Nanoparticle formula for coating outer structural layer of hair

Abstract

The present invention relates to a nanoparticle formulation for coating the outer layer of a hair structure, the composition of which comprises a natural oil extract. The formula comprises rice bran oil, hydrogenated olive oil, olive oil (Olea eupaea fruit oil), unsaponified olive oil (Olea eupaea unsaponified fruit oil), a rice bran extract existing in a rice bran fat form, a nonionic surfactant, an emulsifier, sodium benzoate and deionized water. The formula can be used as an alternative material for hair care products, has a phase size of 150-200 nanometers, and aims to prevent protein loss of healthy hair caused by ultraviolet radiation and high temperature. The technology can be realized in a wet hair state or an outer layer structure without oil components by coating the outer layer of the hair structure in a targeted manner.

Description

Technical Field

[0001] In the field of chemical engineering, specific research involves nanoparticle formulations for coating the outer layer of hair, in which natural oil extracts are an indispensable ingredient. Background Technology

[0002] Nanoproducts refer to items that utilize nanotechnology in their production process or incorporate nanoparticles to achieve specific properties or functions. Cosmetic products often involve nanoparticles manufactured using nanoemulsion systems. This system consists of an oil phase, an aqueous phase, and a high concentration of surfactants, and is primarily used in skincare products with the following characteristics or functions: (1) encapsulating or retaining active ingredients; (2) enhancing the stability of active ingredients in the product, preventing degradation due to light, air, or reactions with other components; (3) improving the solubility and skin absorption rate of active ingredients; (4) controlling the release of active ingredients, thereby prolonging their efficacy; and (5) preventing skin moisture loss and helping to maintain skin hydration.

[0003] The hair shaft is the part of the hair that grows above the scalp, primarily composed of keratin (a fibrous protein). Its structure includes the medulla, cortex, and cuticle. The medulla, located at the innermost layer of the hair shaft, typically contains air gaps and is mainly composed of loosely arranged cells. The cortex is the thickest layer, rich in most of the hair's keratin and melanin; melanin determines hair color. Melanin granules are distributed throughout the cortex, giving hair its natural hue. Furthermore, the cortex contains elongated keratin microfibers, providing the hair with flexibility and elasticity.

[0004] The outermost layer of hair, called the cuticle, is composed of hard keratin arranged in overlapping scales, similar to fish scales. This structure strengthens the hair and acts as a protective barrier, preventing dirt from penetrating and damaging it. Furthermore, the cuticle acts as a sealant, protecting the inner layers from moisture and natural oil loss, helping to maintain the hair's shine and healthy appearance. However, ultraviolet (UV) radiation and high temperatures can damage the integrity of the cuticle, leading to keratin loss and thus harming hair health.

[0005] Ultraviolet (UV) radiation, especially UVA and UVB, can severely damage hair, affecting the cuticle and hair roots. Prolonged exposure to UV rays degrades melanin in the hair, leading to fading color and a dry, damaged appearance. UVB rays, on the other hand, break down proteins and amino acids in the hair shaft and roots, potentially causing hair damage, loss, and even baldness.

[0006] As is well known, to prevent sun damage to hair, specific hair care products can be used after each shampoo, before styling, or before sun exposure. These products include leave-in conditioners or heat protection sprays rich in UV-protective ingredients to protect hair from sun damage. These products help retain hair moisture while providing extra protection. Furthermore, these products are often rich in natural oils such as sweet almond oil, argan oil, coconut oil, camellia seed oil, and olive oil. These natural oils not only provide sun protection and heat protection but also offer excellent moisturizing effects, nourishing hair strands and further enhancing hair health and manageability.

[0007] Thai patent application filed on July 1, 2005 (application number: 0501003048) discloses a leave-in hair care composition in the form of an oil-in-water (O / W) emulsion, comprising wax in the form of a wax dispersion. The wax component is characterized by an oil with a melting point above 45°C, and the wax content in the composition is 5% to 60% of the total weight, more preferably 20% to 50%, and most preferably 30% to 45% of the total weight of the composition. Suitable waxes include fatty alcohols and fatty acids that are solid at room temperature, such as paraffin wax, triglycerides, or mixtures thereof. A portion of the wax is emulsified into the oil phase, and the wax content in the emulsion should not exceed 30% by weight, preferably not exceeding 10% by weight. The oil phase consists of non-volatile oils with a melting point below 40°C, selectable from triglycerides, fatty acid esters, fatty alcohols, fatty acids, and mineral oils, including coconut oil, olive oil, and their derivatives or mixtures. At 35°C, when measured at a shear rate of 5 s⁻¹, the dynamic viscosity of these oils is less than 1000 mPa·s. The suitable content of the oil phase in the composition should be greater than 10% by weight, preferably 5% to 50%, more preferably 10% to 40%, and optimally 15% to 30%. The composition contains an oil-structuring agent, such as hydrophobically modified clay, which, under the action of a polar activator (such as propylene carbonate or a 95:5 ethanol-water mixture), polarizes the edges of the clay particles, forming a network structure through polar interactions. The oil-structuring agent accounts for 0.5% to 20% by weight of the total oil phase. Furthermore, the emulsion consists of a nonionic surfactant or a mixture thereof, particularly a mixture of polyoxyethylene sorbitan monolaurate (20EO, 80%) and sorbitan monostearate (Span20, 20%), aimed at obtaining an O / W type emulsion with a high hydrophilic-lipophilic balance (HLB). The formulation of this surfactant system uses a mixture of surfactants with different HLB values ​​to provide a high HLB value, thereby ensuring optimal emulsion stability.

[0008] A Thai patent application filed on July 1, 2005 (application number: 0501003048) discloses the use of polymeric substances in hair styling, an application that is already widely used commercially. The amount of these substances ranges from 0.1% to 10% of the total weight of the formulation, with a preferred amount of 0.5% to 8% and a most preferred amount of 0.75% to 6% relative to the total weight of the formulation. The hair styling compound is added to the composition as a supplementary ingredient, and depending on the type of product, additional ingredients may be added simultaneously to adjust the formulation, which can be selected by those skilled in the art as needed. These ingredients include a suitable aqueous phase containing 0.01% to 10% by weight of a thickener, such as carbomer. The components of the invention may also include a carrier or carrier mixture suitable for hair, used in amounts from 0.5% to 99.5% of the total weight of the formulation. Solvents, such as water, C1-C6 alcohols, or mixtures thereof, are used to dissolve or disperse the hair styling compound. In addition, it should contain pH adjusters, such as sodium citrate and citric acid, as well as other common ingredients suitable for all product forms, including sunscreens, preservatives, antioxidants, anti-dandruff agents, and emulsifiers, to form an emulsion of carrier components. The resulting product is a hair styling cream that reduces stickiness while maintaining the shape of the hairstyle. It can be used to fix hairstyles, reshape hairstyles, condition hair, provide moisture and shine, reduce hair damage, increase hair shine, control hair volume, and straighten hair, among other things.

[0009] A Thai patent application filed on March 14, 2008 (application number: 0803000414) discloses a method for preparing an oil-in-water nanoemulsion containing antioxidants and having a particle size in the nanometer (nm) range, for use as an ingredient in cosmetics. The oil phase can be selected from jojoba oil, rice bran oil, sunflower seed oil, olive oil, or mixtures thereof, in a content ranging from 0.1% to 30.0% by weight. This oil phase is mixed with a phase emulsifier selected from amino acid derivatives and alkyl glycosides or mixtures thereof, in a content ranging from 0.5% to 20.0% by weight. The components are mixed at a temperature below 60 degrees Celsius, followed by the gradual addition of water at a rate of 50 to 500 grams per minute while maintaining the temperature below 60 degrees Celsius until a homogeneous mixture is formed. The result is a pale blue, translucent liquid, indicating the presence of internal phase particles in the nanometer range. Then, water and / or an aqueous phase consisting of water-soluble ingredients, which may include preservatives, surfactants, colorants, active ingredients, and thickeners, at concentrations between 50.0% and 99.0% (by weight), are gradually added, and the mixture is mixed at a temperature below 60 degrees Celsius. The temperature of the mixture is then lowered to below 35 degrees Celsius, a process that results in a final nanoemulsion product with an internal phase size of less than 500 nanometers. The resulting nanoemulsion offers benefits such as protecting hair from damage, maintaining hair shine, and reducing dryness and split ends.

[0010] A Thai patent application filed on September 25, 2015 (application number: 1503001576) discloses a formulation with Sangyod rice extract as the main or active ingredient for topical application to human hair and scalp to stimulate hair growth. The composition contains 0.10% to 50.00% Sangyod rice extract by weight and may be used in combination with one or more other compounds selected from cationic surfactants, waxes, thickeners, emulsifiers, natural oils (such as rice bran oil, coconut oil, castor oil, olive oil, almond oil, avocado oil, and mixtures thereof), solvents, silicones, moisturizers, preservatives, pH adjusters, adjuvants, or combinations thereof. The formulation is specifically designed to enhance hair care and promote hair growth through the synergistic effect of these carefully selected ingredients.

[0011] The inventions described in the Thai patent application filed on July 1, 2005 (application number: 0501003048) and the Thai patent application filed on September 25, 2015 (application number: 1503001576) do not explicitly involve nanotechnology related to hair care formulations. While the invention in patent (application number: 1503001576) mentions nanoscale particle sizes, particularly internal phase sizes of less than 500 nanometers achieved by reducing interfacial tension to extremely low levels to enhance the delivery of active ingredients to the skin, it does not explicitly or clearly explain the application of nanotechnology in hair care formulations. Furthermore, although the correlation between nanoparticle concentration and product efficacy has been established, it does not explicitly state the content of nanoparticles in products that claim to prevent hair damage, maintain shine, and prevent dryness and split ends.

[0012] On August 18, 2023, the Khon Kaen Medical Science Center, District 7, published information about rice and its cosmetic applications through the knowledge management system on the Department of Medical Sciences website. The published information specifically mentioned rice bran extract, a pale yellow liquid containing key active ingredients used in cosmetics, such as oryzanol, α-tocopherol, and tocotrienols, although at low concentrations. The information also mentioned a product called Original. Commercial rice bran water extract products are widely used in sunscreen formulations due to their UV protection properties. It can also be added as an antioxidant to anti-aging cosmetics.

[0013] A study on the antioxidant activity of rice bran extract from Buriram Jasmine Rice variety 105 was published in Volume 7, Issue 2, pages 66-67 of *The Journal of Science and Technology, Buriram Rajabhat University*. The study, published by Chuleekarn Sainet on December 26, 2023, notes that rice bran, a byproduct of milling brown rice into white rice (edible rice), has traditionally been used primarily as animal feed. However, rice bran is now being processed to enhance its value as rice bran oil. By weight, rice bran contains 12.45% fat, 10.90% protein, 45.31% carbohydrates, and 13.51% fiber. It also contains polyphenolic compounds such as phenolic acids, flavonoids, vitamin E, and gamma-oryzanol. The content of these compounds in rice bran is higher than in most vegetables, fruits, legumes, and nuts.

[0014] In 2019, Chudanat Akrachinwanich of the Department of Cosmetic Science and Health Products, Faculty of Pharmacy, Ubon Ratchathani University, published a paper discussing the development of rice bran oil-loaded surfactant vesicles for transdermal drug delivery. Surfactant vesicles are structures formed by the self-assembly of surfactant molecules, which simultaneously possess polarity and nonpolarity within a single molecule. The resulting bilayered vesicles can encapsulate various substances. The vesicles typically have a particle size between 30 and 120 nanometers, serving as efficient carriers for active ingredients and improving the stability, permeability, and release control of encapsulated compounds. This study also revealed the use of high-pressure homogenization to encapsulate rice bran oil in solid lipid nanoparticles (SLNs). The study showed that the developed formulation, tested in 10 volunteers, exhibited significant effects in improving skin hydration and elasticity, with the optimal formulation (particle size less than 200 nanometers) significantly increasing skin hydration and elasticity. Furthermore, a research paper presented by Punyavee Rungprasertphol et al. at the 57th Agricultural University Conference in 2019 discussed the application of rice bran oil in emulsion production. Rice bran oil shares similar physical and chemical properties with shea butter, as it is a relatively hard fat at room temperature but melts well at body temperature, preventing greasy residue on the skin after use. Rice bran oil helps to make lotions smoother, suggesting its potential as a substitute for shea butter in lotion production. Studies have found that lotions made with rice bran oil exhibit similar properties to those made with shea butter, such as oil-in-water stability and the typical shear-thinning behavior of creamy lotions. This indicates that rice bran oil has the potential to be used as an ingredient in cosmetic creams or lotions.

[0015] On March 27, 2020, at the 21st National Postgraduate Academic Conference held at Khon Kaen University, a study on a method for extracting bioactive compounds from rice bran, published by Akkharakiat Puangsaeng et al. on March 27, 2020, was presented. This study compared the efficiency of two organic solvents—ethanol (80% v / v) and ethyl acetate (80% v / v)—in extracting phenolic compounds from rice bran. The results showed that the volume percentage of phenolic compounds extracted with 80% ethanol was higher than that extracted with 80% ethyl acetate, because phenolic compounds have higher polarity and interact more effectively with the polar solvent ethanol. Results from the 1,1-diphenyl-2-trinitrophenylhydrazine radical scavenging experiment showed that when no heating was performed during extraction and 80% ethanol was used as the solvent, the rice bran extract effectively inhibited 1,1-diphenyl-2-trinitrophenylhydrazine radicals, achieving an inhibition rate of 50% at a concentration of 1.01 mg / mL.

[0016] A study on the application of brown rice extract in skin cream products was published in Volume 15, Issue 2, pp. 41-43 of the *Phranakhon Rajabhat Research Journal: Science and Technology Edition*. Conducted by Kanjanarat Sukrat and his team, the study was completed between July and December 2020. The study indicated that 70% v / v ethanol, as a solvent, yielded the highest yield of active compounds from brown rice, achieving an extraction rate of 12.788%, compared to 50% v / v ethanol or 95% v / v ethanol. The antioxidant activity assays showed that the DPPH free radical scavenging activity ranged from 0.460 to 0.592 mg TE / g per gram of extract; the ABTS free radical scavenging activity ranged from 8.864 to 9.572 mg VEAC / g per gram of extract; and the FRAP reducing capacity ranged from 22.061 to 24.479 μM Fe(II) equivalents / g per gram of extract. Furthermore, the total phenolic content of the extract was 2.6643 mg GAE / g per gram of extract, and the total flavonoid content was 0.425 mg QE / g per gram of extract, highlighting its powerful bioactive properties for potential skincare applications.

[0017] Rice bran oil possesses UV-protective properties, making it suitable for inclusion in sunscreen formulations with antioxidant properties. By combining rice bran oil-related technologies with rice bran extracts, a nanoparticle formulation has been developed specifically to coat the outermost layer of the hair shaft. This formulation utilizes natural oil extracts, particularly ethanol-extracted rice bran oil, which is both hydrophilic and hydrophobic. While this crude extract exhibits excellent water solubility, its dual nature poses a challenge as an ingredient in hair care products designed to prevent protein loss from healthy hair due to UV radiation and heat exposure. Given the inherent hydrophobicity of the hair shaft, i.e., its low reactivity with water molecules, this invention provides a novel solution to improve the application of rice bran components in hair care products.

[0018] A Thai patent application filed on August 9, 2012 (application number: 1203000832) discloses a nanosurfactant vesicle herbal emulsion product for hair care. The nanobioparticles used in this formulation are composed of various substances, including alkyl esters (such as sorbitol esters), alkylamines, fatty acids, and amino acids. The properties of the nanoliposomes are discussed; these liposomes are nanoscale particles that enhance membrane permeability while maintaining good encapsulation efficiency and stability. One step in the preparation method involves mixing the components of the oil phase (used to form the particulate membrane) (including cholesterol, cholesterol esters, cetyl ether-20, and cetyl alcohol) and melting them together with rice bran oil and sesame oil for encapsulation. Then, at a temperature of approximately 65 degrees Celsius, the oil phase is added to an aqueous phase containing Centella asiatica extract at approximately 65 degrees Celsius. The mixture is then stirred at 7200 rpm for 10 minutes. When the mixture temperature drops to approximately 50 degrees Celsius, add preservatives such as parabens (dispersed in propylene glycol), chlorphenesin, methylisothiazolinone, and / or benzalkonium chloride. Finally, add water to bring the total volume to 100%.

[0019] The structure of the nanoparticle wall forms a novel composite material for the following reasons. Based on existing scientific research, the hydrophobic region of the particle wall protrudes from the outer surface, making it suitable as an ingredient in hair root care products. The hair root is the area where hair is embedded under the scalp. It is well known that the scalp contains hair follicles, which are composed of hair root cells, sweat glands, and sebaceous glands. Sebaceous glands extend around the hair root cells to the hair follicle opening, where they produce sebum, helping to keep hair soft and shiny. The hydrophobicity of sebum creates cohesive forces between the sebum and the structure of the nanoliposome particle membrane, allowing the nanoliposome particles to aggregate together to form spherical droplets. This clustering behavior allows the nanomicrobes to target the hair root area to enhance the efficacy of Centella asiatica extract, which contains a variety of active compounds. These compounds include: asiaticoside, which can stimulate hair growth, nourish hair, and delay graying; asiatic acid, which is very effective in reducing scalp inflammation; asiaticoside, which has wound-healing and anti-scalp inflammation properties; and asiaticoside, which helps reduce inflammation caused by abnormal skin cell division.

[0020] Therefore, the nanoliposomes described in the prior art have limitations when used as ingredients in leave-in hair care products to prevent protein loss from healthy hair due to UV radiation and heat. Although the outer structure of hair is hydrophobic, meaning it does not mix or bind with water molecules, it is well known that the outer layer of hair is highly susceptible to damage due to the lack of oily components. Simultaneously, the high water content in the outer layer of hair when wet after shampooing leads to brittle hair strands that are prone to breakage and shedding. This is because the hair structure absorbs hydrogen from the air and expands accordingly, loosening the smooth cuticle scales. As a result, the outer cuticle layer becomes disordered, causing the hair to become curly. This reduces the hydrophobicity of the hair. Based on current scientific knowledge, the lack of cohesion between the membrane structure of nanoliposome particles and the highly moist outer layer of hair affects the particles' ability to form a stable protective layer.

[0021] However, lipid nanoparticles still offer significant advantages over other methods in drug delivery or active ingredient delivery. A paper published on June 30, 2013, by Ampol Maitreewech and colleagues at Mahidol University's Faculty of Pharmacy, on its website, discloses information related to the development of nanoparticles and delivery systems. The article discusses lipids, substances used as formulation ingredients, which can increase the surface area of ​​particles, improve adhesion to the skin, and achieve better coverage when applied to the skin. The skin becomes more moisturized and its permeability is enhanced, thereby improving the absorption efficiency of the active ingredient or drug released from the particles. Among nanoparticles prepared in the form of lipid nanoparticles, nanostructured lipid carriers (NLCs) exhibit better encapsulation efficiency of drugs or active ingredients and provide better control over their release process compared to solid lipid nanoparticles (SLNs). This is because in solid lipid nanoparticle formulations, the active ingredient or substance is embedded in an ordered lattice structure, while in nanostructured lipid carrier formulations, these substances are embedded in a disordered structure, thus enabling the encapsulation of more active ingredients and substances. In this invention, the oil phase comprising rice bran oil exhibits some technical features that are wholly or partially known to the public. Details are as follows:

[0022] A study by Thakorn Chantadee and colleagues on the application of fatty acids in pharmaceuticals was published in the *Thai Pharmaceutical Bulletin*, Volume 14, Issue 1, page 5, in 2019. This study explored the mechanism by which fatty acids enhance skin permeability. Fatty acids disrupt the lipid layer in the stratum corneum cell membrane and increase lipid fluidity. Fatty acids with skin-permeability-enhancing properties have been reported to include oleic acid, linoleic acid, and palmitic acid. These fatty acids are found in rice bran oil, as described in previous scientific studies.

[0023] In 2007, Siriporn Liangkopkit published a report on rice bran oil on the website of the Herbal Information Centre at Mahidol University's Faculty of Pharmacy. The report discussed the main fatty acids in rice bran oil, including oleic acid (41.17%) and linoleic acid (39.73%), both unsaturated fatty acids, and palmitic acid (14.35%), a saturated fatty acid. This aligns with commercial data regarding the use of oleic acid in hair care products for moisturizing, nourishing the scalp, and reducing inflammation. Linoleic acid can enhance the scalp barrier function and reduce hair loss; palmitic acid is commonly used as a sunscreen, surfactant, detergent, and moisturizer, and is widely used in the production of detergents, soaps, and cleaning products in the cosmetics industry.

[0024] Furthermore, a Thai patent application filed on August 9, 2012 (application number: 1203000832) discloses a sunscreen formulation containing rice bran oil, which includes tocopherol-based active compounds. These compounds are particularly suitable for UV protection using lipid nanoparticles. For example, a study on novel sunscreen formulations has shown that encapsulating tocopherol acetate in solid lipid nanoparticles improves chemical stability and UV protection efficiency compared to conventional lipid nanoparticles (SLNs). Therefore, rice bran oil, as a key ingredient, can enhance the efficacy of rice bran extract in the preparation of lipid nanoparticle formulations designed to prevent protein loss in healthy hair caused by UV radiation and high temperatures.

[0025] A Thai invention patent application (application number: 0501001321), filed on March 24, 2005, discloses all or part of publicly known technical features. This application describes a liquid cleansing composition commonly used to enhance the feel of the skin after shampooing or bathing, often achieved through modification. These compositions may include materials such as oils or polymers that adhere to the skin surface through various mechanisms, for example, by utilizing positively charged (cationic) materials to bind to the negatively charged (anionic) surface of the skin. The invention includes, in a weight ratio of 1 to 35%, a selection from anionic surfactants, nonionic surfactants, amphoteric surfactants, or cationic surfactants, or mixtures thereof. Furthermore, the composition contains 0.1 to 10% (by weight) of a cationic polymer and at least 5% (by weight) of light-modified solid particles. These particles perform particularly well when their surfaces are modified with selected reagents (such as amino acids, proteins, fatty acids, lipids, phospholipids or lecithin, oligomers, anionic polymers, cationic polymers or combinations thereof and their derivatives), which significantly enhance the adhesion of photomodifiers to the skin.

[0026] A Thai invention patent application filed on March 24, 1997 (application number: 9701001137) discloses all or part of publicly known technical features. This patent discusses a hair conditioning shampoo composition containing cationic hair conditioners (including cationic surfactants and cationic polymers). These shampoos particularly require cationic surfactants and cationic polymers to control static electricity, prevent tangling of wet hair, and provide a silky feel during and after rinsing. Adhesion of such conditioners is a key characteristic for achieving effective conditioning. However, when cationic conditioners are used in combination with anionic cleansers, a water-insoluble complex forms and adheres to the hair, but this is often insufficient to achieve the desired conditioning effect and may instead lead to dirty or greasy hair.

[0027] The following reasoning explains the process of forming new compounds according to the present invention. Its integrated technical features enhance the interactions between chemical components, thereby generating a new product. The technical features of any chemical substances involved in this invention are wholly or partially known to the public, as detailed below:

[0028] It is well known that when encapsulating hydrophobic active substances or drugs, up to 90 to 98% of such substances can be efficiently retained within lipid nanoparticles. In contrast, the encapsulation efficiency of hydrophilic active substances may be only 20 to 30%. Various methods exist for preparing nanoparticles, including high-pressure homogenization under high or low temperature conditions, solvent emulsification and evaporation, emulsion diffusion techniques, and phase inversion processes.

[0029] A Thai patent application filed on September 20, 2018 (application number: 1803002148) discloses information related to a Chinese patent application (application number: CN106265164 A). This patent discloses a cosmetic composition with properties that promote hair growth and repair the scalp. The composition comprises 0.5 to 10% by weight of camellia extract and 1 to 10% by weight of rice bran oil nanoemulsion. A specific embodiment of the cosmetic formulation for hair care includes the following ingredients: camellia seed oil containing solid lipids (such as glyceryl monostearate) at 1 to 10% by weight of the total ingredients; liquid lipids, such as rice bran oil, olive oil, coconut oil, almond oil, or mixtures thereof, at 5 to 20% by weight of the total mixture; a thickener at 0.1 to 5% by weight of the total mixture; a surfactant (such as polysorbate-80) at 1 to 25% by weight of the total mixture; and nanoparticles encapsulating camellia seed oil at 0.1 to 30% by weight of the total ingredients. The weight ratio of tea seed oil to nanoparticles in the composition is 0.5:1 to 2:1. The formulation may also include additives such as sodium benzoate or preservatives, colorants, fragrances, opacifiers, or mixtures thereof.

[0030] This invention describes a nanoparticle formulation designed to coat the outer layer of hair with a layer of natural oil extracts. This innovation demonstrates a clear combination of hydrophilic (hygroscopic) and hydrophobic (water-repellent) substances, forming a novel nanoemulsion product whose nanoparticles have a positively charged outer surface, thereby creating an effective coating mechanism on the outer cuticle of the hair. To enhance the hydrophobicity of hair in a wet state after shampooing, the positively charged nanoemulsion product can adhere to the negatively charged hair cuticle, helping to regulate static electricity without the need for cationic surfactants. Unlike Thai Patent Application No. 9701001137, filed March 24, 1997 (which uses nonionic surfactants), this invention prevents the formation of insoluble complexes that could adhere to the hair, ensuring effective conditioning without leaving greasy residue. The formulation also includes an oil phase combination comprising rice bran oil, hydrogenated olive oil, olive oil, and unsaponifiable olive oil, demonstrating a technological advantage in enhancing and encapsulating the rice bran extract, providing UV and heat protection for healthy hair. The nanoparticles of this invention have an internal phase size of 150 to 200 nanometers, which differs from the nanoparticles encapsulating tea seed oil involved in the Thai patent application filed on September 20, 2018 (application number: 1803002148). This formulation improves hair surface texture by optimizing the interaction between liquid lipid nanostructure lipid carriers (NLCs) and rice bran oil, encapsulating the outer layer of hair without leaving solid fat deposits. Therefore, this formulation can produce a targeted effect on the hair cuticle after shampooing without forming oil buildup on the hair surface. This nanoparticle formulation is a novel invention and has never been disclosed before. Summary of the Invention

[0031] This invention relates to a nano-formulation designed to coat the outer structural layer of hair, incorporating natural oil extracts. The composition comprises rice bran oil, hydrogenated olive oil, olive oil (Olea europaea fruit oil), and unsaponifiable olive oil (Olea europaea fruit oil), as well as rice bran extract in the form of rice bran butter. Furthermore, the composition contains a nonionic surfactant, an emulsifier, sodium benzoate, and deionized water. This combination aims to enhance the coating on the outer structure of hair, providing beneficial properties derived from natural oils and extracts.

[0032] The purpose of this invention is to develop a nano-formulation for coating the outer structural layer of hair, using natural oil extracts as an alternative to hair care applications. This invention employs a targeted surface coating technology, applied to the outer cuticle layer of hair after shampooing, or applied to the outer structure of hair without oil components, protecting healthy hair proteins from the effects of UV radiation and heat. Furthermore, this new product expands the application of rice bran extract beyond traditional cosmetics, anti-aging formulas, and skin creams, thereby enhancing the added value of rice bran extract. Detailed Implementation

[0033] According to the present invention, a nano-formulation for coating the outer cuticle of hair incorporates natural oil extracts, specifically comprising:

[0034]

[0035]

[0036] Its unique feature lies in the combination of oil-phase components, including rice bran oil, hydrogenated olive oil, olive oil (Olea europaea fruit oil), and unsaponifiable olive oil (Olea europaea unsaponifiable fruit oil). This combination encapsulates and enhances the efficacy of the rice bran extract, which exists in the form of rice bran butter, while simultaneously leveraging the beneficial properties of the oil-phase components for hair care. Therefore, this product helps to effectively nourish and protect hair, providing significant hair care benefits, specifically manifested in the following characteristics:

[0037] Rice bran oil is rich in polyphenols, which have powerful antioxidant properties, and contains fatty acids that nourish hair.

[0038] Hydrogenated olive oil is a stabilizing ingredient with properties similar to saturated fats. Its increased viscosity helps to enhance hair's moisture retention, prevent damage, and strengthen hair strands. Furthermore, it contributes to product stability and extends shelf life.

[0039] Olive oil (Olea europaea) is rich in fatty acids beneficial to hair, such as oleic acid. It contains antioxidants and vitamin E, which deeply nourish and moisturize hair, reduce split ends, and protect and repair damaged hair strands.

[0040] Unsaponifiable olive oil (Olea europaea unsaponifiable fruit oil) helps enhance hair's moisture and elasticity, while also improving its shine and softness.

[0041] The rice bran extract in this invention exists in the form of crude extract and rice bran butter, and it has the property of protecting hair from protein loss caused by ultraviolet radiation (UV) and heat damage.

[0042] The nonionic surfactants used in this invention can be selected from polysorbate-20, polysorbate-60, polysorbate-80, sorbitan monolaurate-20, sorbitan monolaurate-40, or sorbitan monolaurate-60. These surfactants can enhance the conditioning properties of hair while preventing it from becoming dirty or sticky.

[0043] The emulsifiers used in this invention can be selected from glyceryl stearate, glyceryl monostearate, cetearyl alcohol, cetyl alcohol, or stearyl alcohol. They can be used as stabilizers to link liquid particles in the oil phase with liquid particles in the aqueous phase, thereby forming a stable emulsion. They can also be used as thickeners.

[0044] Sodium benzoate, used as a preservative in this invention, has good water solubility. It is dissolved in the aqueous phase using deionized water as the solvent.

[0045] This nanoparticle product, designed to coat the outer cuticle of hair, contains natural oil extracts as ingredients. Based on nanotechnology related to hair care ingredients, it forms a novel composition. This composition exhibits a smooth, emulsion texture and is able to alter the surface properties of the hair cuticle. Nanostructured lipid carriers (NLCs) enhance the adhesion of active ingredients. This process improves the cohesion between the liquid lipid nanoparticles and rice bran butter, acting as a coating on the outer surface of the hair without leaving greasy residue. Its technical effect is designed to cover the outer structure of the hair, especially when the hair is wet after washing or when the cuticle area is dry.

[0046] One example of using nanoparticle products to coat the outer surface structure of hair is their incorporation into a novel hair conditioner formulation containing natural oil extracts. This formulation effectively prevents healthy hair from losing protein under UV radiation and high temperatures. The total protein content in hair was measured using the bisquinolinic acid (BCA) protein assay, with bovine serum albumin as a standard protein, to compare and determine the total protein content. Keratin (a fibrous protein) accounts for approximately 88% of the hair composition and is the main protein analyzed. The study found that the novel hair cream formulation containing 2% of the nanoparticle product described in this invention reduced protein loss due to UV radiation and heat exposure to 23 micrograms and 17 micrograms per milliliter of hair, respectively. In contrast, the protein loss values ​​for a basic cream formulation without nanoparticles were 30 micrograms per milliliter of hair and 29 micrograms per milliliter of hair, respectively. Therefore, it can be concluded that the hair cream formulation containing nanoparticles is more effective in protecting healthy hair from protein loss due to UV radiation and heat compared to a basic cream formulation without nanoparticles. However, the results of this study only demonstrate the characteristics of the invention and do not limit its application in any way.

[0047] Nanoparticle products for coating the surface structure of hair contain the natural oil extracts described in this invention and are suitable for commercial use. It is an alternative ingredient that can be used in hair care products to prevent the loss of protein from healthy hair due to UV radiation and high temperatures. This effect is achieved by applying a targeted coating technique to the outer cuticle structure of the hair, especially when the hair is wet after washing or in areas of the hair surface that are not oily.

[0048] One example of the method for preparing rice bran extract according to the present invention involves extraction using ethanol as a solvent. After extraction, the extract is dried and concentrated by a rotary evaporator at a spindle speed of 120 rpm and a temperature of 45 degrees Celsius. The resulting rice bran extract is in the form of rice bran butter and is stored at a low temperature of -20 degrees Celsius.

[0049] The total phenolic content (TPC) of the rice bran extract described in this invention was analyzed using the Folin-Ciocalteu method. The results showed that the total phenolic content in each gram of dried extract was 22.88 to 23.54 mg gallic acid equivalents (mg GAE).

[0050] Analysis of the total flavonoid content (TFC) in rice bran extract using the aluminum chloride colorimetric method showed that the total flavonoid content in each gram of dried extract ranged from 37.08 to 39.30 mg quercetin equivalents (mg QE).

[0051] The antioxidant activity of the rice bran extract extracted in this invention was evaluated using the DPPH method, and the antioxidant activity value per gram of dried extract was found to be 88.35 to 90.31 mg trachotoxin equivalents (mg TE).

[0052] The antioxidant activity of the rice bran extract developed in this invention was determined by the ABTS method, and the antioxidant activity per gram of dried extract was 85.10 to 87.12 mg quercetin equivalents (mg QE).

[0053] The active ingredients in the rice bran extract of this invention were analyzed by quadrupole time-of-flight mass spectrometry (Q-TOF) liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) and high performance liquid chromatography (Agilent HPLC 1260). The results showed the following active ingredients: syringic acid (area 83.79%), vanillic acid (area 6.11%), caffeic acid (area 4.65%), and trans-3-hydroxycinnamic acid (area 5.46%).

[0054] According to the present invention, human skin fibroblasts (CCD-986Sk-CRL-1947) were used to conduct a cytotoxicity test on rice bran extract to evaluate its toxicity to human skin cells. The results showed that the rice bran extract at a concentration of 6.25 mg / mL exhibited the highest cell viability, ranging from 94.61% to 99.79%. Under a 40x magnifying microscope, cells treated with all concentrations of rice bran extract showed good growth and were densely distributed in the culture wells, with morphology similar to the control group cells without rice bran extract treatment.

[0055] To better understand the present invention, an example of a method for preparing nanoparticles and coating them onto the outer surface structure of hair according to the present invention is provided below, wherein a natural oil extract is used as an ingredient. This example is only for illustrating the features of the present invention and does not limit the scope of the invention in any way.

[0056] Example 1: A nanoparticle formulation for coating the outer surface structure of hair with natural oil extracts as an ingredient, comprising the following components:

[0057]

[0058] As described in this invention, the preparation process of nanoparticles for coating the outer structural layer of hair with natural oil extracts in liquid nanoparticle form includes the following steps: preparing an oil phase in proportion, the oil phase components including rice bran oil, hydrogenated olive oil, olive oil (Olea europaea fruit oil), and unsaponifiable olive oil (Olea europaea unsaponifiable fruit oil). Subsequently, these oil phase components are mixed and melted. An aqueous phase is prepared according to a formulation, the aqueous phase components including rice bran extract, nonionic surfactant, emulsifier, sodium benzoate, and deionized water, and the aqueous phase components are mixed. Next, the oil phase and aqueous phase are mixed, thoroughly stirred, and subjected to particle size reduction treatment. According to this invention, the internal phase size of the obtained nanoparticles is 150 to 200 nanometers (nm).

[0059] The best method of the present invention is as described above, in the full disclosure portion of the present invention.

Claims

1. A nanoparticle formulation for coating the outer structural layer of hair, comprising a natural oil extract as an ingredient, characterized in that, include:

2. The nanoparticle formulation for coating the outer structural layer of hair according to claim 1, characterized in that, The nonionic surfactant is selected from the following substances: polysorbate-20, polysorbate-60, polysorbate-80, sorbitan monolaurate-20, sorbitan monolaurate-40, or sorbitan monolaurate-60.

3. The nanoparticle formulation for coating the outer structural layer of hair according to claim 1, characterized in that, The emulsifier is selected from the following substances: glyceryl stearate, glyceryl monostearate, cetearyl alcohol, cetyl alcohol, or stearyl alcohol.

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