MXPA01006733A - Sunscreen compositions - Google Patents

Abstract

A cosmetic sunscreen composition is provided which includes at least one organic sunscreen, a crosslinked non-emulsifying siloxane elastomer, a volatile siloxane and water. The composition is an oil-in-water emulsion to provide an aesthetically pleasing light skinfeel and rich viscosity, even in the presence of greater than 25%sunscreen oils.

Description

EADOR SOLAR BLOCK COMPOSITIONS BACKGROUND OF THE INVENTION The invention relates to sunscreen compositions, in particular to those in the form of lotion and cream.

Related art Sunscreen compositions are commonly used during outdoor work or leisure for protection of exposed skin from sunburn, cancer and even photo-aging. Many effective sunscreen preparations are sold commercially or are described in the cosmetic or pharmaceutical literature. In general, sunscreen preparations are formulated as creams, lotions or oils that contain as the active agent a chemical compound absorbing ultraviolet radiation. The active agent works by blocking the passage of erythematogenic radiation, thereby preventing its penetration into the skin. The ideal sunscreen formulation should be non-toxic and non-irritating to the skin tissue and should be capable of convenient application in a uniform continuous film. The product should be chemically and physically stable enough, in order to provide an acceptable shelf life over storage. It is particularly desirable that the preparation retain its protective effect over a prolonged period after application. In this way, the active agent, when present in the skin, must be resistant to photodegradation or chemistry, to absorption through the skin and to easy removal. For aesthetic reasons, the product should be substantially odorless (or be able to be perfumed) and should not stain the skin or clothing. Sunscreen agents, in order to diminish effectiveness, can be categorized as highly chromophoric monomeric organic compounds, inorganic compounds and minimally chromophoric polymeric organic solids. U.S. Patent No. 5,219,558 (Woodin, Jr. et al.) And U.S. Patent No. 4.91 9,934 (Deckner et al.) Describe photoprotection compositions, wherein the active sun blocking agents are the variety of monomeric chromophoric organic compounds. Examples characterize commercially common sunblocks, such as octyl methoxycinnamate (Parsol MCX), benzophenone-3 (Oxybenzone) and octyl dimethyl PABA. The normal prestige cosmetic blockers, are a product of Estee Lauder sold under the trademark "Resilience Lift Face and Throat Crème SPF 15" (Cream for face and neck of elasticity SPF 15). Octyl methoxycinnamate and titanium dioxide are active sunscreen agents formulated in a base which includes water, Polysilicone-1 1, cyclomethicone, emulsifiers and a variety of other minor ingredients. Much of this technology is reported in U.S. Patent 5,599,533 (Stepniewski et al.), Which focuses on water-in-oil emulsions containing organopolysiloxane elastomers.

Chromophoric monomeric organic compounds are subject to certain problems. One of the most important problems is skin irritation. These compounds, when present in the skin, must be resistant to removal by transpiration, skin oils or water. The formulations containing these materials therefore require additives to ensure the substantivity. Even with the best additives, friction and water resistance are never fully achieved. Therefore, it would be highly desirable to minimize the levels of such compounds in any sunscreen composition. The total replacement of chromophoric organic compounds, although desirable, is not currently feasible for high SPF compositions, which also require certain types of aesthetics. Inorganic particulate compounds, such as titanium dioxide, have been employed as sunblock agents. In fact, titanium dioxide is quite popular with traders who advertise them as "natural sun blockers". The problem with inorganic particulate compounds, is that high SPF values can only be achieved with high concentrations of these materials. Unfortunately, the aesthetic suffers at such high concentrations. The transparent formulas become opaque. High loads also tend to form visible white films on the skin, which consumers perceive negatively. Polymeric organic particulates are a final category of materials, which have found use in sunscreen formulations. U.S. Patent No. 5,008, 100 (Zecchino et al.) Reports oil-in-water emulsions containing polyethylene particles as a co-active sunscreen agent along with traditional chromophoric organic oceans. Similar to inorganic materials, polymer particles are limited in their effectiveness as sunblock. High amounts of such materials will have adverse effects on the aesthetics of the formula. FR-A-2 759 583 (L'Oreal) discloses sunscreen compositions that incorporate an organic sun blocking agent and an organopolysiloxane elastomer in an emulsion system. The emulsions can be either oil-in-water or water-in-oil systems. EP-A-0 61 0 01 5 (Dow Corning Corporation) reports cosmetic compositions of sunscreen containing a silicone pressure sensitive adhesive. These compositions have improved skin substantivity characteristics. Accordingly, an object of the present invention is to provide a sunscreen composition that maximizes the sun protection factor, but minimizes the level of monomeric chromophoric organic compound. Another object of the present invention is to provide a sunscreen composition in the form of an oil and water emulsion that exhibits improved aesthetics when applied to the skin. Yet another object of the present invention is to provide a sunscreen composition in the form of an oil and water emulsion which exhibits a good skin feel and maintains an adequate viscosity.

These and other objects of the present invention will be more readily apparent from the description and examples that follow.

BRIEF DESCRIPTION OF THE INVENTION A cosmetic sunscreen composition is provided, which includes: (i) from 0.1 to 40% by weight of an organic sunscreen agent with an active chromophoric group within the range of ultraviolet radiation from 290 to 400 nm; (ii) from 1 to 90% by weight of water; (iii) from 0.05 to 10% of a non-emulsifying, cross-linked siloxane elastomer; (iv) from 10 to 80% of a volatile siloxane; and wherein the composition is an oil-in-water emulsion.

DETAILED DESCRIPTION OF THE INVENTION It has now been found that properties of exceptional aesthetics (e.g., light skin feel), stability and rich viscosity (non-aqueous) are achieved by the combination of an organic sunblock, a non-emulsifying siloxane elastomer reticulated and a volatile siloxane. It is particularly important that the system be an oil-in-water emulsion instead of a water-in-oil type. A first essential element of the present invention is a sun blocking agent. The agent should have at least one chromophoric group that absorbs within the ultraviolet range somewhere from 290 to 400 nm. The chromophoric organic sunscreen agents can be divided into the following categories (with specific examples), which include: p-aminobenzoic acid, its salts and its derivatives (ethyl, isobutyl, glyceryl esters, p-dimethylaminobenzoic acid); anthranilates (o-aminobenzoates; methyl, menthyl, phenyl, benzyl, phenylethyl, linalyl, terpinyl and cyclohexenyl esters); salicylates (octyl, amyl, phenyl, benzyl, menthyl, glyceryl and dipropylene glycol esters); cinnamic acid derivatives (methyl and benzyl esters, alpha-phenyl cinnamonitrile, butyl cinnamoyl pyruvate); dihydroxycinnamic acid derivatives (umbelliferone, methylumberliferone, methylaceto-umbelliferone); trihydroxycinnamic acid derivatives (esculetin, methylesculetin, daphnetin and the glucosides, esculin and daphnin); hydrocarbons (diphenylbutadiene, stilbene); dibenzalacetone and benzalacetophenone; naphtholsulfonates (sodium salts of 2-naphthol-3,6-disulfonic acids and 2-naphthol-6,8-disulfonic acids); dihydroxy naphthoic acid and its salts; o- and p-hydroxydiphenyldisufonates; coumarin derivatives (7-hydroxy, 7-methyl, 3-phenyl); diazoles (2-acetyl-3-bromoindazole, phenyl benzoxazole, methyl naphthoxazole, various aryl benzothiazoles); quinine salts (bisulfate, sulfate, chloride, oleate and tannate); quinoline derivatives (salts of 8-hydroxyquinoline, 2-phenylquinoline); hydroxy-o-tnetoxy-substituted benzophenones; uric and viluric acids; tannic acid and its derivatives; hydroquinone; benzophenones (oxybenzone, sulisobenzone, dioxybenzone, benzoresorcinol, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, octabenzone, 4-isopropyldibenzoylmethane, butylmethoxydibenzoylmethane, ethacrylene and 4-isopropyl- dibenzoylmethane).

Particularly useful are 2-ethylhexyl p-methoxycinnamate, 4,4'-t-butyl methoxydibenzoylmethane, 2-hydroxy-4-methoxybenzophenone, octyldimethyl p-aminobenzoic acid, digaloyltrioleate, 2,2-dihydroxy-4-methoxybenzophenone, - [ethyl (bis (hydroxypropyl)] aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate, glycerol p-aminobenzoate, 3,3,5-trimethylcyclohexyl-salicylate, methylanthranilate, p-dimethylaminobenzoic acid or aminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2- (p-dimethylaminophenyl-5-sulfoniumbenzaxazoic acid, and mixtures thereof) Suitable commercially available organic sunscreen agents are those identified under the following table.

TABLE I The amounts of the aforementioned sunblock agents will generally vary from about 1 to about 4%, preferably from about 20 to about 38%, optimally from about 25 to about 35% by weight. The crosslinked non-emulsifying siloxane elastomers are a second essential element of this invention. They will have an average number average molecular weight in excess of 2,000, preferably in excess of 1,000,000 and optimally will vary from approximately 10,000 to approximately 20 million. The term "non-emulsifying" defines a siloxane from which the polyoxyalkylene units are absent. Advantageously, the elastomers are formed from a divinyl compound, particularly a polymer with at least two free vinyl groups, which react with Si-H bonds of a polysiloxane skeleton, such as a molecularly spherical MQ resin. The elastomer compositions are commercially available from General Electric Company under the product designation General Electric Silicone 1229 and SFE 839 under the proposed CTFA name of Cyclomethicone (Cyclomethicone) and Vinyl Dimethicone / Methicone Cross Polymer (cross-linked vinyl dimethicone / methicone polymer) , delivered as 20-35% and 5-1 0% respectively, in each elastomer product in a cyclomethicone carrier. A related elastomer composition under the CTFA name of Cyclopentasiloxane (Cyclopentasiloxane) and Polysilicone-1 1 are available as Gransil SR-CYC (7.0 +/- 2% elastomer in cyclomethicone) from Grant Industries, Inc., Elmwood Park, New Sweater. The commercial products of General Electric and Grant Industries ordinarily are processed additionally by subjecting them to a high pressure treatment (approximately 351.5 kg / cm2) in a Sonolator with recycling in 10 to 60 steps. The sonolation reaches a resulting fluid with average elastomer particle size ranging from about 0.01 to about 1 00 microns, preferably 1 to 30 microns. The viscosity of the resulting fluid is best when it ranges from about 300 to about 20,000 cps at 25 ° C, as measured by a Brookfield LV viscosimeter (size 4 bar, 60 rpm, 15 s). The amounts of the cross-linked non-emulsifying siloxane elastomer (without cyclomethicone carrier) should vary from about 0.01 to about 10%, preferably from about 0.1 to about 2%, optimally from about 0.5 to about 1% by weight of the composition sunscreen cosmetics. Although relatively high concentrations of elastomer provide improved skin feel properties, too high concentrations result in reduced viscosity of the formulated sunscreen composition. The aesthetically suitable viscosities of the sunscreen compositions formulated as measured in a Brookfield RVF viscometer (spindle No. 3, 10 rpm at 25 ° C) can vary from about 1,000 to about 200,000, preferably from about 1. 500 to about 30,000, optimally from about 2,000 to about 5,000 cps.

A third essential element of the present invention is that of a non-volatile siloxa. The term "volatile" refers to those materials that have a measurable pressure at ambient conditions. Volatile polyorganosiloxanes useful herein may be cyclic or linear. Preferred cyclic silicones include polydimethylsiloxanes containing from about 3 to about 9 silicon atoms, preferably containing from about 4 to about 5 silicon atoms, generally known as cyclomethicones. Preferred linear silicone oils include polydimethylsiloxanes containing from about 3 to about 9 silicon atoms. Linear volatile silicones generally have viscosities of less than about 5 centistokes at 25 ° C, while cyclic materials have viscosities of less than about 10 centistokes, the preferred range being from about 0.1 to about 8 centistokes. Examples of silicone oils useful in the present invention include: Dow Corning 244, Dow Corning 245, Dow Corning 344, Dow Corning 345 and Dow Corning 200 (manufactured by Dow Corning Corporation); Silicone 7207 and Silicone 7158 (manufactured by Union Carbide Corporation); SF 1 202 (manufactured by General Electric). The amounts of volatile siloxane will vary from about 10 to about 80%, preferably from about 20 to about 70%, optimally from about 30 to about 65% by weight. The compositions of the present inventions will contain water at levels ranging from about 1 to about 90%, preferably from about 10 to about 75%, more preferably from about 20 to about 50%, optimally from about 30 to about 45. % in weigh. The surfactants will be an additional component of the compositions according to the present invention. These may be selected from nonionic, anionic, cationic or amphoteric emulsifying agents. They may vary in amount anywhere from about 0.1 to about 20% by weight. Illustrative surfactants, especially those for oil-in-water emulsions, are cetyl phosphate, available under the trademark Amphisol A®, manufactured by Givaudan Corporation, which can be used in combination with silicone copolyols, such as Abil EM 94®, available of Goldschmidt Company. Other suitable surfactants include Brij 72® (steareth-2) in combination with Brij 72® (estearet-21) both from ICI Corporation. The compositions of the invention may optionally contain one or more skin conditioning agents. These agents can be selected from humectants, exfoliants or emollients. The humectants are polyhydric alcohols intended to moisturize, reduce scale and stimulate the removal of scale from the skin. Normal polyhydric alcohols include polyalkylene glycols and more preferably, alkylene polyols and their derivatives. Illustrative are propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, glycerin, ethoxylated glycerin, propoxylated glycerin and mixtures thereof. Most preferably, the humectant is glycerin. The amounts of humectant can vary anywhere from about 1 to about 50%, preferably from about 10 to about 40%, optimally from about 25 to 35% by weight. The exfoliants according to the present invention can be selected from alpha-hydrocarboxylic acids, beta-hydroxycarboxylic acids and salts of these acids. Most preferred are glycolic, lactic and salicylic acids and their alkali metal or ammonium salts. When the conditioning agent is an emollient, can be selected from hydrocarbons, fatty acids, fatty alcohols and esters. Petrolatum is the most preferred hydrocarbon type of emollient conditioning agent. Other hydrocarbons that may be employed include mineral oil, polyolefins, such as polydecene and paraffins, such as isohexadecane (for example, Permethyl 99® and Permethyl 101®). The fatty acids and alcohols will have from 10 to 30 carbon atoms. Illustrative of this category are pelargonic, lauric, myristic, palmic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and euricic alcohols and acids. The oil ester emollients may be those selected from one or more of the following classes: 1. Triglyceride esters, such as vegetable and animal fats and oils. Examples include castor oil, cocoa butter, safflower oil, cottonseed oil, corn oil, olive oil, cod liver oil, almond oil, avocado oil, palm oil, sesame oil, squalene, Kikui oil and soybean oil. 2. Acetoglyceride esters, such as acetylated monoglycerides. 3. Ethoxylated glycerides, such as ethoxylated glyceryl monostearate. 4. Alkyl esters of fatty acids having 10 to 20 carbon atoms. Methyl, isopropyl and butyl fatty acid esters are useful herein. Examples include hexyl laurate, isohexyl laurate, isohexyl palmitate, isopropyl palmitate, decyl oleate, isodecyl oleate, hexadecyl stearate, decyl stearate, isopropyl isostearate, diisopropyl adipate, diisohexyl adipate, dihexyldecyl adipate, diisopropyl sebacate, lauryl lactate, myristyl lactate and cetyl lactate. 5. Alkenyl esters of fatty acids having 1 0 to 20 carbon atoms. Examples thereof include oleyl myristate, oleyl stearate and oleyl oleate. 6. Ether esters, such as esters of fatty acids of ethoxylated fatty alcohols. 7. Esters of polyhydric alcohols. Esters of mono- and di-fatty acids of ethylene glycol, esters of mono- and di-fatty acids of diethylene glycol, esters of mono- and di-fatty acids of polyethylene glycol (200-6000), esters of mono- and di-fatty acids of propylene glycol, polypropylene glycol monooleate 2000, polypropylene glycol monostearate 2000, ethoxylated propylene glycol monostearate, esters of glyceryl mono- and di-fatty acids, polyglycerol polyglyceryl esters, ethoxylated glyceryl monostearate, 1,2-butylene glycol monostearate, distearate 1,2-butylene glycol, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters and polyoxylethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters. 8. Esters of waxes, such as beeswax, spermaceti, myristyl myristate, stearyl stearate. The amounts of the skin conditioning agent can vary from about 1 to about 50%, preferably from about 3 to about 25%, optimally from about 5 to about 20% by weight. The waterproofing agents may also be included in compositions of this invention. They may be present at levels from about 0.01 to about 10% by weight. Illustrative is the PVP / eicosene copolymer. Thickening agents may be employed, such as carbomers, CMC gums, xanthan gum and combinations thereof for compositions of this invention. Carbomers, such as Carbopol 1 382®, available from B. F. Goodrich Com pany are particularly preferred. These thickeners are crosslinked acrylic polymers. The amounts of thickener (base of solids without water) can vary from about 0.001 to about 5%, preferably from about 0.01 to about 1%, optimally 0.1 to about 0.5% by weight. Minor auxiliary ingredients may also be included, such as preservatives, fragrances, anti-foaming agents, opacifiers and dyes, each in their effective amounts to achieve their respective functions. The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise indicated.

EXAMPLES 1 -8 The following formulations are normal cosmetic compositions of sunscreen according to the present invention.

TABLE II EXAMPLE 9 This Example evaluates the effect of the type of emulsion and ratio of the percentage of elastomer to the viscosity of the final cosmetic product. Table 1 shows the base formulation for a water-in-oil emulsion according to the prior art. Table IV sets out the base formulation of an oil-in-water emulsion according to the present invention. The comparative viscosity results are listed in Table V.

TABLE III Water-in-oil emulsion TABLE IV Oil-in-water emulsion TABLE V Effective emulsion type and elastomer concentration ** Brookfield RVF Viscometer: W / O measured with spindle no. 3 at 10 rpm at 25 ° C. O / W measured with the TC spindle at 10 rpm at 25 ° C.

It is evident from Table V that the viscosities of the oil continuous phase emulsions resulted in substantially lower viscosities, poorer, than those achieved with the continuous water phase emulsions. In fact, the viscosity decreases as the amount of elastomer increases in water-in-oil emulsion compositions. The description and examples above illustrate selected embodiments of the present invention. In light of this, variations and modifications will be suggested for someone skilled in the art, all of which are within the spirit and scope of this invention.

Claims (8)

CLAIMING IS

1 . A sunscreen cosmetic composition comprising: (i) from 0.1 to 40% by weight of the composition of an organic sunscreen agent with an active chromophoric group within the range of ultraviolet radiation from 290 to 400 nm; (ii) from 1 to 90% by weight of the water composition; (iii) from 0.05 to 10% by weight of the composition of a cross-linked non-emulsifying siloxane elastomer, which is formed from a divinyl compound that reacts with Si-H bonds of a polysiloxane; (iv) from 10 to 80% by weight of the composition of a volatile siloxane, which is a cyclomethicone; and wherein the composition is an oil-in-water emulsion. The composition according to claim 1, further comprising from 1 to 50% by weight of the composition of a skin conditioning agent, selected from the group consisting of humectants, exfoliants, emollients and mixtures thereof. 3. The composition according to any preceding claim further comprising from 0.001 to 2% by weight of the composition of a cross-linked acrylic polymer. 4. The composition according to claim 3, wherein the polymer is a carbomer. 5. The composition according to any preceding claim, wherein the organic sunscreen is selected from the group consisting of benzophenone-3, homosalate, butylmethoxydibenzoylmethane, octyl methoxycinnamate, octyl salicylate and combinations thereof. The composition according to any preceding claim, wherein the organic sunscreen agent is at least one agent with total amount ranging from about 12 to about 20% by weight. The composition according to claim 6, comprising three organic sun blocking agents. The composition according to any preceding claim, wherein the elastomer is present in an amount from 0.1 to 2% by weight of the composition. SUMMARY A cosmetic sunscreen composition is provided, which includes at least one organic sunblock, a cross-linked non-emulsifying siloxane elastomer, a volatile siloxane, and water. The composition is an oil-in-water emulsion to provide a light, aesthetically pleasing skin feel, and rich viscosity, even in the presence of more than 25% sun-blocking oils.