Light stabilizer and application thereof
By using the light stabilizer APP320 with a superconjugated structure, the problem that the ultraviolet absorber cannot return to the ground state quickly in the excited state is solved, the photolysis reaction and oxygen radical oxidation are reduced, and the stability and skin protection of the ultraviolet absorber are improved. Effect.
Patent Information
- Application Number
- CN202411272862.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2024-12-13
AI Technical Summary
The existing ultraviolet absorbers are in a high-energy excited state for a long time after absorbing ultraviolet rays, resulting in photochemical reactions and the generation of reactive oxygen radicals, destroying molecular structure and accelerating skin aging, and cannot effectively return to the ground state quickly, losing their ultraviolet absorption capacity.
Using the photo stabilizer APP320 with a superconjugated structure, the energy of the excited state molecules is transferred, and the circulation between them and the ground state is accelerated, which prevents or reduces the occurrence of photolysis reactions, and protects the photoinstability that is easily oxidized by oxygen radicals. Compounds.
Effectively reduce the photolysis reaction of ultraviolet absorbers, extend their protection time, protect other light-unstable substances, prevent oxygen radical oxidation, and improve ultraviolet absorption capacity and light stability.
Smart Images
Figure CN119118871A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of light stabilizers, and in particular relates to a light stabilizer and application thereof. Background Art
[0002] UV absorbers protect the skin from UV damage by absorbing UV rays and blocking them from reaching the skin surface.
[0003] The molecules of these absorbers are in a lower energy ground state in the absence of light. After absorbing ultraviolet energy, they transition to a higher energy excited state. First, they reach the singlet state. These excited absorber molecules can release the absorbed energy back to the ground state through some means, such as emitting fluorescence, intramolecular conversion, singlet quenching, etc., and then return to the ground state. Molecules that have not returned to the ground state may reach the triplet state through intersystem crossing. Triplet molecules can also release the absorbed energy through phosphorescence, triplet quenching, intersystem crossing from triplet to ground state, etc., return to the ground state, and then cycle to absorb ultraviolet rays again. This process is repeated continuously, so that the absorber has the effect of blocking ultraviolet rays.
[0004] Whether a UV absorber is efficient or not depends not only on how much UV light it can absorb, or which wavelength of UV light it absorbs, but more importantly on its ability to react in the cycle of ground state-excited state-ground state. Some UV absorbers that have very good absorption capacity cannot effectively complete these cycles. After absorbing UV light, they remain in a high-energy excited state for a long time, causing photochemical reactions to occur, which in turn destroys its molecular structure and loses its original UV absorption capacity. In addition, these excited molecules may also transfer energy to oxygen, generate reactive oxygen free radicals (ROS), and accelerate skin aging. Therefore, an effective means is needed to quench these excited molecules, so that they return to the ground state faster and avoid these harmful reactions. Summary of the invention
[0005] In order to solve the above problems, the present invention provides a new type of photostabilizer APP320, which is a molecule with a hyperconjugated structure. It can transfer the energy of excited state molecules, accelerate the cycle between the excited state and the ground state of these molecules, prevent or reduce the occurrence of photolysis reactions, and enable these molecules to exist stably for a long time under ultraviolet light.
[0006] In addition, the present invention further found that the light stabilizer of the present invention can not only help the UV absorber molecules to quickly return from the excited state to the ground state, reducing the occurrence of photolysis reactions, but also has a protective effect on other light-unstable active substances that are excited by ultraviolet rays to undergo isomerization and photoreactions. Furthermore, the light stabilizer of the present invention can also protect light-unstable compounds that are easily oxidized by oxygen free radicals, wherein the free radicals may come from singlet oxygen formed by the light-sensitive substances in the surrounding environment absorbing light energy and reacting with oxygen after being excited. The light stabilizer of the present invention can quench the excited photosensitive molecules, preventing them from transferring energy to oxygen to form free radicals, thereby avoiding the light-unstable compounds from being oxidized by free radicals.
[0007] Specifically, in one aspect, the present invention provides a light stabilizer having a structure shown in formula (I), which is named APP320 herein:
[0008]
[0009] In another aspect, the present invention provides use of the photostabilizer described herein for improving the photostability of a photolabile compound.
[0010] Furthermore, the photo-labile compound includes a compound that is excited to generate excited state molecules under light, or a compound that is easily oxidized by oxygen free radicals generated by a photosensitive substance under light.
[0011] Furthermore, the illumination includes ultraviolet radiation.
[0012] Furthermore, the photolabile compound includes a photolabile ultraviolet absorber, a photolabile antioxidant or other photolabile compounds.
[0013] Furthermore, the photolabile compound includes butyl methoxydibenzoylmethane, resveratrol, and phenethylresorcinol.
[0014] Further, the light stabilizer enhances the UV absorption capacity of the light-unstable UV absorber.
[0015] Furthermore, the light stabilizer prevents the light-labile compound from changing color under light.
[0016] In another aspect, the present invention also provides a photostable composition comprising a photostabilizer as described herein and a photolabile compound.
[0017] Furthermore, the mass percentage content of the light stabilizer in the composition is 0.1% to 10%.
[0018] Furthermore, the mass percentage of the light stabilizer in the composition is 1% to 5%.
[0019] Furthermore, the mass percentage of the light stabilizer in the composition is 1.5% to 3%.
[0020] Furthermore, the photo-labile compound includes a compound that is excited to generate excited state molecules under light, or a compound that is easily oxidized by oxygen free radicals generated by a photosensitive substance under light.
[0021] Furthermore, the illumination includes ultraviolet radiation.
[0022] Furthermore, the photolabile compound includes a photolabile ultraviolet absorber, a photolabile antioxidant or other photolabile compounds.
[0023] Furthermore, the photolabile compound includes butyl methoxydibenzoylmethane, resveratrol, and phenethylresorcinol.
[0024] Further, the composition is a sunscreen, cosmetic or skin care composition. It may also include cosmetic adjuvants, such as those conventionally used in such preparations, such as preservatives, bactericides, fragrances, antifoaming agents, dyes, pigments with color effects, thickeners, moisturizers and / or wetting agents, fats, oils, waxes or other conventional ingredients of sunscreen, cosmetic or skin care preparations, other conventional ingredients include alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents, silicone derivatives or combinations thereof.
[0025] Beneficial effects of the present invention
[0026] The light stabilizer APP320 of the present invention is a molecule with a hyperconjugated structure, which can transfer the energy of excited state molecules, thereby accelerating the cycle between the excited state and the ground state of these molecules. This allows the light stabilizer of the present invention to help UV absorber molecules quickly return from the excited state to the ground state, reduce the occurrence of photolysis reactions, and protect other light unstable substances that are excited by ultraviolet rays to generate excited state energy and thus undergo isomerization and photoreactions, while also preventing the oxidation of compounds that are easily oxidized by oxygen free radicals generated by light-sensitive substances under light. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 Shown is the possible photolysis reaction of butyl methoxydibenzoylmethane under light irradiation.
[0028] Figure 2 Shown is the UV absorption curve of butyl methoxydibenzoylmethane as a function of time.
[0029] Figure 3The phosphorescence emission spectra of the APP320 functional group (APP-3) and butyl methoxydibenzoylmethane are shown.
[0030] Figure 4 The graph shows the UV absorption curves of sunscreen lotions containing AVO with and without photostabilizer before and after light exposure.
[0031] Figure 5 A first-order reaction kinetic diagram for the photolysis of butyl methoxydibenzoylmethane is shown.
[0032] Figure 6 The color change process of resveratrol after light exposure and the mechanism by which photostabilizers protect it from color change are shown.
[0033] Figure 7 The results of photostability tests of oil-in-water emulsions containing resveratrol with and without photostabilizer are shown.
[0034] Figure 8 The discoloration process of phenylethyl resorcinol under light and the mechanism by which photostabilizers protect it from discoloration are shown.
[0035] Fig. 9 Shown are the results of photostability tests of emulsions containing phenylethylresorcinol with and without added photostabilizer. DETAILED DESCRIPTION
[0036] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.
[0037] Example 1: APP320 protects photolabile UV absorbers
[0038] Take the UV A absorber butyl methoxydibenzoylmethane (AVO) as an example. AVO is an excellent UVA (320-400nm) absorber, but it may cause the following under light exposure: Figure 1 A series of photolysis reactions are shown (only some of the possible photolysis reactions are shown here). After receiving the energy of ultraviolet radiation, some molecules cannot return to the ground state in time. The long-term high-energy state will cause these photolysis reactions to occur, and the ultraviolet absorption of the newly generated molecules will change, losing the original absorption capacity of the UVA segment (320-400nm), such as Figure 2The UV absorption curve of the light source changes with time. According to Beer-Lambert law, A=εbc, it can be seen that the change of UV A absorption value can reflect the change of substance concentration (c). As the illumination time increases, in the absence of light stabilizer, AVO undergoes photolysis reaction to reduce the concentration.
[0039] like Figure 3 As shown, from the analysis of the potential of APP320 to protect AVO on the phosphorescence spectrum, it can be seen that the energy level of APP-3 (the precursor of APP320) (228 kJ / mol) is lower than the triplet energy levels of the two isomers of AVO, the enol form (245 kJ / mol) and the keto form (295 kJ / mol). According to the principle of energy transfer from high to low, APP320 can absorb the energy of these two triplet isomers, help them quickly return to the ground state, and reduce the occurrence of photodecomposition reactions.
[0040] Next, the light protection effect of APP320 was experimentally verified to confirm that the use of APP320 light stabilizer can effectively reduce the photolysis of butyl methoxydibenzoylmethane (AVO) and prolong its UV protection effect.
[0041] Sunscreen lotions containing AVO with and without photostabilizer were prepared as shown in Table 1.
[0042] Table 1
[0043] INCI name of raw material Formula without APP320 Formula containing APP320 Acrylate copolymer 1.50 1.50 APP320 (no INCI name yet) / 3.00 Polysorbate-60 0.50 0.50 PEG-100 Stearate 2.00 2.00 Glyceryl Stearate 1.00 1.00 Cetearyl Alcohol 1.00 1.00 Ceteareth-6 Olivate 1.00 1.00 C12-15 Alkyl Benzoate 22.50 22.50 Butyl Methoxydibenzoylmethane 3.00 3.00 Disodium EDTA 0.05 0.05 water 60.30 57.30 Xanthan gum 0.15 0.15 Butanediol 3.00 3.00 1,2-Hexanediol 1.00 1.00 Cetearyl Olivate, Sorbitan Olivate 3.00 3.00
[0044] The two samples were coated on a quartz plate with the same film thickness, and their UV absorption curves were tested before and after exposure to light. Figure 4 As shown in the graph, the blue curve is the absorption before illumination, and the orange curve is the absorption after illumination. As shown in the graph, with 6.7mW / cm 2 After 12 minutes of exposure to a simulated light source (total irradiance 4800 mJ / cm 2 ), the absorption curve of the sunscreen without photostabilizer was greatly reduced, and the absorption value at the characteristic absorption peak of AVO at 357 nanometers was reduced by 91%. According to Beer-Lambert law A=εbc, 91% of avobenzone was photolyzed; while the formula with added stabilizer still had more than 80% of AVO remaining after illumination, indicating that the use of APP320 photostabilizer can reduce the photolysis of AVO and improve the absorption efficiency of UV absorbers.
[0045] Furthermore, the photolysis first-order reaction kinetic constant of AVO was used to reflect the photolysis rate of the two formulations. Figure 5As shown, the ordinate is the natural logarithm of the ultraviolet absorption value Ln(A), and the abscissa is the illumination time. The K value of the equation of the linear relationship formed by these points represents the first-order kinetic constant of the photolysis reaction, which is -0.0393 for the formula containing photostabilizer and -0.205 for the formula without photostabilizer. This means that the photolysis rate of AVO in the formula without stabilizer is (-0.205 / -0.0393=)5.2 times the photolysis rate of AVO in the formula with stabilizer.
[0046] Example 2: APP320 protects photolabile active substances
[0047] APP320 can not only help UV absorber molecules quickly return from the excited state to the ground state and reduce the occurrence of photolysis reactions, but the same mechanism is also effective for photosensitizing active substances.
[0048] Resveratrol is a very common antioxidant and is widely used in skin care products. However, it has poor light stability and can easily deteriorate and turn yellow. Figure 6 The figure shows a rough color change process. After absorbing ultraviolet energy, the resveratrol molecule is excited and changes from trans to cis. The cis isomer continues to absorb energy, and the molecule undergoes a photoreaction to generate colored photolysis products. The APP320 light stabilizer transfers the energy of the excited molecule and returns it to the ground state, reducing the occurrence of isomerization and photoreaction and avoiding the generation of colored photolysis products.
[0049] The oil-in-water emulsions containing resveratrol with and without light stabilizer were prepared according to the formula shown in Table 2. Figure 7 As shown, after placing these samples outdoors for one month, it was found that the formula without APP320 had turned brown, while the sample with APP320 had only a slight color change.
[0050] Table 2
[0051] INCI name #1 #2 #3 Glyceryl Stearate, PEG-100 Stearic Acid 3 3 3 Cetearyl Olivate, Sorbitan Olivate 2 2 2 Cetearyl Alcohol 1.5 1.5 1.5 APP320 3 1.5 0 Caprylic / capric triglyceride 10 10 10 1,3-Butanediol 2 2 2 Resveratrol 0.1 0.1 0.1 Deionized water 74.5 76 77.5 Glyceryl Stearate, PEG-100 Stearic Acid 3 3 3 Disodium EDTA 0.1 0.1 0.1 Carbomer 0.2 0.2 0.2 Sodium hydroxide 0.6 0.6 0.6
[0052] Example 3: APP320 protects compounds susceptible to oxidation by oxygen free radicals generated by light-sensitive substances under light irradiation
[0053] like Figure 8 As shown in the figure, the whitening active substance phenethyl resorcinol may be oxidized by free radicals to form colored methylene quinone. These free radicals may come from the light-sensitive substances in the surrounding environment that absorb light energy and are excited to react with oxygen to form singlet oxygen.
[0054] Emulsions containing phenylethyl resorcinol with and without light stabilizer were prepared as shown in Table 3. These samples were compared before and after light exposure. Fig. 9As shown in the figure, it is found that the formula without APP320 changes color more seriously, while the sample with APP320 changes color only slightly. This shows that after adding the light stabilizer, the light stabilizer quenches the excited photosensitive molecules, preventing them from transferring energy to oxygen to form free radicals, and avoiding the oxidation of phenylethyl resorcinol to form yellow methylene quinone intermediates.
[0055] Table 3
[0056] INCI name #1 #2 Glyceryl Stearate, PEG-100 Stearic Acid 3 3 Cetearyl Olivate, Sorbitan Olivate 2 2 Cetearyl Alcohol 1.5 1.5 APP320 3 0 Caprylic / capric triglyceride 10 10 1,3-Butanediol 2 2 Phenylethyl resorcinol 1 1 Deionized water 73.6 76.6 Glyceryl Stearate, PEG-100 Stearic Acid 3 3 Disodium EDTA 0.1 0.1 Carbomer 0.2 0.2 Sodium hydroxide 0.6 0.6
[0057] It should be noted that the preferred embodiments of the present invention are given in the specification of the present invention, but the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the present invention specification; further, for ordinary technicians in this field, they can be improved or transformed according to the above description, and all these improvements and transformations should belong to the protection scope of the claims attached to the present invention.
Claims
1. A light stabilizer, characterized in that: The light stabilizer has a structure shown in formula (I):
2. Use of the photostabilizer according to claim 1 for improving the photostability of photostability of photostability compounds.
3. The use according to claim 2, characterized in that: The photolabile compound includes a compound that is excited to generate an excited state molecule under light, or a compound that is easily oxidized by oxygen free radicals generated by a photosensitive substance under light. Furthermore, the photolabile compound includes a photolabile ultraviolet absorber, a photolabile antioxidant or other photolabile compounds.
4. The use according to claim 2 or 3, characterized in that The photolabile compounds include butyl methoxydibenzoylmethane, resveratrol, and phenethylresorcinol.
5. The use according to claim 3, characterized in that: The light stabilizer enhances the UV absorption capability of the light-labile UV absorber.
6. A light-stable composition, characterized in that The method comprises the light stabilizer according to claim 1 and a light-labile compound.
7. The composition according to claim 6, characterized in that The mass percentage of the light stabilizer in the composition is 0.1% to 10%.
8. The composition according to claim 6, characterized in that The mass percentage of the light stabilizer in the composition is 1% to 5%.
9. The composition according to claim 6, characterized in that The photolabile compound includes a compound that is excited to generate an excited state molecule under light, or a compound that is easily oxidized by oxygen free radicals generated by a photosensitive substance under light, Furthermore, the photolabile compound includes a photolabile ultraviolet absorber, a photolabile antioxidant or other photolabile compounds.
10. The composition according to claim 9, characterized in that The photolabile compounds include butyl methoxydibenzoylmethane, resveratrol, and phenethylresorcinol.