Ethylhexyl triazinone sun-screening agent suitable for sensitive skin and process

Abstract

The invention discloses an ethylhexyl triazinone sun-screening agent suitable for sensitive skin and a preparation process. Ethyl hexyl triazinone is dissolved in caprylic / capric triglyceride and is emulsified by a low-content nano emulsifier to form a nano-scale oil-phase sun-screening inner core; sodium alginate, chitosan and calcium chloride construct a pH response type nano-carrier through a cross-linking system, and the pH response type nano-carrier is used for embedding and loading the nanoscale oil-phase sunscreen inner core through a nanoparticle structure; deionized water is used as a basis and is mixed with glycerol and disodium ethylene diamine tetraacetate to form a water-phase matrix which is used for dispersing the pH-responsive nano-carrier. According to the invention, the oil phase content of the system and the addition amount of the emulsifier are obviously reduced, the skin feeling is improved, the irritation is reduced, the direct contact between the ethylhexyl triazinone and the skin is isolated through the embedding and loading effect of the carrier, the transdermal permeation of the ethylhexyl triazinone is reduced, and the irritation risk to the sensitive skin is reduced; in addition, the whole sun-screening agent is mild and soothing in formula, fresh and non-sticky, and more uniform in film formation.

Description

Technical Field

[0001] This invention relates to a sunscreen agent and process, and more particularly to an ethylhexyl triazine ketone sunscreen agent and process suitable for sensitive skin. Background Technology

[0002] Ethylhexyl triazone is a high-quality UVB / UVA-II sunscreen ingredient that is highly effective, photostable, has low transdermal absorption, and is low in irritation. It is widely used in current sunscreen products.

[0003] Traditional ethylhexyl triazine ketone sunscreens are mostly open systems, lacking nanocarriers and encapsulation systems. However, ethylhexyl triazine ketone is a solid or high-viscosity oil, requiring dissolution in a large amount of oil before it can be added to the formula. Therefore, traditional ethylhexyl triazine ketone sunscreens generally suffer from the drawbacks of being greasy and heavy, resulting in a poor skin feel. This heavy oil can clog pores and aggravate inflammation, making traditional ethylhexyl triazine ketone sunscreens unsuitable for sensitive skin. Furthermore, in order to stably disperse the oil-soluble ethylhexyl triazine ketone in a water-based system, emulsification is required. However, ethylhexyl triazine ketone is prone to crystallization and requires high stability in the emulsion system. High doses of highly irritating emulsifiers are needed to maintain system stability, which can easily damage the skin barrier, further increasing the risk of sensitization and irritation. Consequently, traditional ethylhexyl triazine ketone sunscreens are difficult to meet the gentle sun protection needs of sensitive skin. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, this invention provides an ethylhexyl triazine ketone sunscreen agent and its manufacturing process suitable for sensitive skin.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: an ethylhexyl triazine ketone sunscreen suitable for sensitive skin, comprising the following components in parts by weight: Ethylhexyl triazine 2.0-5.0 parts, sodium alginate 1.0-2.0 parts, chitosan 0.3-1.5 parts, calcium chloride 0.05-0.2 parts, caprylic / capric triglyceride 3.0-5.0 parts, low content nano-emulsifier 1.5-3.0 parts, 1,2-pentanediol 2.0-4.0 parts, glycerol 3.0-5.0 parts, disodium ethylenediaminetetraacetate 0.05-0.1 parts, preservative 0.5-0.8 parts, deionized water 70-75 parts; Ethylhexyltriazine is dissolved in caprylic / capric triglyceride and emulsified with a low amount of nano-emulsifier to form a nano-scale oil-phase sunscreen core; Sodium alginate, chitosan, and calcium chloride are used to construct a pH-responsive nanocarrier through a cross-linking system. The pH-responsive nanocarrier encapsulates and loads a nanoscale oil-phase sunscreen core through a nanoparticle structure. Based on deionized water, a water-phase matrix is ​​formed by mixing glycerol and disodium EDTA, and a pH-responsive nanocarrier encapsulating an oil-phase sunscreen core is dispersed in the water-phase matrix.

[0006] Preferably, the ethylhexyl triazine ketone sunscreen also contains 0.05–0.15 parts of xanthan gum.

[0007] Preferably, the nanoemulsifier is nano-sized polyglycerol-6 distearate or Tween 80.

[0008] Preferably, the preservative is phenoxyethanol.

[0009] Preferably, under normal skin conditions of pH 4.5–6.0, the pH-responsive nanocarrier tightly binds chitosan and sodium alginate to lock in the nano-scale oil phase sunscreen core. Under pH-responsive conditions of sensitive skin (pH 6.0–7.0), the charge effect of chitosan is weakened, and the carrier cross-linked with sodium alginate can swell in a controlled manner, releasing a nano-scale oil-phase sunscreen core.

[0010] A preparation process for an ethylhexyl triazine ketone sunscreen suitable for sensitive skin includes the following steps: Step 1: Preparation of nanoscale oil-phase sunscreen core: A two-stage emulsification process was used to prepare a nanoscale oil-phase sunscreen core with a particle size of less than 100 nm by using ethylhexyl triazine ketone, caprylic / capric triglyceride, and nano-emulsifier. Step 2, Preparation of sodium alginate phase: Add disodium ethylenediaminetetraacetate and glycerol to the remaining deionized water and stir until completely dissolved; Add sodium alginate and stir at high speed until completely dissolved to obtain a homogeneous sodium alginate phase. Keep warm for later use. Step 3, preparation of the chitosan phase: Chitosan was dissolved in an acidic aqueous solution and stirred until the chitosan was completely dissolved to obtain the chitosan phase, which was then set aside. Step 4, Preparation of the colostrum: The well-insulated nano-level oil-phase sunscreen core was slowly added to the sodium alginate phase and emulsified under high-speed shear conditions for 5-10 minutes to obtain an O / W type primary emulsion. Step 5, electrostatic self-assembly and ionic cross-linking: Under stirring conditions, the chitosan phase solution is slowly added dropwise to the O / W type primary emulsion, and stirring is continued for 20-40 minutes to allow sodium alginate and chitosan to form a core-shell structure precursor through electrostatic interaction. Continue to slowly add calcium chloride aqueous solution, stirring for 30-60 minutes, until the calcium chloride solution is completely added. 2+ Ionic crosslinking of sodium alginate solidifies pH-responsive nanocarrier structures; Step Six, Thickening and Adjusting Viscosity: Add xanthan gum solution to the solution product obtained in step five, stir until homogeneous, and adjust the viscosity of the system. Step 7, Preservatives and Post-treatment: After cooling the sunscreen agent adjusted in step six to below 35 ℃, add the preservative, stir evenly, and then defoam, filter, and discharge the material to obtain the pH-responsive nanocarrier ethylhexyl triazine ketone sunscreen agent.

[0011] Preferably, in step one, the secondary emulsification process is as follows: ethylhexyl triazine ketone and caprylic / capric triglyceride nanoemulsifier are added to the oil phase container according to the weight requirements; Heat to 45–55 °C and stir until ethylhexyltriazine is completely dissolved to obtain a uniform and transparent primary emulsion oil phase; Take 3-5 parts by weight of deionized water and continuously add it dropwise to the primary emulsified oil phase for dilution. Through spontaneous microemulsification, obtain a nano-scale oil phase sunscreen core with a particle size of less than 100 nm.

[0012] Preferably, in step three, the acidic aqueous solution is either a dilute citric acid aqueous solution or a dilute lactic acid aqueous solution, and the chitosan phase is prepared when the pH is adjusted to 4.0-5.5.

[0013] Preferably, in step six, the suitable range of system viscosity is 3000–6000 mPa·s at 25 °C.

[0014] This invention discloses an ethylhexyl triazine ketone sunscreen agent and process suitable for sensitive skin, with ethylhexyl triazine ketone oil phase as the core and sodium alginate-chitosan / Ca as the core. 2+ A pH-responsive nanocarrier, ethylhexyltriazineone, is constructed using a cross-linked network as the shell. Compared to existing technologies, this sunscreen significantly reduces the oil phase content and emulsifier addition by replacing the dissolving effect of a large amount of oil in traditional formulations with a pH-responsive nanocarrier. This improves skin feel and reduces irritation. The carrier encapsulates and loads ethylhexyltriazineone, isolating it from direct contact with the skin and reducing its transdermal penetration, thus lowering the risk of irritation to sensitive skin. Furthermore, the entire sunscreen formula is gentle and soothing, and the nano-sized particles make the system texture finer, leaving it refreshing and non-sticky after application, with a more uniform film formation, effectively enhancing the product's user experience. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to specific embodiments.

[0016] Addressing the current technical limitations of traditional open-system sunscreens with ethylhexyl triazine as the core ingredient, which are often unsuitable for sensitive skin, this invention proposes an ethylhexyl triazine sunscreen suitable for sensitive skin. A pH-responsive nanocarrier is constructed using a sodium alginate-chitosan / Ca²⁺ crosslinking system, encapsulating ethylhexyl triazine within the nanoparticles formed by this pH-responsive nanocarrier. Because the sunscreen ingredient is carried by a pH-responsive nanocarrier, there is no need to rely on external oils as solvents. This reduces the stickiness of the sunscreen product and requires only a small amount of emulsifier to form a stable nano-dispersion, significantly improving the suitability of the ethylhexyl triazine sunscreen for sensitive skin.

[0017] First, the ethylhexyl triazine ketone sunscreen agent for sensitive skin disclosed in this invention comprises the following components in parts by weight: Ethylhexyl triazine 2.0-5.0 parts, sodium alginate 1.0-2.0 parts, chitosan 0.3-1.5 parts, calcium chloride 0.05-0.2 parts, caprylic / capric triglyceride (MCT) 3.0-5.0 parts, low content nano-emulsifier 1.5-3.0 parts, 1,2-pentanediol 2.0-4.0 parts, glycerol 3.0-5.0 parts, xanthan gum 0.05-0.15 parts, disodium EDTA 0.05-0.1 parts, preservative 0.5-0.8 parts, deionized water 70-75 parts; The ethylhexyl triazine is dissolved in caprylic / capric triglyceride and emulsified with a low content of nano-emulsifier to form a nano-level oil-phase sunscreen core. The sodium alginate, chitosan, and calcium chloride are cross-linked to construct a pH-responsive nanocarrier, which encapsulates a nanoscale oil-phase sunscreen core through a nanoparticle structure. Based on the aforementioned deionized water, glycerol, xanthan gum, and disodium EDTA are mixed to form an aqueous matrix, in which a pH-responsive nanocarrier encapsulating an oil-phase sunscreen core is dispersed.

[0018] Ethylhexyl Triazone is the core sunscreen active ingredient, which mainly absorbs the UVB band (280-320 nm) and also has strong absorption of the UVA-II band (320-340 nm), making it a highly efficient broadband UVB / UVA-II sunscreen agent.

[0019] Although ethylhexyltriazine has good photostability, direct contact with the skin may still cause skin irritation. Furthermore, the open system of ethylhexyltriazine requires a large amount of oil as a solvent, resulting in high emulsification difficulty and sticky sunscreen products. Based on this, the present invention constructs a pH-responsive nanocarrier using a sodium alginate-chitosan / Ca²⁺ crosslinking system, and utilizes the nanoparticle structure of the pH-responsive nanocarrier to encapsulate the core sunscreen active ingredient, ethylhexyltriazine.

[0020] Sodium alginate, a naturally derived polysaccharide, forms a three-dimensional polymer network structure when combined with water, constructing the framework of a pH-responsive nanocarrier. Furthermore, as an anionic polysaccharide polymer, sodium alginate interacts electrostatically with cationic materials such as chitosan to form a pH-responsive nanocarrier, enabling subsequent encapsulation and loading of ethylhexyl triazine. Additionally, sodium alginate possesses moisturizing and soothing properties, enhancing the gentleness of the formula and making it suitable for sunscreen products for sensitive skin.

[0021] Chitosan, as a cationic polysaccharide, electrostatically combines with anionic sodium alginate. Furthermore, normal skin is typically weakly acidic (pH 4.5–6.0). Chitosan's high protonation level allows it to bind tightly to sodium alginate, locking in the sunscreen and ensuring it remains on the stratum corneum or skin surface to form a uniform film. This contributes to a longer-lasting, wash-resistant protective film, enhancing the sunscreen's effectiveness. For sensitive skin, which has a higher pH (typically 6.0–7.0), the charge effect of chitosan is weakened, and the carrier swells moderately, enabling controlled, sustained release of the sunscreen. This controlled release avoids instantaneous irritation from high concentrations of ethylhexyl triazine ketone sunscreen on the skin surface. Combined with the biocompatibility and repair functions of sodium alginate and the chitosan matrix itself, the sunscreen disclosed in this invention is highly suitable for the low-irritation needs of sensitive skin.

[0022] Calcium chloride is mainly used to provide a source of divalent cations (Ca). 2+ It undergoes ionic cross-linking with the carboxyl groups of sodium alginate to form a stable cross-linked structure. The pH-responsive nanocarrier structure after cross-linking is more compact, which can reduce the burst release of the encapsulated ethylhexyl triazine ketone sunscreen, achieve more stable controlled release, and prolong the sunscreen effect.

[0023] Therefore, the sunscreen agent disclosed in this invention encapsulates oil-soluble ethylhexyl triazine ketone within sodium alginate-chitosan / Ca... 2+The nanoparticle structure formed within the product can significantly reduce the amount of dissolving oils used, thereby avoiding problems such as greasy and heavy sunscreen products and poor skin feel. Furthermore, the significant reduction in the amount of oil used also helps to optimize the use of emulsifiers, avoiding the use of high doses and strong irritants, thus significantly reducing the probability of adverse effects of emulsifiers on the skin barrier, making the sunscreen product of this invention more suitable for use on sensitive skin.

[0024] Nano-emulsifiers are used for emulsification treatment prior to the encapsulation of ethylhexyl triazine ketone. Nano-sized polyglycerol-6 distearate or Tween 80 is used to break the ethylhexyl triazine ketone oil phase into nano-sized droplets, which are then encapsulated using a pH-responsive nanocarrier. Due to the reduced amount of dissolving oils, the amount of nano-emulsifier added is significantly reduced, resulting in a low-content emulsifier in the overall sunscreen system.

[0025] Furthermore, both polyglycerol-6 distearate and Tween 80 are nonionic nanoemulsifiers that can effectively reduce the interfacial tension between oil and water, prepare ethylhexyl triazine ketone nanoemulsions with uniform particle size, improve system stability, and are mild and low-irritant, making them suitable for pH-responsive nanocarrier sunscreen formulations for sensitive skin.

[0026] Caprylic / capric triglyceride (MCT), as a moderately polar oil, can enhance the solubility of ethylhexyl triazine ketone in the oil phase. A small amount of MCT can meet the requirements for nanoscale emulsification of ethylhexyl triazine ketone. By completely dissolving ethylhexyl triazine ketone into liquid oil droplets through MCT, combined with emulsifiers, ethylhexyl triazine ketone, nano-emulsifiers, and MCT together form the nanoscale core of a pH-responsive nanocarrier.

[0027] 1,2-Pentanediol is used as a moisturizer, solubilizer, and preservative enhancer. Adding a small amount can improve the solubility of ethylhexyl triazine ketone and assist in stabilizing the emulsion of nanoemulsifiers, thus allowing more room to reduce the amount of nanoemulsifiers added. Furthermore, since sodium alginate is a microbial nutrient source, it can easily lead to the growth of bacteria, molds, and other microorganisms in the system, reducing the product's preservative stability. 1,2-Pentanediol also enhances the preservative effect, which helps to reduce the amount of preservatives used subsequently and improves the gentleness of this sunscreen formula to suit the needs of sensitive skin.

[0028] Glycerol, xanthan gum, disodium EDTA, and deionized water form an aqueous matrix and serve as a continuous external phase for pH-responsive nanocarriers. This can be used to disperse pH-responsive nanoparticles encapsulating ethylhexyltriazine.

[0029] Glycerin serves as a moisturizer and skin soothermer, enhancing the gentleness of the sunscreen formula, improving skin feel, reducing system irritation, and making it suitable for sensitive skin. Xanthan gum serves as a thickener and stabilizer in the aqueous phase and can be used selectively. The viscosity of the system can be adjusted according to the amount of xanthan gum added, preventing the layering and sedimentation of nanoparticles and optimizing the spreadability of the sunscreen product of this invention.

[0030] Disodium ethylenediaminetetraacetate (EDTA-disodium) acts as a metal ion chelating agent, capable of chelating Ca in the aqueous phase. 2+ Mg 2+ The presence of metal ions helps prevent premature cross-linking and flocculation of sodium alginate, while also improving the anti-corrosion efficiency and storage stability of sunscreen products.

[0031] Furthermore, considering the requirements for adding natural polysaccharides such as sodium alginate and for preservation, as well as the need to avoid the adverse effects of adding irritating preservatives on sensitive skin, the sunscreen product disclosed in this invention selects phenoxyethanol as a preservative. The amount added is low. Phenoxyethanol has broad-spectrum antibacterial properties and is mild in composition, so it will not irritate sensitive skin. It has excellent compatibility, is not a formaldehyde releaser, and is compatible with sodium alginate, chitosan, and xanthan gum without affecting pH response and cross-linking.

[0032] Furthermore, the present invention also discloses a preparation process for an ethylhexyl triazine ketone sunscreen suitable for sensitive skin, comprising the following process steps: Step 1: Preparation of nanoscale oil-phase sunscreen core: Add 2.0-5.0 parts by weight of ethylhexyl triazine ketone, 3.0-5.0 parts by weight of caprylic / capric triglyceride (MCT), and 1.5-3.0 parts by weight of nano-emulsifier (polyglycerol-6 distearate or Tween 80) to the oil phase container; Heat to 45–55 °C and stir until ethylhexyltriazine is completely dissolved to obtain a uniform and transparent primary emulsion oil phase; Take 3-5 parts by weight of deionized water and add it dropwise to the primary emulsified oil phase. Gradually add the aqueous phase for dilution to promote the formation of spontaneous microemulsion. Through secondary emulsification, obtain a nano-scale oil phase sunscreen core with a particle size of less than 100 nm. This invention uses microemulsion technology to prepare nanoscale oil-phase sunscreen cores. The secondary emulsification relies on the thermodynamic spontaneity of the system and does not require additional high energy input to obtain nanoscale oil-phase sunscreen cores with a particle size of less than 100 nm. It has the advantages of simple operation and applicability to large-scale industrial production.

[0033] Step 2, Preparation of sodium alginate phase: Add 0.05-0.1 parts by weight of disodium ethylenediaminetetraacetate and 3.0-5.0 parts by weight of glycerol to the remaining deionized water, and stir until completely dissolved; Add 1.0-2.0 parts by weight of sodium alginate, stir at high speed until completely dissolved and free of lumps, to obtain a homogeneous sodium alginate phase for later use; First, a sodium alginate phase is prepared, and disodium ethylenediaminetetraacetate (EDTA-disodium) is used to chelate metal ions in water to prevent sodium alginate from cross-linking and flocculating prematurely. Step 3, preparation of the chitosan phase: Dissolve 0.3-1.5 parts by weight of chitosan in an appropriate amount of acidic aqueous solution (such as dilute citric acid aqueous solution or dilute lactic acid aqueous solution) to adjust the pH to 4.0-5.5, and stir until the chitosan is completely dissolved to obtain the chitosan phase for later use; The pH is adjusted using low-irritant acidic solutions such as dilute citric acid aqueous solution and dilute lactic acid aqueous solution, which is mild and low-irritant and suitable for sensitive skin. Moreover, the acidic environment provided by dilute citric acid aqueous solution and dilute lactic acid aqueous solution can protonate the amino groups of chitosan, thereby completely dissolving it and forming a homogeneous cationic polymer solution, which ensures subsequent electrostatic self-assembly with sodium alginate.

[0034] Step 4, Preparation of the colostrum: The well-insulated nano-level oil-phase sunscreen core was slowly added to the sodium alginate phase and emulsified under high-speed shear conditions for 5-10 minutes to obtain an O / W type primary emulsion. Step 5, electrostatic self-assembly and ionic cross-linking: Under stirring conditions, the chitosan phase solution is slowly added dropwise to the O / W type primary emulsion, and stirring is continued for 20-40 minutes to allow sodium alginate and chitosan to form a core-shell structure precursor through electrostatic interaction. Continue to slowly add 0.05–0.2 parts by weight of calcium chloride aqueous solution, and continue stirring for 30–60 minutes to complete the Ca... 2+ Ionic crosslinking of sodium alginate solidifies pH-responsive nanocarrier structures; In this step, sodium alginate and chitosan self-assemble through electrostatics and form a three-dimensional cross-linked network shell under the action of Ca²⁺, thereby physically encapsulating and confining the nanoscale oil-phase sunscreen core within the nanocarrier. This results in a nanoscale oil-phase sunscreen core and a pH-responsive nanocarrier shell structure. Consequently, the carrier encapsulation isolates ethylhexyl triazine ketone from direct contact with the skin, reducing its transdermal penetration and lowering the risk of irritation to sensitive skin by the sunscreen product of this invention.

[0035] Step Six, Thickening and Adjusting Viscosity: Add 0.05–0.15 parts by weight of xanthan gum solution to the solution product obtained in step 5, stir until homogeneous, and adjust the viscosity of the system to a suitable range. Usually, the viscosity of the formulation at 25 °C is controlled to be 3000–6000 mPa·s. Step 7, Preservatives and Post-treatment: After adjusting the viscosity in step six, cool the sunscreen agent to below 35 ℃, add 0.5-0.8 parts by weight of preservative, stir evenly, and then perform conventional treatments such as degassing, filtration, and discharge to obtain the pH-responsive nanocarrier ethylhexyl triazine ketone sunscreen agent.

[0036] In summary, the ethylhexyl triazine ketone sunscreen agent and process for sensitive skin disclosed in this invention have the following technical advantages compared with the prior art: (1) Constructing a pH-responsive nanocarrier to encapsulate ethylhexyl triazine ketone can significantly reduce the amount of dissolving oil compared to traditional open systems, thereby significantly reducing the amount of nano-emulsifier added. On the one hand, it avoids the heavy and sticky feel of sunscreen products caused by oil, which is not friendly to sensitive skin. On the other hand, it avoids the skin barrier damage caused by the addition of strong irritants and high concentrations of emulsifiers, further improving the suitability of this sunscreen for sensitive skin. (2) A pH-responsive nanocarrier was constructed by using sodium alginate, chitosan and calcium chloride through a cross-linking system. This not only avoids direct contact of ethylhexyl triazine with the skin, but also enables the controlled release of sunscreen according to the skin condition. For sensitive skin, the pH value is usually 6.0 to 7.0, which is weakly alkaline. The charge effect of chitosan is weakened, which makes the pH-responsive nanocarrier swell appropriately, thereby achieving controlled release and meeting the low-irritation needs of sensitive skin.

[0037] (3) The cross-linking system of sodium alginate, chitosan and calcium chloride has a three-dimensional polymer network structure, which can restrict the migration of ethylhexyl triazine ketone molecules embedded therein, effectively prevent the sunscreen product from crystallizing and precipitating during storage, and improve the storage stability and shelf life of the sunscreen product.

[0038] (4) The addition of natural polysaccharide components such as seaweed polysaccharide and mild ingredients such as low-irritant preservatives makes this sunscreen product have a mild moisturizing and soothing effect, improves the mildness of the formula, and is suitable for use on sensitive skin.

[0039] (4) Ethylhexyl triazine ketone achieves nanoscale emulsification through a two-step emulsification method, and then cross-links with sodium alginate and chitosan as pH-responsive nanocarriers. The mixed cross-linking load is more uniform, forming a stable encapsulation structure. In addition, the nanoscale oil droplets are more delicate, which is better than the thick and sticky feel of traditional sunscreens, and helps to form a more uniform and dense protective film, improving the UV blocking efficiency.

[0040] The following specific embodiments further illustrate the ethylhexyl triazine ketone sunscreen agent and process suitable for sensitive skin disclosed in this invention.

[0041] Example 1 This embodiment discloses an ethylhexyl triazine ketone sunscreen suitable for sensitive skin, the formulation of which is as follows: 2.0 parts of ethylhexyl triazine, 1.0 part of sodium alginate, 0.3 parts of chitosan, 0.05 parts of calcium chloride, 3.0 parts of caprylic / capric triglyceride (MCT), 1.5 parts of low-content nano-emulsifier, 2.0 parts of 1,2-pentanediol, 3.0 parts of glycerol, 0.05 parts of xanthan gum, 0.05 parts of disodium EDTA, 0.5 parts of preservative, and 70 parts of deionized water; Using the preparation process disclosed in this invention, an ethylhexyl triazine ketone sunscreen suitable for sensitive skin is prepared according to the above-mentioned formulation, comprising the following process steps: Step 1: Preparation of nanoscale oil-phase sunscreen core: Add 2.0 parts by weight of ethylhexyl triazine ketone, 3.0 parts by weight of caprylic / capric triglyceride (MCT), and 1.5-3.0 parts by weight of nano-emulsifier (Tween 80) to the oil phase container; Heat to 45–55 °C and stir until ethylhexyltriazine is completely dissolved to obtain a uniform and transparent primary emulsion oil phase; Take 3 parts by weight of deionized water and add it dropwise to the primary emulsified oil phase to obtain a nano-scale oil phase sunscreen core with a particle size of less than 100 nm. Step 2, Preparation of sodium alginate phase: Add 0.05 parts by weight of disodium ethylenediaminetetraacetate and 3.0 parts by weight of glycerol to the remaining 67 parts by weight of deionized water, and stir until completely dissolved; Add 1.0 part by weight of sodium alginate, stir at high speed until completely dissolved and free of lumps, to obtain a homogeneous sodium alginate phase, and keep warm for later use; Step 3, preparation of the chitosan phase: Dissolve 0.3 parts by weight of chitosan in an appropriate amount of acidic aqueous solution (dilute citric acid aqueous solution) to adjust the pH to 4.0-5.5, and stir until the chitosan is completely dissolved to obtain the chitosan phase for later use; Step 4, Preparation of the colostrum: The well-insulated nano-level oil-phase sunscreen core was slowly added to the sodium alginate phase and emulsified under high-speed shear conditions for 5-10 minutes to obtain an O / W type primary emulsion. Step 5, electrostatic self-assembly and ionic cross-linking: Under stirring conditions, the chitosan phase solution is slowly added dropwise to the O / W type primary emulsion, and stirring is continued for 20-40 minutes to allow sodium alginate and chitosan to form a core-shell structure precursor through electrostatic interaction. Continue to slowly add 0.05 parts by weight of calcium chloride aqueous solution, and continue stirring for 30-60 min to solidify the pH-responsive nanocarrier structure; Step Six, Thickening and Adjusting Viscosity: Add 0.05 parts by weight of xanthan gum solution to the solution product obtained in step 5, stir until uniform, and adjust the viscosity of the system to 3000-6000 mPa·s; Step 7, Preservatives and Post-treatment: After cooling the sunscreen agent adjusted in step six to below 35 ℃, add 0.5 parts by weight of preservative (phenoxyethanol), stir evenly, and then perform conventional treatments such as degassing, filtration, and discharge to obtain the pH-responsive nanocarrier ethylhexyl triazine ketone sunscreen agent of this embodiment.

[0042] Example 2 This embodiment discloses an ethylhexyl triazine ketone sunscreen suitable for sensitive skin, the formulation of which is as follows: 5.0 parts of ethylhexyl triazine, 2.0 parts of sodium alginate, 1.5 parts of chitosan, 0.2 parts of calcium chloride, 5.0 parts of caprylic / capric triglyceride (MCT), 3.0 parts of low-content nano-emulsifier, 4.0 parts of 1,2-pentanediol, 5.0 parts of glycerol, 0.15 parts of xanthan gum, 0.1 parts of disodium EDTA, 0.8 parts of preservative, and 75 parts of deionized water; The same preparation process as in Example 1 was used, with the only difference being the weight proportions of each formulation component, to prepare the pH-responsive nanocarrier ethylhexyltriazine ketone sunscreen of this example.

[0043] Example 3 This embodiment discloses an ethylhexyl triazine ketone sunscreen suitable for sensitive skin, the formulation of which is as follows: 2.5 parts ethylhexyl triazine, 1.5 parts sodium alginate, 0.8 parts chitosan, 0.1 parts calcium chloride, 4 parts caprylic / capric triglyceride (MCT), 2.25 parts low-content nano-emulsifier, 3 parts 1,2-pentanediol, 4 parts glycerol, 0.1 parts xanthan gum, 0.75 parts disodium EDTA, 0.75 parts preservative, 72.5 parts deionized water; The same preparation process as in Example 1 was used, with the only difference being the weight proportions of each formulation component, to prepare the pH-responsive nanocarrier ethylhexyltriazine ketone sunscreen of this example.

[0044] The ethylhexyl triazine ketone sunscreen obtained in Examples 1 to 3 was used as the experimental group, and the commercially available open-system ethylhexyl triazine ketone sunscreen was used as the control group. The sunscreens in the experimental group and the control group were subjected to the chicken embryo chorioallantoic membrane test (HET-CAM) and transdermal absorption test (Franz diffusion cell) to test their suitability for sensitive skin. Among them, the chicken embryo chorioallantoic membrane test (HET-CAM) uses the vascular reaction on the chicken embryo chorioallantoic membrane (CAM) as the observation index, and records the three damage phenomena of bleeding, coagulation and angiogenesis after sample treatment and the time of occurrence. The stimulation score (IS) is calculated according to the standard formula IS=301 / H+301 / C+301 / L−3, where H represents the time of bleeding (seconds), C represents the time of coagulation (seconds), and L represents the time of angiogenesis (seconds). For the stimulus score IS, IS < 1 indicates no irritation, 1 ≤ IS < 5 indicates mild irritation, 5 ≤ IS < 10 indicates moderate irritation, and IS ≥ 10 indicates strong irritation.

[0045] The results of the chicken embryo chorioallantoic membrane test (HET-CAM) are as follows: if no result is observed for 301 seconds, it is recorded as 301:

[0046] The test results of the chicken embryo chorioallantoic membrane test show that the ethylhexyl triazine ketone sunscreens prepared in Examples 1 to 3 are all non-irritating and have properties that are friendly to sensitive skin.

[0047] The transdermal absorption test (Franz diffusion cell) was conducted according to GB / T 27818-2011 "In vitro test methods for skin absorption of chemicals". The cumulative permeation, steady-state transdermal rate, and permeability coefficient parameters were calculated. The test results are as follows:

[0048] The transdermal absorption test results showed that the 24-hour cumulative penetration amount, steady-state transdermal rate, and penetration coefficient of the ethylhexyl triazine sunscreen prepared in Examples 1 to 3 were significantly lower than those of the control group, and the skin retention rate was over 70%. This indicates that the system can effectively reduce the transdermal penetration of ethylhexyl triazine, so that ethylhexyl triazine is mainly retained in the stratum corneum of the skin, reducing the risk of irritation from penetration into the dermis, and meeting the safety requirements of sensitive skin.

[0049] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention are also within the protection scope of the present invention.

Claims

1. An ethylhexyl triazine ketone sunscreen suitable for sensitive skin, characterized in that: It contains the following components in parts by weight: Ethylhexyl triazine 2.0-5.0 parts, sodium alginate 1.0-2.0 parts, chitosan 0.3-1.5 parts, calcium chloride 0.05-0.2 parts, caprylic / capric triglyceride 3.0-5.0 parts, low content nano-emulsifier 1.5-3.0 parts, 1,2-pentanediol 2.0-4.0 parts, glycerol 3.0-5.0 parts, disodium ethylenediaminetetraacetate 0.05-0.1 parts, preservative 0.5-0.8 parts, deionized water 70-75 parts; The ethylhexyl triazine is dissolved in caprylic / capric triglyceride and emulsified with a low content of nano-emulsifier to form a nano-level oil-phase sunscreen core. The sodium alginate, chitosan, and calcium chloride are cross-linked to construct a pH-responsive nanocarrier, which encapsulates and loads a nanoscale oil-phase sunscreen core through a nanoparticle structure. Based on the aforementioned deionized water, glycerol and disodium ethylenediaminetetraacetate are mixed to form an aqueous matrix, and a pH-responsive nanocarrier encapsulating an oil-phase sunscreen core is dispersed in the aqueous matrix.

2. The ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 1, characterized in that: The ethylhexyl triazine ketone sunscreen also contains 0.05–0.15 parts of xanthan gum.

3. The ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 2, characterized in that: The nanoemulsifier is nano-grade polyglycerol-6 distearate or Tween 80.

4. The ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 3, characterized in that: The preservative is phenoxyethanol.

5. The ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 4, characterized in that: Under normal skin conditions with a pH value of 4.5 to 6.0, the pH-responsive nanocarrier tightly binds chitosan and sodium alginate to lock in the nano-scale oil phase sunscreen core. Under sensitive skin conditions with a pH value of 6.0–7.0, the chitosan charge effect of the pH-responsive nanocarrier is weakened, and the carrier cross-linked with chitosan and sodium alginate can swell in a controlled manner, releasing the nano-scale oil phase sunscreen core in a slow-release manner.

6. A preparation process for an ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin as described in claim 5, characterized in that: The process includes the following steps: Step 1: Preparation of nanoscale oil-phase sunscreen core: A two-stage emulsification process was used to prepare a nanoscale oil-phase sunscreen core with a particle size of less than 100 nm by using ethylhexyl triazine ketone, caprylic / capric triglyceride, and nano-emulsifier. Step 2, Preparation of sodium alginate phase: Add disodium ethylenediaminetetraacetate and glycerol to the remaining deionized water and stir until completely dissolved; Add sodium alginate and stir at high speed until completely dissolved to obtain a homogeneous sodium alginate phase. Keep warm for later use. Step 3, preparation of the chitosan phase: Chitosan was dissolved in an acidic aqueous solution and stirred until the chitosan was completely dissolved to obtain the chitosan phase, which was then set aside. Step 4, Preparation of the colostrum: The well-insulated nano-level oil-phase sunscreen core was slowly added to the sodium alginate phase and emulsified under high-speed shear conditions for 5-10 minutes to obtain an O / W type primary emulsion. Step 5, electrostatic self-assembly and ionic cross-linking: Under stirring conditions, the chitosan phase solution is slowly added dropwise to the O / W type primary emulsion, and stirring is continued for 20-40 min, so that sodium alginate and chitosan can form a core-shell structure precursor through electrostatic interaction; Continue to slowly add calcium chloride aqueous solution, stirring for 30-60 minutes, until the calcium chloride solution is completely added. 2+ Ionic crosslinking of sodium alginate solidifies pH-responsive nanocarrier structures; Step Six, Thickening and Adjusting Viscosity: Add xanthan gum solution to the solution product obtained in step five, stir until homogeneous, and adjust the viscosity of the system. Step 7, Preservatives and Post-treatment: After cooling the sunscreen agent adjusted in step six to below 35 ℃, add the preservative, stir evenly, and then defoam, filter, and discharge the material to obtain the pH-responsive nanocarrier ethylhexyl triazine ketone sunscreen agent.

7. The preparation process of the ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 6, characterized in that: In step one, the secondary emulsification process is as follows: ethylhexyl triazine ketone and caprylic / capric triglyceride nanoemulsifier are added to the oil phase container according to the weight requirements; Heat to 45–55 °C and stir until ethylhexyltriazine is completely dissolved to obtain a uniform and transparent primary emulsion oil phase; Take 3-5 parts by weight of deionized water and continuously add it dropwise to the primary emulsified oil phase for dilution. Through spontaneous microemulsification, obtain a nano-scale oil phase sunscreen core with a particle size of less than 100 nm.

8. The preparation process of the ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 7, characterized in that: In step three, the acidic aqueous solution is either dilute citric acid aqueous solution or dilute lactic acid aqueous solution, and the pH is adjusted to 4.0-5.5 to prepare the chitosan phase.

9. The preparation process of the ethylhexyl triazine ketone sunscreen agent suitable for sensitive skin according to claim 8, characterized in that: In step six, the suitable range of system viscosity is 3000–6000 mPa·s at 25 ℃.

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