Use of fatty ester as a solubilizing agent for a liposoluble UV filter

Abstract

Use of fatty ester as a solubilizer of UV filter The invention relates to the use of a 2-octanol monoester of the following formula: R1-C(=O)OR2 in which R1 designates an alkyl group comprising from 5 to 35 carbon atoms and R2 designates 1-methylheptyl, as a solubilizing agent of liposoluble UV filter, the mass ratio of the liposoluble UV filter(s) to the 2-octanol monoester(s) being between 0.02 and 0.50.

Description

Title of the invention: Use of fatty ester as a solubilizing agent for a liposoluble UV filter

[0001] The present invention relates to the use of a 2-octanol mono-ester as a solubilizing agent for a liposoluble UV filter.

[0002] It is known that radiation with wavelengths between 280 nm and 400 nm allows the human epidermis to tan, while radiation with wavelengths between 280 and 320 nm, known as UVB rays, hinders the development of a natural tan. Exposure to this radiation is also likely to cause a detrimental change in the biomechanical properties of the epidermis, resulting in the appearance of wrinkles and leading to premature skin aging.

[0003] It is also known that UVA rays, with wavelengths between 320 and 400 nm, penetrate the skin more deeply than UVB rays. UVA rays cause immediate and persistent tanning of the skin. Daily exposure to UVA rays, even for short periods, under normal conditions can damage collagen and elastin fibers, resulting in changes to the skin's microrelief, the appearance of wrinkles, and uneven pigmentation (spots, uneven skin tone).

[0004] To date, a wide variety of photoprotective compositions are already known to protect keratinous materials, and more specifically the skin, against the harmful effects induced by UVA and / or UVB radiation. Essentially, they contain a combination of several organic and / or inorganic UV filters as an active anti-UV agent, delivered in an oily and / or aqueous phase and are generally offered in a formulation such as a mist, emulsion or gel.

[0005] It is also known that high filter ratios are needed to achieve high levels of filtering efficiency.

[0006] However, high levels of UV filters do not lend themselves to the easy development of compositions with a stabilized and pleasant texture.

[0007] One of the first problems encountered concerns the solubilization of these filters. Dispersion can be observed. However, once the composition is applied to the skin, the UV protection obtained is completely inhomogeneous.

[0008] Furthermore, the introduction of high concentrations of UV filters generally causes destabilization problems in the composition. Precipitation or crystallization of the filters may be observed. In the case of biphasic compositions, this instability can sometimes even cause phase separation of the emulsion and / or a loss of viscosity of the composition, rendering the formulation ineffective or even unusable.

[0009] Thus, the quality and stability of the formulation have a direct impact on the expected UV protection.

[0010] Consequently, there is a real need for new solvents for these solar applications, using complex compounds.

[0011] The present invention aims to propose a new use of an organic solvent improving the solubilization of liposoluble UV filters, leading to stable and homogeneous compositions.

[0012] The invention relates to the use of a 2-octanol monoester of the following formula: RrC(=O)OR2 in which Ri denotes an alkyl group comprising 5 to 35 carbon atoms and R2 designates the 1-methylheptyl group, as a solubilizing agent for liposoluble UV filters, the mass ratio of the liposoluble UV filter(s) to the 2-octanol monoester(s) being between 0.02 and 0.50. Detailed description of the invention

[0013] Other features, aspects, objects and advantages of the present invention will become even clearer upon reading the following description.

[0014] It is specified that the expressions "from ... to ..." and "between ... and ...." used in this description should be understood as including each of the limits mentioned. 2-Octanol monoester

[0015] The useful 2-octanol monoester according to the invention has the following formula: RrC(=O)OR2 in which Ri denotes an alkyl group comprising from 5 to 35 carbon atoms, preferably from 6 to 35 carbon atoms, more particularly from 7 to 31 carbon atoms, preferably from 9 to 25 carbon atoms, and more particularly from 11 to 23 carbon atoms, and R2 denotes the 1-methylheptyl group.

[0016] By "alkyl group" is meant a saturated or unsaturated hydrocarbon chain, linear, branched or cyclic, which may optionally bear an aromatic ring, and which may optionally bear one or more hydroxy, alkoxy Ci-C6, amino, alkylamino Ci-C6, or dialkylamino Ci-C6 functional groups, derived, for example, from saturated fatty acids, with a linear or branched chain, or from unsaturated fatty acids, with a linear or branched chain, and optionally converted into saturated fatty acids by hydrolysis generation (according to techniques well known to those skilled in the art), and / or hydroxylated fatty acids, linear or branched chain, and possibly converted into saturated fatty acids by dehydration (according to techniques well known to those skilled in the art).

[0017] Preferably, the alkyl group is a saturated hydrocarbon chain, linear or branched, comprising 11 to 23 carbon atoms.

[0018] The mono-ester of 2-octanol can be easily obtained by esterification of an acid as defined above with 2-octanol.

[0019] The acid may be selected from hexanoic (or caproic) acid, heptanoic (or enanthic) acid, octanoic (or caprylic) acid, nonanoic (or pelargonic) acid, decanoic (or capric) acid, undecanoic acid, undecylenic acid, dodecanoic (or lauric) acid, tetradecanoic (or myristic) acid, pentadecanoic acid, hexadecanoic (or palmitic) acid, palmitoleic acid, heptadecanoic (or margaric) acid, octadecanoic (or stearic) acid, 9-octadecenoic (or oleic) acid, 9,12-octadecadienoic (or linoleic) acid, 9,12,15-octadecatrienoic (or linolenic acid), nonadecanoic acid, icosanoic (or arachidic) acid, arachidonic acid, ga-doleic acid, heneicosanoic acid, docosanoic (or behenic) acid, erucic acid, brassidic acid, tricosanoic acid, tetracosanoic (or li-gnoceric) acid, nevronic acid, pentacosanoic (or hyaenic),hexacosanoic acid (or cerotic acid), heptacosanoic acid (or carboceric acid), octacosanoic acid (or montanic acid), nonacosanoic acid, triacontanoic acid (or melissic acid), hentriacontanoic acid, dotriacontanoic acid (or laceroic acid), tritriacontanoic acid (or psyllic acid), tetratriacontanoic acid (or geddic acid), pentatriacontanoic acid (or ceroplastic acid), hexatriacontanoic acid, methoxycinnamic acid, dimethylaminobenzoic acid, hydroxystearic acid, anacardic acid, salicylic acid, and benzoic acid.

[0020] Preferably, the ester according to the invention is derived from an acid selected from hexanoic (or caproic) acid, heptanoic (or enanthic) acid, octanoic (or caprylic) acid, nonanoic (or pelargonic) acid, decanoic (or capric) acid, undecanoic acid, undecylenic acid, dodecanoic (or lauric) acid, tetradecanoic (or myristic) acid, pentadecanoic acid, hexadecanoic (or palmitic) acid, palmitoleic acid, heptadecanoic (or margaric) acid, octadecanoic (or stearic) acid, 9-octadecenoic (or oleic) acid, 9,12-octadecadienoic (or linoleic) acid, 9,12,15-octadecatrienoic acid (or linolenic acid), nonadecanoic acid, icosanoic acid (or arachidic acid), arachidonic acid, gadoleic acid, heneicosanoic acid, docosanoic acid (or behenic acid), erucic acid, brassidic acid, tricosanoic acid, tetracosanoic acid (or lignoceric acid), neuronic acid, pentacosanoic acid (or hyenic acid), hexacosanoic acid (or cerotic acid), heptacosanoic acid (or carboceric acid), octacosanoic acid (or montanic acid), nonacosanoic acid, triacontanoic acid (or melissic acid), hentriacontanoic acid, dotriacontanoic acid (or laceroic acid), tritriacontanoic acid (or psyllic acid), tetratriacontanoic acid (or geddic acid), pentatriacontanoic acid (or ceroplastic acid), hexatriacontanoic acid, methoxycinnamic acid, dimethylaminebenzoic acid, hydroxystearic acid, anacardic acid, salicylic acid, and acid benzoic acid.

[0021] Thus, the ester can be chosen from 1-methylheptyl laurate, 1-methylheptyl myristate, 1-methylheptyl palmitate, 1-methylheptyl stearate, 1-methylheptyl arachidate, 1-methylheptyl isostearate, 1-methylheptyl ricinoleate, 1-methylheptyl hydrostearate, or a mixture thereof. Preferably, the 2-octanol monoester is 1-methylheptyl palmitate.

[0022] Several mono-esters of 2-octanol can be used as solubilizing agents for one or more liposoluble UV filters.

[0023] By solubilization, it is understood in the context of the present invention that the composition formed of the liposoluble UV filter(s) and the 2-octanol monoester(s) according to the invention is monophasic at room temperature.

[0024] Preferably, 1-methylheptyl palmitate is used as a solubilizing agent for liposoluble UV filters.

[0025] Preferably, 1-methylheptyl palmitate is used as the sole solubilizing agent for liposoluble UV filters. Liposoluble UV filters

[0026] The mono-ester according to the invention is particularly effective for solubilizing liposoluble UV filters.

[0027] Preferably, the liposoluble UV filters are selected from avobenzone, ethylhexyl-triazone, benzophenone-3, octocrylene, benzophenone-2, benzophenone-6, benzophenone-8, menthylanthranilate, ethylhexylsalicylate, 4-methylbenzylidene camphor, octyl-N,N-dimethyl PABA, ethylhexyl dimethyl PABA, ethylhexyl methoxycinnamate, isoamyl methoxycinnamate, butyl methoxydibenzoylmethane, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, drometrizole trisiloxane, methylene bis-benzotriazolyl tetramethylbutylphenol, diethylhexyl butamido triazone, ethylhexyl triazone, isoamyl p-methoxycinnamate, polysilicone-15, tris biphenyl triazine, homomenthyl salicylate, and mixtures thereof.

[0028] Preferably, the mass ratio of the liposoluble UV filter(s) to the 2-octanol monoester(s) is between 0.02 and 0.40, more particularly between 0.03 and 0.30, and even more preferably between 0.04 and 0.20. Solar composition

[0029] The 2-octanol monoester according to the invention can be used in a sun composition comprising at least one liposoluble UV filter, the 2-octanol monoester(s) being used as a solubilizing agent for the liposoluble filter(s).

[0030] According to one embodiment of the invention, the solar composition may comprise several 2-octanol mono-esters as solubilizing agents.

[0031] The compositions according to the invention may be in the form of oil, water-in-oil emulsion or oil-in-water.

[0032] These compositions are stable and homogeneous. By "homogeneous", it is understood that the composition is in the form of a single phase, without grains suspended in the composition or on the walls of the container that are visible to the naked eye, and / or has a uniform texture.

[0033] The ester(s) according to the invention have the advantage of being able to be the only organic solvent in the composition.

[0034] The oil phase comprises at least one mono-ester according to the invention and at least one liposoluble UV filter as defined above.

[0035] However, it is always possible to consider a mixture of organic solvents. According to this embodiment, the sunscreen composition may then comprise at least one lipophilic compound selected from fatty acids, fatty alcohols, esters other than the 2-octanol monoester according to the invention, butters, waxes (for example, beeswax), oils, preferably an oil selected from mineral oils (for example, paraffin oil, petrolatum oil, mineral oils having a boiling point of 300 to 400°C), oils of animal origin (for example, squalene, squalane, perhydrosqualene), vegetable oils (for example, sweet almond oil, calophyllum oil, palm oil, apricot kernel oil, avocado oil, jojoba oil, olive oil, castor oil, cereal germ oils, the liquid fraction of shea butter), compounds unsaponifiables derived from natural oils,synthetic oils (e.g., hydrogenated polyisobutene, fatty acid esters such as purcellin oil, butyl myristate, isopropyl myristate, cetyl myristate, isopropyl palmitate, butyl stearate, hexadecyl stearate, isopropyl stearate, octyl stearate, isocetyl stearate, decyl oleate, hexyl laurate, propylene glycol dicaprylate, lanolic acid-derived esters such as disopropyl lanolate, isocetyl lanolate, acetylglycerides, alcohol octanoates, other than 2-octanol lemonoester used, polyalcohol octanoates, alcohol decanoates, other than 2-octanol monoester used, polyalcohol decanoates, including glycol octanoates, glycerol octanoates, glycol decanoates, decanoates, glycerol, alcohol ricinoleates, polyalcohol ricinoleates), terpenes, polyterpenes, phytosterol, silicone oils (e.g. cyclomethicones, low molecular weight polydimethylsiloxanes or silicone oils, high molecular weight polydimethylsiloxanes or silicone gums, polymethylsiloxanes, dimethiconols, phenyl polydimethylsiloxanes, low molecular weight siloxanols, high molecular weight siloxanols, trimethylsiloxysilicates), fluorinated oils (e.g. fluorinated perfluoroethers and fluorinated silicones).

[0036] When the composition includes an aqueous phase, it is also possible to provide for the presence of at least one water-soluble UV filter.

[0037] The solar composition may also include at least one inorganic UV filter. Preferably, the inorganic UV filter is selected from titanium dioxide particles, zinc oxide particles, coated mineral particles, in particular coated with a hydrophobic compound, for example stearic acid, and combinations thereof.

[0038] The solar composition may include one or more other components selected from preservatives, sensory agents, film-forming agents, sun protection factor boosters (empty spheres inside), rheology modifying agents, emulsifiers, emollients, humectants, perfumes, colorants, pigments, active ingredients and mixtures thereof.

[0039] Concrete, but by no means limiting, examples illustrating the invention will now be given. Examples

[0040] 1 / Synthesis of 2-octanol palmitate

[0041] 2-Octanol (768 g), palmitic acid (780 g), and 1.15 g of tin oxalate are heated under a nitrogen atmosphere. The esterification reaction begins at 170°C with the formation of water. After 3 hours, the water produced is extracted under vacuum from the reaction medium. The vacuum is reduced for 4 hours to approximately 15 mbar. The final temperature is 230°C. The excess alcohol is distilled, and the ester is cooled to 90°C. It is then washed in 300 mL of water to remove the catalyst, dried, filtered, and 1086 g of ester are obtained.

[0042] 2 / Preparation of solar compositions

[0043] Solar compositions are prepared. Table 1 below lists the constituents of the tested compositions. The content of the constituents is expressed partly by weight.

[0044] Composition A is comparative. Composition B is according to the invention.

[0045] The components are mixed at 50°C until the products are solubilized.

[0046] [Table 1] A (comparative) B (invention) Fat-soluble sunscreen1 7.74 7.74 2-Ethylhexyl palmitate2 92.26 - 1-Methylheptyl palmitate - 92.26 Mass ratio 0.084 0.084

[0047] 1 Parsol 1789 (butyl-methoxydibenzoylmethane) sold by DSM

[0048] 2-Ethylhexyl palmitate sold by the company Croda under the name com Crodamol OP commercial

[0049] 3 / Evaluation of compositions

[0050] The compositions are assessed visually. In particular, the presence of crystals is noted.

[0051] These prepared compositions were cooled to 50°C after the UV filter had dissolved. The ambient temperature is denoted t0. The compositions were then evaluated at 1 hour, 7 days, and 6 months. Throughout this period, the compositions were stored at room temperature and protected from light. The results are shown in Table 2 below.

[0052] [Table 2] Shelf life: 1 hour, 7 days, 6 months. Composition A: Presence of: Comparative crystals, crystals, crystals, crystals. Composition B: According to the invention, homogeneous, homogeneous, homogeneous, homogeneous.

[0053] It is observed that composition B according to the invention is homogeneous, unlike the comparative composition A. In composition A, the liposoluble UV filter in crystalline form is visible at the bottom of the container.

[0054] These results show that the 1-methylheptyl monoester solubilizes the liposoluble UV filter, unlike the 2-ethylhexyl monoester, the homogeneity of the composition according to the invention is preserved, and is stable over time.

Claims

Demands

1. Use of a 2-octanol monoester of the following formula: RrC(=O)OR2 in which Ri denotes an alkyl group comprising from 5 to 35 carbon atoms and R2 denotes 1-methylheptyl, as a solubilizing agent for a liposoluble UV filter, the mass ratio of the liposoluble UV filter(s) to the 2-octanol monoester(s) being between 0.02 and 0.

50.

2. Use according to claim 1, characterized in that the alkyl group Ri of the 2-octanol monoester comprises from 6 to 35 carbon atoms, preferably from 7 to 31 carbon atoms, preferably from 9 to 25 carbon atoms, more particularly from 11 to 23 carbon atoms.

3. Use according to claim 1 or 2, characterized in that the 2-octanol monoester is 1-methylheptyl palmitate.

4. Use according to any one of the preceding claims, characterized in that the liposoluble UV filter is selected from avobenzone, ethylhexyltriazone, benzophenone-3, octocrylene, benzophenone-2, benzophenone-6, benzophenone-8, menthylanthranilate, ethylhexylsalicylate, 4-methylbenzylidene camphor, octyl-N,N-dimethyl PABA, ethylhexyl dimethyl PABA, ethylhexyl methoxycinnamate, isoamyl methoxycinnamate, butyl methoxydibenzoylmethane, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, drometrizole trisiloxane, methylene bis-benzotriazolyl tetramethylbutylphenol, diethylhexyl butamido triazone, ethylhexyl triazone, isoamyl p-methoxycinnamate, polysilicone-15, tris biphenyl triazine, homomenthyl salicylate, and mixtures thereof.

5. Use according to any one of the preceding claims, characterized in that the mass ratio of the liposoluble UV filter(s) to the 2-octanol monoester(s) is between 0.02 and 0.40, and more particularly between 0.03 and 0.30, and even more preferably between 0.04 and 0.

20.

6. Use according to any one of the preceding claims, characterized in that the mono-ester is used in a solar composition in the form of an oil, an oil-in-water emulsion or a water-in-oil emulsion.

7. Use according to claim 6, characterized in that the solar composition further comprises one or more components selected from water-soluble UV filters, inorganic UV filters, preservatives, sensory agents, film-forming agents, sun protection factor boosters, rheology modifying agents, emulsifiers, emollients, humectants, perfumes, colorants, pigments and active ingredients and mixtures thereof.