Nanostructured lipid carrier gel as well as preparation method and application thereof

Abstract

The invention provides lipid carrier gel with a nano structure as well as a preparation method and application of the lipid carrier gel, and relates to the technical field of sunscreen products. The lipid carrier gel with the nanostructure comprises a lipid carrier dispersion with the nanostructure and a gel matrix, wherein the nanostructure lipid carrier dispersion comprises a lipid material, a composite sunscreen active component, a natural sunscreen synergist, an emulsifier, a co-emulsifier and water; wherein the composite sunscreen active component is prepared from ethyl hexyl triazinone, diethylamino hydroxybenzoyl hexyl benzoate and bis-ethyl hexyloxyphenol methoxyphenyl triazine; the natural sunscreen synergist is prepared from rutin and ferulic acid. According to the lipid carrier gel with the nanostructure, three selected high-efficiency and light-stable chemical sun-screening agents and two natural plant synergists are compounded and encapsulated by using an NLC technology, and finally, the sun-screening gel which is high in sun-screening efficiency, good in light stability, low in skin permeability and comfortable to use is obtained.

Description

Technical Field

[0001] This invention relates to the technical field of sunscreen products, and in particular to a nanostructured lipid carrier gel, its preparation method, and its application. Background Technology

[0002] Ultraviolet (UV) radiation has a wavelength of 200-400 nanometers (nm) and can be categorized into UVA (320-400 nm), UVB (290-320 nm), and UVC (200-290 nm). UVC is completely absorbed by the ozone layer and generally does not harm the skin. UVB is the root cause of sunburn, primarily affecting the epidermis and causing acute sunburn, erythema, and swelling. UVA has strong penetrating power, reaching directly to the dermis. While it causes slow but long-term damage, UVA also stimulates melanin formation in the dermis, leading to tanning and premature skin aging. UV radiation directly damages DNA in skin cells. FDA guidelines state that prolonged sun exposure increases the risk of skin cancer and premature aging. Using broad-spectrum sunscreens with an SPF greater than 15 can reduce the risk of sun-induced skin cancer and premature skin aging; therefore, sunscreen is crucial in daily life.

[0003] Sunscreen products typically contain three types of sunscreen ingredients: inorganic sunscreens, organic sunscreens, and sunscreen synergists. Inorganic sunscreens, also known as UV shielding agents, commonly use titanium dioxide (TiO2) or zinc oxide (ZnO). Their mechanism of action is to form a protective film on the skin surface, reducing UV exposure through reflection and scattering. Organic sunscreens, also known as UV absorbers, mainly include camphor derivatives, cinnamic acid esters, salicylic acid esters, benzoyl esters, benzophenone, triazine derivatives, benzoazole derivatives, and alkanes. Sunscreens that absorb UVB mainly include salicylates and their derivatives, cinnamic acid esters, etc.; those that absorb UVA include butyl methoxydibenzoylmethane, etc.; and those that can absorb both UVB and UVA include benzophenone and its derivatives, etc. Sunscreen enhancers, primarily composed of plant-derived ingredients, enhance the skin's ability to resist ultraviolet rays and reduce skin damage through photoprotective effects such as reducing skin DNA damage, scavenging excess oxygen free radicals in the skin, resisting photoaging, and inhibiting inflammation and erythema.

[0004] Solid liposomes, a type of active component carrier newly developed in the early 1990s, are solid microparticles formed by the solidification and crystallization of solid lipids during cooling or phase separation, with the active component encapsulated within the lipid structure. Currently, there are two types: solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). NLCs are considered the "second-generation lipid carriers" developed after SLNs. The lipid portion of NLCs is composed of a mixture of solid and liquid lipids. The introduction of liquid lipids breaks the regular crystalline "brick-like" structure of the original solid lipids in SLNs, resulting in an "imperfect" lipid arrangement that can provide more defective structures, accommodate more drug molecules, and increase drug loading. The structural models of NLCs are mainly divided into matrix homogeneous models, core-shell encapsulation models, and outer layer encapsulation models. The main preparation methods include high-pressure homogenization, ultrasonic dispersion, solvent diffusion, and microemulsion methods.

[0005] However, existing sun protection technologies have many limitations: (1) Inorganic sunscreens: have poor sun protection effect, so they are used in large quantities. Inorganic sunscreens can cause a "false whitening" effect on the skin, and have poor dispersibility and are prone to agglomeration, affecting the skin feel and transparency of the product. Some studies have shown that titanium dioxide is easily excited to produce free radicals of reactive oxygen species under ultraviolet light, leading to photoaging of the skin and causing transdermal absorption of titanium, which has adverse effects on human health.

[0006] (2) Organic sunscreens: Many organic sunscreens have poor photostability and are easily photodegraded under ultraviolet light, losing their protective ability and even producing degradation products that irritate the skin, which may lead to contact sensitization and photosensitization. Some organic sunscreens may be absorbed through the skin and enter the systemic circulation, posing potential health risks. Studies have confirmed that after a single large-area application, several common chemical sunscreens (such as oxybenzone, avobenzone, octocrylene, and ethanoylene) can be detected in the blood at concentrations significantly higher than the safety threshold. Therefore, sunscreens do indeed penetrate into the bloodstream, and some sunscreens, after penetrating the skin, can cause allergies, hormonal imbalances, endocrine disruption, teratogenicity in the fetus, and potential carcinogenic risks.

[0007] (3) Sunscreen enhancers: The sunscreen performance of single plant-based sunscreen enhancers is not as good as that of chemical sunscreens and physical sunscreens.

[0008] In summary, existing technologies often require a combination of sunscreen agents to provide comprehensive UV protection, as a single agent is insufficient. However, simple physical mixing may not address the issues of sensitization, poor photostability, and skin penetration of chemical sunscreens.

[0009] Therefore, developing a composite sunscreen system based on advanced carrier technology that reduces the skin penetration of sunscreen agents, synergistically enhances the performance of multiple sunscreen agents, and adds antioxidant and repair functions has important application value.

[0010] In view of this, the present invention is hereby proposed. Summary of the Invention

[0011] The purpose of this invention is to provide a nanostructured lipid carrier gel, its preparation method, and its application. The nanostructured lipid carrier gel is prepared by compounding three highly efficient and photostable chemical sunscreens with two natural plant synergists, and encapsulating them using NLC technology to finally form a gel formulation. This successfully produces a nano-lipid carrier sunscreen gel with high sun protection efficacy, good photostable properties, low skin permeability, and comfortable user experience.

[0012] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a nanostructured lipid carrier gel, the nanostructured lipid carrier gel comprising a nanostructured lipid carrier dispersion and a gel matrix; The nanostructured lipid carrier dispersion comprises lipid materials, composite sunscreen active ingredients, natural sunscreen synergists, emulsifiers, co-emulsifiers, and water. The compound sunscreen active ingredients include ethylhexyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, and bis-ethylhexyloxyphenol methoxyphenyl triazine; the natural sunscreen synergists include rutin and ferulic acid.

[0013] Furthermore, the lipid material includes carnauba wax and caprylic / capric triglycerides.

[0014] Furthermore, the mass ratio of carnauba wax to caprylic / capric triglyceride is (1~3):1.

[0015] Further, the mass ratio of ethylhexyl triazine ketone, diethylamino hydroxybenzoyl hexyl benzoate and bis-ethylhexyloxyphenol methoxyphenyl triazine is (1~2):(1~2):(0.5~1.5).

[0016] Furthermore, the mass ratio of rutin to ferulic acid is (1~2):1.

[0017] Furthermore, the emulsifier includes lecithin and poloxamer 188.

[0018] Furthermore, the mass ratio of lecithin to poloxamer 188 is (1~2):(2~1).

[0019] Furthermore, the co-emulsifier includes glycerin.

[0020] Furthermore, the nanostructured lipid carrier dispersion comprises, by mass percentage: 5-15% lipid material, 3-10% composite sunscreen active ingredient, 0.5-3% natural sunscreen synergist, 2-6% emulsifier, 1-5% co-emulsifier, and the balance being water.

[0021] Furthermore, the gel matrix comprises carbomer, pH adjuster, preservative and water.

[0022] Furthermore, the gel matrix comprises, by mass percentage: 0-1.2% carbomer, 0-0.8% pH adjuster, 0-0.8% preservative, and the balance being water.

[0023] Furthermore, the gel matrix comprises Carbomer 980.

[0024] Furthermore, the pH adjuster includes triethanolamine.

[0025] Furthermore, the preservative includes phenoxyethanol.

[0026] Furthermore, the mass ratio of the nanostructured lipid carrier dispersion to the gel matrix is ​​(2~7):(8~3).

[0027] In a second aspect, the present invention provides a method for preparing a lipid carrier gel with a nanostructure as described in the first aspect, the method comprising: The oily components in the raw materials and excipients of the nanostructured lipid carrier dispersion are mixed to obtain the oil phase; The aqueous components in the raw materials and excipients of the nanostructured lipid carrier dispersion are mixed with water to obtain an aqueous phase; The oil phase is added to the aqueous phase and subjected to shearing to obtain a crude emulsion; The crude emulsion was homogenized to obtain a nanoemulsion. The nanoemulsion was cooled to obtain the nanostructured lipid carrier dispersion; The nanostructured lipid carrier dispersion and the gel matrix are mixed to obtain the nanostructured lipid carrier gel.

[0028] Furthermore, the oily components include carnauba wax, caprylic / capric triglyceride, ethylhexyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, rutin, ferulic acid, and lecithin; the aqueous components include poloxamer 188 and glycerin.

[0029] Furthermore, the mixing temperature of each oily component is 75~85℃; the mixing temperature of each aqueous component and a portion of water is 75~85℃.

[0030] Furthermore, the temperature of the shearing process is 75~85℃, the rotation speed of the shearing process is 10000~18000rpm, and the shearing time is 5~10min.

[0031] Furthermore, the homogenization process is carried out at a temperature of 75-85°C, at a pressure of 500-800 bar, and for 3-5 cycles.

[0032] Furthermore, the cooling process involves lowering the nanoemulsion to room temperature, with a cooling rate of 1~5℃ / min.

[0033] Furthermore, the preparation method of the gel matrix includes: mixing the carbomer and water, followed by swelling treatment and standing treatment to obtain swollen carbomer.

[0034] Furthermore, the swelling treatment specifically involves: sprinkling the carbomer on the surface of water and stirring it until it is completely dispersed and swollen to obtain the swollen carbomer.

[0035] Furthermore, the stirring temperature is 20~30℃, the stirring speed is 100~500 rpm, and the stirring time is 30~120 min.

[0036] Furthermore, the temperature for the settling treatment is 20~30℃, and the settling time is 2~24 h.

[0037] Further, the mixing includes: adding the nanostructured lipid carrier dispersion to a swollen carbomer under vacuum conditions; wherein the vacuum pressure is below -0.03 MPa.

[0038] Furthermore, the mixing of the nanostructured lipid carrier dispersion and the swollen carbomer is carried out under stirring conditions; wherein the stirring temperature is 20~30℃, the stirring speed is 50~400 rpm, and the stirring time is 5~30 min.

[0039] Furthermore, the mixture further includes a neutralization treatment and / or a preservative treatment; wherein the neutralization treatment includes adjusting the pH of the gel to 6.0~7.0 using a pH adjuster; and the preservative treatment includes adding a preservative.

[0040] Thirdly, the present invention provides the application of a lipid carrier gel with a nanostructure as described in the first aspect in the preparation of sunscreen products.

[0041] Compared with the prior art, the present invention has the following beneficial effects: (1) The nanostructured lipid carrier gel of the present invention embeds active substances in the microporous structure of the nanostructured lipid carrier (NLC), avoiding the influence of external environment oxygen and light, and greatly solving the problems of oxidation of active components and light instability, thus effectively exerting its efficacy. (2) The lipid carrier gel with nanostructure described in this invention can achieve controlled release of active substances, thereby solving the problem of skin irritation caused by high concentration of active substances on the skin surface, while ensuring that they are almost not absorbed through the skin and participate in blood circulation. (3) The lipid carrier gel with nanostructure described in this invention uses a composite sunscreen active ingredient and a natural sunscreen synergist. The two work together to show a synergistic effect of sunscreen effect, while also reducing the penetration of sunscreen agents into the skin and improving the safety of sunscreen formula.

[0042] (4) The lipid carrier gel with nanostructure described in this invention has the characteristics of easy spread and easy adhesion of fluid, while maintaining the gel shape, which can make good contact with the skin and has a refreshing texture. Detailed Implementation

[0043] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In a first aspect, the present invention provides a nanostructured lipid carrier gel, the nanostructured lipid carrier gel comprising a nanostructured lipid carrier dispersion and a gel matrix; The nanostructured lipid carrier dispersion includes lipid materials, composite sunscreen active ingredients, natural sunscreen synergists, emulsifiers, and co-emulsifiers. The composite sunscreen active ingredients include ethylhexyl triazine (EHT), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), and bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT). The natural sunscreen enhancers include rutin and ferulic acid.

[0046] It should be noted that this invention, by preparing a nanostructured lipid carrier gel encapsulating three chemical sunscreen active ingredients and two plant-derived ingredients as a natural sunscreen synergist, can produce the following beneficial results: (1) Highly efficient synergistic sun protection: The three chemical sunscreens have strong absorption and complement each other in both the UVA and UVB bands, achieving seamless protection from short-wave UVB to long-wave UVA. NLC simultaneously encapsulates three broad-spectrum UVA / UVB sunscreens and two antioxidants, significantly improving SPF and PA values ​​through the scattering / absorption of nanoparticles and the synergistic effect of antioxidants.

[0047] (2) Significantly enhances photostability: The selected chemical sunscreens themselves have good photostability. In addition, the lipid matrix and antioxidants provide protection for the chemical sunscreens, effectively reducing photodegradation under ultraviolet irradiation and maintaining long-lasting sun protection effect.

[0048] (3) Significantly reduces skin permeability and irritation: The carrier effect of NLC effectively encapsulates lipid-soluble ingredients, reducing direct contact between sunscreen and skin, and significantly reducing transdermal penetration of various active ingredients. The anti-inflammatory and soothing properties of ferulic acid and rutin further reduce potential irritation risks and improve product safety.

[0049] (4) Synergistic antioxidant protection: The addition of rutin and ferulic acid provides biochemical level antioxidant protection, which makes up for the shortcomings of pure physical / chemical sunscreen and realizes the triple protection concept of "physical shielding + chemical absorption + biological antioxidant".

[0050] (5) Improved user experience: NLC technology improves the greasy and heavy feeling caused by high concentration of sunscreen agents. The gel matrix gives the product a refreshing and non-greasy feel and makes it easy to apply.

[0051] Ethylhexyltriazine ketone (EHT), a colorless and odorless compound, is a highly efficient UVB absorber with a maximum absorption peak at around 314 nm, precisely covering the core UVB band. Its triazine ring in its molecular structure gives it extremely high photostability, making it resistant to decomposition under prolonged UV exposure and providing long-lasting and effective protection against UVB-induced sunburn and redness. In this invention, it is encapsulated in NLC (nitrogenous liquid chloride), further reducing the possibility of direct contact with light and maximizing its stability. EHT is typically used in sunscreens in combination with other UVA sunscreens to achieve full-spectrum UV protection.

[0052] Diethylaminohydroxybenzoylhexyl benzoate (DHHB) is a highly effective organic UVA sunscreen with a maximum absorption peak of approximately 354 nm, perfectly covering the UVA-I band (340-400 nm), the main ultraviolet wavelength that causes deep photoaging and wrinkles in the skin. When combined with UVB absorbers, it is a key component for achieving broad-spectrum sun protection. Its large molecular weight makes it difficult to penetrate the skin, resulting in high safety.

[0053] Bis-ethylhexyloxyphenol methoxyphenyl triazine, also known as UV absorber UV-627 or BEMT for short, is a new generation of broad-spectrum UV absorber that can absorb both UVA and UVB. Its unique molecular structure allows it to release energy as harmless heat after absorbing photons through intramolecular hydrogen bonding, making it one of the most photostable sunscreens. It not only provides protection itself but also acts as a "shield" to protect other sunscreen agents in the formula, reducing their photodegradation and thus improving the overall photostable stability and sun protection efficacy of the formulation.

[0054] Rutin, also known as rutin glycoside, is widely found in many plants such as Sophora japonica buds, buckwheat, Eucalyptus globulus, and tobacco leaves. It is a widely sourced natural flavonoid compound. Rutin can enhance the UVA resistance of sunscreen products. When combined with UVA sunscreen agents, it can enhance the photostability of chemical sunscreen agents and improve the antioxidant properties and SPF of the formula. It also has the ability to resist UVB, effectively scavenging free radicals generated by ultraviolet rays and reducing oxidative damage, thus playing a "synergistic" role in sun protection, reducing the amount of sunscreen agent needed and increasing the SPF and UVA-PF values ​​of the system.

[0055] Ferulic acid, chemically known as 3-methoxy-4-hydroxycinnamic acid, is a derivative of cinnamic acid and belongs to the phenolic acid class of compounds. It is widely found in various plants, with higher concentrations found in angelica, asafoetida, vanilla beans, and wheat bran. Ferulic acid offers excellent protection against skin cell damage caused by ultraviolet radiation. Due to the combination of the phenolic hydroxyl group and extended side chain in its structure, ferulic acid not only possesses excellent antioxidant activity but also the ability to absorb ultraviolet radiation, stabilize the formation of phenoxy groups, and terminate free radical reactions. Adding ferulic acid to sunscreens can increase the sun protection factor (SPF) and prevent inflammatory reactions. Sunscreens formulated with ferulic acid and chemical sunscreens have a synergistic sun protection effect, increasing the SPF value and UVA protection factor (UVA-PF) of the formulated sunscreen.

[0056] As an optional implementation, the lipid material includes solid lipid carnauba wax and liquid lipid caprylic / capric triglyceride.

[0057] It should be noted that carnauba wax is a natural plant-derived solid wax that forms a robust lattice structure at room temperature, providing a rigid framework and effectively encapsulating drugs. This allows for the slow release of active ingredients, enhancing controlled-release effects and reducing burst release. Caprylic / capric triglyceride (GTCC), as a liquid lipid, does not crystallize at room temperature. When mixed with molten carnauba wax and cooled, GTCC disrupts the orderly arrangement of carnauba wax molecules, embedding itself within the crystalline lattice of the solid lipid. This breaks the lattice's integrity, forming a non-crystalline, defective, porous lipid structure, further enhancing the drug-carrying capacity of the carrier. GTCC, as an excellent solvent, fully dissolves the drug, ensuring uniform dispersion throughout the lipid mixture, thereby improving encapsulation efficiency. Together, they form an ideal lipid matrix characterized by structural stability, high drug loading efficiency, precise controlled release, and comfortable use.

[0058] As an optional implementation, the mass ratio of carnauba wax to lipid caprylic / capric triglyceride is (1~3):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, etc.

[0059] As an optional implementation, the mass ratio of ethylhexyl triazine ketone, diethylamino hydroxybenzoyl hexyl benzoate, and bis-ethylhexyloxyphenol methoxyphenyl triazine is (1~2):(1~2):(0.5~1.5); Among them, ethylhexyl triazine ketone: "1~2" can be, for example, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.; diethylamino hydroxybenzoyl hexyl benzoate: "1~2" can be, for example, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.; bis-ethylhexyloxyphenol methoxyphenyl triazine: "0.5~1.5" can be, for example, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, etc.

[0060] As an optional implementation, the mass ratio of rutin to ferulic acid is (1~2):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1, 2:1, etc.

[0061] As an optional implementation, the emulsifier includes lecithin and poloxamer 188.

[0062] It should be noted that the emulsifier is composed of lecithin and poloxamer 188. Lecithin molecules have a hydrophilic phosphocholine head and a hydrophobic fatty acid tail, enabling efficient adsorption at the lipid-aqueous interface, significantly reducing interfacial tension and promoting nanoparticle formation. Lecithin itself is a lipid with excellent compatibility with carnauba wax and GTCC, seamlessly integrating into the lipid matrix. This helps form and stabilize the irregular crystal structure unique to NLCs. This structure can accommodate more drugs, increasing drug loading and preventing drug precipitation during storage, maintaining long-term stability. The natural lipid structure of lecithin is highly homologous to the stratum corneum of the skin, enhancing the affinity of NLCs for the skin and prolonging residence time at the administration site. Poloxamer 188, with its hydrophilic polyoxyethylene chains, forms a thick hydration layer on the surface of the nanoparticles. When particles approach each other, these hydration layers generate strong steric repulsion, effectively preventing particle aggregation due to van der Waals forces. This is crucial for the long-term physical stability of high surface energy nanosystems. Poloxamer 188 can adsorb onto the surface of nanoparticles, inhibiting the dissolution of lipids in small particles and recrystallization on large particles, thereby inhibiting particle growth and maintaining nanoscale uniformity. It can also further reduce surface tension and work with lecithin to improve the interfacial film. Through the complementary properties and synergistic functions of the two emulsifiers, an emulsification system with high efficiency, stable system, skin-friendly and gentle texture is obtained. It is compatible with the lipid system of the present invention, ensuring that NLC maintains a stable nanostructure in the gel matrix for a long time. At the same time, it provides double protection to avoid NLC demulsification and aggregation, and reduces the precipitation and oxidation of sunscreen active ingredients (EHT, DHHB, BEMT) and natural synergists (rutin, ferulic acid) encapsulated in the lipid carrier, greatly improving the long-term storage stability of the product.

[0063] As an optional implementation, the mass ratio of lecithin to poloxamer 188 is (1~2):(2~1); Among them, lecithin: "1~2" can be, for example, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.; poloxamer 188: "2~1" can be, for example, 2, 1.8, 1.6, 1.4, 1.2, 1, etc.

[0064] As an optional implementation, the co-emulsifier includes glycerin.

[0065] It should be noted that the co-emulsifier is glycerol. Glycerol can adjust the viscosity of the aqueous phase, reduce the interfacial tension between oil and water, and synergistically enhance emulsification efficiency with lecithin / poloxam 188. This helps to form smaller, more uniformly distributed nanoparticles and reduces aggregation or Ostwald ripening during storage. Glycerol can also act as an "interface modifier," enhancing the compatibility between the lipid core and the external aqueous phase and reducing drug leakage. Glycerol not only strengthens the stability of the NLC system and optimizes the emulsification effect by synergistically combining the emulsifier and lipid materials, ensuring the nanostructure stability and controlled release effect of the NLC, but also enhances the moisturizing and water-locking effect of the gel by binding the moisture in the stratum corneum of the skin with the moisture in the environment through hydrogen bonds.

[0066] As an optional implementation, the nanostructured lipid carrier dispersion comprises, by mass percentage: 5-15% lipid material, 3-10% composite sunscreen active ingredient, 0.5-3% natural sunscreen synergist, 2-6% emulsifier, 1-5% co-emulsifier, and the balance being water.

[0067] As an optional implementation, the mass percentage of lipid material is 5-15% based on the total mass of the nanostructured lipid carrier dispersion as 100%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc.

[0068] As an optional implementation, based on the total mass of the nanostructured lipid carrier dispersion as 100%, the mass percentage of the composite sunscreen active ingredient is 3-10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0069] As an optional implementation, the mass percentage of the natural sunscreen synergist is 0.5-3% based on the total mass of the nanostructured lipid carrier dispersion as 100%, for example, it can be 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, etc.

[0070] As an optional implementation, the emulsifier has a mass percentage of 2-6% based on the total mass of the nanostructured lipid carrier dispersion as 100%, for example, it can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.

[0071] As an optional implementation, the mass percentage of the co-emulsifier is 1-5% based on the total mass of the nanostructured lipid carrier dispersion as 100%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0072] As an optional implementation, the gel matrix includes carbomer, pH adjuster, preservative and water.

[0073] As an optional implementation, the gel matrix comprises, by weight percentage: 0-1.2% carbomer, 0-0.8% pH adjuster, 0-0.8% preservative, and the balance being water.

[0074] As an optional implementation, the mass percentage of the gel matrix is ​​0 to 1.2% based on the total mass of the gel matrix as 100%, for example, it can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, etc.

[0075] As an optional implementation, the pH adjuster has a mass percentage of 0-0.8% based on the total mass of the gel matrix as 100%, for example, it can be 0%, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.

[0076] As an optional implementation, the preservative content is 0-0.8% by mass, based on the total mass of the gel matrix as 100%, for example, it can be 0%, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.

[0077] As an optional implementation, the gel matrix includes Carbomer 980.

[0078] As an optional implementation, the pH adjuster includes triethanolamine.

[0079] As an optional implementation, the preservative includes phenoxyethanol.

[0080] As an optional implementation, the mass ratio of the nanostructured lipid carrier dispersion to the gel matrix is ​​(2~7):(8~3); Among them, the nanostructured lipid carrier dispersion “2~7” can be, for example, 2, 3, 4, 5, 6, 7, etc.; the gel matrix “8~3” can be, for example, 8, 7, 6, 5, 4, 3, etc.

[0081] In a second aspect, the present invention provides a method for preparing a lipid carrier gel with a nanostructure as described in the first aspect, the method comprising: The oily components in the raw materials of the nanostructured lipid carrier dispersion are mixed to obtain the oil phase; The aqueous components of the raw material in the nanostructured lipid carrier dispersion are mixed with water to obtain an aqueous phase; The oil phase is added to the aqueous phase and subjected to shearing to obtain a crude emulsion; The crude emulsion was homogenized to obtain a nanoemulsion. The nanoemulsion was cooled to obtain the nanostructured lipid carrier dispersion; The nanostructured lipid carrier dispersion and the gel matrix are mixed to obtain the nanostructured lipid carrier gel.

[0082] As an optional implementation, the oily components include carnauba wax, caprylic / capric triglyceride, ethylhexyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, rutin, ferulic acid, and lecithin.

[0083] As an optional implementation, the preparation steps of the oil phase are as follows: carnauba wax, caprylic / capric triglyceride, ethylhexyl triazine ketone, diethylamino hydroxybenzoyl benzoate hexyl ester, bis-ethylhexyloxyphenol methoxyphenyl triazine, rutin, ferulic acid, and lecithin are mixed, heated and melted in a water bath, and stirred evenly to obtain the oil phase.

[0084] As an optional implementation, the aqueous components include poloxamer 188 and glycerin.

[0085] As an optional implementation, the aqueous phase is prepared by dissolving poloxamer 188 and glycerol in a certain amount of water, heating and stirring until completely dissolved to obtain the aqueous phase.

[0086] As an optional implementation, the mixing temperature of each oily component is 75~85℃, for example, it can be 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, etc.

[0087] As an optional implementation, the mixing temperature of each aqueous component and a portion of water is 75~85℃, for example, it can be 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, etc.

[0088] As an optional implementation, the temperature of the shearing process is 75~85℃, for example, it can be 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, etc.

[0089] As an optional implementation, the rotational speed of the shearing process is 10,000 to 18,000 rpm, for example, 10,000 rpm, 11,000 rpm, 12,000 rpm, 13,000 rpm, 14,000 rpm, 15,000 rpm, 16,000 rpm, 17,000 rpm, 18,000 rpm, etc.

[0090] As an optional implementation, the shearing process takes 5 to 10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.

[0091] As an optional implementation, the homogenization temperature is 75~85℃, for example, it can be 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, etc.

[0092] As an optional implementation, the homogenization process is carried out at a pressure of 500 to 800 bar, for example, 500 bar, 550 bar, 600 bar, 650 bar, 700 bar, 750 bar, 800 bar, etc.

[0093] As an optional implementation, the homogenization process is repeated 3 to 5 times, for example, 3 times, 4 times, 5 times, etc.

[0094] As an optional implementation, the cooling is to reduce the nanoemulsion to room temperature.

[0095] As an optional implementation, the cooling rate is 1~5℃ / min, for example, it can be 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min, 3℃ / min, 3.5℃ / min, 4℃ / min, 4.5℃ / min, 5℃ / min, etc.

[0096] As an optional implementation, the preparation method of the gel matrix includes: mixing the carbomer and water, followed by swelling treatment and standing treatment to obtain swollen carbomer.

[0097] As an optional implementation, the swelling treatment specifically involves: sprinkling the carbomer on the surface of water and stirring it until it is completely dispersed and swollen to obtain the swollen carbomer.

[0098] As an optional implementation, the temperature of the stirring treatment is 20~30℃, for example, it can be 20℃, 22℃, 24℃, 25℃, 26℃, 28℃, 30℃, etc., the stirring speed is 100~500 rpm, for example, it can be 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, etc., and the stirring time is 30~120 min, for example, it can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc.

[0099] As an optional implementation, the temperature of the settling treatment is 20~30℃, for example, it can be 20℃, 22℃, 24℃, 25℃, 26℃, 28℃, 30℃, etc., and the settling treatment time is 2~24 h, for example, it can be 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, etc.

[0100] As an optional implementation, the mixing includes adding the nanostructured lipid carrier dispersion to a swollen carbomer under vacuum conditions.

[0101] As an optional implementation, the pressure of the vacuum is below -0.03 MPa, for example, it can be -0.03 MPa, -0.04 MPa, -0.05 MPa, -0.06 MPa, -0.08 MPa, -0.1 MPa, etc.

[0102] As an optional implementation, the mixing of the nanostructured lipid carrier dispersion and the swollen gel matrix is ​​carried out under stirring conditions; wherein, the stirring temperature is 20~30℃, for example, 20℃, 22℃, 24℃, 25℃, 26℃, 28℃, 30℃, etc., the stirring speed is 50~400 rpm, for example, 50 rpm, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, etc., and the stirring time is 5~30 min, for example, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc.

[0103] As an optional implementation, the mixture may further include a neutralization treatment and / or an anti-corrosion treatment.

[0104] As an optional implementation, the neutralization treatment includes adjusting the pH of the gel to 6.0-7.0 using a pH adjuster, such as 6.0, 6.2, 6.4, 6.6, 6.8, 7.0, etc.

[0105] As an optional implementation, the anti-corrosion treatment includes adding a preservative.

[0106] As an optional implementation, the preparation method of the nanostructured lipid carrier gel specifically includes the following steps: I. Preparation of nanostructured lipid carrier dispersions: (1) Preparation of oil phase: Carnauba wax, caprylic / capric triglyceride, ethylhexyl triazine, diethylamino hydroxybenzoyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, rutin, ferulic acid and lecithin are mixed to obtain oil phase; (2) Preparation of aqueous phase: Poloxamer 188, glycerol and water were mixed to obtain an aqueous phase; (3) Preparation of primary emulsion: The oil phase is added to the aqueous phase and sheared to obtain a crude emulsion; (4) High-pressure homogenization: The crude emulsion is homogenized to obtain a nano-emulsion; (5) Cooling and solidification: Cool the nanoemulsion to obtain the nanostructured lipid carrier dispersion (this process causes solid lipids to precipitate out, forming an irregular crystal structure of NLC).

[0107] II. Gel preparation: (1) Swelling carbomer: The carbomer is mixed with water and subjected to swelling treatment and standing treatment to obtain swollen carbomer.

[0108] (2) Mixing: The nanostructured lipid carrier dispersion and the swollen carbomer are mixed, and the pH of the system is adjusted to 6.0~7.0 using a pH adjuster to form a gel; finally, a preservative is added and stirred evenly to obtain the nanostructured lipid carrier gel.

[0109] Thirdly, the present invention provides the application of a lipid carrier gel with a nanostructure as described in the first aspect in the preparation of sunscreen products.

[0110] The present invention will be further illustrated below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0111] Examples 1-3 Examples 1-3 provide three different formulations of lipid carrier gels with different nanostructures; the formulations of each example are shown in Table 1 below: Table 1

[0112] The preparation methods of the nanostructured lipid carrier gels provided in Examples 1-3 specifically include the following steps: I. Preparation of nanostructured lipid carrier dispersions: (1) Preparation of oil phase: Carnauba wax, caprylic / capric triglyceride, ethylhexyl triazine ketone, diethylamino hydroxybenzoyl benzoate hexyl ester, bis-ethylhexyloxyphenol methoxyphenyl triazine, rutin, ferulic acid and lecithin are heated and melted in a water bath at 80°C and stirred evenly to obtain the oil phase.

[0113] (2) Preparation of aqueous phase: Poloxamer 188 and glycerol were dissolved in deionized water and heated to 80°C in another beaker and stirred until completely dissolved to obtain the aqueous phase.

[0114] (3) Preparation of primary emulsion: Under high-speed shearing (13000 rpm), the oil phase is slowly poured into the aqueous phase and sheared at 80℃ for 8 min to obtain crude emulsion.

[0115] (4) High-pressure homogenization: The crude emulsion was immediately transferred to a high-pressure homogenizer and homogenized 4 times at 80°C and 700 bar pressure to obtain nano-emulsion with fine particle size and uniform distribution.

[0116] (5) Cooling and solidification: The homogenized nanoemulsion is immediately placed in a water bath and cooled to room temperature while being stirred (cooling rate is 3℃ / min); this process causes solid lipids to precipitate out, forming an irregular crystal structure of the nanostructured lipid carrier dispersion, thus obtaining the nanostructured lipid carrier dispersion.

[0117] II. Gel preparation: (1) Swelling Carbomer: Slowly sprinkle Carbomer 980 onto the surface of the remaining deionized water while stirring with a stirrer (400 rpm, 25°C, 60 min) to avoid clumping. Continue stirring until completely dispersed and swollen to obtain a swollen carbomer matrix, and let it stand overnight.

[0118] (2) Mixing: Vacuum is drawn and the vacuum pressure is controlled to be ≤-0.03MPa. The above-mentioned nanostructured lipid carrier dispersion is slowly added to the swollen carbomer matrix and stirred with a stirrer (100 rpm, 25℃, 20 min) to ensure that the NLC and gel are mixed evenly and to avoid introducing too many air bubbles.

[0119] (3) Neutralization gel: Adjust the pH to 6.5 with triethanolamine to form a gel.

[0120] (4) Add phenoxyethanol and stir until homogeneous to obtain the lipid carrier gel with nanostructure provided in the corresponding embodiment.

[0121] Example 4 This embodiment provides a nanostructured lipid carrier gel, which differs from Example 1 only in that carnauba wax is replaced with an equal mass of glyceryl monostearate, while the other settings are the same as in Example 1.

[0122] Example 5 This embodiment provides a nanostructured lipid carrier gel, which differs from Example 1 only in that caprylic / capric triglyceride is replaced with an equal mass of isopropyl myristate, while the other settings are the same as in Example 1.

[0123] Comparative Example 1 This comparative example provides a lipid carrier gel with a nanostructure; the only difference from Example 1 is that rutin and ferulic acid are no longer added, the content of ethylhexyl triazine is increased to 1.8%, the content of diethylamino hydroxybenzoyl hexyl benzoate is increased to 1.8%, and the content of bis-ethylhexyloxyphenol methoxyphenyl triazine is increased to 0.7%, while other settings are the same as in Example 1.

[0124] Comparative Example 2 This comparative example provides a nanostructured lipid carrier dispersion, which differs from Example 1 only in that carbomer 980 and triethanolamine are no longer added. The other formulations are the same as in Example 1, and the preparation method is the same as that of the nanostructured lipid carrier dispersions in Examples 1-3.

[0125] Comparative Example 3 This embodiment provides a sunscreen lotion, which includes an oil phase and an aqueous phase; The oil phase, by mass percentage, comprises: EHT 2%, DHHB 2%, BEMT 1%, rutin 0.8%, ferulic acid 0.4%, caprylic / capric triglyceride 10%, carnauba wax 4%, Tween 80 2%, and Span 80 1%.

[0126] The aqueous phase comprises, by mass percentage: 5% glycerol, 0.2% carbomer, 0.5% phenoxyethanol, ethanolamine (appropriate amount), and deionized water up to 100%.

[0127] The sunscreen lotion is prepared using a conventional emulsification method, including: The oil and water phases were heated to 80°C, mixed, homogenized (13000 rpm, 8 min), and cooled to room temperature. No NLC technology was used.

[0128] Comparative Example 4 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that ethylhexyl triazine ketone is no longer added, the content of diethylamino hydroxybenzoyl hexyl benzoate is increased to 2%, the content of bis-ethylhexyloxyphenol methoxyphenyl triazine is increased to 1%, the content of rutin is increased to 0.8%, and the content of ferulic acid is increased to 0.5%. Other settings are the same as in Example 1.

[0129] Comparative Example 5 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that diethylamino hydroxybenzoyl hexyl benzoate is no longer added, the content of ethylhexyl triazine is increased to 2%, the content of bis-ethylhexyloxyphenol methoxyphenyl triazine is increased to 1%, the content of rutin is increased to 0.8%, and the content of ferulic acid is increased to 0.5%. Other settings are the same as in Example 1.

[0130] Comparative Example 6 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that bis-ethylhexyloxyphenol methoxyphenyl triazine is no longer added, the content of ethylhexyl triazine is increased to 1.6%, the content of diethylamino hydroxybenzoyl hexyl benzoate is increased to 1.6%, the content of rutin is increased to 0.6%, and the content of ferulic acid is increased to 0.5%. Other settings are the same as in Example 1.

[0131] Comparative Example 7 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that rutin is no longer added, the content of ethylhexyl triazine is increased to 1.6%, the content of diethylamino hydroxybenzoyl hexyl benzoate is increased to 1.6%, the content of bis-ethylhexyloxyphenol methoxyphenyl triazine is increased to 0.6%, and the content of ferulic acid is increased to 0.5%. Other settings are the same as in Example 1.

[0132] Comparative Example 8 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that ferulic acid is no longer added, the content of ethylhexyl triazine is increased to 1.6%, the content of diethylamino hydroxybenzoyl hexyl benzoate is increased to 1.6%, the content of bis-ethylhexyloxyphenol methoxyphenyl triazine is increased to 0.55%, and the content of rutin is increased to 0.55%. Other settings are the same as in Example 1.

[0133] Comparative Example 9 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that carnauba wax is no longer added, and the content of caprylic / capric triglycerides is increased to 6.0%. All other settings are the same as in Example 1.

[0134] Comparative Example 10 This comparative example provides a lipid carrier gel with a nanostructure. The only difference from Example 1 is that caprylic / capric triglyceride is no longer added, and the content of carnauba wax is increased to 6.0%. All other settings are the same as in Example 1.

[0135] Test Example 1 Light stability test Test samples: lipid carrier gels with nanostructures provided in Examples 1-5, lipid carrier gels with nanostructures provided in Comparative Example 1, lipid carrier dispersions with nanostructures provided in Comparative Example 2, sunscreen lotion provided in Comparative Example 3, and lipid carrier gels with nanostructures provided in Comparative Examples 4-10.

[0136] Test method: The sample was uniformly coated on a quartz plate and irradiated with a UV light source (simulating sunlight) at a dose equivalent to one MED (minimum erythema dose). The changes in the content of the main sunscreen agents before and after irradiation were determined by HPLC, and the residual rate was calculated.

[0137] The specific test results are shown in Table 2 below: Table 2

[0138] Note: "-" indicates that this ingredient is not present in this group and no relevant data was detected.

[0139] Based on the photostability results, we can conclude that: NLC gel formulations, combined with sunscreen synergists, significantly improve photostability. As shown in Table 2, comparing Examples 1-3 with Comparative Examples 1-3, the Example series (NLC gel + rutin / ferulic acid) exhibited the highest residual photoperiod, significantly superior to Comparative Example 1 (no synergist), Comparative Example 2 (no gel matrix, only dispersion), and Comparative Example 3 (traditional emulsion). This indicates that the NLC carrier itself can effectively reduce the photodegradation rate of all chemical sunscreens, thanks to the encapsulation and protection of the sunscreen by the lipid matrix, reducing its direct contact with ultraviolet light. Rutin and ferulic acid, as antioxidants / synergists, preferentially sacrifice themselves under ultraviolet irradiation, quenching reactive oxygen species and free radicals generated by sunscreen decomposition or ultraviolet light, thereby greatly protecting the chemical sunscreen molecules and synergistically reducing photodegradation, maintaining their long-term effectiveness. The gel formulation may further reduce the migration and photoreaction of active ingredients by forming a dense network. Therefore, the NLC carrier gel and antioxidant synergistically reduce photodegradation.

[0140] Solid / liquid lipids are preferred to increase photostability. The photostability of Examples 4 (glyceryl monostearate) and 5 (isopropyl myristate) was slightly lower than that of Example 1 (carnauba wax + caprylic / capric triglyceride). This indicates that the specific lipid matrix formed by carnauba wax (high melting point, good crystallinity) and caprylic / capric triglyceride provides superior encapsulation and protection for sunscreen agents. Comparative Examples 9 (no solid lipids) and 10 (no liquid lipids) showed a significant decrease in stability. This demonstrates that a proper ratio of solid to liquid lipids is crucial for forming stable NLCs and providing effective protection. The absence of either component will disrupt the carrier structure, leading to sunscreen agent exposure.

[0141] Sunscreen agents and synergists work synergistically to improve photostability. Comparative Examples 4-6 (each lacking one sunscreen agent): While the stability of the remaining sunscreen agents did not decrease significantly, this sacrificed broad-spectrum protection, which may affect the overall protective effect in practical applications. Comparative Examples 7-8 (each lacking rutin or ferulic acid): The stability of all sunscreen agents was significantly lower than that of Example 1 with the complete formulation, but higher than that of Comparative Example 1 without any synergists. This demonstrates that both synergists are indispensable and have a synergistic effect, together forming a highly efficient "internal" photostability system.

[0142] Test Example 2 In vitro transdermal test Test samples: lipid carrier gels with nanostructures provided in Examples 1-5, lipid carrier gels with nanostructures provided in Comparative Example 1, lipid carrier dispersions with nanostructures provided in Comparative Example 2, sunscreen lotion provided in Comparative Example 3, and lipid carrier gels with nanostructures provided in Comparative Examples 4-10.

[0143] Test Method: The Franz diffusion cell method was used, with Bama miniature pig skin (0.5±0.25 mm thick) as the skin barrier. The receiving solution was a mixture of 1.0% polyoxyethylene oil ether and physiological saline. Each sample (approximately 20 mg accurately weighed) was evenly applied to the skin surface of the supply chamber. The chamber was maintained at 32±1℃ and magnetically stirred at 600 rpm. Samples of the receiving solution were taken at 1 h, 2 h, 4 h, 6 h, and 8 h. High-performance liquid chromatography-mass spectrometry (HPLC-MS) was used to detect the cumulative permeation and residual amount of the three active ingredients in the receiving solution. The sum of these two values ​​was the total permeation, and the cumulative transdermal rate was calculated (transdermal rate = total permeation / actual drug content).

[0144] The specific test results are shown in Table 3 below: Table 3

[0145] Based on the transdermal results: NLC carrier gel effectively blocks the transdermal penetration of sunscreen agents, resulting in high safety. As shown in Table 3, the transdermal permeability of Comparative Example 1 (without plant-based sunscreen synergists), Comparative Example 2 (NLC dispersion), Comparative Example 3 (conventional emulsion), Comparative Example 7 (without rutin), and Comparative Example 8 (without ferulic acid) were all higher than the examples, indicating that the NLC carrier gel significantly reduced the transdermal permeability of sunscreen agents. This is because the solid lipid core and nanoscale size of the NLC carrier allow it to form a dense film on the skin surface and remain primarily through the hair follicle pathway, rather than penetrating the active epidermis. The gel matrix immobilizes the NLC carrier, reducing contact with the external environment, thus reducing transdermal penetration of sunscreen agents and improving system safety. Simultaneously, ferulic acid and rutin may possess properties that enhance skin barrier function or interact with stratum corneum components, further "locking in" the sunscreen agents encapsulated in the NLC, minimizing the risk of systemic exposure and further enhancing safety.

[0146] The formulation composition has a certain impact on transdermal permeability. Examples 4-5 showed higher transdermal permeability than Example 1, indicating that changing the lipids may alter the crystal structure, encapsulation efficiency, and interaction with the gel matrix of the NLC, resulting in slightly weaker barrier properties. Comparative Example 9 (without solid lipids) showed a sharp increase in transdermal permeability because the lack of a solid lipid backbone prevented effective NLC formation, resulting in a near-nanoemulsion state where the sunscreen agent was more easily released and penetrated. Comparative Example 10 (without liquid lipids) showed a lower transdermal permeability. Its perfect crystal matrix formation allowed the drug to be easily squeezed out onto the particle surface or into the aqueous phase, leading to drug leakage during storage and potentially a decrease in effective drug loading during actual use. Therefore, an appropriate solid-liquid lipid ratio (e.g., carnauba wax + GTCC) is crucial for the stability and barrier function of NLCs. Compared to Comparative Examples 4-6, a combination of full-spectrum sunscreen agents is a prerequisite for providing complete protection, and each component in this system can obtain good protection.

[0147] Therefore, considering both photostability and transdermal absorption, the nanostructured lipid carrier gel prepared by this invention, which encapsulates three chemical sunscreens and two plant-derived sunscreen synergistic ingredients, can improve the photostability of chemical sunscreens and reduce transdermal absorption.

[0148] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nanostructured lipid carrier gel, characterized in that, The nanostructured lipid carrier gel comprises a nanostructured lipid carrier dispersion and a gel matrix; The nanostructured lipid carrier dispersion comprises lipid materials, composite sunscreen active ingredients, natural sunscreen synergists, emulsifiers, co-emulsifiers, and water. The compound sunscreen active ingredients include ethylhexyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, and bis-ethylhexyloxyphenol methoxyphenyl triazine; the natural sunscreen synergists include rutin and ferulic acid.

2. The lipid carrier gel with a nanostructure according to claim 1, characterized in that, The lipid material includes carnauba wax and caprylic / capric triglycerides; Preferably, the mass ratio of carnauba wax to caprylic / capric triglyceride is (1~3):

1.

3. The lipid carrier gel with a nanostructure according to claim 1, characterized in that, The mass ratio of ethylhexyl triazine ketone, diethylamino hydroxybenzoyl hexyl benzoate, and bis-ethylhexyloxyphenol methoxyphenyl triazine is (1~2):(1~2):(0.5~1.5); Preferably, the mass ratio of rutin to ferulic acid is (1~2):

1.

4. The lipid carrier gel with a nanostructure according to claim 1, characterized in that, The emulsifiers include lecithin and poloxamer 188; Preferably, the mass ratio of lecithin to poloxamer 188 is (1~2):(2~1); Preferably, the co-emulsifier includes glycerin.

5. The lipid carrier gel with a nanostructure according to claim 1, characterized in that, The nanostructured lipid carrier dispersion comprises, by mass percentage: 5-15% lipid material, 3-10% composite sunscreen active ingredient, 0.5-3% natural sunscreen synergist, 2-6% emulsifier, 1-5% co-emulsifier, and the balance being water.

6. The lipid carrier gel with a nanostructure according to claim 1 or 5, characterized in that, The gel matrix comprises carbomer, pH adjuster, preservative and water; Preferably, the gel matrix comprises, by weight percentage: 0-1.2% carbomer, 0-0.8% pH adjuster, 0-0.8% preservative, and the balance being water; Preferably, the carbomer includes carbomer 980; Preferably, the pH adjuster comprises triethanolamine; Preferably, the preservative includes phenoxyethanol; Preferably, the mass ratio of the nanostructured lipid carrier dispersion to the gel matrix is ​​(2~7):(8~3).

7. A method for preparing a lipid carrier gel with a nanostructure according to any one of claims 1 to 6, characterized in that, The preparation method includes: The oily components in the raw materials and excipients of the nanostructured lipid carrier dispersion are mixed to obtain the oil phase; The aqueous components in the raw materials and excipients of the nanostructured lipid carrier dispersion are mixed with water to obtain an aqueous phase; The oil phase is added to the aqueous phase and subjected to shearing to obtain a crude emulsion; The crude emulsion was homogenized to obtain a nanoemulsion. The nanoemulsion was cooled to obtain the nanostructured lipid carrier dispersion; The nanostructured lipid carrier dispersion and the gel matrix are mixed to obtain the nanostructured lipid carrier gel.

8. The method for preparing the nanostructured lipid carrier gel according to claim 7, characterized in that, The oily components include carnauba wax, caprylic / capric triglyceride, ethylhexyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, rutin, ferulic acid, and lecithin; the aqueous components include poloxamer 188 and glycerin. Preferably, the mixing temperature of each oily component is 75~85℃; the mixing temperature of each aqueous component and a portion of water is 75~85℃. Preferably, the temperature of the shearing process is 75~85℃, the rotation speed of the shearing process is 10000~18000 rpm, and the shearing time is 5~10 min; Preferably, the homogenization process is carried out at a temperature of 75-85°C, at a pressure of 500-800 bar, and for 3-5 cycles. Preferably, the cooling is to reduce the nanoemulsion to room temperature, and the cooling rate is 1~5℃ / min.

9. The method for preparing the nanostructured lipid carrier gel according to claim 7, characterized in that, The preparation method of the gel matrix includes: mixing carbomer and water, followed by swelling treatment and standing treatment to obtain swollen carbomer; Preferably, the swelling treatment specifically involves: sprinkling the carbomer on the surface of water and stirring until it is completely dispersed and swollen to obtain the swollen carbomer; Preferably, the temperature of the stirring treatment is 20~30℃, the stirring speed is 100~500 rpm, and the stirring time is 30~120 min; Preferably, the temperature for the settling treatment is 20~30℃, and the settling treatment time is 2~24 h; Preferably, the mixing comprises: adding the nanostructured lipid carrier dispersion to a swollen carbomer under vacuum conditions; wherein the vacuum pressure is below -0.03 MPa; Preferably, the mixing of the nanostructured lipid carrier dispersion and the swollen carbomer is carried out under stirring conditions; wherein the stirring temperature is 20~30℃, the stirring speed is 50~400 rpm, and the stirring time is 5~30 min; Preferably, the mixture further includes a neutralization treatment and / or a preservative treatment; wherein the neutralization treatment includes adjusting the pH of the gel to 6.0-7.0 using a pH adjuster; and the preservative treatment includes adding a preservative.

10. The use of a lipid carrier gel with a nanostructure according to any one of claims 1 to 6 in the preparation of sunscreen products.

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