Supramolecular salicylic acid and preparation method and application thereof

Abstract

The application relates to the technical field of supramolecular, in particular to a supramolecular salicylic acid and a preparation method and application thereof, the preparation method comprises the following steps: mixing salicylic acid, a ligand and an auxiliary agent, stirring and ultrasonicating to obtain the supramolecular salicylic acid; the ligand comprises L-lysine or arginine; and the molar ratio of the salicylic acid to the ligand is 1:1. The supramolecular salicylic acid prepared by mixing the salicylic acid and the ligand in a certain proportion and dissolving them in the auxiliary agent improves the solubility, stability and permeability of the salicylic acid. The supramolecular salicylic acid prepared by the application has good solubility and stability, strong permeability, small skin irritation, a simple and environment-friendly preparation method and is suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of supramolecular technology, and in particular to a supramolecular salicylic acid, its preparation method, and its applications. Background Technology

[0002] Salicylic acid is a lipid-soluble active ingredient. It has poor solubility in water at room temperature but is readily soluble in polar organic solvents such as ethanol and ether. However, the use of organic solvents can lead to a poor skin feel and cause some damage to the skin. Furthermore, organic solvents also have insufficient stability during storage and use.

[0003] Salicylic acid is often added to cosmetic products as an active ingredient, and it has the following effects: Salicylic acid can promote the metabolism of keratinocytes, accelerate the shedding of melanin, and promote the regeneration of epidermal cells, thereby achieving the effects of brightening skin tone and refining skin texture; Free radicals are one of the important factors leading to skin aging. They attack skin cells, causing oxidative damage, which in turn leads to signs of aging such as fine lines, wrinkles, and age spots. Salicylic acid has the ability to scavenge free radicals. By neutralizing free radicals, it reduces the damage of free radicals to skin cells, reduces skin wrinkles, improves skin elasticity, and thus delays the skin aging process; Salicylic acid can also act as a stratum corneum renewal promoter, and in skin care product formulations, it has the effects of controlling oil and removing acne, fading acne scars, and improving pores.

[0004] Salicylic acid is acidic and can be irritating when in direct contact with the skin. Furthermore, its poor solubility, stability, and permeability affect the quality of cosmetics.

[0005] Supramolecular chemistry is based on the theory of non-covalent intermolecular interactions, studying supramolecular assemblies formed by two or more molecules through weak interactions such as hydrogen bonds, π-π stacking, van der Waals forces, and hydrophilic-hydrophobic effects. Applying supramolecular technology to the cosmetics field allows for the development of safer, more effective, and more environmentally friendly supramolecular raw materials, resulting in improved stability, solubility, processability, and bioavailability, thereby enhancing the efficacy of these materials.

[0006] However, there is relatively little research on the combination of supramolecular technology and salicylic acid in the market at present, and some of the products that have been researched still have defects such as poor stability and strong irritation.

[0007] Therefore, there is an urgent need to provide a method for preparing supramolecular salicylic acid to improve its solubility, stability and permeability, thereby improving the quality of salicylic acid in cosmetics. Summary of the Invention

[0008] The purpose of this invention is to provide a supramolecular salicylic acid, its preparation method, and its application, in order to solve the problems existing in the above-mentioned background art.

[0009] like Figure 1As shown, to achieve the above objective, the present invention provides a method for preparing supramolecular salicylic acid, comprising the following steps: Salicylic acid, ligands, and additives are mixed, stirred, and sonicated to obtain supramolecular salicylic acid; the ligands include L-lysine or arginine, and the molar ratio of salicylic acid to ligands is 1:1.

[0010] As a preferred embodiment of the present invention, the additive includes 1,3-butanediol.

[0011] As a preferred embodiment of the present invention, the mass ratio of salicylic acid to the additive is 1:6~8, and can be selected as 1:7.

[0012] As a preferred embodiment of the present invention, the stirring method is magnetic stirring.

[0013] As a preferred embodiment of the present invention, the stirring temperature is 75~80℃, and can be selected as 78℃.

[0014] As a preferred embodiment of the present invention, the stirring time is 3.5 to 4 hours.

[0015] In this invention, after obtaining a mixed solution by stirring, the mixed solution is cooled to room temperature and then placed in an ultrasonic device for ultrasonication.

[0016] As a preferred embodiment of the present invention, the frequency of the ultrasound is 85~90Hz, and can be selected as 88Hz.

[0017] As a preferred embodiment of the present invention, the ultrasound duration is 35-40 minutes, and can be selected as 38 minutes.

[0018] After the ultrasound is completed, the air bubbles generated during the ultrasound process are removed to obtain supramolecular salicylic acid.

[0019] The present invention also provides supramolecular salicylic acid prepared by the above preparation method.

[0020] This invention also provides the application of the above-mentioned supramolecular salicylic acid in cosmetic products.

[0021] The present invention has the following beneficial effects: This invention provides a method for preparing supramolecular salicylic acid, comprising the following steps: Salicylic acid, ligands, and additives are mixed, stirred, and sonicated to obtain supramolecular salicylic acid; the ligands include L-lysine or arginine, and the molar ratio of salicylic acid to ligands is 1:1.

[0022] The ligands used in this invention are L-lysine or arginine, both of which are basic amino acids. They can bind to the carboxyl group of salicylic acid through ionic or hydrogen bonding to form a stable supramolecular complex. This reduces the self-aggregation of salicylic acid molecules, prevents recrystallization in solution, and improves its solubility in polar solvents. Furthermore, the amino groups in L-lysine and arginine neutralize the acidity (pH) of salicylic acid, reducing its irritation to the skin. The resulting supramolecular structure allows salicylic acid to be more evenly dispersed in the formula, making it easier to penetrate the stratum corneum during application, thus enhancing exfoliation and pore-cleansing effects. Additionally, the supramolecular structure of the supramolecular salicylic acid system can "encapsulate" the salicylic acid, slowing its release rate on the skin surface, thereby providing a long-lasting skincare effect.

[0023] This invention further specifies that the adjuvant includes 1,3-butanediol, which can not only further assist in the dissolution of salicylic acid, but also form hydrogen bonds with salicylic acid and amino acids, stabilizing the supramolecular structure and preventing salicylic acid from layering or precipitation due to temperature changes or prolonged storage, thereby improving the stability of the supramolecular system. Furthermore, 1,3-butanediol itself also has moisturizing properties, which can alleviate skin dryness that may be caused by salicylic acid and further reduce irritation.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of the preparation method of supramolecular salicylic acid provided by the present invention; Figure 2 These are the infrared spectra of the supramolecular salicylic acid obtained in Examples 1 and 4 of this invention; Figure 3 This is a schematic diagram of the stable state of the low-temperature group in the stability test experiment of this invention on day 14; Figure 4 This is a schematic diagram of the stable state of the low-temperature group in the stability test experiment of this invention on day 28; Figure 5 This is a schematic diagram of the stable state of the laboratory temperature group in the stability test of this invention on day 28; Figure 6 This is a schematic diagram of the stable state of the high-temperature group in the stability test experiment of this invention on day 28; Figure 7 This is the absorbance-concentration standard curve of salicylic acid in the permeability test experiment of this invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0027] Example 1 This embodiment provides a method for preparing supramolecular salicylic acid, including the following steps: Salicylic acid, L-lysine, and 1,3-butanediol were mixed in a certain proportion and placed in a magnetic stirrer. The mixture was stirred at 75°C for 4 hours to obtain a mixed solution. The molar ratio of salicylic acid to L-lysine was 1:1, and the mass ratio of salicylic acid to 1,3-butanediol was 1:6. After cooling the mixed solution to room temperature, place it in an ultrasonic device and sonicate it at a frequency of 85 Hz for 40 minutes to complete the ultrasonic treatment. After removing the bubbles generated during the ultrasonic process, supramolecular salicylic acid, denoted as SA:Lys, is obtained.

[0028] Example 2 This embodiment provides a method for preparing supramolecular salicylic acid, including the following steps: Salicylic acid, L-lysine, and 1,3-butanediol were mixed in a certain proportion and placed in a magnetic stirrer. The mixture was stirred at 80°C for 3.5 hours to obtain a mixed solution. The molar ratio of salicylic acid to L-lysine was 1:1, and the mass ratio of salicylic acid to 1,3-butanediol was 1:8. After cooling the mixed solution to room temperature, place it in an ultrasonic device and sonicate it at a frequency of 90 Hz for 35 minutes to complete the ultrasonic treatment. The bubbles generated during the ultrasonic process are removed to obtain supramolecular salicylic acid.

[0029] Example 3 This embodiment provides a method for preparing supramolecular salicylic acid, including the following steps: Salicylic acid, L-lysine, and 1,3-butanediol were mixed in a certain proportion and placed in a magnetic stirrer. The mixture was stirred at 75°C for 3.5 hours to obtain a mixed solution. The molar ratio of salicylic acid to L-lysine was 1:1, and the mass ratio of salicylic acid to 1,3-butanediol was 1:7. After cooling the mixed solution to room temperature, place it in an ultrasonic device and sonicate it at a frequency of 88 Hz for 38 minutes to complete the ultrasonic treatment. The bubbles generated during the ultrasonic process are removed to obtain supramolecular salicylic acid.

[0030] Example 4 This embodiment provides a method for preparing supramolecular salicylic acid, which is basically the same as that in Example 1, except that L-lysine is replaced with arginine. The resulting supramolecular salicylic acid is denoted as SA:Arg.

[0031] Example 5 This embodiment provides a method for preparing supramolecular salicylic acid, which is basically the same as that in Example 2, except that L-lysine is replaced with arginine.

[0032] Example 6 This embodiment provides a method for preparing supramolecular salicylic acid, which is basically the same as that in Example 3, except that L-lysine is replaced with arginine.

[0033] Example 7 This embodiment provides a method for preparing supramolecular salicylic acid, which is basically the same as that in Example 1, except that the magnetic stirring temperature is 80°C.

[0034] Example 8 This embodiment provides a method for preparing supramolecular salicylic acid, which is basically the same as that in Example 4, except that the magnetic stirring temperature is 80°C.

[0035] Comparative Example 1 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that L-lysine is replaced with betaine.

[0036] Comparative Example 2 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that L-lysine is replaced with carnitine.

[0037] Comparative Example 3 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that the molar ratio of salicylic acid to L-lysine is 2:1.

[0038] Comparative Example 4 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that the molar ratio of salicylic acid to L-lysine is 1.5:1.

[0039] Comparative Example 5 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that the molar ratio of salicylic acid to L-lysine is 1.3:1.

[0040] Comparative Example 6 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that the molar ratio of salicylic acid to L-lysine is 1:1.3.

[0041] Comparative Example 7 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that the molar ratio of salicylic acid to L-lysine is 1:1.5.

[0042] Comparative Example 8 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that the molar ratio of salicylic acid to L-lysine is 1:2.

[0043] Comparative Example 9 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the molar ratio of salicylic acid to arginine is 2:1.

[0044] Comparative Example 10 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the molar ratio of salicylic acid to arginine is 1.5:1.

[0045] Comparative Example 11 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the molar ratio of salicylic acid to arginine is 1.3:1.

[0046] Comparative Example 12 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the molar ratio of salicylic acid to arginine is 1:1.3.

[0047] Comparative Example 13 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the molar ratio of salicylic acid to arginine is 1:1.5.

[0048] Comparative Example 14 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the molar ratio of salicylic acid to arginine is 1:2.

[0049] Comparative Example 15 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, the only difference being that the magnetic stirring temperature is 60°C.

[0050] Comparative Example 16 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, the only difference being that the magnetic stirring temperature is 65°C.

[0051] Comparative Example 17 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, the only difference being that the magnetic stirring temperature is 70°C.

[0052] Comparative Example 18 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, the only difference being that the magnetic stirring temperature is 60°C.

[0053] Comparative Example 19 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, the only difference being that the magnetic stirring temperature is 65°C.

[0054] Comparative Example 20 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that the magnetic stirring temperature is 70°C.

[0055] Comparative Example 21 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that 1,3-butanediol is replaced with deionized water.

[0056] Comparative Example 22 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that 1,3-butanediol is replaced with glycerol.

[0057] Comparative Example 23 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 1, except that 1,3-butanediol is replaced with ethanol.

[0058] Comparative Example 24 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that 1,3-butanediol is replaced with deionized water.

[0059] Comparative Example 25 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that 1,3-butanediol is replaced with glycerol.

[0060] Comparative Example 26 The preparation method of this comparative example is basically the same as that of the supramolecular salicylic acid provided in Example 4, except that 1,3-butanediol is replaced with ethanol.

[0061] Characterization tests: The molecular assembly degree of the supramolecular salicylic acid prepared in Examples 1 and 4 was characterized by Fourier transform infrared spectroscopy (FTIR) using a Nicolet Magna 560 instrument. The specific procedure was as follows: the supramolecular salicylic acid samples prepared in Examples 1 and 4 were ground and mixed with spectrally pure KBr at a mass ratio of 1:100. The mixture was then pressed into transparent thin films under 10 MPa pressure before being analyzed by the instrument. The instrument parameters were set as follows: spectral acquisition range 4000~400 cm⁻¹. -1 4cm resolution -1 A total of 32 scans were performed, and the average spectrum was taken. The results are shown in [the table below]. Figure 2 .

[0062] from Figure 2 It can be seen that the hydroxyl absorption peak of salicylic acid is at 3235.8 cm⁻¹. -1 The presence of hydrogen bonds at 1655.9 cm⁻¹ is due to the broad stretching vibration of the OH group. -1 The absorption peak at 1155.2 cm⁻¹ is due to the C=O stretching vibration, a typical characteristic of the carbonyl group in carboxylic acids. -1 The absorption peak at 3311.9 cm⁻¹ is due to the CO stretching vibration, indicating the presence of a carboxyl group; L-lysine has an absorption peak at 3311.9 cm⁻¹. -1 The absorption peak at 1584.3 cm⁻¹ is due to the stretching vibration of NH₂, indicating the presence of an amino group (-NH₂). -1 The absorption peak at 3300.7 cm⁻¹ is due to the CO stretching vibration, indicating the presence of a carboxyl group; arginine has an absorption peak at 3300.7 cm⁻¹. -1 The absorption peak at 1619.4 cm⁻¹ is due to the stretching vibration of NH₄⁺, indicating the presence of a guanidinium group. -1 The absorption peak at this point is due to C=N / C=NH2 + Stretchable. Its length is 1133.5cm. -1 There is an absorption peak at 3300 cm⁻¹, which is due to CN stretching; 1,3-butanediol has an absorption peak at 3300 cm⁻¹. -1 The presence of an absorption peak is due to the stretching vibration of OH, indicating the presence of a hydroxyl group; the supramolecular salicylic acid (salicylic acid-L-lysine system) in Example 1 showed an absorption peak at 3369.4 cm⁻¹. -1 The broadening of the NH and OH absorption peaks may be due to hydrogen bonding enhancement or charge transfer, and this is observed at 1653.7 cm⁻¹. -1 The C=O absorption peak shifted slightly, possibly due to electrostatic interactions or hydrogen bonding between the carboxyl and amino groups; the supramolecular salicylic acid (salicylic acid-arginine system) in Example 4 showed an absorption peak at 3294.7 cm⁻¹. -1 The broadening of the NH and OH absorption peaks may be due to enhanced hydrogen bonding or charge transfer, and this is observed at 1558.9 cm⁻¹. -1The C=O absorption peak shifted slightly, possibly due to electrostatic interactions or hydrogen bonding between the carboxyl and amino groups. Therefore, the supramolecular salicylic acid (salicylic acid-L-lysine system) in Example 1 and the salicylic acid-arginine system in Example 4 formed complexes through hydrogen bonding and electrostatic interactions, causing changes in the characteristic peaks. This demonstrates that both L-lysine and arginine can form supramolecular structures with salicylic acid.

[0063] Performance testing: The effect of ligand type on the dissolution state of supramolecular salicylic acid system was tested. Specifically, during the preparation of Examples 1 and 4 and Comparative Examples 1 and 2, the dissolution state of the ligands and the solid precipitation of the obtained supramolecular salicylic acid after standing at room temperature for 7 days were observed. The results are shown in Table 1.

[0064] Table 1. Effects of ligand type on the solubility state of supramolecular salicylic acid system

[0065] As shown in Table 1, when the ligands are L-lysine and arginine, no solid precipitates are observed in the supramolecular salicylic acid system after standing at room temperature for 7 days. This indicates that the solution stability of the salicylic acid system is better than that of betaine and carnitine under the above two ligands.

[0066] The effect of the amount of ligand on the dissolution state of the supramolecular salicylic acid system was tested, specifically by observing the dissolution status of the ligand during the preparation of Examples 1, 4 and Comparative Examples 3-14. The results are shown in Table 2.

[0067] Table 2. Effect of ligand dosage on the solubility state of the supramolecular salicylic acid system

[0068] As can be seen from Table 2, when the ligand is L-lysine or lysine, salicylic acid can be completely dissolved when the molar ratio of salicylic acid to ligand is 1:1, while other molar ratios do not result in complete dissolution.

[0069] The effect of stirring (magnetic stirring) temperature on the dissolution state of the supramolecular salicylic acid system was tested. Specifically, the dissolution status of the ligands during the preparation of Examples 1, 4, 7, 8 and Comparative Examples 15-20 was observed, and the results are shown in Table 3.

[0070] Table 3. Effect of stirring temperature on the dissolution state of the supramolecular salicylic acid system

[0071] As can be seen from Table 3, the solids in the system are completely dissolved only when the stirring temperature is ≥75℃.

[0072] The effect of different types of additives on the solubility state of supramolecular salicylic acid systems was tested, specifically including: The dissolution of ligands during the preparation of Examples 1, 4 and Comparative Examples 21-26 was observed, and the results are shown in Table 4.

[0073] Table 4. Effects of different types of additives on the solubility state of the supramolecular salicylic acid system

[0074] As shown in Table 4, L-lysine, arginine, and salicylic acid are completely dissolved in solids in glycerol, ethanol, and 1,3-butanediol. However, in the system with glycerol, solids will continuously precipitate after standing for a period of time, and the resulting supramolecular solution system has poor stability. The supramolecular solution system with ethanol and 1,3-butanediol has strong stability, but ethanol has a certain degree of irritation, which affects the user experience when used in cosmetics. Therefore, 1,3-butanediol was chosen as an auxiliary agent.

[0075] Solubility, stability, and permeability tests of the supramolecular salicylic acid systems in Examples 1-6: Solubility testing employs a gradient addition method, during which the solution is continuously heated and stirred until saturated. The actual amount dissolved is then calculated using a mass fraction analysis method. The specific process includes: The mass fraction of salicylic acid in the supramolecular salicylic acid system in Examples 1 to 6 was calculated respectively. Then, it was dissolved in 20 mL of deionized water until saturation was achieved to obtain the amount of supramolecular salicylic acid dissolved in deionized water in each example. The actual amount of salicylic acid dissolved in each example was then obtained. The results are shown in Table 5.

[0076] It has been determined that the actual solubility of salicylic acid alone in 20 mL of deionized water is 0.04 g.

[0077] Table 5 Solubility Test Results

[0078] As shown in Table 5, the actual amount of salicylic acid dissolved in Examples 1, 2, and 3 was 1.36g, 1.35g, and 1.35g, respectively, which was about 34 times higher than that of 0.04g of salicylic acid alone; the actual amount of salicylic acid dissolved in Examples 4, 5, and 6 was 1.88g, 1.89g, and 1.87g, respectively, which was about 47 times higher than that of 0.04g of salicylic acid alone.

[0079] Stability testing was conducted using multiple temperature experiments. Equal amounts of samples prepared in Examples 1 and 4 were sealed in transparent glass vials and stored in constant temperature incubators at -20℃ (low temperature group), 25℃ (room temperature group), and 60℃ (high temperature group), respectively. Three samples were set up in parallel for each temperature condition, with storage periods of 7 days, 14 days, and 28 days. The sample status was recorded at regular intervals by visual observation, with a focus on monitoring physical stability indicators such as crystal (solid) precipitation and phase separation. The results are shown in Table 6.

[0080] The stable state of the low-temperature group on day 14 is shown below. Figure 3 See you in 28 days Figure 4 ; The steady-state status of the room temperature group on day 28 is shown in the figure. Figure 5 ; The stable state of the high-temperature group on day 28 is shown in the figure. Figure 6 .

[0081] Table 6 Stability Test Results

[0082] From Table 6 and Figures 3-6 It can be seen that both the room temperature group and the high temperature group remained transparent at all time points of 7 days, 14 days, and 28 days, with no solid precipitation. Figure 5 and Figure 6 The low-temperature group remained transparent after 7 and 14 days without solid precipitation, but slight flocculation occurred on day 28. Figure 4 As shown, however, it essentially melts after returning to room temperature. Therefore, the supramolecular salicylic acid prepared in this invention has a relatively stable structure at room temperature and high temperature, while at low temperature, it may be necessary to add some cryoprotectants to extend its shelf life.

[0083] Permeability testing is performed using a UV-Vis spectrophotometer, and the specific method is as follows: Six concentrations of salicylic acid solutions were prepared: 0.0033 mg / mL, 0.0067 mg / mL, 0.0133 mg / mL, 0.02 mg / mL, 0.0267 mg / mL, and 0.0333 mg / mL. The corresponding absorbance was measured, and an absorbance-concentration standard curve was plotted. Permeability was measured using a Franz diffusion cell system and a TP-6 ​​intelligent transdermal testing instrument. Ex vivo pigskin was used as the barrier medium, and a phosphate buffer solution with pH 5.5 was prepared as the receiving solution. Permeation was continuously performed in a 32°C circulating water bath for 4 hours, with samples taken every hour and their absorbance measured. Finally, the cumulative permeation amount of salicylic acid was calculated based on the salicylic acid absorbance-concentration standard curve. The results are shown in Table 7.

[0084] The absorbance-concentration standard curve for salicylic acid is shown below. Figure 7 .

[0085] Figure 7 In this context, SA represents salicylic acid, Lys represents L-lysine, Arg represents arginine, 1,3-But represents 1,3-butanediol, SA:Lys represents supramolecular salicylic acid prepared in Example 1, and SA:Arg represents supramolecular salicylic acid prepared in Example 4.

[0086] Table 7. Results of Salicylic Acid Permeability Test

[0087] As can be seen from Table 7, the cumulative permeation of supramolecular salicylic acid obtained in Examples 1-6 over 4 hours was 10.2%, 12.1%, 9.7%, 21.5%, 17.4%, and 18.8% higher than that of salicylic acid alone, respectively. The cumulative permeation of salicylic acid in supramolecular salicylic acid was higher than that of salicylic acid alone.

[0088] The salicylic acid and the supramolecular salicylic acid prepared in Examples 1-6 were subjected to irritation tests according to the relevant requirements of the human skin test in the "Cosmetic Safety Technical Specifications" (2015 edition). The skin irritation reaction scores are shown in Table 8.

[0089] Table 8 Skin Irritation Response Scoring Table

[0090] Weigh out 5g each of salicylic acid and supramolecular salicylic acid prepared in Examples 1-6, dissolve them evenly in 100g of deionized water to prepare test samples. Select 35 healthy skin volunteers aged 18-40 years, and ensure that no cosmetics are used on the test area within 8 hours before the test. Divide them into seven groups. Each group is tested with the sample prepared in the specific example. Apply the sample evenly to the face by gently pressing and rubbing it with the palm of your hand. After 15 hours, observe the skin condition according to the standards in Table 8. The results are shown in Table 9.

[0091] Table 9 Skin Test Results

[0092] As shown in Table 9, the redness score of single salicylic acid was 3.78 and the stinging score was 3.26, both indicating moderate irritation. However, the supramolecular salicylic acid prepared in the example had redness and stinging scores below 0.5, indicating no irritation. This is because the amino groups in L-lysine and arginine can neutralize the acidity (pH value) of salicylic acid, reducing its irritation to the skin.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing supramolecular salicylic acid, characterized in that, Includes the following steps: Salicylic acid, ligands, and additives are mixed, stirred, and sonicated to obtain supramolecular salicylic acid. The ligand includes L-lysine or arginine, and the molar ratio of salicylic acid to the ligand is 1:

1.

2. The method for preparing supramolecular salicylic acid according to claim 1, characterized in that, The adjuvant includes 1,3-butanediol.

3. The method for preparing supramolecular salicylic acid according to claim 1, characterized in that, The mass ratio of salicylic acid to additives is 1:6~8.

4. The method for preparing supramolecular salicylic acid according to claim 1, characterized in that, The stirring temperature is 75~80℃.

5. The method for preparing supramolecular salicylic acid according to claim 1, characterized in that, The stirring time is 3.5 to 4 hours.

6. The method for preparing supramolecular salicylic acid according to claim 1, characterized in that, The frequency of the ultrasound is 85~90Hz.

7. The method for preparing supramolecular salicylic acid according to claim 1, characterized in that, The ultrasound session lasted 35-40 minutes.

8. Supramolecular salicylic acid prepared by any one of claims 1-7.

9. The application of the supramolecular salicylic acid according to claim 8 in cosmetic products.

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