauryl ether sulfate, and 1%–3% sodium olefin sulfonate.

8. The use according to claim 6, characterized in that, The conditioning and thickening component comprises the following components by weight percentage: 0.08%–0.15% polyquaternium-67, 0.1%–0.2% hydroxypropyl guar hydroxypropyltrimethylammonium chloride, and 7%–12% water; the post-conditioning component comprises the following components by weight percentage: 0.4%–0.7% sodium chloride and 0.2%–0.4% flavoring.

9. The use according to claim 6, characterized in that, The effective preservative component also includes the following components in weight percentage: 0.1% to 0.15% ethylhexylglycerin and 0.5% to 1% phenoxyethanol.

10. The use of the chelated zinc composition according to any one of claims 6 to 9 in a personal care product, characterized in that, The forms of the hair care products include shampoo, shower gel, hand soap, conditioner, hair spray, hair treatment cream, scrub, leave-in hair care products, cream soap, bar soap, shampoo bar, hair conditioner, dry shampoo spray, and body cleansing powder.

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