MXPA01001096A - Sunscreen compositions - Google Patents

Abstract

The present invention relates to compositions suitable for use assunscreens which have improved storage stability and improved retention of UV absorbance capability. Methods of using the compositions are also disclosed. The compositions comprise an emulsion comprising a safe and effective amount of a UVA-absorbing dibenzoylmethane sunscreen active in one or more oil phases, a safe and effective amount of a formaldehyde donor preservative in one or more aqueous phases, and an emulsifier.

Description

SOLAR FILTER COMPOSITIONS FIELD OF THE TECHNIQUE The present invention relates to compositions suitable for use as sunscreens having an excellent storage stability so that their ultraviolet A absorbance and microbial preservation capacity are effvely conserved. The invention relates especially to emulsions containing an oil phase comprising a sunscreen active of dibenzoylmethane absorbing ultraviolet A and an aqueous phase comprising a formaldehyde donor preservative.

BACKGROUND OF THE INVENTION It is well known that exposure to sunlight can involve a series of risks to the skin. These damaging eff can result not only from sunbathing but also from exposure to sunlight associated with outdoor activities. The main short-term risk of prolonged exposure to sunlight is erythema, i.e. sunburn, which is a result of ultraviolet B radiation having a wavelength of about 290 nm in about 320 nm . However, in the long term, they can occur malignant changes on the surface of the skin. Numerous epidemiological studies show a strong relationship between exposure to sunlight and human skin cancer. Another long-term risk of ultraviolet radiation is premature aging of the skin, which is mainly caused by UVA radiation having a wavelength of about 320 nm to about 400 nm. This condition is characterized by the appearance of wrinkles and changes in the pigmentation of the skin, along with other physical changes such as the appearance of cracks, telangisis, ecchymosis and loss of elasticity. Adverse eff associated with exposure to ultraviolet radiation are discussed more extensively in DeSimone, "Sunscreen and Suntan Products," Handbook of Nonprescription Drugs, 7th Ed., Chapter 26, pgs. 499-511 (American Pharmaceutical Association, Washington, D.C., 1982); Grove and Forbes, "A Method for Evaluation of the Photoproton Action of Sunscreen Agents Against UV-A Radiation," International Journal of Cosmetic Science, 4, pgs. 15-24 (1982); and in the U.S. Patent. No. 4,387,089, DePoio, issued June 7, 1983. As a result of the aforementioned risks typically associated with exposure to sunlight, the general public interest in the market for sunscreen products has grown considerably. In today's commercial market, not only are there sunscreen products for sunbathing but there are also a variety of personal care products that contain sunscreen, particularly cosmetic products that * & amp; &j are used daily. "Personal care products" refer to general health and beauty auxiliary products recognized as formulated to beautify and fix the skin and hair. For example, personal care products include sunscreen products (for example, lotions, 5 skin creams, etc.), cosmetics, toiletries, and pharmaceutical products that do not require a prescription made for topical use. A wide variety of sunscreen assets have been used in personal care products. It is advisable that the active sunscreen or active system provide a broad spum of ultraviolet proton, that is, proton against UVA radiation and UVB radiation. It is even more convenient that sunscreen assets be formulated to provide stable, effve and aesthetically attractive sunscreen products. In addition, for economic reasons it is convenient that the sunscreen assets are approved for widespread use. The dibenzoylmethane compounds are a class 15 of sunscreen compounds that provide a broad spum of ultraviolet proton and are authorized for widespread use. In personal care products, sunscreen assets are often formulated with water, since the resulting systems tend to be more aesthetically appealing to the user. However, the presence of water promotes the growth of microorganisms that can cause the deterioration of the sunscreen product. This deterioration can inconveniently alter a product, making it physically or chemically unsightly or reducing the useful life of the product. In some cases, these j ^ ji _ ^^ ^ [^? i ßÉÍBL - S! l ^^ - z ^ - go ¡¡¡¡-fet ta ^^^^. ___w. t¿AgwJ_ ^ ^ __ * ___. »« ___ * deteriorated sunscreen products may even be harmful to humans. Thus, sunscreen products are generally designed in an effort to minimize the deterioration of the desired storage duration of the product. Typically, antimicrobial preservatives are included in aqueous sunscreen products to prolong their shelf life during storage and use and to preserve product efficacy (ie, ultraviolet ray absorbency). Antimicrobial preservatives should not irritate the skin, they should be effective against microorganisms that are typically found in aqueous sunscreen products which pose a great risk to consumers, and / or which usually cause instability of the sunscreen product (it is to say, chemical collateral reactions and consequently the inefficiency of the product), must be profitable, and formulated easily. A wide variety of antimicrobial preservatives are commonly used in personal care products, including parabens, isothizolinones, formaldehyde-donor preservers such as hydantoins, alcohols, and others such as those described in Preservatives Documentary / Encyclopedia issue of Cosmet. & Toilet., Vol. 102, No. 12 (1987). However, the formulation of aqueous systems containing dibenzoylmethane sunscreen actives is not simple. In particular, it is known that conservative formaldehyde donors interact with dibenzoylmethanes. Although not intended to be limited in theory, it is believed that an aldol reaction product is formed when the dibenzoylmethanes are combine with conservative formaldehyde donors. Over time, this reaction tends to result in low storage stability, i.e., increased microbial growth in the product and / or loss of ultraviolet absorbency of the dibenzoylmethane sunscreen. Surprisingly it has been found that compositions that include an emulsion having at least one oil phase comprising a dibenzoylmethane sunscreen active and at least one aqueous phase comprising a formaldehyde donor conservative exhibit excellent storage stability and retention of ultraviolet * absorbance capacity. The growth of microorganisms in the product and also the deterioration of the product are avoided, inhibited or delayed effectively in such a way that the duration of the product is extended. It has also been found that these compositions provide a means for distributing the dibenzoylmethane sunscreen active in the skin in a non-irritating manner.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a composition suitable for use as a sunscreen comprising an emulsion containing a) at least one oil phase comprising an effective and safe amount of a dibenzoylmethane sunscreen active absorbing UVA. b) __jK __? __ a ___! _ * ___ at least one aqueous phase comprising water and a safe and effective amount of a formaldehyde donor preservative, and c) an emulsifier. In another embodiment, the present invention relates to a composition suitable for use as a sunscreen comprising an emulsion prepared with the method consisting of: a) combining an oil and a sunscreen active of UVA-absorbing dibenzoylmethane to form a oily mixture; b) separately combine water and a formaldehyde preservative to form an aqueous mixture; and c) combining the oil mixture, aqueous mixture and an emulsifier to form an emulsion; wherein the composition comprises a safe and effective amount of UVA absorbing dibenzoylmethane sunscreen active and a safe and effective amount of the formaldehyde donor preservative. The invention also relates to methods for using the compositions as a sunscreen.

DETAILED DESCRIPTION OF THE INVENTION The compositions of the present invention are suitable as sunscreens and have excellent storage stability and retention of their ultraviolet absorbance capacity. The essential components of these compositions are described below.

Also included is a non-exclusive description of several optional and preferred components useful in the embodiments of the present invention. The present invention may comprise, contain, or contain essentially any of the required or optional ingredients and / or limitations described herein. The present compositions may comprise, contain or contain essentially the emulsion described herein. All percentages and ratios are calculated on a weight basis unless indicated otherwise. All percentages are calculated based on the total composition unless otherwise indicated. All molar weights are average molecular weights in weight and are given in units of grams per mole. All ingredient levels do not include solvents, by-products or other impurities that may be present in commercially available sources, unless otherwise specified. All measurements are made at room temperature, which is approximately 22.7 ° C unless otherwise specified. All documents referenced herein, including patents, patent applications and printed publications, are included herein in their entirety, by way of reference, in this explanation.

".JuBMÜfeS - The phrase" safe and effective amount "refers to an amount of a compound, component or composition (as applied) sufficient to induce a positive effect (eg, photo-protection), but low enough to avoid serious collateral effects (for example, undue toxicity or allergic reaction), that is, provide a reasonable ratio of benefit and risk within the field of sound medical judgment.

Emulsion The compositions of the present invention comprise an emulsion having at least one oil phase comprising an oil and a UVA absorbing dibenzoylmethane sunscreen active, at least one aqueous phase comprising water and a formaldehyde donor preservative. , and one or more emulsifiers. The emulsion typically comprises from about 1% to about 75% total oil phase and from about 25% to about 99% total aqueous phase. In emulsion technology, the term "dispersed phase" means that the phase exists as small particles or droplets that are suspended in, and surrounded by, a continuous phase. In the compositions of the invention, an oil phase may be dispersed in a continuous water phase or the water phase may be dispersed in a continuous oil phase. Preferred compositions herein comprise an oil phase dispersed in a continuous water phase. The emulsions of those present -. > . < j.

Compositions can be formulated in a variety of forms, including but not limited to, oil in water, water in oil, water in oil in water, and oil in water in silicone emulsions. The preferred emulsions are oil in water. The emulsions can have a wide scale of 5 viscosities, for example, from about 1 cps to about 1,000,000 cps. The oil phase comprises one or more oils and the oil-soluble components of the present composition, including at least one dibenzoylmethane sunscreen active. The emulsions typically comprise from about 0.1% to about 50% oil. Suitable oils can be derived from animals, plants or oil and can be natural or synthetic (ie made by man). Preferred oils are substantially insoluble in water, very Preferably essentially insoluble in water. Suitable oils include, but are not limited to, mineral oil; petrolatum; straight and branched chain hydrocarbons having from about 7 to about 40 carbon atoms; esters of alcohol of C? -C3Q of carboxylic acids of C1-C30 and dicarboxylic acids of C2-C30, mono-, di- and triglycerides of C 1 -C 30 carboxylic acids, alkylene glycol esters of C 1 -C 30 carboxylic acids; propoxylated and ethoxylated derivatives of the aforementioned materials; C3o mono and polyesters of sugars and related materials; fatty alcohols, ethers, oils ^ 1 ^^^ gj ^^^^ g ^^^ gj ^^^^^^^ ____ ^ _____ i ^ ii _______________ ^ ______ ^^^^ g ^ ^ gg ^^^^^^^^^? ^^^ w ^ organopolysiloxane, vegetable oils and hydrogenated vegetable oils; animal fats and oils or their mixtures. Some examples of suitable oils are described in the patent of E.U.A. No. 2,831, 854, the US patent. No. 4,005,196 to Jandacek, granted on January 25, 1977; Patent 5 of E.U.A. No. 4,005,195, to Jandecek, granted on January 25, 1997, the patent of E.U.A. No. 5,306,516, to Letton et al., Granted on April 26, 1994; the patent of E.U.A. No. 5,306,515, to Letton et al., Granted on April 26, 1994; the patent of E.U.A. No. 5,305,514, to Letton et al., Granted on April 26, 1994; U.S. Patent No. 4,797,300 to Jandacek et al. granted on January 10, 1989; the patent of E.U.A. No. 3,963,699, to Rizzí et al., Granted on June 15, 1976; the patent of E.U.A. No. 4,518,772, to Volpenhein, issued May 21, 1985; and the patent of E.U.A. No. 4,517,360, to Volpenhein, issued May 21, 1985; and the patent of E.U.A. No. 5,069,897, to Orr, issued on December 3, 1991, The Oils Preferred include C? 2-15 alkylbenzoate, cetyl palmitate, isodecyl neopentanoate, isononyl isonanoate, isopropyl myristate, isopropyl palmitate, sos sostearteartear í í í í í í í colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol colesterol oct oct oct, octyldocanol, octyldodecanol, butyl ether PPG-14, stearyl ether PPG-11, hydrogenated polyisobutene, isoeicosane, isohexadecane, polydecene, cetyldimethicone, cyclomethicone, dimethicone, copolyol dimethicone, dimethiconol, phenyltrimethicone, and lanolin. The dibenzoylmethane sunscreen active provides protection against ultraviolet radiation of wavelengths between approximately 320 nm at approximately 400 nm (ie, the asset provides protection against UVA and UVB). Some examples of said dibenzoylmethane sunscreen actives are described in the U.S.A. No. 4,489,057, granted to Welters et al., On December 18, 1984; the patent of E.U.A. No. 4,387,089, granted to Depolo on June 7, 1983; and in Sunscreens. Developmente, Evaluation, and Regulatory Aspects, edited by N.J. Lowe and N.A: Shaath, Marcel Dekker, Inc. (1990). Suitable dibenzoylmethane sunscreen actives include, but are not limited to, those selected from the group consisting of 2-methyldibenzoylmethane, 4-methyldibenzoylmethane, 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane, 2,5-dimethylbenzoylmethane, 4,4'-diisorpoylbenzoylmethane, 4- (1,1-dimethylethyl) -4'-methoxydibenzoylmethane, 2-methyl-5-isopropyl-4'-methoxybenzoylmethane, 2-methyl-5-tert-butyl- 4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane, 2,6-dimethyl-4'-tert-butyl-4-4'-methoxy-dibenzoylmethane, and mixtures thereof. The preferred dibenzoylmethane sunscreen actives include those selected from the group consisting of 4- (1,1-dimethylethyl) -4'-methoxydibenzoylmethane, sopropyldibenzoylmethane, and mixtures thereof. 4- (1,1-dimethylethyl) -4'-methoxydibenzoylmethane is very preferred. Sunscreen active 4- (1,1-dimethylethyl) -4'methoxydibenzoyl-methane, which is also known as methoxydibenzoylmethane or avobenzone, is commercially available under the name Parsol® 1789 from Givaudan.-roure (International) S.A. (Basel, Switzerland) and Eusolex® 9020 from Merck & Co., Inc. (Whitehouse Station, NJ). The sunscreen 4-isopropyldibenzoylmethane, which is also known as isopropidibenzoylmethane, is commercially available from Merck under the name of Eurolex® 8020. The sunscreen active of dibenzoylmethane is present in a safe and effective amount to provide a broad spectrum of ultraviolet protection either independently or in combination with other UV protective assets that may be present in the composition, preferably in a total amount of from about 0.1%, to about 10%, most preferably from about 0.2% to about 7%, and most preferably from about 0.4% to about 5%. The exact amounts of the dibenzoylmethane sunscreen active can vary depending on the desired sun protection factor, ie the "FPS" of the composition and the desired level of protection against UVA. (SPF is a commonly used photoprotection measure of a sunscreen against erythema.) SPF is defined as the ratio of ultraviolet energy needed to produce minimal erythema on protected skin and that needed to produce the same minimum skin erythema. not protected in the same individual, see Federal Register, 43, No. 166, pp. 38206-38269, August 25, 1978). The dibenzoylmethane sunscreen active is substantially in at least one oil phase; for example, at least about 50%, preferably at least about 75% of the dibenzoylmethane sunscreen active is in one or more oil phases.

The aqueous phase comprises water and the water-soluble components of the present composition, including one or more formaldehyde donor preservers. Typically, the emulsion comprises about 20% about 98% in water. 5 The formaldehyde donor preserver is an antimicrobial preservative, that is, a compound or substance that kills microorganisms or prevents, inhibits or retards its growth and reproduction. For purposes of the present invention formaldehyde donor preservatives include the same formaldehyde and any other preservative antimicrobial that forms or releases formaldehyde in a composition. Preferred preservatives are formed by linking formaldehyde to a heterocyclic organic compound of which the formaldehyde is then released slowly over time. Formaldehyde donor preservers are described in U.S. Patent No. 5,681,852. granted to Bessett on October 28, 1997 and patent of E.U.A. No. 5,037,843. granted to Schoenberg on August 6, 1991. Some preferred formaldehyde donor preservers are DMDM hydantoin (1,3-dimethylol-5,5-dimethylhydantoin), DM hydantoin (5,5-dimethylhydantoin), and mixtures thereof. The DMDM hydantoin and -DM are commercially available from Lonza, Inc. (Basel, Switzerland) under the names Glydant and Dantoin DMH, respectively, the DMDM hydantoin is highly preferred.

The formaldehyde preservative is used in a safe and effective antimicrobial amount, preferably from about 0.01% to about 1%, most preferably from about 0.02% to about 0.5%, and most preferably from about 0.05% to about 0.3% by weight of the composition. The formaldehyde donor preserver is substantially in at least one aqueous phase; for example, at least about 50%, preferably at least about 75% of the preservative is present in one or more aqueous phases. One or more emulsifiers are used in an amount effective to stabilize the emulsion. Some suitable emulsifiers include a wide variety of nonionic, cationic, anionic, and zwitterionic emulsifiers. See McCutcheon's, Detergents and Emulsifiers, North American Edition (1986), published by Allured Publishing Corporation; patent of E.U.A. No. 5,011,681 issued to Ciotti et al. On April 30, 1991; patent of E.U.A. No. 4,421, 769 granted to Dixon et al. On December 20, 1983; and patent of E.U.A. No. 3,755,560 issued to Dickert et al. On August 28, 1973. Suitable types of emulsifiers include, but are not limit to glycerin esters, propylene glycol esters, polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, sorbitol esters, esters of sorbitan anhydrides, with carboxylic acid polymers, glucose esters and ethers, ethoxylated ethers, alcohols ethoxylates, alkyl phosphates, polyoxyethylene fatty ether phosphates, fatty acid amides, acylactylates, soaps and mixtures thereof. Suitable emulsifiers include, but are not limited to, TEA stearate, olet-3 phosphate DEA, polyethylene glycol monolaturate 5 20 sorbitan (polysorbate 20), polyethylene glycol 5 soy sterol, steareth-2, steareth-20, steareth- 21, ceteareth-20, ether methylgluous PPG-2 disterate, ceteth-10, polysorbate 80, cetyl phosphate, potassium cetyl phosphate, diethanolamine cetylphosphate, polysorbate 60, glyceryl stearate, PEG-100 stearate, and mixtures thereof. Preferred emulsifiers are steareth-2, steareth-21, stearate TEA, diethylamine cetyl phosphate, potassium cetyl phosphate, and mixtures thereof. The emulsifier may be used individually or as a mixture of two or more and may comprise from about 0.1% to about 10%, most preferably from about 0.15% to about 7%, and most preferably from about 0.25% to about % of the compositions of the present invention. The emulsions and compositions of the present invention can be formulated in a wide variety of product types, including creams, lotions, milks, sticks, mousses, gels, tonic oils and aerosols. The preferred compositions are "formulated as lotions," "creams, gels and aerosols. These product forms can be used for a variety of applications, including, but not limited to, hand and body lotions, cleansing creams, facial softeners, anti-acne preparations, topical analgesics, make-up including foundation foundations and pencils. lips, and the like. Any additional component that is required to formulate said products may vary depending on the type of product and may be routinely chosen by one skilled in the art. If the emulsions or compositions of the present invention are formulated as an aerosol and applied to the skin as an aerosol application product, a propellant is preferably added to the composition. Some examples of suitable propellants include chlorofluorinated hydrocarbons of low molecular weight. A more complete, non-limiting explanation of propellants useful herein can be found in Sagarin, Cosmetics Science and Technology, 2nd Edition, Vol. 2. p. 443-465 (1972).

Optional components The compositions of the present invention may contain a variety of other ingredients as conventionally used in a given type of product as long as they do not unacceptably alter the benefits of the invention. These optional components must be suitable for application to human skin, ie, when incorporated into the composition, they are suitable for use in contact with human skin without undue toxicity, incompatibility, instability, allergic response, and the like, within the scope of the invention. judgment of the manufacturer or competent doctor. The CTFA Cosmetic Ingredient Handbook, Second Edition (1992) describes a wide variety of non-limiting cosmetic and pharmaceutical ingredients commonly used in the skin care industry, which ^ .J __ ^^ ___ ^ __. they are suitable for use in the compositions of the present invention. Some examples of these kinds of ingredients are: abrasive, absorbent and aesthetic components such as fragrances, pigments, colorations / dyes, essential oils, skin sensitizers, astringents, etc. (for example, clove oil, menthol, camphor, eucalyptus oil, eugenol, methyl lactate, Hamamelis virginiana distillate), anti-acne agents (eg resorcinol, sulfur, salicylic acid, erythromycin, zinc, etc.), cake antiforming agents, antifoaming agents, additional antimicrobial agents (for example iodopropyl carbylcarbamate), antioxidants, binders, biological additives, pH regulating agents, body-forming agents, chelating agents, chemical additives, dyes, cosmetic astringents, cosmetic biocides, denaturants, therapeutic astringents, external analgesics, film formers or materials, for example, polymers, to assist the film-forming and substantive properties of the composition (e.g. with eicosene and vinylpyrrolidone polymer), humectants, opacifiers, adjusters pH, propellants, reducing agents, sequestrants, skin whitening agents (or age luminance agents) (eg, hydroquinone, kojic acid, ascorbic acid, magnesium ascorbyl phosphate, ascorbylglucosamine), skin conditioning agents (humectants, including heterogeneous and occlusive), skin relaxing and / or healing agents (e.g. panthenol and its derivatives) (for example ethylpantenol), aloe vera, pantothemic acid and its derivatives, allantoin, bisabolol, and glycyrrhizinate ^^ s1 ^^ * ^^^ í $ g & £ * ^ gjj ^ de dipotasio), agents for the treatment of the skin, including agents to prevent, slow, stop and / or reverse wrinkles in the skin (alphahydroxy acids such as lactic acid and glycolic acid and betahydroxy acids as salicylic acid) , thickeners, and vitamins and their derivatives (tocopherol, tocopherol acetate, beta carotene, retinoic acid, retinol, retinoids, retinylpalmitate, niacin, niacinamide, and the like). The compositions may contain carrier components as are known in the art. Such carriers may include one or more compatible solid liquids or solid filler diluents or carriers that are suitable for use in human skin. The compositions may contain one or more of said optional components. Preferred compositions optionally contain one or more materials selected from the UVB sunscreen assets, active anti-acne, artificial tanning agents, moisturizers, moisturizers, skin conditioners, and thickening / structuring agents. a) UVB sunscreen active agents Preferred compositions of the present invention optionally comprise a UVB sunscreen active, which absorbs ultraviolet radiation having a wavelength of about 290 nm to about 320 nm. As used herein, an optional UVB sunscreen asset means an active different from the dibenzoylmethane sunscreen active, which may itself possess properties of £ »2 £ b * sr UVB absorption. Said compositions comprise an effective amount of the UVB active to provide protection against UVB radiation independently or in combination with other ultraviolet protective actives that may be present in the compositions, preferably from about 0.5% to about 20% of a sunscreen active of UVB. The exact amounts of UVB sunscreen active can vary depending on the chosen sunscreen and the desired SPF of the product. A wide variety of UVB sunscreen assets are useful for this. Some non-limiting examples of these sunscreen assets are described in the U.S. patent. No. 5,087,445, to Haffey et al., Issued February 11, 1992; and patent of E.U.A. Nos. 5,073,371 and 5,073,372, to Turner et al., Issued Dec. 17, 1991. Preferred UVB sunscreen assets are selected from the group consisting of octyl methoxycinnamate, octocrylene, camphor 4-methylbenzylidene, 2-phenylbenzimidazole-5-sulfonic acid , octyl salicylate, zinc oxide, titanium dioxide, iron oxide, and mixtures thereof. Preferred UVB sunscreen actives are selected from the group consisting of octyl methoxycinnamate, octocrylene, 2-phenyl-benzimidazole-5-sulfonic acid, zinc oxide and mixtures thereof. "Neutralized salt and acid forms of acidic sunscreens are also useful herein.

Anti-acne active The compositions of the present invention may comprise one or more anti-acne active. Some examples of useful anti-acne actives are described in more detail in the U.S. patent. No. 5,607,980 granted to McAtee et al. On March 4, 1997. c) Artificial tanning agents The compositions of the present invention may optionally comprise one or more artificial tanning agents. Suitable tanning agents include dihydroxyacetone, tyrosine and tyrosine esters. See The Merck Index, Tenth Edition, entry 3167, p. 463 (1983), and "Dihidroxiacetone for Cosmetics", E. Merck Technical Bulletin, 03-304 110, 319 897, 180 588. d) Structuring agent The compositions of the present invention may contain a structuring agent. Structurants are particularly preferred in the oil-in-water emulsions of the present invention. Without being limited by theory, it is believed that the structuring agent helps to provide the rheological characteristics to the composition that contribute to the stability of the composition. For example, the structuring agent tends to assist in the formation of liquid crystalline gel network structures. The structuring agent can also function as an emulsifier or surfactant. Preferred compositions of this invention comprise from about 0.5% to about 20%, most preferably from about 1% to about 10%, most preferably from about 1% to about 5% of one or more structuring agents. The preferred structuring agents of the present invention are selected from the group consisting of stearic acid, palmitic acid, stearyl alcohol, cetyl alcohol, behenyl alcohol, stearic acid, palmitic acid, the polyethylene glycol ether of stearyl alcohol having an average of about 1 to about 21. ethylene oxide units, the polyethylene glycol ether of the cetyl alcohol having an average of about 1 to about 5 ethylene oxide units and mixtures thereof. Preferred structuring agents of the present invention are selected from the group consisting of stearyl alcohol, cetyl alcohol, behenyl alcohol, the polyethylene glycol ether of stearyl alcohol having a percentage of about two units of ethylene oxide (steareth-2), the polyethylene glycol ether of stearyl alcohol having an average of about 21 units of ethylene oxide (steareth- 21), the polyethylene glycol ether of cetyl alcohol having an average of about 2 ethylene oxide units and mixtures thereof. Even more preferred structuring agents are selected from the group consisting of stearic acid, palmitic acid, stearyl alcohol, cetyl alcohol, behenyl alcohol, steareth-2, steareth-21, and mixtures thereof. ^ g ^^^ y¡aa '- •', - ^ Aih & e) Thickening agent (including gelling agent thickeners) The compositions of the present invention may comprise one or more thickening agents, preferably from about 0.1% to about 5%, most preferably from about 0.1% to about 3% and most preferably from about 0.25% to about 2% by weight of the composition. The non-limiting classes of thickening agents include those selected from the group consisting of: (i) Carboxylic acid polymers These polymers are crosslinked compounds containing one or more monomers derived from acrylic acid, substituted acrylic acids, and salts and esters of these acids acrylics and acrylic acids substituted, in which the interlacing agent contains two or more carbon-carbon double bonds and is derived from a polyhydric alcohol. The polymers useful in the present invention are described in more detail in the U.S.A. No. 5,087,445 to Haffey et al., Granted on February 11, 1992, patent of E.U.A. No. 4,509,949, to Huang et al., Granted on April 5, 1985; patent of E.U.A. No. 2,798,053, to Brown granted on July 2, 1957; and CTFA International Cosmetic Ingredient Dictionary, Fourth edition 1991, p. 12 and 80. ¡^^^^^^^^^^^ g faith | ! Some examples of commercially available carboxylic acid polymers useful herein include carbomers, which are homopolymers of acrylic acid crosslinked with allyl ethers of sucrose or pentaerythritol. The carbomers are available as the Carbopol® 900 series from B.F. Goodrich (eg Carbopol® 954). In addition, other polymeric carboxylic acid agents include copolymers of C- or C-30 alkyl acrylates with one or more monomers of acrylic acid, methacrylic acid or one of their short chain esters (ie C alcohol alcohol), in which the entangled agent is an allyl ether of sucrose or pentaerythritol. These copolymers are known as three-dimensional acrylates / polymers of C-? O-30 alkyl acrylate and are commercially available as Carbopol® 1342, Carbopol® 1382, Pemulen TR-1, and Pemulen TR-2, from B.F. Goodrich. In other words, some examples of carboxylic acid polymers thickeners useful herein are those selected from the group consisting of carbons, acrylates / polymers of three dimensions of C 10 -C 30 alkyl acrylate, and mixtures thereof. (ii) Interlaced polyacrylate polymers The compositions of the present invention may optionally comprise entangled polyacrylate polymers useful as thickeners or gelling agents including cationic and nonionic polymers, with cationics generally being preferred. Some examples of interlaced nonionic polyacrylate polymers and cationic polyacrylate polymers interlacing are described in the US patent. No. 5,100,660 to Hawe et al., Granted on March 31, 1992; patent of E.U.A. No. 4,849,484, to Heard, granted on July 18, 1989; patent of E.U.A. No. 4,835,206 to Farrar et al., Issued May 30, 1989, U.S. Patent No. 5 4,628,078 to Glover and others granted December 9, 1986, U.S. Patent. No. 4,599,379 to Flesher et al., Granted on July 8, 1989; and EP 228,868, to Farrar et al. published July 15, 1987. (iii) Polyacrylamide polymers. The compositions of the present invention may optionally comprise polyacrylamide polymers, especially nonionic polyacrylamide polymers including the substituted branched or unbranched polymers. Most preferred among these polyacrylamide polymers is the non-ionic polymer which is given the designation CTFA polyacrylamide and isoparacin and laureth-7, available under the trade name Sepigel 305 from Seppic Corporation (Fairfield, NJ). Other polyacrylamide polymers useful herein include multiple block copolymers of acrylamides and substituted acrylamides with acrylic acids and substituted acrylic acids. Some examples Commercially available from these copolymers. of multiple blocks include Hypan SR150H, SS500V, SS500W, SSSA100H, from lipo Chemicals, Inc., (Patterson, NJ).

(V) polysaccharides. A wide variety of polysaccharides are useful herein. "Polysaccharides" refers to gelling agents that contain a column of repeating sugar units (ie, carbohydrate). Some non-limiting examples of polysaccharide gelling agents include those selected from the group consisting of cellulose, carboxymethylhydroxyethylcellulose, cellulose acetate propionate carboxylate, hydroxyethylcellulose, hydroxyethylethylcellulose, hydroxypropylmethylcellulose, methylhydroxyethylcellulose, microcrystalline cellulose, sodium cellulose sulfate and mixtures thereof. As well In this case, the alkylsubstituted celluloses are useful. In these polymers, the hydroxy groups of the cellulose polymers are hydroxyalkyl (preferably hydroxyethylated or hydroxypropyl) to form a hydroxyalkylated cellulose which is then modified with a straight chain of C ?0-C30 or branched chain alkyl group via a linkage of ether.

Typically these polymers are ethers of straight or branched chain alcohols of C? O-C30 with hydroxyalkyl celluloses. Some examples of alkyl groups useful herein include those selected from the group consisting of stearyl, isostearyl, lauryl, myristyl, cetyl, acetyl, cocoyl (i.e., alkyl groups derived from coconut oil alcohols), palmityl, oleyl, linoleyl, linolenyl, resinoleyl, behenyl and their mixtures. Preferred among the alkylhydroxyalkylcellulose ethers is the material which is given the CTFA designation cetylhydroxyethylcellulose, which is the ether of cetyl alcohol and -_ ^ .__ "» _ «____- 3 * *, j? Fa? ^^ hydroxyethylcellulose. This material is sold under the trade name Natrosol ® CS Plus from Aqualon Corporation (Wilmington, DE). Other useful polysaccharides include scleroglucans comprising a linear chain of linked glucose units (1-3) with a linked glucose (1-6) every three units, of which a commercially available example is Clearogel ™ CS11 from Michel Mercier Products lnc. (Mountainside, NJ). (v) Gums Other gelling agents and thickeners useful herein include materials that are derived primarily from natural sources. Some non-limiting examples of these gelling agent gums include materials selected from the group consisting of gum arabic, agar, algin, algimic acid, ammonium alcinate, almylopectin, calcium alginate, calcium carrageenan, carnitine, carrageenan detrin, gelatin, gelatin gum , guar gum, hydroxypropyltrimonium chloride, extorite, hyaluronic acid, hydrated silica, hydroxypropylchitosan, hydroxypropylguar, karaya gum, Kelp locust bean gum, natto gum, potassium alginate, potassium carragaenin, propylene glycol alginate, sclerotium gum, carboixmethyldextran sodium, carrageenan sodium, tragacant gum, xanthan gum, and their mixtures. Preferred compositions of the present invention include a thickening agent selected from the group consisting of acid polymers .,. J * X ~ ^ *. -,, ._- .. w- _tt? Rr * - '-' ~ * A * "* -" carboxylic, crosslinked polyacrylate polymers, polyacrylamide polymers and their mixtures most preferably selected from the group consisting of acid polymers carboxylic, polyacrylamide polymers and their mixtures. f) Moisturizers, Moisturizers and Skin Conditioners Preferred compositions optionally comprise one or more moisturizers, moisturizers or skin conditioners. A variety of these materials may be employed and each may be present at a level of from about 0.01% to about 20%, most preferably from about 0.1% to about 10%, and most preferably from about 0.5% to about 7%. These materials include, but are not limited to, guanidine; glycolic acid and glycolate salts (eg, ammonium and quaternary alkylammonium); lactic acid and lactate salts (eg, ammonium and quaternary alkylammonium); aloe vera in any of its various forms (eg, aloe vera gel); polyhydroxyalcohols such as sorbitol, glycerol, hexanetriol, propylene glycol, butylene glycol, hexylene glycol and the like; polyethylene glycols; sugars and starches; sugar and starch derivatives (eg, alkoxylated glucose); hyaluronic acid; lactate monoethanolamine; and its mixtures. Also useful herein are the propoxylated glycerols described in the U.S.A. No. 4,976,853, to Orr et al., Issued December 11, 1990. Also useful are mono-esters and C1-C30 polyesters of sugars and related materials. These esters are derived from a portion of sugar or polyol and one or more portions of carboxylic acid. These ester materials are described in the US patent: A. No. 2,831, 854, E: U: A: No. 4,005,196, to Jandacek, issued January 25, 1977, in the US patent. No. 5,306,516 to Letton et al., Granted on April 26, 1994; the patent of E.U.A. No. 5,306,515, to Letton et al., Granted on April 26, 1994; the patent of E.U.A. No. 5,305,514 to Letton et al., Granted on April 26, 1994; the patent of E.U.A. No. 4,797,300 to Jandacek et al., Granted on January 10, 1989; U.S. Patent No. 3,963,699, to Rizzi et al., issued June 15, 1976; the patent of E.U.A. No. 4,518,772, to Volpenhein, issued May 21, 1985; the patent of E.U.A. 4,517,360 to Volpenhein, granted on May 21, 1985.

Methods for protecting the skin from ultraviolet radiation The compositions of the present invention are suitable for use as a sunscreen to provide protection to human skin against the damaging effects of ultraviolet radiation including, but not limited to, sunburn and premature aging of the skin. The present invention thus also relates to methods for protecting human skin against the damaging effects of ultraviolet radiation, including attenuating or reducing the amount of ultraviolet radiation that comes into contact with the surface of the skin. To protect the skin, a safe and effective (photoprotective) amount of the composition is applied topically to the skin. "Topical application" refers to the application of the present compositions by spreading, spraying, etc. on the surface of the skin. The exact amount applied may vary depending on the desired level of UV protection. Typically they are applied from about 0.5 mg of composition per cm2 of skin to about 25 mg of composition per cm2 of skin.

EXAMPLES The following examples better describe and show modalities within the field of the present invention. The examples are given solely for purposes of illustration and are not intended to limit the present invention, since many variations thereof are possible without departing from the essence and scope of the invention. The following sunscreen products are representative of the present invention. trade and lydant Plus . j gff SitBMr ^^^^^ H ^ Mix the components of premix 1 in a suitable container. In addition, combine the following Steareth-2, Steareth-21 premix components in a suitable container: C? 2-15 cetyl alcohol, stearyl alcohol, behenyl alcohol, benzoate of C12-15 alcohols, 5 octocrylene and avobenzone. Heat both premixtures separately at about 75 ° C by mixing. Slowly add premix 3 to premix 1 while stirring. Cool to about 60 ° C and then add the Sepigel 305. Continue to grind until the mixture reaches 55 ° C and then cool further mixing. Mix the components 10 of premix 2 and heat to 45 ° C. Once the main batch is cooled to 45 ° C, add premix 2 and continue cooling while mixing. Further cool the batch mixture to approximately 30 ° C by shaking and emptying in suitable storage containers.

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Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. A composition suitable for use as a sunscreen characterized in that the composition comprises an emulsion comprising: a) at least one oil phase comprising an oil and a dibenzoylmethane sunscreen active absorbing UVA; b) at least one aqueous phase comprising water and a donor preservative 10 formaldehyde; and c) an emulsifier; characterized in that the composition comprises, based on the weight of the composition, a safe and effective amount of UVA-absorbing dibenzoylmethane sunscreen and a safe and effective amount of a formaldehyde donor preservative.

2. The composition according to claim 1, 15 further characterized in that the composition comprises, by weight of the composition, from 0.2% to 7% of the dibenzoylmethane sunscreen active and from 0.02% to 0.5% of the formaldehyde donor preservative.

3. The composition according to any of the preceding claims, further characterized in that the composition 20 comprises, by weight of the composition, 0.4% to 5% of the dibenzoylmethane sunscreen active and 0.05% to 0.3% of the formaldehyde donor preservative.

^^^^^^^^^^^^^^^^^^^ 4. The composition according to any of the preceding claims, further characterized in that the dibenzoylmethane sunscreen active is selected from the group consisting of 2-methyldibenzoylmethane, 4-methyldibenzoylmethane, 4-isopropyldibenzoylmethane, 4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane, 2,5-dimethyldibenzoylmethane, 4,4'-diisopropylbenzoylmethane, 4- (1, 1- dimethylethyl) -4'-methoxydibenzoylmethane, 2-methyl-5-isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxydibenzoylmethane, 2,4-dimethyl-4'-methoxydibenzoylmethane, 2, 6-dimethyl-4'-tert-butyl-4'-methoxydibenzoylmethane, and mixtures thereof.

5. The composition according to any of the preceding claims, further characterized in that the dibenzoylmethane sunscreen active is selected from the group consisting of 4-isopropyldibenzoylmethane, 4- (1,1-dimethylethyl) -4'-methoxydibenzoylmethane, and its mixtures

6. The composition according to any of the preceding claims, further characterized in that the formaldehyde donor preservative is selected from the group consisting of DMDM, DMDM hydantoin, DM hydantoin and mixtures thereof.

7. The composition according to any of the preceding claims, further characterized in that the formaldehyde donor preservative is DMDM hydantoin.

8. - The composition according to any of the preceding claims, further characterized in that the composition comprises a safe and effective amount of UVB sunscreen active.

9. The composition according to claim 8, further characterized in that the UVB sunscreen active is selected from the group consisting of octyl methoxycinnamate, octocrylene, 4-methylbenzylidene camphor, 2-phenyl-benzimidazole-5-sulfonic acid, octylsalicylate. , zinc oxide, titanium dioxide, iron oxide and their mixtures.

10. The composition according to any of the preceding claims, further characterized in that at least 75% of the total amount of dibenzoylmethane sunscreen active in the composition is in one or more of the oil phases and therefore less 75% of the conservative formaldehyde donor is in one or more of the aqueous phases. fatott ... .- * ^. ~ ._ _...._ __fi_ < • - * "* - * - -» "- '» -? ? * Mt. "Jm