Composition containing cyclodextrin-coated vitamin A precursor as well as preparation method and application of composition

Abstract

The invention relates to a composition containing a cyclodextrin-coated vitamin A precursor as well as a preparation method and application of the composition, and belongs to the technical field of skin care products. The preparation method of the composition with the vitamin A precursor wrapped by cyclodextrin comprises the following steps: uniformly mixing phenylalanine and an ethanol solution, preheating, adding hexylcinnamyl aldehyde, and stirring at a constant temperature to obtain a mixed solution; and heating and stirring the cyclodextrin compound and deionized water, slowly adding the mixed solution, continuously stirring, adding the vitamin A precursor, and continuously stirring, thereby obtaining the product. The two cyclodextrin derivatives are compounded and coated with the Schiff base compound and the vitamin A precursor with oxidation resistance, the core material can be protected from being influenced by light, heat and oxygen in the external environment, the oxidation resistance and the high-temperature resistance of the composition are effectively improved by cooperating with different efficient oxidation resistance mechanisms and introducing a stable organic structure, and the stability of the composition is improved. The composition is applied to skin care products.

Description

Technical Field

[0001] The invention belongs to the technical field of skin care products and relates to a composition containing cyclodextrin-encapsulated vitamin A precursor, a preparation method and an application thereof. Background Art

[0002] Vitamin A is a fat-soluble vitamin that is easily oxidized, and ultraviolet light can accelerate its oxidative damage. Furthermore, retinoic acid is highly irritating, can cause severe vasodilation, and can cause peeling, and therefore is prohibited from direct use in skincare products. Consequently, only retinoic acid precursors or derivatives can be used in skincare products. These precursors or derivatives can only be converted into retinoic acid in the body to ultimately exert their effects, promoting collagen production and achieving wrinkle reduction. The longer the conversion process, the more directly impacts the effectiveness of the process, so a shorter process is preferred. While vitamin A derivatives are less irritating due to their larger molecular weight, they are also more difficult to absorb and have lower conversion rates. In comparison, retinoic acid precursors, retinol and aldehyde, are more easily absorbed due to their smaller molecular weight. Furthermore, their shorter conversion process allows for faster onset of action, allowing for smaller dosages compared to derivatives. As retinoic acid precursors, retinol and aldehyde are inherently irritating and easily oxidized, making their packaging crucial.

[0003] Cyclodextrin is a macrocyclic compound formed by linking pyranose chiral units through glycosidic bonds. The special hydrophilic and hydrophobic interactions and cavity structure of cyclodextrin can selectively include and complex some compounds. In addition, the numerous hydroxyl groups on the edge of its cavity can be modified with groups with different functional properties, thereby increasing the interaction sites between it and the analyte. Summary of the Invention

[0004] The purpose of the present invention is to provide a composition containing a cyclodextrin-encapsulated vitamin A precursor, as well as a preparation method and application thereof. The present invention compounds two cyclodextrin derivatives to encapsulate a Schiff base compound and a vitamin A precursor with antioxidant ability, thereby protecting the core material from the influence of light, heat, and oxygen in the external environment. By synergizing different high-efficiency antioxidant mechanisms and introducing a stable organic structure, the antioxidant ability and high-temperature resistance of the composition are effectively improved.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A cyclodextrin-encapsulated vitamin A precursor composition, the preparation method of which comprises the following steps: Step 1: Mix phenylalanine and ethanol solution, add hexylcinnamaldehyde and stir to mix evenly to obtain a mixed solution; Step 2: Heat and stir the cyclodextrin complex and deionized water, add the mixed solution and continue to stir evenly, add the vitamin A precursor and continue to stir evenly, and obtain the product.

[0006] As a preferred technical solution of the present invention, in step 1, phenylalanine and ethanol solution are mixed and preheated, and then hexylcinnamaldehyde is added and stirred at a constant temperature to obtain a mixed solution.

[0007] As a preferred technical solution of the present invention, in step 2, the cyclodextrin complex and deionized water are heated and stirred, the mixed solution is slowly added with continuous stirring, and the vitamin A precursor is added with continuous stirring to obtain the product.

[0008] As a preferred technical solution of the present invention, in step 1, the mass ratio of phenylalanine, ethanol solution and hexylcinnamaldehyde is (2.6-3.0): (60-70): (1.8-2.1).

[0009] As a preferred technical solution of the present invention, in step 2, the mass ratio of the cyclodextrin complex, the mixed solution, and the vitamin A precursor is (2.5-3.8): (20-25): (2.0-4.0). The amount of water can be adjusted accordingly as needed.

[0010] As a preferred technical solution of the present invention, in step 2, the cyclodextrin complex is prepared by mixing hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin in a mass ratio of (2.0-2.3): (3.0-3.5).

[0011] As a preferred technical solution of the present invention, in step 2, the vitamin A precursor is one or both of vitamin A aldehyde and vitamin A alcohol.

[0012] As a preferred technical solution of the present invention, in step 1, the stirring temperature is 55-62°C.

[0013] As a preferred technical solution of the present invention, in step 1, the stirring time is 4-5 hours.

[0014] As a preferred technical solution of the present invention, in step 1, the preheating temperature is 40°C; and the constant temperature stirring is stirring at a temperature of 55-62°C for 4-5 hours.

[0015] As a preferred technical solution of the present invention, in step 1, the mass fraction of the ethanol solution is 50-70%.

[0016] As a preferred technical solution of the present invention, in step 2, the heating and stirring temperature is 60-65° C. This can better dissolve the raw materials without damaging them.

[0017] As a preferred technical solution of the present invention, in step 2, the heating and stirring time is 20-30 minutes. The time can be adjusted accordingly according to the mixing conditions, as long as the mixture is fully mixed.

[0018] As a preferred technical solution of the present invention, in step 2, the heating and stirring is stirring at a temperature of 60-65° C. for 20-30 minutes.

[0019] As a preferred technical solution of the present invention, in step 2, the speed of the continuous stirring or continued stirring is 600-800 rpm. The stirring speed can be adjusted accordingly according to the mixing situation to ensure that the raw materials are fully mixed.

[0020] As a preferred technical solution of the present invention, in step 2, the continuous stirring or continued stirring time is 40-50 minutes. The time can be adjusted accordingly according to the mixing situation, as long as the mixture is fully mixed.

[0021] As a preferred technical solution of the present invention, in step 2, the continued stirring is stirring at a rotation speed of 600-800 rpm for 40-50 minutes.

[0022] The above features can be combined arbitrarily unless they conflict with each other.

[0023] The invention discloses a skin care product comprising the above-mentioned cyclodextrin-encapsulated vitamin A precursor composition.

[0024] The present invention discloses the use of the above-mentioned cyclodextrin-encapsulated vitamin A precursor composition in the preparation of skin care products.

[0025] Beneficial effects of the present invention: In some examples of the present invention, the amino group of phenylalanine and the aldehyde group of hexylcinnamaldehyde form a porous Schiff base structure, which effectively improves the high temperature resistance of the composition.

[0026] In some examples of the present invention, hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin are compounded, and the cavity diameters and cavity volumes of different cyclodextrins are different, which effectively promotes the entry of Schiff base compounds and vitamin A precursors into cyclodextrins and encapsulation to obtain cyclodextrin complexes. The cyclodextrin complexes can protect the core material from the influence of light, heat, and oxygen in the external environment, effectively improving the antioxidant capacity and high temperature resistance of the composition.

[0027] Some examples of the present invention effectively improve the antioxidant capacity and high temperature resistance of the composition by coordinating different high-efficiency antioxidant mechanisms and introducing stable organic structures.

[0028] In some embodiments of the present invention, water-insoluble vitamin A precursors are converted into inclusions that are easily dispersed in an aqueous phase. These inclusions are easy to use and can be better applied to various skin care products, thereby expanding the application areas of vitamin A precursors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a photo of the 5% vitamin A aldehyde sample after preparation (date: 2024.10.16).

[0030] Figure 2 This is a photo of the 2% vitamin A alcohol sample after preparation (date: 2024.10.16).

[0031] Figure 3 This is a photo of a 5% vitamin A aldehyde sample in an accelerated stability test (date: March 25, 2025).

[0032] Figure 4 This is a photo of a 2% vitamin A alcohol sample undergoing accelerated stability testing (date: March 25, 2025). DETAILED DESCRIPTION

[0033] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0034] Example 1 A method for preparing a cyclodextrin-encapsulated vitamin A precursor composition comprises the following steps: Step 1: Phenylalanine and an ethanol solution are mixed and preheated, and then hexylcinnamaldehyde is added and stirred at a constant temperature to obtain a mixed solution; wherein the preheating temperature is 40° C.; the constant temperature stirring is stirring at a temperature of 55° C. for 4 hours; and the mass ratio of phenylalanine, ethanol solution, and hexylcinnamaldehyde is 2.6:60:1.8; Step 2: Heat and stir the cyclodextrin complex and deionized water, slowly add the mixed liquid and continue stirring, add vitamin A precursor and continue stirring, to obtain; wherein, the heating and stirring is stirring at a temperature of 60°C for 20 minutes; the continued stirring is stirring at a speed of 600 rpm for 40 minutes; the mass ratio of the cyclodextrin complex, deionized water, mixed liquid and vitamin A precursor is 2.5:75.5:20:2.0; the cyclodextrin complex is formed by mixing hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin in a mass ratio of 2.0:3.0; the vitamin A precursor is vitamin A aldehyde.

[0035] Example 2 A method for preparing a cyclodextrin-encapsulated vitamin A precursor composition comprises the following steps: Step 1: Phenylalanine and an ethanol solution are mixed and preheated, and then hexylcinnamaldehyde is added and stirred at a constant temperature to obtain a mixed solution; wherein the preheating temperature is 40° C.; the constant temperature stirring is stirring at a temperature of 58° C. for 4.5 hours; and the mass ratio of phenylalanine, ethanol solution, and hexylcinnamaldehyde is 2.8:65:2; Step 2: Heat and stir the cyclodextrin complex and deionized water, slowly add the mixed solution and continue stirring, add vitamin A precursor and continue stirring to obtain; wherein, the heating and stirring is stirring at a temperature of 62°C for 25 minutes; the continued stirring is stirring at a speed of 700 rpm for 45 minutes; the mass ratio of the cyclodextrin complex, deionized water, mixed solution and vitamin A precursor is 3.2:71.8:22:3.0; the cyclodextrin complex is formed by mixing hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin in a mass ratio of 2.2:3.2; the vitamin A precursor is vitamin A aldehyde.

[0036] Example 3 A method for preparing a cyclodextrin-encapsulated vitamin A precursor composition comprises the following steps: Step 1: Phenylalanine and an ethanol solution are mixed and preheated, and then hexylcinnamaldehyde is added and stirred at a constant temperature to obtain a mixed solution; wherein the preheating temperature is 40° C.; the constant temperature stirring is stirring at a temperature of 62° C. for 5 hours; and the mass ratio of phenylalanine, ethanol solution, and hexylcinnamaldehyde is 3.0:70:2.1; Step 2: Heat and stir the cyclodextrin complex and deionized water, slowly add the mixed solution and continue stirring, add vitamin A precursor and continue stirring to obtain the product; wherein, the heating and stirring is stirring at a temperature of 65°C for 30 minutes; the continued stirring is stirring at a speed of 800 rpm for 50 minutes; the mass ratio of the cyclodextrin complex, deionized water, mixed solution and vitamin A precursor is 4.75:59:31.25:5.0; the cyclodextrin complex is formed by mixing hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin in a mass ratio of 2.3:3.5; the vitamin A precursor is vitamin A aldehyde.

[0037] Example 4 A method for preparing a cyclodextrin-encapsulated vitamin A precursor composition comprises the following steps: Step 1: Phenylalanine and an ethanol solution are mixed and preheated, and then hexylcinnamaldehyde is added and stirred at a constant temperature to obtain a mixed solution; wherein the preheating temperature is 40° C.; the constant temperature stirring is stirring at a temperature of 62° C. for 5 hours; and the mass ratio of phenylalanine, ethanol solution, and hexylcinnamaldehyde is 3.0:70:2.1; Step 2: Heat and stir the cyclodextrin complex and deionized water, slowly add the mixed solution and continue stirring, add vitamin A precursor and continue stirring to obtain; wherein, the heating and stirring is stirring at a temperature of 65°C for 30 minutes; the continued stirring is stirring at a speed of 800 rpm for 50 minutes; the mass ratio of the cyclodextrin complex, deionized water, mixed solution and vitamin A precursor is 3.8:167.2:25:4.0; the cyclodextrin complex is formed by mixing hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin in a mass ratio of 2.3:3.5; the vitamin A precursor is vitamin A alcohol.

[0038] Example 5 Compared with Example 3, Example 5 is different in that hydroxypropyl-β-cyclodextrin is used instead of hydroxypropyl-γ-cyclodextrin, and the other components, preparation steps and parameters are the same.

[0039] Example 6 Compared with Example 3, Example 6 is different in that hydroxypropyl-γ-cyclodextrin is used instead of hydroxypropyl-β-cyclodextrin, and the other components, preparation steps and parameters are the same.

[0040] Example 7 Compared with Example 3, Example 7 is different in that the mass ratio of phenylalanine, ethanol solution and hexylcinnamaldehyde is 1.8:70:2.1, and the other components, preparation steps and parameters are the same.

[0041] Comparative Example 1 Compared with Example 3, the difference in Comparative Example 1 is that cinnamaldehyde replaces hexylcinnamaldehyde, and the other components, preparation steps and parameters are the same.

[0042] Comparative Example 2 Compared with Example 3, Comparative Example 2 is different in that hexyl cinnamaldehyde is not used, and the remaining components, preparation steps and parameters are the same.

[0043] Comparative Example 3 Compared with Example 3, Comparative Example 3 is different in that phenylalanine is not used, and the other components, preparation steps and parameters are the same.

[0044] The compositions prepared in Examples 1-7 and Comparative Examples 1-3 were freeze-dried and then subjected to the following performance tests. The test results are shown in Table 1.

[0045] Test Example 1: Determination of DPPH free radical scavenging ability DPPH was prepared with anhydrous ethanol to prepare 2×10 -4mol / L solution, the composition of Example 1-7 and the composition of Comparative Example 1-3 were used as samples to be tested. Several 2 mL portions of the test solution, anhydrous ethanol, and DPPH solution were prepared. After mixing, they were placed at room temperature for 30 minutes. The absorbance was measured at a wavelength of 517 nm to obtain Ai. Each sample was measured in parallel 3 times and the average value was taken. Vc was used as a positive control, and the absorbance value was measured with anhydrous ethanol instead of DPPH as a control Aj blank. The absorbance Ac was measured by mixing DPPH solution and anhydrous ethanol. The scavenging rate of each sample to be tested for DPPH free radicals was calculated according to the following formula: DPPH free radical scavenging rate (%) = .

[0046] The results are shown in Table 1.

[0047] Table 1 DPPH free radical scavenging rate (%) Example 1 86.2 Example 2 86.5 Example 3 87.1 Example 4 84.8 Example 5 72.2 Example 6 71.7 Example 7 73.6 Comparative Example 1 68.9 Comparative Example 2 62.8 Comparative Example 3 65.2 It can be seen from the data in Table 1 that, compared with Comparative Examples 1-3, the cyclodextrin-encapsulated vitamin A precursor composition prepared in Examples 1-7 of the present invention has a significant effect on scavenging DPPH free radicals and has good antioxidant capacity.

[0048] Test Example 2 The prepared composition was sealed in a colorless transparent bottle and stored in an oven at 48°C for accelerated stability testing. The color and stratification of the samples were visually inspected on different days, and samples were taken for pH testing. The results are shown in Table 2. Figures 1 to 4 The sample was prepared on October 16, 2024.

[0049] Table 2

[0050] Table 2 shows that the 5% vitamin A aldehyde (Example 3) maintained color stability at 48°C for 58 days from 20241016 to 20241213, fully meeting industry standards. The reason is similar to that of vitamin A alcohol. Based on its chemical properties, vitamin A aldehyde is more susceptible to oxidation and discoloration than alcohol. However, the 5% aldehyde exhibited a longer stability in high-temperature accelerated oxidation tests than the 2% alcohol. This is likely not due to experimental error, but rather to the higher 5% content and darker initial color. Small amounts of oxidation obscure the color and make it less noticeable. Considering that our testing duration was over 30 times the industry standard, we ultimately concluded that the test results are reliable.

[0051] Table 2 shows that the color of 2% vitamin A alcohol (Example 4) remained stable at 48°C for 44 days from 20241016 to 20241129, indicating that vitamin A alcohol remained stable with minimal oxidation during this period, followed by increased oxidation. According to the latest cosmetics industry standards, standard raw materials or finished cosmetics must exhibit no discoloration or delamination for 24 hours at 45°C. Many products do not require this. However, as an active ingredient, we tested it using requirements far exceeding industry standards, and the results showed that it fully met these standards.

[0052] The present invention forms a porous Schiff base structure through the amino group of phenylalanine and the aldehyde group of hexylcinnamaldehyde, and through compounding hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin, using different cavity diameters and cavity volumes, effectively promotes the entry of Schiff base compounds and vitamin A precursors. The cyclodextrin complex can protect the core material from the influence of light, heat, and oxygen in the external environment, effectively improving the antioxidant capacity and high temperature resistance of the composition. Compared with cinnamaldehyde, hexylcinnamaldehyde contains a long carbon chain, which is more conducive to its entry into the hydrophobic interior of the cyclodextrin complex. At the same time, the hydrogen bonding force between hexylcinnamaldehyde and the vitamin A precursor containing a long carbon chain is stronger. The addition of a slightly excessive amount of phenylalanine can effectively increase the adsorption of the vitamin A precursor. That is, by encapsulating the vitamin A precursor, the composition coated with phenylalanine, hexylcinnamaldehyde and the vitamin A precursor can achieve a synergistic and efficient antioxidant effect. The formation of the Schiff base compound and the introduction of the highly stable benzene ring structure can both promote the improvement of the high temperature resistance of the composition.

[0053] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A cyclodextrin-encapsulated vitamin A precursor composition, characterized in that: The preparation method comprises the following steps: Step 1: Mix phenylalanine and ethanol solution, add hexylcinnamaldehyde and stir to mix evenly to obtain a mixed solution; Step 2: Heat and stir the cyclodextrin complex and deionized water, add the mixed solution and continue to stir evenly, add the vitamin A precursor and continue to stir evenly, and obtain the product.

2. The cyclodextrin-encapsulated vitamin A precursor composition according to claim 1, characterized in that: In step 1, the mass ratio of phenylalanine, ethanol solution and hexylcinnamaldehyde is (2.6-3.0): (60-70): (1.8-2.1).

3. The cyclodextrin-encapsulated vitamin A precursor composition according to claim 1, characterized in that: In step 2, the mass ratio of the cyclodextrin complex, the mixed solution and the vitamin A precursor is (2.5-3.8): (20-25): (2.0-4.0).

4. The cyclodextrin-encapsulated vitamin A precursor composition according to claim 1, characterized in that: In step 2, the cyclodextrin complex is prepared by mixing hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin in a mass ratio of (2.0-2.3): (3.0-3.5).

5. The cyclodextrin-encapsulated vitamin A precursor composition according to claim 1, characterized in that: In step 1, the stirring temperature is 55-62° C. and / or the stirring time is 4-5 h.

6. The cyclodextrin-encapsulated vitamin A precursor composition according to claim 1, characterized in that: In step 2, the heating and stirring temperature is 60-65° C. and / or the heating and stirring time is 20-30 min.

7. The cyclodextrin-encapsulated vitamin A precursor composition according to claim 1, characterized in that: In step 2, the rotation speed of the continuous stirring or continued stirring is 600-800 rpm and / or the time of the continuous stirring or continued stirring is 40-50 min.

8. The cyclodextrin-encapsulated vitamin A precursor composition according to any one of claims 1 to 7, characterized in that: The vitamin A precursor is one or both of vitamin A aldehyde and vitamin A alcohol.

9. A skin care product, characterized in that: A composition containing the cyclodextrin-encapsulated vitamin A precursor according to any one of claims 1 to 8.

10. Use of the cyclodextrin-encapsulated vitamin A precursor composition according to any one of claims 1 to 8 in the preparation of skin care products.

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