A soothing panthenol-succinic acid eutectic and methods of making and using same

Abstract

The application discloses a panthenol-succinic acid eutectic mixture for soothing and repairing, and a preparation method and application thereof, and belongs to the technical field of cosmetics. The technical problem to be solved is to provide a panthenol-succinic acid eutectic mixture, which can effectively avoid panthenol low-temperature crystallization, poor water solubility of succinic acid and cytotoxicity, and has a good cell scratch repairing effect. The technical solution is that the panthenol-succinic acid eutectic mixture is composed of panthenol and succinic acid.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, specifically to a soothing and repairing panthenol-succinic acid eutectic, its preparation method, and its application. Background Technology

[0002] For understanding the technical content of this invention: Panthenol is a classic repairing and moisturizing active ingredient in cosmetics and topical skin preparations. It can penetrate the stratum corneum, participate in skin lipid and protein metabolism, repair damaged skin barriers, and has multiple effects such as moisturizing, soothing redness, and promoting wound repair. It is widely used in product systems such as serums, lotions, repair creams, and medical gels. Succinic acid, as a natural dibasic organic acid, is a mild and low-irritant fruit acid. It can regulate skin keratin metabolism, inhibit acne-causing bacteria, and provide antioxidant and soothing effects. At the same time, it can optimize the preservative system of the formula and adapt to the slightly acidic physiological environment of the skin. It has broad application prospects in oil-controlling, soothing, and repairing skin care products. The combination of these two can form a synergistic system of moisturizing and anti-inflammatory repair, which is an optimal combination for repairing sensitive skin and oily and acne-prone skin.

[0003] Existing conventional physical compounding and multi-solvent solubilization processes have several insurmountable technical drawbacks. In conventional simple physical mixing systems, panthenol exhibits significant low-temperature crystallization defects, resulting in poor formulation storage stability; succinic acid itself has poor water solubility and a strong tendency to crystallize, making it difficult to achieve stable high-concentration additions through conventional compounding; existing improvement methods include alkali neutralization to form salts, organic solvent dissolution, and betaine eutectic modification, but neutralization to form salts significantly weakens the anti-inflammatory and keratin conditioning activities of succinic acid.

[0004] Relevant patent documents retrieved: The document, published in China (CN117551277B) on April 19, 2024, discloses a low-pH azelaic acid liquid supramolecular self-recognition system and its preparation and application. By mixing and heating azelaic acid, succinic acid, and panthenol, a low-pH azelaic acid liquid supramolecular self-recognition system is obtained, which effectively improves the solubility of azelaic acid. This patent is the closest to the prior art of this invention, and both contain succinic acid and panthenol. However, the patented product must introduce azelaic acid as a core building block, making it only suitable for acne treatment, whitening, and oil control products. For infant skincare, post-operative repair, and dry and sensitive skin products that only require gentle repair with panthenol and succinic acid and do not require acne-removing acids, this ternary system will cause additional irritation due to the presence of azelaic acid, resulting in poor formula compatibility. Furthermore, this patent does not address the issue of low-temperature crystallization of panthenol, only solving the precipitation defect of azelaic acid. After separating azelaic acid, the binary mixture of panthenol and succinic acid cannot form a stable liquid state, and a large amount of crystals still precipitate at low temperatures. At the same time, it does not optimize the cell irritation of the binary system, and cannot meet the development needs of gentle repair products.

[0005] The publication, published in China (CN111728916) on October 2, 2020, discloses a soothing and multi-moisturizing cream containing panthenol, senna flower extract, daisy flower extract, sodium lactate, serine, glycine, arginine, aspartic acid (succinic acid), leucine, glutamic acid, threonine, histidine, pyrrolidone carboxylic acid, and other soothing ingredients and multiple moisturizing factors. This formulation uses a conventional physical compounding method, which cannot solve the problems of panthenol's low-temperature crystallization and succinic acid's poor water solubility and cytotoxicity at high concentrations.

[0006] Eutectic mixtures are homogeneous mixtures formed by the non-covalent interactions of two or more components through intermolecular hydrogen bonds and other bonds, with melting points significantly lower than the individual melting points of each component. In recent years, eutectic mixtures have attracted widespread attention in cosmetics, pharmaceuticals, and food industries due to their advantages such as simple preparation, environmental friendliness, and high designability. However, the selection of compatible molecules in an eutectic mixture system is crucial; the type and content of these molecules directly affect the formation of a supramolecular self-recognition system.

[0007] The prior art represented by the aforementioned documents has at least the following unresolved technical problems or defects: Currently, the industry lacks a binary eutectic raw material composed solely of panthenol and succinic acid, formed through intermolecular hydrogen bonding self-assembly. Existing processes cannot simultaneously address the three core technical challenges of low-temperature crystallization of panthenol, poor water solubility of succinic acid, and high cytotoxicity of the compound system. Therefore, developing a panthenol-succinic acid binary eutectic, which binds free active groups through intermolecular hydrogen bonds, simultaneously avoids low-temperature crystallization of panthenol and precipitation of succinic acid, reduces cytotoxicity, simplifies raw material components, and expands application scenarios for gentle repair cosmetics and topical formulations, possessing significant industrialization value. Summary of the Invention

[0008] The purpose of this invention is to provide: A panthenol-succinic acid eutectic and related technologies are proposed to address the challenges of simultaneously avoiding low-temperature crystallization of panthenol, precipitation of succinic acid, and reducing cytotoxicity in existing technologies.

[0009] Terminology Explanation: Unless otherwise defined, all technical terms in this document have the same meanings as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains. Unless otherwise stated, all patents, patent inventions, and publications cited in this document are incorporated herein by reference in their entirety. If multiple definitions exist for terms in this document, the definitions in this chapter shall prevail.

[0010] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0011] Definitions of standard chemical terms can be found in the references "Chinese Pharmacopoeia 2025 Edition", "Spectrometric Identification of Organic Components (8th Edition)" and "In-depth Analysis of CCK-8 Cell Experiments".

[0012] Unless otherwise stated, conventional methods within the scope of the art shall be used.

[0013] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0014] The term "panthenol" as used in this article, also known as provitamin B5 or panthenol, is a precursor to vitamin B5 and has three optical isomers: D-panthenol, L-panthenol, and DL-panthenol. D-panthenol is the active configuration metabolized by the human body and is a core active ingredient in repair products. DL-panthenol (racemic version) contains approximately 50% D-panthenol, retaining some physiological activity while offering a cost advantage, and is commonly used in mass-market personal care products such as shampoos and shower gels. L-panthenol, lacking physiological activity, is not the primary focus of this invention.

[0015] The term "succinic acid" used in this article, also known as succinic acid, with the chemical name 1,4-succinic acid, is a naturally occurring dicarboxylic acid with antibacterial, anti-inflammatory, antioxidant, and pH-regulating effects. It has limited solubility in water, and crystals precipitate when the concentration is higher than 8%.

[0016] The term "eutectic" as used in this article refers to a homogeneous mixture formed by two or more components (usually hydrogen bond donor HBD and hydrogen bond acceptor HBA) through non-covalent interactions such as intermolecular hydrogen bonds and van der Waals forces, whose melting point is significantly lower than the individual melting points of each component, and which is usually liquid at room temperature.

[0017] The term "chemical shift" as used in this article refers to the change in electron cloud density of the active hydrogens (such as -OH, -COOH, -NH, etc.) involved in hydrogen bonding when hydrogen bonds are formed, which causes the chemical shift of their characteristic peaks to move towards a lower field (higher ppm value).

[0018] The term "solubility" as used in this article refers to the maximum amount of solute that can dissolve in a given amount of solvent under certain temperature and pressure conditions. It is a fundamental physical property of pharmaceuticals and chemicals.

[0019] The term "cell viability" used in this article refers to the metabolic activity and proliferative capacity of cells, reflecting the health of cell survival. High cell viability indicates a large number of surviving cells and vigorous metabolism; decreased cell viability suggests cell damage or toxicity. In fields such as cosmetic safety evaluation, cell viability is one of the most fundamental assessment indicators.

[0020] The term "CCK-8 method" used in this article refers to a highly sensitive, non-radioactive colorimetric detection method for determining the number of viable cells in cell proliferation and toxicity experiments. Its reaction mechanism involves WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfonic acid benzene)-2H-tetrazole monosodium salt), which, in the presence of the electron carrier 1-methoxy-5-methylphenazine sulfate dimethyl ester, is reduced by dehydrogenases in the mitochondria of viable cells to produce orange-yellow, water-soluble formazan. The amount of formazan produced is directly proportional to the number of viable cells. The number of viable cells is indirectly quantified by detecting the absorbance (OD value) at a wavelength of 450 nm using a microplate reader.

[0021] In a first aspect, the present invention provides: a panthenol-succinic acid eutectic, composed of panthenol and succinic acid, which remains a clear and transparent liquid at -20°C.

[0022] Among its technical features are panthenol and succinic acid.

[0023] The panthenol is selected from at least one of D-panthenol and DL-panthenol.

[0024] The molar ratio of panthenol to succinic acid is 1-3:1-1.2, preferably 1-2:1.

[0025] Based on further solutions to the technical problems of the present invention, or simultaneous solutions to multiple technical problems, the preferred solution in the technical solution provided in the first aspect of the present invention includes: The first preferred option is a panthenol-succinic acid eutectic, composed of panthenol and succinic acid.

[0026] This technical solution not only solved the technical problem of "low-temperature crystallization of panthenol", but also further solved the technical problem of "poor water solubility of succinic acid".

[0027] The second preferred embodiment is that the molar ratio of panthenol to succinic acid is 1-2:1.

[0028] This technical solution not only solves the technical problem of "low-temperature precipitation of panthenol" but also improves the "safe concentration of succinate in cells".

[0029] Secondly, the present invention provides a method for preparing a panthenol-succinic acid eutectic, comprising the following steps: Panthenol and succinic acid are heated and stirred under vacuum until completely melted to form a clear and transparent homogeneous liquid. The mixture is then cooled to room temperature to obtain the panthenol-succinic acid eutectic.

[0030] The vacuum condition is a vacuum degree of 650-750 Pa; preferably 700-750 Pa; and more preferably 740-750 Pa.

[0031] The heating temperature is 90-100℃; preferably 95-100℃.

[0032] The stirring speed is 100-300 rpm; preferably 200-300 rpm.

[0033] The stirring time is 2-6 hours; preferably 3-5 hours; more preferably 3.5-4.5 hours.

[0034] Thirdly, the present invention provides the use of the above-mentioned panthenol-succinic acid eutectic in the preparation of cosmetics for improving skin barrier function, enhancing skin hydration, or promoting skin repair.

[0035] Fourthly, the present invention provides a cosmetic composition comprising the above-mentioned panthenol-succinic acid eutectic and excipients.

[0036] The panthenol-succinic acid eutectic in the cosmetic composition is 1-5% by weight.

[0037] Fifthly, the present invention provides that the dosage form of the cosmetic composition is selected from shampoos, serums, facial masks, lotions, emulsions, creams, gels, or sprays.

[0038] Examples 1-5 of this invention at least support the protection of the molar ratio of panthenol and succinic acid in the panthenol-succinic acid eutectic and the parameters of the preparation method.

[0039] The molar ratio of panthenol to succinic acid is derived from the corresponding technical features "1:1, 1:1.2, 1.5:1, 2:1, 3:1" in the foregoing explanation and / or Examples 1-5, summarized by the common feature "1-3:1-1.2". Therefore, those skilled in the art can reasonably infer that the technical feature "molar ratio of panthenol to succinic acid", its subordinate concepts, its substantially equivalent technical means, and technical means that can replace it within the scope of conventional technical means and common knowledge based on the existing level of technology should all fall within its protection scope.

[0040] The panthenol mentioned herein is derived from the common feature "panthenol" by referring to the corresponding technical features "D-panthenol, DL-panthenol" as explained above and / or in Examples 1-5. Therefore, those skilled in the art can reasonably presume that the technical feature "panthenol," its subordinate concepts, its substantially equivalent technical means, and technical means that can replace it within the scope of conventional technical means and common knowledge based on the existing level of technology should all fall within its protection scope.

[0041] The vacuum degree, heating temperature, stirring speed, and time mentioned herein are derived from the corresponding technical features "650 Pa, 750 Pa", "90℃, 95℃, 100℃", "100 rpm, 200 rpm, 300 rpm", "2h, 3h, 4h, 5h, 6h" in the foregoing explanation and / or Examples 1-5, summarized by the common features "650-750 Pa", "90-100℃", "100-300 rpm", and "2-6h". Therefore, those skilled in the art can reasonably infer that the technical features "vacuum degree, heating temperature, stirring speed, and time", their subordinate concepts, their essentially equivalent technical means, and technical means that can replace them based on existing technology and conventional technical means and common knowledge should all fall within its protection scope.

[0042] The beneficial effects of this invention are as follows: 1. The panthenol-succinic acid eutectic provided by the present invention has excellent low-temperature stability.

[0043] 2. The panthenol-succinic acid eutectic provided by the present invention can significantly improve the solubility of succinic acid.

[0044] 3. The panthenol-succinic acid eutectic provided by this invention increases the concentration of succinic acid that is safe for cells.

[0045] 4. The preparation method of the panthenol-succinic acid eutectic of the present invention is green, safe and simple.

[0046] Furthermore, based on the present invention: Based on the comparison between Example 1 and Comparative Example 2, the panthenol-succinic acid eutectic prepared in this invention significantly improved cell viability at concentrations of 0.05%-0.5%. At a concentration of 0.3%, cell viability reached 149%, and at 0.5%, it remained at 149%, indicating approximately 50% cell proliferation. In contrast, in Comparative Example 2, cell viability was only 109% at a concentration of 0.3%, and dropped sharply to 34% at a concentration of 0.5%, exhibiting significant cytotoxicity. These results demonstrate that the formation of a eutectic between panthenol and succinic acid not only increased the safe concentration of succinic acid but also unexpectedly acquired cell proliferation-promoting activity. Attached Figure Description

[0047] Figure 1 for 1 H NMR spectrum. Detailed Implementation

[0048] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0049] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0050] Example 1: Preparation of panthenol-succinic acid eutectic 20.5 g of D-panthenol and 11.8 g of succinic acid (molar ratio 1:1) were placed in a 100 ml reaction vessel. The vacuum pump was turned on, and the vacuum degree was adjusted to 750 Pa. The mixture was heated in an oil bath to 95 °C, and stirring was started. The mixture was stirred at 200 rpm for 4 hours until it melted to form a clear and transparent homogeneous liquid. After cooling to room temperature (25 °C), a transparent and viscous panthenol-succinic acid eutectic was obtained.

[0051] Example 2: Preparation of panthenol-succinic acid eutectic 20.5 g of DL-panthenol and 14.2 g of succinic acid (molar ratio 1:1.2) were placed in a 100 ml reaction vessel. The vacuum pump was turned on, and the vacuum degree was adjusted to 650 Pa. The mixture was heated to 95 °C in an oil bath, and stirring was started. The mixture was stirred at 300 rpm for 6 hours until it melted to form a clear and transparent homogeneous liquid. After cooling to room temperature (25 °C), a transparent and viscous panthenol-succinic acid eutectic was obtained.

[0052] Example 3: Preparation of panthenol-succinic acid eutectic 30.8 g of D-panthenol and 11.8 g of succinic acid (molar ratio 1.5:1) were placed in a 100 ml reaction vessel. The vacuum pump was turned on, and the vacuum degree was adjusted to 650 Pa. The mixture was heated to 90 °C in an oil bath, and stirring was started at 100 rpm for 5 h. The mixture melted to form a clear and transparent homogeneous liquid. After cooling to room temperature (25 °C), a transparent and viscous panthenol-succinic acid eutectic was obtained.

[0053] Example 4: Preparation of panthenol-succinic acid eutectic 41.1 g of D-panthenol and 11.8 g of succinic acid (molar ratio 2:1) were placed in a 100 ml reaction vessel. The vacuum pump was turned on, and the vacuum degree was adjusted to 750 Pa. The mixture was heated to 90 °C in an oil bath, and stirring was started at 100 rpm for 3 h. The mixture melted to form a clear, transparent, homogeneous liquid. After cooling to room temperature (25 °C), a transparent, viscous panthenol-succinic acid eutectic was obtained.

[0054] Example 5: Preparation of panthenol-succinic acid eutectic 61.6 g of D-panthenol and 11.8 g of succinic acid (molar ratio 3:1) were placed in a 100 ml reaction vessel. The vacuum pump was turned on, and the vacuum degree was adjusted to 650 Pa. The mixture was heated to 100 °C in an oil bath, and stirring was started at 100 rpm for 2 hours. The mixture melted to form a clear, transparent, homogeneous liquid. After cooling to room temperature (25 °C), a transparent, viscous panthenol-succinic acid eutectic was obtained.

[0055] Comparative Example 1 A low-pH azelaic acid / succinic acid / panthenol ternary liquid supramolecular self-recognition system was prepared according to Example 3 of patent CN117551277B.

[0056] Comparative Example 2 20.5 g of D-panthenol and 11.8 g of succinic acid (molar ratio 1:1) were mixed thoroughly. The results showed that the obtained sample was an opaque mixture containing a large number of succinic acid particles.

[0057] Comparative Example 3 The only difference from Example 1 is that the oil bath heating temperature is 85°C; otherwise, it is the same as Example 1. The results showed that the obtained sample was a translucent liquid with precipitates at the bottom.

[0058] Comparative Example 4 The only difference from Example 2 was the increased amount of succinic acid, resulting in a molar ratio of DL-panthenol to succinic acid of 1:1.5, i.e., 20.5g of DL-panthenol and 17.7g of succinic acid. The results showed that the obtained sample was a transparent liquid with succinic acid-insoluble matter at the bottom.

[0059] Verification of technical effectiveness and / or analysis of technical problem solving 1. Visual inspection The samples prepared in the above embodiments and comparative examples were subjected to visual inspection.

[0060] Table 1: Results of Visual Inspection

[0061] The results of the examples show that, under vacuum heating and melting conditions, panthenol and succinic acid in a molar ratio of 1-3:1-1.2 can form a homogeneous, transparent, and phase-separated binary eutectic through intermolecular hydrogen bonds; while in Comparative Example 2, succinic acid particles were exposed due to simple physical mixing and no hydrogen bond self-assembly; in Comparative Example 3, the temperature was insufficient and the mixture did not melt completely; in Comparative Example 4, the excess succinic acid exceeded the hydrogen bond capacity limit, resulting in partial crystallization.

[0062] 2. Low-temperature stability test Samples prepared in Examples 1-5 and Comparative Examples 1-4 were placed in a -20℃ refrigerator and left to stand for 48 hours before being taken out for observation. D-panthenol was set up as a control group.

[0063] Table 2: Stability Results

[0064] Panthenol solidifies and crystallizes within 2 hours at -20°C, while succinic acid has poor water solubility and readily crystallizes. After the two form a eutectic, they remain clear and transparent liquid after standing at -20°C for 48 hours, proving that the hydrogen bond network disrupts the regular packing of panthenol molecules and simultaneously restricts the self-polymerization of succinic acid carboxyl groups.

[0065] 3. Water solubility test Samples prepared from Examples 1-5 and Comparative Examples 1-4 were tested for solubility according to the General Chapter 9023 of the Chinese Pharmacopoeia 2025.

[0066] Table 3: Water solubility test results - 1

[0067] Furthermore, the eutectic prepared in Example 1 was compared with Comparative Example 2 to test its solubility characteristics in water at different concentrations in a refrigerator refrigeration environment.

[0068] Table 4: Results of Refrigerated Water Solubility Test - 2

[0069] The results showed that succinic acid crystallized in aqueous solution >8%. After panthenol and succinic acid formed a eutectic, the solubility of succinic acid in water was greatly improved (>20%), which effectively solved the problem of the limited water solubility of succinic acid.

[0070] 4. Proton spectrum ( 1H NMR characterization Examples 1, 4, and 2 were tested in a 600 MHz NMR instrument to observe the peak shape and shift of active hydrogens (such as –OH and –NH) in D-panthenol and succinic acid.

[0071] The results are as follows Figure 1 As shown, the mixed 1H spectrum of Comparative Example 2 is a superposition of the peaks of D-panthenol and succinic acid, with no obvious peak shift or new peak appearance, indicating that no significant intermolecular hydrogen bonding occurred between the physically mixed D-panthenol and succinic acid. However, the 1H spectra of Examples 1 and 4 reveal that the eutectic mixture of D-panthenol and succinic acid completely retains the characteristic signals of succinic acid (characteristic methylene peak at 2.4 ppm) and D-panthenol (characteristic peaks in the alkyl region at 0.8-1.5 ppm and the oxygen-containing hydrogen region at 3-4 ppm). Simultaneously, the methylene peak of succinic acid at 2.4-2.6 ppm shows a significant low-field shift and peak broadening, indicating that its carboxyl group participates in the formation of intermolecular hydrogen bonds. Significant chemical shifts and peak splitting occurred in both the oxygen-containing hydrogen region (3-4 ppm) and the alkyl region (1.1-1.5 ppm) of the D-panthenol core, directly proving that a strong intermolecular hydrogen bond network was constructed between the carboxyl group on succinic acid and the hydroxyl group of D-panthenol.

[0072] 5. Cell viability test Cell viability was tested on samples prepared in Examples 1-5 and Comparative Examples 1-2 using the CCK-8 assay. Cell viability was detected after 24 hours of treatment with human skin keratinocytes (HaCaT).

[0073] HaCaT cells were seeded into 96-well plates. After the cells reached the logarithmic growth phase, the culture medium was discarded, and 100 μL of test samples at different concentrations were added to treat the cells. After 24 h of culture, the culture medium was discarded, and 100 μL of 10% CCK-8 solution was added. The cells were incubated for 2 h, and the absorbance was measured at 450 nm using a microplate reader. Cell viability was calculated as follows:

[0074] In the formula, A blank: absorbance containing only culture medium and CCK-8 solution; A. Negative control: Absorbance containing added cells and CCK-8 solution; Sample A: Absorbance containing the sample, cells, and CCK-8 solution.

[0075] Table 5: Cell viability test results

[0076] Physically mixed or pure succinic acid exhibits cytotoxicity at high concentrations; in low-melting-point mixtures, the carboxyl groups are bound by hydrogen bonds, resulting in free H+. +The decrease in uncomplexed acid not only eliminated cytotoxicity but also unexpectedly exhibited cell proliferation-promoting activity.

[0077] 6. Cell scratch repair test The cell repair capabilities of each component were evaluated using a cell scratch assay. Samples prepared in Comparative Examples 1-2 and eutectic mixtures prepared in Examples 1-5 were tested respectively.

[0078] Well-grown human keratinocytes (HaCaT) were selected, digested, and diluted to a cell density of 2.5 × 10⁻⁶. 5 Cells were seeded at a rate of 2 mL / well in 6-well plates, with 3 replicates per group, and incubated for 24 h. The culture medium was removed, and 2.5 mL of the test group was added to each well. The cell culture plate was then incubated for another 24 h. A 200 µL pipette tip was used to create a scratch pattern. After scratching, the cells were washed with PBS, and a photograph was taken immediately at 0 h. After photographing, the PBS was removed. 2.5 mL of culture medium was added, and incubation continued for another 24 h. After incubation, the cells were washed three times with PBS, and photographs were taken at the same location using the same magnification objective lens. The photographs were standardized, and the healing rate was calculated.

[0079] The healing rate is calculated as follows: Healing rate % = (Scratch area at 0h - Scratch area after 24h) / Scratch area at 0h 100% The culture medium used in this experiment was a high-glucose DMEM medium containing 2% serum and 1% penicillin and streptomycin.

[0080] Examples 1-5: The panthenol-succinic acid eutectic samples prepared in Examples 1-5 were prepared using culture medium at a concentration of 0.3%; Comparative Examples 1-2: The test samples prepared by using culture medium with 0.3% of Comparative Examples 1-2 were used.

[0081] Positive control group: high-glucose DMEM containing 10% serum and 1% penicillin and streptomycin; Blank control group: culture medium; Table 6: Results of Cell Scratch Repair Test

[0082] The panthenol-succinic acid eutectic of this invention achieved a scratch repair healing rate greater than 65% for all cells, with Example 1 reaching 75.6%, significantly higher than the positive control group (71.4%) and the blank control group (55.2%). In contrast, Comparative Example 1 (ternary azelaic acid system) showed a scratch repair healing rate of only 59.8%, and Comparative Example 2 (physical mixing of panthenol and succinic acid without forming a eutectic) showed a healing rate of only 56.7%, close to the blank control. These results demonstrate that after panthenol and succinic acid form a binary eutectic, they synergistically enhance keratinocyte migration and wound repair capabilities through an intermolecular hydrogen bond network, a feat that cannot be achieved by the individual action of panthenol or succinic acid.

[0083] Application Example 1: Shampoo products containing panthenol-succinic acid eutectic. Formula composition: See Table 7 below (by weight percentage) Table 7 Shampoo Product Formulation Composition

[0084] Preparation method: 1. Disperse phase A (cocamidoyl MEA, cocamidopropyl betaine, sodium methyl cocoyl taurate, sodium lauryl ether sulfate, disodium EDTA, sodium C14-16 olefin sulfonate) in deionized water, heat to 75℃ and stir to dissolve, obtaining phase A aqueous solution. 2. Dissolve phase B (polyquaternium-67, hydroxypropyl guar gum hydroxypropyltrimethylammonium chloride) completely in water, add to the phase A aqueous solution obtained in step 1 and stir evenly to obtain a mixed aqueous solution. 3. After cooling to 45℃, add panthenol-succinic acid eutectic and phenoxyethanol, stir until completely dissolved, to obtain the shampoo product.

[0085] Scalp Soothing and Repair Test Subjects: A total of 40 healthy participants, aged 20-60 years, were recruited, with an equal number of men and women. Inclusion criteria: Good general health, no history of serious heart, liver, kidney or other vital organ diseases, no acute scalp inflammation, open wounds or severe seborrheic dermatitis, and no participation in other clinical trials within the past month. Pregnant or breastfeeding women were excluded.

[0086] Grouping: A randomized, double-blind, parallel-controlled design was adopted, and 40 subjects were randomly divided into a product group and a control group, with 20 subjects in each group and the two groups were matched for gender.

[0087] Test samples: The product group used test shampoos containing panthenol-succinic acid eutectic; the control group used a blank matrix placebo (without panthenol-succinic acid eutectic) that was identical in appearance, smell, and texture to the test products.

[0088] Usage instructions and frequency: D0 (baseline visit): After the subjects arrive at the research center and their baseline (D0) data is collected, they will all wash their hair once under the guidance of the researchers. D0-D1: Do not wash your hair again after washing until the D1 visit; D2-D7: Subjects returned home and shampooed their hair once a day according to their usual shampooing habits; D7 (Mid-term Visit): The subjects washed their hair again after the D7 data was collected at the research center; D7-D10: Do not wash your hair again after washing your hair until the visit on D10; D10 (Final Visit): Subjects visit the research center to collect D10 data.

[0089] Test time points: Indicators were collected at D0 (baseline), D7 (7 days after use), and D10 (3 days after discontinuation).

[0090] Testing Method: Transepidermal water loss (TEWL) of the scalp was measured using the Tewameter™ nano transepidermal water loss meter. The same senior dermatologist scored the scalp redness before and after use according to the "Visual Assessment Grading Standard for Skin Erythema": 0 = no erythema, 1 = light red, 2 = red, 3 = dark red. The improvement rate of scalp redness was calculated using the following formula: Table 8 Transepidermal water loss (TEWL) and scalp redness score (n=20)

[0091] As shown in Table 8, there were no statistically significant differences in baseline (D0) TEWL and redness scores between the two groups, indicating comparability. After 7 days of use (D7), the TEWL in the product group decreased by 39.4% from baseline, significantly better than the 22.4% in the control group; the improvement rate of scalp redness in the product group reached 26.94%, higher than the 18.72% in the control group. After 3 days of sample discontinuation (D10), the TEWL in the control group rebounded from D7 (increasing by 7.7%), with no significant change in the redness improvement rate; while the TEWL in the product group further decreased to 26.34 g / (m²·h), and the redness improvement rate remained at 27.46%, demonstrating a good long-lasting barrier soothing and repairing effect. The above results indicate that the panthenol-succinic acid eutectic of the present invention can effectively reduce transepidermal water loss of the scalp, improve scalp erythema symptoms, and is not prone to rebound after discontinuation, making it suitable for daily care of sensitive scalps.

[0092] Application Example 2: Serum containing panthenol-succinic acid eutectic Formulation composition (by weight percentage): 5% panthenol-succinic acid eutectic prepared in Example 1, 3% glycerol, 2% butylene glycol, 0.1% sodium hyaluronate, 0.2% carbomer, 0.2% triethanolamine, 0.5% phenoxyethanol, and deionized water to make up to 100%.

[0093] Preparation method: Carbomer was dispersed in deionized water, glycerol, butylene glycol and sodium hyaluronate were added, the mixture was heated to 70°C and stirred to dissolve, the temperature was lowered to 45°C and panthenol-succinic acid eutectic was added and stirred until completely dissolved, the pH was adjusted to 6.0 with triethanolamine, phenoxyethanol was added, and the mixture was homogenized to obtain the essence.

[0094] Application Example 3: Emulsions containing panthenol-succinic acid eutectic Formulation composition (by weight percentage): 3% panthenol-succinic acid eutectic prepared in Example 4, 5% squalane, 3% caprylic / capric triglyceride, 2% glyceryl stearate, 1.5% cetearyl alcohol, 4% glycerol, 0.3% ceramide NP, 0.15% carbomer, 0.15% triethanolamine, 0.5% phenoxyethanol, and deionized water to 100%.

[0095] Preparation method: The oil phase (squalane, caprylic / capric triglyceride, glyceryl stearate, cetearyl alcohol, ceramide NP) and the aqueous phase (deionized water, glycerol, carbomer) were heated to 75°C respectively; the oil phase was added to the aqueous phase and homogenized and emulsified; after cooling to 40°C, the panthenol-succinic acid eutectic prepared in Example 4, triethanolamine and phenoxyethanol were added and stirred evenly to obtain the emulsion.

[0096] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A panthenol-succinic acid eutectic, characterized in that, The eutectic is composed of panthenol and succinic acid, and is a clear and transparent liquid at -20°C.

2. The panthenol-succinic acid eutectic according to claim 1, characterized in that, The molar ratio of panthenol to succinic acid is 1-3:1-1.

2.

3. The panthenol-succinic acid eutectic according to claim 1, characterized in that, The molar ratio of panthenol to succinic acid is 1-2:

1.

4. The panthenol-succinic acid eutectic according to claim 1, characterized in that, The panthenol is selected from at least one of D-panthenol and DL-panthenol.

5. The method for preparing the panthenol-succinic acid eutectic according to any one of claims 1-4, characterized in that, The process includes the following steps: taking panthenol and succinic acid, heating and stirring under vacuum until completely melted to form a clear and transparent homogeneous liquid, and cooling to room temperature to obtain the panthenol-succinic acid eutectic.

6. The preparation method according to claim 5, characterized in that, The vacuum conditions are 650-750 Pa, the heating temperature is 90-100℃, the stirring speed is 100-300 rpm, and the stirring time is 2-6 hours.

7. Use of the panthenol-succinic acid eutectic according to any one of claims 1-4 in the preparation of cosmetics for improving skin barrier function, enhancing skin hydration or promoting skin repair.

8. The use according to claim 7, characterized in that, The promotion of skin repair includes promoting the healing of skin wounds.

9. A cosmetic composition, characterized in that, Includes the panthenol-succinic acid eutectic as described in any one of claims 1-4 and the excipients.

10. The cosmetic composition according to claim 9, characterized in that, The panthenol-succinic acid eutectic is present in the cosmetic composition at a weight percentage of 1-5%, and the dosage form of the cosmetic composition is selected from shampoos, serums, facial masks, lotions, creams, gels, or sprays.

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