Cosmetic products with solar protection comprising porous powders coated with lipophilic agents with SPF booster effect

Abstract

Photo-protective cosmetic products comprising solar filters and lipo-porous powders with boosting effects of the protection against the sun, where in such lipo-porous powders comprise: - an inorganic component chosen from the group comprising diatomaceous earths, silica, zeolite; - a functionalized coating agent chosen from the group consisting in triethoxycaprylylsilane, trimethoxy caprylyl silane, cetyl trimethoxysilane, Isopropyl Titanium Triisostearate, Sodium Stearoyl Glutamate; triethoxycaprylylsilane being particularly preferred; wherein the inorganic component is surface treated with said functionalized coating agent, which provides lipophilic properties. Method for the preparation of said lipo-porous powders.

Description

“COSMETIC PRODUCTS WITH SOLAR PROTECTION COMPRISING POROUS POWDERS COATED WITH LIPOPHILIC AGENTS WITH SPF BOOSTER EFFECT”.* * * *DESCRIPTION

[0001] The present invention relates to porous powders coated with lipophilic agents to be used as boosters for the sun protection factor in cosmetic composition comprising sunscreens.

[0002] The exposition to sunrays is known to cause sunburn, erythema, skin ageing; in the worst case can cause melanoma and squamous cell carcinoma. The use of solar filters can prevent these problems.

[0003] It is known that solar filters can be of two kinds:- organic chemicalAn exemplary, not exhaustive list of chemical sunscreens comprises (INCI names): Diethylamino Hydroxybenzoyl Hexyl Benzoate, Ethylhexyl Triazone, Diethylhexyl Butamido Triazone, Bis- Ethylhexyloxyphenol Methoxyphenyl Triazine, Drometrizole Trisiloxane, Phenylbenzimidazole Sulfonic Acid, Isoamyl p- Methoxycinnamate, Ethylhexyl Salicylate, Butyl Methoxydibenzoylmethane, Phenylbenzimidazole Sulfonic Acid, Disodium Phenyl Dibenzimidazole Tetrasulfonate, Methylene Bis- Benzotriazolyl Tetramethylbutylphenol, Terephthalylidene Dicamphor Sulfonic Acid, Octocrylene, Homosalate, Ethylhexyl Methoxycinnamate and derivatives thereof.- inorganic chemical, also known as mineral or physical sunscreens Inorganic chemical sunscreens are essentially zinc oxide (ZnO) and titanium dioxide (TiCL).For the sake of clarity, in the present application, the expressions “solar filter” and “sunscreen” are used interchangeably.

[0004] It is known that sunrays comprise an ultraviolet component, inparticular UVA (315 - 400 nm), UVB (280 - 315 nm) and UVC (100 - 280 nm).

[0005] The degree of protection provided by sunscreens and compositions comprising sunscreens is customarily expressed through a parameter called SPF (Sun Protection Factor). The official European method for determining SPF is described in the ISO 24444:2019 https: / / www.iso.ors / standard / 72250.htmJ or ISO 24442:2022 standard

[0006] In addition to SPF, especially in Asian countries a different system is used for evaluating the protection degree offered by sunscreens, which appears on sun care products with the designation PA. In short, the system Protection Grade of UVA measures the protection from UVA rays that the sunscreen provides. The system is based on the PPD (Persistent Pigment Darkening) reaction. In lieu of measuring erythema, the PA method uses the UVA radiation to cause a browning or tanning of the skin. Theoretically, a solar filter with a PPD of 10 indicates that it will take about 10 times longer for a person’s skin to develop a tan from UVA radiation with the sunscreen on compared to without it.

[0007] Both SPF and PA parameters are measured in vivo. Approximately, it can be stated that SPF measures skin protection from UVB radiations, while PA measures skin protection from UVA radiations.

[0008] Since cosmetics are applied on human skin tissue, they are generally exposed to sunrays. As ultraviolet radiations are involved in tissue ageing, some cosmetics, like e.g. day creams or foundations, comprise molecules capable of absorbing or reflecting such radiations, conferring a cosmetic effect. Moreover, there are cosmetic products specifically designed for photoprotection (aka SPF formulations), like sun care products, which comprise sunscreens.

[0009] It was shown that some chemical sunscreens are toxic to marine fauna and corals, which lead to their prohibition in some geographicalareas like Hawaii, Key West (Florida, USA), Virgin Islands (USA), Bonaire e Palau.

[0010] In cosmetics, agents that booster the effect of sunscreens are known, e.g. from WO 2020182936 Al having the title Sunscreen compositions containing porous metal oxide spheres and in US 11793738 B2 having the title Lipo-amino acid alkyl esters as SPF boosters.

[0011] CN 115212138 A describes a composite silica sunscreen powder, comprising silica, nano titanium dioxide, solvent, polydimethylsiloxane and triethoxycaprylylsilane. Such composition has the effect of improving the sunscreen effect.

[0012] US 2014 / 363387 Al describes a wet or slurry method to produce cosmetic powders consisting of a silicate powder that is treated with both a lipophilic agent and a chemical UV filter: the resulting powder is a complex with both molecules. The document also describes UV-protecting cosmetic formulations comprising said cosmetic powders, having low loadings of cosmetic sunscreens.

[0013] WO 2013 / 039483 Al describes an invention similar to the previous one, wherein the composition comprises pigments in addition to lipo-treated substrates and chemical UV filters. The presence of at least one pigment is mandatory.

[0014] Such photoprotection boosters (SPF boosters) do not act as photoprotectors, but in the presence of sunscreens can enhance their activity and efficacy. The use of SPF boosters has been of special interest in the last years, due to the growing debate about stability and safety of sunscreens for skin health and the environment. Therefore, the discovery of substances with SPF booster effect opens up a new perspective for providing cosmetic products.

[0015] SPF boosters can work through a variety of mechanisms. Most of them increases UV absorption and the thickness of the skin barrier (through the thickening of the stratum corneum). Others increase the dispersingproperties of the sunscreen, while still others improve UVA ray absorbance and the photo-stability of the sunscreen.

[0016] Notwithstanding their efficacy in the protection against sun rays, SPF boosters have some drawbacks. Natural SPF boosters have problems of texture and cost. Synthetic SPF boosters pose some risks due to the fact that they are not natural but synthetic substances, and hence there is the possibility that they still contain traces of the toxic reagents that have been used during their synthesis. Therefore, there is a strong need of new substances that can be used as SPF boosters and combining several favourable properties. These favourable properties include a natural (or natural-like) source and a high booster efficacy (e.g. an efficacy allowing a significant reduction of the need of sunscreens).

[0017] Two recently introduced parameters concerning the natural origin of cosmetic raw materials and of cosmetic products are the Natural Origin Index (NOI) or “naturalness index”, and the Natural Origin Content (NOC), according to ISO 16128-2:2017 standard “Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients — Part 2: Criteria for ingredients and products”

[0018] NOI is a value indicating the extent to which a cosmetic ingredient complies with the definition of natural ingredient, derived natural ingredient or mineral derived ingredient indicated in the ISO 16128-1 :2016 standard “Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients and products — Part 1 : Definitions for ingredients” https: / / www Jsoiorg / ^an ar / 625(.3Jrimi. NOI can take values >0.5 and <1, wherein 1 is the maximum degree of natural origin, while the ingredients with a calculated value of <0.5 have a NOI equal to 0.

[0019] The NOC of a product is the mass percentage, comprised between 0% and 100%, of all the natural ingredients, natural portions of ingredients and ingredients of natural origin in the product. It is calculated asthe sum of the relative concentrations of the ingredients of a product, multiplied by their corresponding NOI.

[0020] For the sake of clarity, lipophilicity is defined as the capability to repel water, that can be demonstrated by means of the classical methods to evaluate a powder surface energy (penetration, in a pressed powder, by a droplet of a liquid of known surface tension, e.g. water). Lipophilic (hydrophobic) materials can be defined as having a surface energy below 72 mN / m at room temperature. Silica, zeolites and diatomaceous earth are hydrophilic in nature.

[0021] For the sake of clarity, porosity is defined as the feature of the powders to display microporous or mesoporous cavities that can be characterized using microscopy (e.g. SEM) for mesopores or gas adsorption measurements for micropores (e.g. BET analysis followed by BJH pore distribution analysis). Porosity allows for a high specific surface area (square meters per gram of material) to a powder.

[0022] Aim of the present invention is providing substances synergistically acting with chemical sunscreens, allowing to booster the protection effect against sun rays.

[0023] Another aim of the present invention is that such substances are of natural origin.

[0024] The invention concerns cosmetic compositions comprising lipo-porous powders as boosters of the sun protection factor (SPF).

[0025] According to the invention, lipo-porous powders provided of SPF booster properties as defined in the claims have been synthetized.

[0026] Such lipo-porous powders, added to the cosmetic compositions comprising sunscreens, increase their SPF; as a consequence, the quantity of sunscreens used in the formula can be significantly reduced, at the same time maintaining high SPF values, or it is possible to potentiate the effect of sun protection of the composition, the sunscreen quantity being equal.

[0027] Such lipo-porous powders consist in diatomaceous earthsand / or silica and / or zeolite with porous properties of natural origin, which have been successively surface-treated with a functional alkoxysilane (like, but not limited to, triethoxycaprylylsilane and / or trimethoxycaprylylsilane and / or cetyl trimethoxysilane), and / or other surface modifiers (e.g. isopropyl titanium triisostearate a sodium and / or stearoyl glutamate).

[0028] Some SPF boosters according to the present invention have been prepared as indicated in Table 1.Table 1

[0029] Diatomaceous earth, silicas (silicon dioxide) and zeolites used in the present invention are ingredients having a NOI = 1. The coating agent at 5% in weight (at a maximum) often has a NOI = 0. Hence, the Booster NOI ranges 0.95 - 1.

[0030] Diatomaceous earth, silica and zeolites can have different shape and granulometry according to desired cosmetic sensoriality and appearance after application on the skin. The inorganic components present in the different Boosters are different for morphology, granulometric distribution and hence cosmetic performance. Indicatively, for all the kinds of used inorganic powders, the dimension of the particles, measured through laser diffraction ranges 0,1 micron to 30 microns.

[0031] Porosity increases the surface area and the presence of an increased number of diffusion centres, so favouring the scattering effect, while the lipophilicity promotes a more effective interaction, especially whenchemical sunscreens are used in the formula, so favouring a more homogeneous dispersion or the film, which is functional to a uniform SPF booster effect. The above-described SPF booster effect has been observed in several typologies of cosmetic formulas and in the presence of different sunscreens, as will be described in the following.

[0032] Specifically, it was observed that the lipophilic powders according to the invention potentiate the action of UVB broad spectrum sunscreens more effectively, providing also a positive correlation with UVA sunscreens. This is correlated with the hypothesized mechanism of action, which occurs through the dispersion of radiations, depending on the wavelength. This supports the diffuse use of the lipo-porous powders according to the present invention, relative to the cosmetic compositions for the applications here described.

[0033] Various methods can be used in order to obtain the SPF boosters according to the present invention. A typical coating process for obtaining the Booster powders is the following:- inserting the inorganic powder into a heated powder mixer;- under stirring, adding the coating agent;- adding a solution of acidic water while continuing to turbulently stir;- bringing temperature to 80°C maintaining it for 4 h under continuous stirring;- at the end, bringing the temperature to 25°C and discharging the powder;- optionally sieving through a sieve having a powder mesh No. 120.

[0034] A first advantage of the present invention is that experimentally, it was observed that when these lipo-porous powders are added to cosmetic composition comprising any sunscreen, the SPF value of the cosmetic composition increases. Therefore, a drastic reduction of the sunscreen necessary for reaching the desired SPF index is possible, so limitingthe risks associated to the prolonged exposition of consumers to high quantities of sunscreen and also reducing the impact on the environment.

[0035] As sunscreens are molecules that can impact on the cost of the finished cosmetic product, and also modify the structure of the formula by altering its texture and / or odour, there is a second advantage of the present invention in terms of cost and agreeableness of the formula, deriving from the decreased quantity of sunscreen in the presence of SPF boosters, the sun protection remaining equal.

[0036] A third advantage of the present invention is that SPF boosters according to the present invention are of natural origin, hence their insertion in a final cosmetic product leads to an improved NOI index of the final cosmetic product.

[0037] The features and the advantages according to the present invention will be made more evident by the following detailed description of an embodiment thereof shown by way of non-limiting example in the accompanying drawings, in which: figures 1A-1E are five charts showing the in vitro effect of the combination of five distinct chemical sunscreens (Ethylhexyl Triazone, Diethylhexyl Butamido Triazone, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine, Butyl Methoxydibenzoylmethane, Diethylamino Hydroxybenzoyl Hexyl Benzoate) combined with four different SPF booster powders (Boosterl, Booster2, Booster3, Booster4) according to the crescent invention, added to the composition in increasing percentages (1%, 3%, 5% 10%) in weight; figure 2A shows a chart describing the in vitro boosting effect on SPF, while figure 2B shows a chart describing the in vitro effect on PA which are obtained by adding the two SPF Booster3 and Booster4 to an oil-in-water emulsion (O / W); the data compare no SPF booster with 3% and 5% of SPF booster; figure 3 A shows a chart describing the in vitro boosting effect of SPF,while figure 3B shows a graph describing the in vitro boosting effect on PA obtained by adding the two SPF Boosters e Booster4 to an oil- in-water emulsion (O / W); the data compare no SPF booster with 3% of Boosters and Booster4, and combinations in different proportion of the two powders (1 : 1, 1:2 and 2: 1); figure 4 shows the results of an in vivo test of the combination that showed the best boosting efficacy (Boosters and Booster4 in a 2: 1 proportion).FORMULA EXAMPLES

[0038] The boosting effect was initially identified when the lipo- porous powders have been used in a previously developed base formula in addition to a system of organic filters tested in vivo.

[0039] Exemplary formulas are shown in the following tales.Formula 1

[0040] Formula 1 exemplifies the matrix (BASE) on which the systematic in vitro testing shown in Figure Iwas performed. For each test the base was used, which was kept fixed in all test, to which just one of the SUN FILTERS was added. The first four sunscreens (SUN FILTER) have been added at 10% in weight, while the fifth filter, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine, was added in a concentration of 5% or 10%. To each of said composition an SPF booster was added in increasing percentage (1%, 3%, 5% 10%). The product was formulated as a solid anhydrous product (stick).

[0041] The in vitro tests (performed according to the method ofhave shown a high potential for the lipo-porous powders. A systematic approach (Design of Experiments) was used, testing several powders selected as potential according to the preliminary results.

[0042] Using said Formula 1 in vitro, some preliminary results were obtained, shown in figures 1A-1E, which allowed to confirm the following hypotheses:1. The boosting effect is consistent and repeatable on organic filters. On the contrary, on inorganic filters (zinc oxide, titanium dioxide), the boosting effect is not very marked and not steadily repeatable (tests not shown).2. The boosting effect is linked to the wavelength of the incident radiation, in particular it is more marked with filters whose main activity occurs in the UVB field, while it is less marked with respect to UVA radiations.

[0043] In the following, the preliminary work lead on an anhydrous formula (Formula 1) was widened to fluid emulsions of the O / W type (oil-in- water) according to Formula 2.Formula 2

[0044] Formula 2 is a generic oil-in-water emulsion that can be used as a sun cream, but the same basis can be used with a different percentage ofsunscreens also as a product for skin care. In such case, according to the required use, also other active ingredients are added, and optionally a fragrance.

[0045] Firstly, tests in vitro were conducted (performed according to ISO24443 :2022 method) using the two best performing powders (Booster3 and Booster4) singly added in increasing percentages (3%, 5%) to Formula 2; figures 2A and 2B show the results of such tests. From these charts it is gathered that, by adding the SPF booster according to the present invention, both SPF and PA increase, but SPF increases more than PA.

[0046] Varying combinations of the two SPF Booster 3 and SPF Booster 4 were tested (1 : 1, 1 :2, 2: 1), always in compositions according to Formula 2. The results of these tests are shown in figures 3 A and 3B, from which is observed that the best combination is Booster3 and Booster4 in a 2: 1 combination.

[0047] Figure 4 shows the results of an in vivo test of the combination showing the best boosting efficacy, i.e. the combination of Booster3 and Booster4 in a 2: 1 proportion. Here, too, similarly to the in vitro tests, the boosting efficacy of the protection from sun rays is better for SPF than for PA.Formula 3

[0048] Formula 3 is a formula of the type oil-in-water (O / W)comprising pigments, representative of a make-up cushion base on which further tests were performed, so obtaining results comparable to the above ones (not shown). Formula 4

[0049] Formula 4 is a formula for products to be applied on lips, e.g. lipsticks and lip balms.

Claims

CLAIMS1. Photo-protective cosmetic product comprising at least a solar protection filter and a cosmetic composition, characterized in that the photo- protective cosmetic product comprises lipo-porous powders coated with lipophilic agents in order to booster the sunscreen protection, wherein said lipo-porous powders comprise:- an inorganic component chosen from the group consisting of diatomaceous earths, silica, zeolite;- at least one functionalized coating agent chosen from the group consisting of triethoxycaprylylsilane, trimethoxycaprylylsilane, cetyl trimethoxysilane, isopropyl titanium triisostearate, sodium stearoyl glutamate; wherein the surface of said inorganic component is treated with said functionalized coating agent, which provides lipophilic properties.

2. Photo-protective cosmetic product with lipo-porous powders according to claim 1, wherein said functionalized coating agent is triethoxycaprylylsilane.

3. Photo-protective cosmetic product with lipo-porous powders according to claim 1 or 2, comprising diatomaceous earths and silica, both coated with triethoxycaprylylsilane, preferably in a proportion of 2: 1 in weight.

4. Photo-protective cosmetic product according to one or more of claims 1-3, wherein the lipo-porous powders contain diatomaceous earths, and / or silica, and / or zeolite, obtained from a natural source and refined.

5. Photo-protective cosmetic product according to one or more of claims 1-4, wherein said diatomaceous earths, and / or silica and / or zeolite have particles of dimensions ranging 0.1 pm to 30 pm.

6. Photo-protective cosmetic product according to claim 1-5, wherein the lipo-porous powders are present in the cosmetic products in a quantity ranging 0.01% to 10.0% in weight.

7. Photo-protective cosmetic product according to claim 1-6, wherein thesolar filters are present in the cosmetic product in a quantity ranging 5.0% to 40.0% in weight.

8. Photo-protective cosmetic product according to one of claims 1-7, wherein the solar filters are chosen from chemical filters, including at least an UVB filter.

9. Photo-protective cosmetic product according to claim 8, wherein the chemical solar filters are chosen from Diethylamino Hydroxybenzoyl Hexyl Benzoate, Ethylhexyl Triazone, Diethylhexyl Butamido Triazone, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine, Drometrizole Trisiloxane, Phenylbenzimidazole Sulfonic Acid, Isoamyl p- Methoxycinnamate, Ethylhexyl Salicylate, Butyl Methoxydibenzoylmethane, Phenylbenzimidazole Sulfonic Acid, Disodium Phenyl Dibenzimidazole Tetrasulfonate, Methylene Bis- Benzotriazolyl Tetramethylbutylphenol, Terephthalylidene Dicamphor Sulfonic Acid, Octocrylene, Homosalate, Ethylhexyl Methoxycinnamate and derivatives thereof.

10. Photo-protective cosmetic product chosen from the group consisting of skin-care products, make-up products, lip products, skin whitening products, anti-wrinkle products, sun creams, having the features defined in any of claims 1-9.

11. Method for the preparation of lipo-porous powders according to claims 1-10, comprising the following steps:- inserting the inorganic powder in a heated powder stirrer;- adding the coating agent under stirring;- adding a solution of acidulated water while stirring in a turbulent way;- bringing temperature at 80°C keeping it for 4h under constant stirring;- at the end, bringing the temperature at 25°C and unloading the powder;- optionally, sifting the lipo-porous powder with a mesh No. 120 sieve.

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