Compositions and process for obtaining uniform coverage by cosmetic products during and after application; Easy quantification of these products.

Abstract

The invention relates to formulation compositions and formulation processes for cosmetic products that can provide uniform and homogeneous coverage on the skin. The invention also relates to methods and a setup enabling practical quantification of the coverage quality (uniformity and homogeneity) of cosmetic products using conventional laboratory equipment. Uniform coverage is essential to all aspects of the skin's beautifying and protective functions. The present invention proposes novel compositions with suitable rheological profiles made possible by lamellar liquid crystal phases at the oil-water interface, leading to a uniform and homogeneous application of the cosmetic product layer on the skin under the most common application conditions.Uniform and complete coverage of all targeted skin areas is essential for achieving the highest levels of protection against external aggressors such as harmful radiation, transepidermal water loss, and other environmental factors. It is also fundamental for enhancing the skin's beauty functions, such as hydration and the effective delivery of skin-enhancing active ingredients.

Description

Title of the invention: Compositions and method for obtaining uniform coverage by cosmetic products during and after application; Easy quantification of these products.

[0001] The present invention relates to formulation compositions and formulation methods for cosmetic products that can provide uniform and homogeneous coverage on the skin. The invention also relates to methods and a configuration allowing practical quantification of the coverage quality (uniformity and homogeneity) of cosmetic products using conventional laboratory equipment. The skin's functions, such as its barrier function, are essential for protecting the body from physical injury and environmental factors, regulating skin hydration, regulating body temperature, protecting against pathogenic invasions, and maintaining an attractive appearance. When the skin is damaged, its ability to serve as an effective barrier is compromised, allowing external irritants and potential pathogens to enter the body. Damaged skin also allows for increased transepidermal water loss, resulting in decreased skin hydration (e.g., dry and irritated skin) and a loss of skin elasticity. Maintaining adequate skin hydration has been shown to improve skin properties and the quality of life for individuals with compromised skin barrier function, such as those with dermatitis and psoriasis. Many cosmetic products and technologies claim to contribute to hydration, but to our knowledge, information on their performance in relation to the quality of product coverage has not been researched. The skin's barrier functions against external factors are particularly sensitive to the quality of cosmetic coverage. For example, cosmetic products that protect the skin from solar radiation use UV-filtering substances to prevent solar radiation from reaching the skin's surface.Just as with house paint, to achieve high-quality skin "masking," sufficient and even coverage of the skin's surface is essential for the UV "masking" power (SPF: sun protection factor, PFA: UVA protection factor) of these cosmetic products. Similarly, for other beauty benefits such as hydration and anti-aging. Regardless of age, uniform and complete coverage of all targeted skin surfaces is essential to achieve high performance levels. Due to the dynamic nature of human skin, which precludes the extensive testing possible on other, more conventional surfaces, very little has been known about the best way to achieve uniform and complete coverage on the various surfaces of human skin. Nor have there been readily available methods for measuring, quantifying, or visualizing the quality of skin coverage provided by cosmetic products on human skin until the present invention. Cosmetic products are most often presented in the form of emulsions. Emulsions are kinetically stable systems that are not thermodynamically stable. They are complex, multiphase formulations designed to optimize various end-use performance characteristics of cosmetic and dermatological substances, such as the stability of active compounds, their bioavailability, sensory properties, and so on. The basic formulation of a classic oil-in-water emulsion includes at least water in the continuous phase, oil in the dispersed phase, and emulsifiers that ensure the stability of the oil droplet dispersion. Some amphiphilic emulsifying components of emulsions can self-associate as lyotropic liquid crystals (LCs) in the presence of water. These LC structures have characteristics and properties intermediate between solids and liquids. A wide variety of LC structures can be encountered; the three most typical are the lamellar (L), cubic (Q), and hexagonal (H) phases.Furthermore, the hydrophobic chain(s) of the emulsifier in the lamellar phase can be in a molten (LA) or crystalline (LB) state. The type of supramolecular structure of the emulsifier is related to the geometry of the amphiphilic molecule and its critical packing parameter. The use of emulsions containing lamellar LCs appears advantageous because this supramolecular organization is similar to that of lipids in the stratum comeum (SC). This generates a greater affinity of this system for the epidermis, aids in the absorption of lamellar phase components into the SC to restore the SC barrier function by compensating for a potential lipid deficiency. In addition to improving water retention by the SC barrier layer, LC emulsions can act as a suitable solubilization medium for hydrophilic substances such as vitamin C, thus providing sustained release of the substance.Emulsions undergo numerous physical and chemical changes when applied to and left on skin surfaces. Each aspect of these changes impacts how the cosmetic product covers the skin and the resulting performance characteristics. The present invention proposes a practical method for quantifying the uniformity of cosmetic coverage and reveals how uniformity is affected from the selection of raw materials to emulsion designs. We have discovered that specific emulsifiers / emulsion structuring agents are essential for establishing nano- and micro-emulsion structures to enable uniform skin coverage under various cosmetic application conditions. We also disclose here a quantification method that tracks the coverage quality at each stage of the cosmetic application process. The term “cosmetic product” means any product as defined in Regulation (EC) No 1223 / 2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products. Summary of the invention

[0002] The present invention is based on the discovery of naturally occurring amphiphilic compositions with a powerful emulsion-stabilizing capacity. These compositions enable unique nanostructures at the oil-water interface, as well as microstructures for emulsion droplets, which further determine the rheological properties of the emulsion under various skin application conditions. In turn, these invented amphiphilic compounds allow for uniform and complete skin coverage by applied cosmetic materials containing such amphiphilic compounds. Consequently, the present invention provides unique cosmetic compositions that can form a uniform and homogeneous skin coverage at the end of the cosmetic product application process.The present invention also proposes a new method and configuration for quantifying the uniformity of skin coverage during various stages of the cosmetic application process. The ability to study and quantify coverage uniformity is essential for developing optimal compositions for the best skin coverage. By using a suitable indicator molecule dissolved in the oil phase of the emulsion and combining optical microscopy with a UV-visible spectrophotometer, the uniformity of cosmetic product coverage can be measured and visualized simultaneously. Uniformity data on human skin can be obtained by repeatedly stripping the tape and subsequently measuring the uniformity of the cosmetic materials on the stripped tapes.In this way, precise information about skin coverage is transferred to the strips, and cosmetic uniformity data on the skin can be obtained without direct measurements on a human subject. This method of measuring cosmetic performance on the skin using a non-skin material is particularly useful for quantifying protective performance. sunscreens of cosmetics. Human subjects do not suffer adverse consequences when using this method, whereas current conventional sunscreen performance testing methods (ISO 24442:2019 and ISO 24444:2019) require testing until failure on the human body and always result in human skin damage. The combination of the new chemical composition of the emulsion with scientific testing and quantification methods has enabled the identification and invention of key emulsion ingredients (emulsifiers) that act as a catalyst for easily achieving uniformity in applied cosmetic products. The described measurement method is particularly novel in that specific UV absorption indicators were used to "display" emulsion uniformity, and the quantification uniformity index was developed based on UV absorbance data. Simultaneous visualization of uniformity can be achieved using an optical microscope. This easy visualization and quantification of the uniformity of cosmetic materials is unprecedented.

[0003] The invention therefore relates to a cosmetic composition for the in situ formation of a uniform layer on the skin of a subject, characterized in that said composition comprises two phases, a continuous phase and a dispersing phase. An emulsifier is used to impact the interface energy between these two phases, which are commonly the oily phase and the aqueous phase.

[0004] According to one embodiment, the composition is characterized in that said emulsifier is non-ionic and amphiphilic and capable of promoting the formation of lamellar liquid-crystal phases at the oil-water interface of cosmetic products. Said emulsifier comprises lipophilic structures derived from olive oil fatty acids. Said emulsifier comprises hydrophilic structures derived from sugar and hydroxylated compounds derived from sugar. Specifically, said hydrophilic structures are based on glucose and its derivatives, sucrose and its derivatives, maltose and its derivatives, and sorbitol and its derivatives. Or said emulsifier comprises hydrophilic structures derived from polyglycerols with varying numbers of repeating units ranging from 3 to approximately 10, and mixtures thereof.

[0005] According to one embodiment, the composition is characterized in that said emulsifier is zwitterionic and amphiphilic and capable of promoting the formation of lamellar liquid crystal phases at the oil-water interface of cosmetic products. Said emulsifier comprises phospholipids and phospholipid derivatives.

[0006] The invention also relates to a method and associated configuration for quantifying the uniformity of cosmetic products applied to substrates; wherein UV-visible spectrophotometer data are used to quantify the degree of uniformity of a cosmetic product as applied to a substrate; wherein a An indicator molecule is added to the cosmetic formulation which otherwise contains no active UV components.

[0007] According to one embodiment of said process, said indicator molecule is a molecule with a significant UV absorption capacity between 200nm and 400nm while its peak molar extinction coefficient is at least 10,000 M'cm, preferably at least 25,000 M'cm, most preferably at least 40,000 M'cm*. The said indicator comprises Avobenzone, alkyl esters of ortho-hydroxyl benzoic acid (such as 2-ethylhexyl 2-hydroxybenzoate), and alkyl esters of phenyl ethylene carboxylic acids (such as 2-Ethylhexyl 2-cyano-3,3-diphenylprop-2-enoate), as well as an inorganic metal oxide capable of absorbing in the wavelength range of 200nm to 400nm, such as zinc oxide, titanium dioxide and mixtures thereof.

[0008] According to one embodiment of said process, a thickness gauge of approximately 10mm to 100mm is moved at a controlled speed to deposit the cosmetic product at a known defined thickness on the substrates.

[0009] According to one embodiment of said process, said folding speed is in the range of about 0.1 cm / s to about 100 cm / s.

[0010] According to one embodiment of said process, a uniformity index is defined as the ratio of the UV absorbance measured of the cosmetic layer at a particular time to the UV absorbance of the same layer at optimal uniformity.

[0011] According to one embodiment of said method, the layer of cosmetic product applied to human skin is transferred onto an adhesive tape compatible with UV measurement. The cosmetic product is completely removed from the skin using several pieces of adhesive tape. The UV absorbance of the cosmetic transfer layer on the tape is measured and summed to represent the quality of the cosmetic coverage on the skin. The strips are affixed regionally and specifically to the skin during UV measurement to ensure that the cosmetic product is accurately transferred from the skin to the strips and that the state of the cosmetic product on the strips is an authentic representation of that of the cosmetic product on the skin.

[0012] The compositions of the invention and the facilitated uniform application of said compositions provide significantly improved cosmetic performance characteristics, of at least 15%, preferably of more than 20%, and more preferably of more than 25%, such as reduced TEWL, improved hydration, improved sun protection performance, compared to a similar formulation without the invented emulsifying chemistry. Brief description of the figures

[0013] [Fig. 1] is an illustration showing how the material's coverage quality Cosmetic uniformity impacts relevant performance characteristics. Radiation blocking capacity was used as an example of a performance characteristic for illustrative purposes. Other performance characteristics, such as protection against transepidermal water loss, preservation of hydration levels, and active ingredient delivery efficacy, are also similarly affected by the degree of uniformity of the applied cosmetic product layer. Each rectangular area represents a fixed dosage (weight / surface area) of cosmetic product with a radiation absorbance of 1. Therefore, each rectangular area reduces the radiation intensity tenfold. Ten rectangles are used in each case, representing the same quantity of cosmetic product applied to the same area of ​​skin. The radiation-blocking power of each rectangle remained the same, indicating no change in the ingredient content of the tested cosmetic material in each case. Three different degrees of uniformity are illustrated here. The right-hand side represents the perfectly uniform distribution of the cosmetic product on the substrate. In total, 5 photons were transmitted to the cosmetic layer out of 500 incoming photons. According to the SPF definition, this perfectly uniform layer provides an SPF of 100. On the left side, two representative scenarios of a non-uniform distribution of the same 10 rectangles are presented. In both cases, significantly more photons (21.2 and 111.11, respectively) were transmitted through the cosmetic film from the same 500 incoming photons. Consequently, both scenarios offer much lower radiation protection capabilities, as defined by the SPF values. This also illustrates the principle of measuring the uniformity of cosmetic coverage using the UV-visible spectrophotometer as described in the present invention. It is demonstrated here that the uniformity of the applied cosmetic material can be revealed very sensitively by its level of incoming irradiation transmission, provided that the cosmetic product contains UV-visible sensitive materials. We chose to use the UV portion of the spectrum due to the sensitivity of the measurement and the absence of color detectable by the human eye. If necessary, a suitable UV-active indicator is added to the cosmetic material to allow for the quantitative measurement of uniformity using the UV-visible spectrophotometer methodology.

[0014] [Fig.2] is an illustration of the configuration used to deposit materials cosmetics on substrates compatible with UV-visible measurement such as quartz plates or polymer plates. Platform 1 provides the base to which the gear control lever 3 can be attached. It also provides the working surface for the deposit gauge 4 and the substrate 2. The platform also houses the necessary electronic and mechanical components used to operate the unit. Various liquid sample application gauges are commercially available. They are common in the coatings industry. Two types of gauges can be used. One type has continuously adjustable deposit thicknesses. The other type is a block gauge, where each side provides a fixed deposit thickness, allowing for a total of 3 to 5 different thicknesses. Both types of deposit gauges can be used in this invention as long as the ability to deposit a material thickness of approximately 10 mm to approximately 100 mm is achieved.

[0015] [Fig.3] Fig.3 is a diagram illustrating the simultaneous visualization of the uniformity of the cosmetic product using an optical microscope and corresponding uniformity data acquired using a UV-visible spectrophotometer during the drying stage of the cosmetic application process. A UV-sensitive cosmetic product containing avobenzone was used in this example. The sample was deposited on a quartz glass plate, and the timer started at 0 minutes. The sample was immediately placed in a controlled position in the UV-visible spectrophotometer, and an absorption spectrum was acquired. The same location on the coated quartz plate was observed under a light microscope at 400x magnification. Appropriate quartz plate sample holders were fabricated to ensure that the same point was observed / measured during this process. The uniformity index quantitatively describes the changes in emulsion droplets during the drying process. The droplets become larger and the oil phase becomes more uniform over time. There is a sharp change in the uniformity index during the drying process between 15 and 20 minutes, corresponding to the phase inversion of the emulsion droplets. This example demonstrates our ability to use a UV-visible spectrophotometer to measure the uniformity of applied cosmetic materials. The quantitative UV measurement data correlates well with visual observation using an optical microscope. The explanation of figures 4 to 8 is incorporated in the text below. Detailed description

[0016] The invention relates to compositions that can be easily applied to obtain uniform coverage of cosmetic product in order to provide hydration skin, UV protection, skin elasticity, and other therapeutic, aesthetic, and / or cosmetic benefits. The present inventions describe new compositions that provide uniform coverage and produce better skin beauty and protection performance than conventional compositions. These compositions are suitable for easy topical application to form a uniform, aesthetically pleasing, invisible, elastic, and skin-conforming layer of cosmetic material. This method of quantification and testing is essential for the discovery of invented formulations and for optimizing the uniformity of cosmetic material coverage. As used here, the term "skin" includes body surfaces where normal skin is intact, compromised, or partially or completely lost or removed. Skin further includes skin imperfections that are generally considered part of "skin." Examples of skin imperfections include wrinkles, blemishes, freckles, acne, moles, warts, lesions, scars, tattoos, bruises, skin disfigurements, birthmarks, sun damage, age damage, spots (e.g., age spots), uneven skin tone, sagging skin, cellulite, stretch marks, loss of skin elasticity, roughness, enlarged pores, hyperpigmentation, telangiectasia, redness, shine, port-wine stains, and melasma. As used herein, the term "uniform" means a layer that is continuous and substantially uniform or of the same thickness over all targeted surfaces. "Apply," "applied," and "application" include all known methods of transferring or administering the compositions of the invention onto the skin or body of a subject. Application may be made by finger, hand, brush, cotton ball, cotton swab, tissue, pad, sponge, roller, spatula, dispenser, drops, spray, splash, foam, serum, spritz, and other suitable methods. "In vitro" means not tested or formed on, in, or over the skin or body of a subject. One aspect of the invention relates to a composition comprising at least one emulsifier, which allows a lamellar liquid-crystal phase for the cosmetic emulsion during at least one application step of the product on a surface such as human skin. The emulsifier is further amphiphilic, consisting of a lipophilic component and a hydrophilic component, both derived from natural-based materials. More specifically, the lipophilic component is derived from fatty acids of vegetable oils. More particularly, the lipophilic component is derived from fatty acids of olive oil. The hydrophilic component is derived from natural polyhydroxy compounds such as Sugar alcohols and polyglycerols. Other suitable emulsifiers, particularly naturally derived emulsifiers such as phospholipids, can be advantageously incorporated into the composition of the described invention to further enhance the ease of formation of the desired lamellar liquid crystal phase during the application of cosmetic products. The lamellar liquid crystal phases with the invented emulsifying structures enable the ideal viscoelasticity of the cosmetic material on the skin surface, promoting uniform and homogeneous coverage of skin with diverse surface topologies and energies. In some embodiments, the composition comprises one or more amphiphilic esters derived from olive oil fatty acids capable of forming lamellar liquid crystalline phases in the cosmetic product. In preferred embodiments, the amphiphilic olive oil fatty acid esters are further derived from natural polyhydroxylated compounds. In other preferred embodiments, the polyhydroxylated compounds are polyglycerols or sugar-based polymers such as sucrose, glucose, sorbitol and its derivatives, chitin, chitosan, cellulose, or starch structures of varying molecular weights. In some embodiments, the composition further comprises one or more additives.Suitable additives include, but are not limited to, touch modifiers, adhesive modifiers, spreadable agents, thinners, adhesion modifiers, volatile siloxanes, emollients, thickeners, solvents, film-forming agents, humectants, preservatives, pigments, skin permeation activators, optical modifiers, pH modifiers, aesthetic modifiers, and combinations thereof. Additional suitable additives are described in the INCI (International Nomenclature of Cosmetic Ingredients) dictionary, which is incorporated herein in its entirety for reference.In some embodiments, the composition further comprises one or more additional agents, including cosmetic agents, therapeutic agents, stimulus-sensitive agents, detection agents, drug-delivery agents, optical agents, coloring agents, pigments, diffusing agents, thermoactive agents, thermally active agents, UV active agents, light active agents, sound active agents, pressure active agents, movement active agents, radioactive agents, electrical agents, magnetic agents, and other beneficial agents. Appropriate cosmetic agents include, but are not limited to, moisturizers, sunscreens, UV protection agents, skin protectants, skin soothing agents, skin brightening agents, skin luminosity agents, skin softeners, skin smoothers, bleaching agents, skin exfoliants, and firming agents. for the skin, cosmeceutical agents, vitamins, antioxidants, cell signaling agents, cell modulation agents, cell interaction agents, skin tanning agents, anti-aging agents, anti-wrinkle anti-spot agents, a-hydroxy acids, b-hydroxy acids, ceramides and a combination thereof. Appropriate therapeutic agents include, but are not limited to, pain relievers, analgesics, anti-itch agents, anti-acne agents (beta-hydroxy acids, salicylic acid, benzoyl peroxide), anti-inflammatory agents, antihistamines, corticosteroids, NSAIDs (non-steroidal anti-inflammatory drugs), antiseptics, antibiotics, antibacterials, antifungals, antivirals, anti-allergics, anti-irritants, insect repellents, phototherapeutics, coagulants, antineoplastics, immune-stimulating agents, immune-suppressing agents, coal tar, anthralin, fluocinonide, methotrexate, cyclosporine, tacrolimus, azathioprine, ceramides, counter-irritants, skin-cooling compounds, and combinations thereof. Suitable beneficial agents include, but are not limited to, antioxidants, vitamins, vitamin D3 analogues, retinoids, minerals, mineral oil, petrolatum, fatty acids, plant extracts, polypeptides, antibodies, proteins, sugars, humectants, emollients, a combination thereof, and other similar agents beneficial for topical application known in art. Another aspect of the present invention relates to a method and process for monitoring, quantifying, and visualizing the uniformity of a cosmetic emulsion material. The uniformity of cosmetic materials is crucial for achieving their intended performance characteristics. For example, [Fig. 1] illustrates how the radiation-filtering capacity of the cosmetic material can be significantly altered simply by changing the uniformity of the material applied to the skin surface. Other types of performance characteristics, such as hydration, prevention of transepidermal water loss (TEWL), or the distribution and delivery of various active ingredients, are also affected in the same way. To date, there is no practical quantitative method for measuring the coverage quality of cosmetic materials.The lack of measurement and control methods has hindered the development of cosmetic products with better application uniformity. The invention relates to a practical method for quantifying the uniformity of coverage of a cosmetic material when applied to a surface. The measurement is based on the incorporation of a UV-absorbing indicator molecule into the formulation and the measurement of the UV absorbance of the applied cosmetic layer. This is scientifically As known and illustrated in [Fig. 1], the UV absorbance of the applied cosmetic layer is directly related to the uniformity of the coverage. The uniformity index of an applied layer is defined as the ratio between the absorbance of the layer applied at the time considered and the absorbance of the most uniform layer (the one with the highest absorbance). For research purposes, substrates suitable for UV measurements, such as quartz plates or various polymer materials like PMMA plates, can be used. These substrates can be pretreated to simulate the characteristics of the target surfaces. A customized setup, such as the one shown in [Fig. 2], can be used to deposit cosmetic materials onto substrates in a controlled manner. To measure the uniformity of the cosmetic material applied to human skin, repeated stripping of the skin area covered with the cosmetic material was performed in a controlled manner using tape stripping. The total absorption of the cosmetic material applied to the skin is accurately transferred to the stripping tapes and can be measured using the cumulative UV spectra of these tapes.The uniformity index of the cosmetic product applied to human skin can be calculated similarly using stripping tape data as previously described for non-human skin substrates. Figure 3 illustrates how cosmetic uniformity data is quantitatively measured during the drying phase of the cosmetic application process. Uniformity can be qualitatively visualized using an optical microscope. Quantitative uniformity measurements, which can be expressed as the absorption values ​​of the UV indicator 3-(4-tert-butylphenyl)-1-(4-methoxyphenyl)propane-1,3-dione (commonly known as Avobenzone), or the uniformity index (defined as the ratio of absorbance at a specific time to ultimate absorbance), are consistent with qualitative observations under the optical microscope. One aspect of the invention relates to a method for using a UV-visible spectrophotometer to quantitatively measure the uniformity of cosmetic products applied directly or transferred onto UV-transparent substrates such as quartz glass, various plates or films made from polymers such as polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), etc. Suitable coatings may optionally be applied to these substrates to facilitate the acceptance of cosmetic products. In the preferred embodiment, the suitable coating materials are organic polymer coatings. Another aspect of the present invention relates to the incorporation of active UV indicators into cosmetic products to enable observation and measurement, using a UV-visible spectrophotometer, of a cosmetic product that is otherwise undetectable by UV. Suitable indicators include organic molecules that can be easily incorporated into the cosmetic formulation. Organic molecules with high molar extinction coefficients (maximum value greater than 10,000 M-lcm-1, preferably greater than 25,000 M-lcm-1, preferably greater than 40,000 M-lcm-1) in the UV wavelength region (200 nm - 400 nm) are particularly well-suited. Preferred indicator molecules are polar and can be readily dissolved in cosmetic oil phases and are thermally and photochemically stable.Examples of organic indicators include avobenzone, alkyl esters of ortho-hydroxylbenzoic acid, alkyl esters of phenylethylenecarboxylic acids, etc. In some embodiments, the UV-sensitive indicator may consist of inorganic substances capable of absorbing in the expected UV wavelength range of 200 nm to 400 nm. These inorganic substances include various semiconducting metal oxides such as zinc oxide and titanium dioxide. The UV-visible spectrophotometer measures transmission over a defined area of ​​the sample and scans the desired wavelength range. As shown in [Fig. 1], the transmission results are highly sensitive to the uniformity of the materials being measured. We have found that the UV-visible spectrophotometer is a practical and easy method for quantifying and observing the uniformity of an applied material, such as a cosmetic product, when used with the application setup and method described here. While the UV-visible spectrophotometer is a common and well-known analytical tool, its use for quantitatively measuring the coverage uniformity of materials, particularly cosmetic material layers, has not been previously explored. Another aspect of the invention relates to the applied composition, which forms a uniform layer on the skin so that transepidermal water loss (TEWL) is reduced. The term "transepidermal water loss" (TEWL) refers to the measurement of the amount of water that passes from inside a body through the epidermal layer to the surrounding atmosphere via diffusion and evaporation. Transepidermal water loss is measured using the transepidermal water loss (TEWL) measurement test as described herein. Differences in TEWL measurements caused by the age, race, sex, and / or skin area of ​​the subject being tested are generally less than the standard error in TEWL measurements. TEWL measurements can be taken at any time at or after approximately 30 minutes, for example, at approximately 1 hour, approximately 4 hours, approximately 6 hours, approximately 12 hours, approximately 24 hours, approximately 30 hours, approximately 36 hours, approximately 48 hours, or between 48 hours and one week after application of the cosmetic product. In some embodiments, the TEWL of the treated skin area is reduced by 15%, preferably 20%, and more preferably by more than 25% compared to untreated skin. Another aspect of the invention relates to the applied composition, which forms a uniform layer on the skin, thereby improving the hydration of the skin in the area treated with the composition. The term "skin hydration" refers to the measurement of the skin's water content, generally using a corneometer, which is based on measuring the capacitance of a dielectric medium near the skin's surface. Skin hydration measurements can be taken at any time, at or after approximately 30 minutes, for example, at approximately 1 hour, 4 hours, 6 hours, 12 hours, 24 hours, 30 hours, 36 hours, 48 ​​hours, or between 48 hours and one week after the application of the cosmetic product. Skin hydration can be measured, for example, using a corneometer according to the procedure described in H. Dobrev, Use of Cutometer to assessment epidermal hydration, Skin Research and Technology 2000, 6(4):239-244.In some embodiments, skin hydration after application of the composition is greater than 15%, preferably 20%, and preferably greater than 25% of that of untreated skin. Skin hydration can also be measured, for example, using the procedure described in Clarys et al., Measurements of stratum corneum hydration: comparison between the capacity method (digital version of the Comeometer CM 825 (R)) and the impedance method (Skicon-200EX (R)), Skin Research and Technology 2011, 18(3):316-23. Another aspect of the invention relates to the applied composition, which forms a uniform layer on the skin, thus improving the sun protection factor (SPF) compared to a control material using the same amount of UV filters without the invented embodiment, where a uniform layer cannot be achieved. The term "sun protection factor (SPF)" refers to the measurement of the UV protection capacity of a sunscreen product. The UVA protection factor (UVAPF) is also commonly measured for protection in the UVA region (325 nm–400 nm). Definitive measurements and measurements of sun protection factors can be found in relevant ISO documents, for example, ISO 24443:2019. In some embodiments, the SPF of the invented composition is 50%, preferably 80%, and even better, more than 100% higher than the non-uniform formulation containing the same amount of UV filters.In preferred embodiments, the composition forms a layer that is cosmetically elegant and has the appearance of normal, healthy, and youthful skin on the subject. on which the composition to which the layer is applied. Therefore, the layer can provide cosmetic and therapeutic benefits that reduce the appearance of any signs of aging, including under-eye bags, laugh lines, crow's feet, forehead wrinkles and fine lines, etc. Unless otherwise stated, all properties of the compositions, layers and / or devices described herein are measured at room temperature (approximately 22 to 25°C) and at an air pressure of approximately 1 atmosphere. Examples

[0017] Example 1: Composition of the invention, test of the uniformity of the compositions applied using the process of the invention, additional test of the hydration and the TEWL and their correlations with the uniformity. A control formulation using a conventional emulsifier and three formulations of the invention, each using an emulsifier of the present invention, were prepared according to the compositions detailed in Table 1 below.

[0018] [Table 1] Information on the formulation of the samples tested in Example 1 Phase ingredients Controi Formulation invention Forrnniattan 1 (¾) invention Formulation 2 W invention Fcr rtiuiatiûn 3 W À VP / ÊKoseoe copoiymer 2.œ 2.00 2.00 2.00 Poiy sorte te 60 0.50 0.50 0.50 Ceteæyi atotei i.æ 1.00 1.00 1.00 Pdassiant cefyi phosphate 2.50 - - - Sorbitan O&eie' - 2.50 - - Sucrose OSvate2 2.50 Pob / gsy ce ty 1-8 O Svate* - - - 2.50 C12-15 Aikyi benzcate 22 æ 22.00 22.00 22.00 fî 8MDBM tAvéhériZètei 3.00 3.00 3.00 3.00 C Discdtum EDTA 0.05 0.05 0.05 Di wter op tes 100 up ta 100 ap ta 100 up te 100 1,3-Butytene ghtei 3,00 3.00 3.0& 3.Ü0 1,2-Pftjpanedtai tæ 1.00 1.00 1.00

[0019] Formulation 1: Synthesized by an esterification process from sorbitan fatty acids and olive oil. Formulation 2: Synthesized by an esterification process from sucrose fatty acids and olive oil. Formulation 3: Synthesized by an esterification process from polyglycerol-6 and olive oil fatty acids. Using the invented gauge and base, each formulation was deposited onto quartz glass plates at a thickness of 9.1 µm. The absorption spectra of these formulation sample plates were recorded between 290 nm and 400 nm using a UV-visible spectrophotometer. The total absorbance varied considerably. between these samples. The control sample exhibited the lowest absorbance and therefore the highest transmission of incoming photons ([Fig. 4]). All formulations contained the same amount of UV active species (Avobenzone), and the same amount of formulation was applied to the unit surface area of ​​the substrate. Based on the detailed analysis previously, this increased transmission by the control formulation sample on the substrate is due to the non-uniform distribution of the cosmetic materials on the substrate surface. While many factors can contribute to the quality of coverage of cosmetic products, the emulsification chemistry used to bind the oil and aqueous phases plays a predominant role.Without being tied to any specific theory, our working mechanism is that these amphiphilic emulsifiers, where the lipophilic components are based on olive oil fatty acids, can readily form lamellar liquid crystal phases, and these phases survive the longest during the cosmetic product application process. The lamellar liquid crystal phases offer optimal rheology, allowing for better and more uniform coverage on substrates. These biomimetic lipid arrangements, in particular, facilitate the uniform coverage of skin surfaces. [Fig.4] represents the UV absorption spectra of the formulations of example 1 applied with the same dosage on quartz glass plates.

[0020] The overall capacity of the applied cosmetic material to block incoming radiation in the 290nm to 400nm range can be quantitatively measured by integrating the effect under the curve (AUC) in its absorption spectra ([Fig. 5]). Because the same dosage of formulations was applied to the same substrate surface, the AUC is a direct measure of the relative uniformity of the material applied to the substrate, with a more uniform distribution resulting in a higher AUC. [Fig.5] represents Total Pair under the curve (AUC) of UV absorption spectra between 290nm and 400nm, Quantitative measurement of the overall radiation blocking capacity of applied cosmetic materials.

[0021] The impact of the formulation on skin hydration and skin barrier function was tested on human volunteers. A total of 10 female volunteers aged 20 to 60 years participated. For the hydration experiment, the hydration level was measured using a CORNEOMETER®. For TEWL, a TEWAMETER® was used. Test formulations of the same weight were applied in the same way to 2 different sites within the same defined area on the forearm. The reported data are averages of all measurements. Hydration and TEWL measurements were taken before product application (TO-baseline) and 2 hours (T2h) after product application. The percentage changes in the hydration level between T0 and T2h are shown in [Fig. 6] for untreated skin and for the 4 The formulations tested all provided improved hydration compared to untreated skin. In addition to the uniformity data, formulations 1, 2, and 3 of the invention provided better hydration performance than the control formulation. [Fig.6] represents the percentage variations in hydration levels between TO and T2h.

[0022] The percentage variations in TEWL between TO and T2h are shown in [Fig. 7] for untreated skin and for the four tested formulations. All formulations provided improved TEWL performance (lower TEWL) compared to untreated skin. In addition to the uniformity data, formulations 1, 2, and 3 of the invention provided better TEWL performance than the control formulation. [Fig.7] represents the percentage change in TEWL between TO and T2h.

[0023] Example 2: Uniformity of a cosmetic product in emulsion controlled in "real time" during the drying process. Formulation 1 of the invention, a UV-sensitive cosmetic product containing avobenzone as described in Table 1, was spread onto a quartz plate and observed using an optical microscope and a UV-visible spectrophotometer. When the sample was deposited onto a quartz glass plate, the timer started at 0 min. The sample was immediately placed in a controlled position in the UV-visible spectrophotometer, and a spectrum was acquired. The same location on the sample plate was observed under the optical microscope at 400x magnification. Supports were fabricated to ensure that the same location on the sample was measured and observed throughout the process. The optical micrograph and UV monitoring data are shown in [Fig. 3]. The uniformity index is defined as the ratio of the AUC at a specific time to the ultimate AUC (the highest AUC).The uniformity index quantitatively describes the change in emulsion droplets during the drying process. The droplets became larger and the oil phase became more uniform over time. There was an abrupt change in the uniformity index during the drying process, corresponding to the phase inversion of the emulsion material. Therefore, we can use a UV-visible spectrophotometer with the invented configuration and method described here to measure the uniformity of applied cosmetic materials. The uniformity data acquired using a UV-visible spectrophotometer correlate well with visual inspection using an optical microscope [Fig. 3]. Example 3: Measurement of the uniformity of a cosmetic product in vitro on human skin and quantification of UV filtering capacity. The control formulation and formulation 1 of the invention were applied to the forearm of a volunteer according to the instructions in ISO 24444:2019, except that a dose of 1.3 mg / cm² was used. Scotch tape was used for stripping. All strips were precisely applied to the marked location on the skin to ensure that the same fixed area was repeatedly stripped. Each strip was immediately measured in a UV-visible spectrophotometer using a custom-made stand so that the same area on the strip was measured for each strip. The UV-visible blank was taken from a skin stripping strip immediately adjacent to the cosmetically treated area. For both formulations, all UV-absorbing materials were completely removed from the skin with the first six strips.The amount of UV absorption on each ribbon or on a combination of ribbons for both formulations was reported in [Fig.8A]. [Fig. 8A] represents the UV spectrum of the different stripping adhesive tapes

[0024] . As shown in [Fig. 8B], the AUC for the 6 bands in total (bands 1-6) represents the total absorption by the cosmetic products applied to the skin. The AUC of bands 1 to 6 for the formulation of invention 1 is higher than that of the control formulation. The same dosage of both formulations was applied. The difference in AUC, i.e., the difference in radiation filtering capacity between these two formulation samples, was due to differences in coverage quality (degree of uniformity). The results obtained here from the application of the product to the skin are parallel to those obtained from the products applied to a quartz plate (Example 1), indicating the reliability of the band transfer process and the overall quantification methodology described in this invention.Furthermore, the method as described in Example 3 is a potentially more humane and quantifiable way of measuring sun protection performance than those commonly used today, which are less quantitative and involve UV burns on human subjects. [Fig.8B] represents the area under the curve (AUC) of different stripping adhesive tapes

Claims

Demands

1. Oil-in-water cosmetic composition intended to provide uniform and homogeneous coverage on the skin, comprising an emulsifier; either non-ionic and consisting of a lipophilic structure derived from olive fatty acids and a hydrophilic structure derived from a sugar, preferably glucose, sucrose, maltose, sorbitol or their derivatives; or non-ionic and consisting of a lipophilic structure derived from olive oil fatty acids and a hydrophilic structure derived from a mixture of polyglycerols with repeating units ranging from 3 to about 10; or zwitterionic and composed of phospholipids.

2. A method for quantifying the uniformity of a cosmetic composition according to claim 1 applied to substrates, wherein said method uses UV-visible spectrophotometer data to quantify the degree of uniformity of said product as applied to a substrate; wherein an indicator molecule is added to said cosmetic composition if it does not itself contain any component exhibiting UV absorbance; understood that said uniformity index is defined as the ratio of the UV absorbance measured of the cosmetic layer at a particular time to the UV absorbance of the same layer at optimum uniformity.

3. A method according to claim 2, wherein said indicator molecule is a molecule with a high UV absorption capacity between 200nm and 400nm while its peak molar extinction coefficient is at least 10,000 M'cm*, preferably at least 25,000 M'cm*, most preferably at least 40,000 M'cm1; said indicator comprises Avobenzone, alkyl esters of ortho-hydroxyl benzoic acid, such as 2-ethylhexyl 2-hydroxybenzoate, and alkyl esters of phenyl ethylene carboxylic acids, such as 2-Ethylhexyl 2-cyano-3,3-diphenylprop-2-enoate, as well as an inorganic metal oxide capable of absorbing in the wavelength range of 200nm to 400nm, such as zinc oxide, titanium dioxide and mixtures thereof.

4. A method according to any one of claims 2 or 3, wherein a thickness gauge of about 10mm to 100mm is moved at a controlled speed to deposit the cosmetic composition at a known defined thickness on the substrates.

5. Method according to claim 4, wherein said folding speed is in the range of 0.1 cm / s to 100 cm / s.

6. A method according to claim 5, wherein the layer of the cosmetic composition applied to human skin is transferred onto an adhesive tape compatible with UV measurement, wherein the cosmetic composition is completely removed from the skin using several pieces of adhesive tape, wherein the UV absorbance of the cosmetic transfer layer on the tape is measured and summed to represent the quality of the cosmetic coverage on the skin, and wherein the strips are fixed regionally and specifically to the skin and during UV measurement to ensure that the cosmetic composition is accurately transferred from the skin onto the strips and that the state of the cosmetic composition on the strips is an authentic representation of that of the cosmetic composition on the skin.

7. Use of a composition according to claim 1 to provide uniform and homogeneous coverage on skin, said uniformity of coverage of said composition being measured, quantified and visualized by one of the methods according to any one of claims 2 to 6, characterized in that the composition reduces transepidermal water loss (TEWL) by at least 15%.

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