MX2008008151A - Cosmetic w/o emulsions with inorganic sunscreen stabilized with conjugated linoleic acid - Google Patents

Abstract

A cosmetic water-in-oil composition is provided which includes a water-in-oil emulsifying silicone surfactant, an ultrafine titanium dioxide and conjugated linoleic acid. The presence of conjugated linoleic acid stabilizes the composition against color degradation and also maintains an approximately steady viscosity.

Description

AG UA COSMIC EMULSIONS IN OIL WITH FI LTRO SOLAR I NORGANICO ESTABI LIZADO WITH ACI DO LI NOLEICO CONJ UGADO BACKGROUND OF THE INVENTION The invention concerns compositions of cosmetic emulsions formulated with stabilized sunscreens and sunscreens against color and viscosity degradation. Sunscreen compositions are commonly used during work or outdoor fun. They protect the exposed skin against burners by the sun, cancer and even photo-aging. In general, sunscreen preparations are formulated as creams, lotions or oils containing as an active agent an ultraviolet radiation that absorbs or at least reflects the chemical compound. The ideal sunscreen formulation should be non-toxic, non-irritating, for skin tissue and capable of convenient application in a continuous film. The active sunscreen agent as well as the composition to which it is formulated should be chemically and physically stable enough. An acceptable shelf life is required for prolonged storage. Chromophoric organic sun block agents are generally the most effective. Unfortunately many of these organic actives cause adverse allergic reactions. Therefore, it is desirable to minimize the level of such materials. Ultrafine inorganic particulate compounds, such as, Zinc oxide and titanium dioxide have been employed as sunscreen agents. Illustrations of this technology are found in US 5 21 5 749 and US 5 1 88 831, both for Nicoll et al. Inorganics are not known as sensitizers generating allergic reactions. However, the stability of such formulations is a notable problem. Adverse effects include viscosity formation and discoloration under prolonged storage conditions. These adverse consequences can be pronounced in particular in emulsions, which are of the continuous oil variety. Accordingly, there remains a need to discover inorganic sunscreen particulate containing formulations for increased storage stability, in particular compositions resistant to significant changes in viscosity and color.

BRIEF DESCRIPTION OF THE INVENTION A cosmetic composition is provided, which is a water-in-oil emulsion, including: (i) from about 0.1 to about 30% by weight of a water-in-oil emulsifying silicone surfactant; (ii) from about 0.1 to about 30% by weight of a titanium dioxide sunscreen agent; and (iii) from about 0.1 to about 10% of a conjugated linoleic acid.

DETAILED DESCRIPTION OF THE INVENTION It has now been discovered that a cosmetic water-in-oil composition containing conjugated linoleic acid can impart both color stability and viscosity to formulations containing particulates of sunscreen-grade titanium dioxide. Ordinarily, unsaturated compounds, of which CLA is an example, would be expected to be unstable and produce a colored body. Therefore, it is surprising to note that CLA had exactly the effect placed on continuous emulsions in oil than suspended titanium dioxide. Only small amounts of CLA were necessary to achieve stabilization results.

Conjugated linoleic acid Conjugated linoleic acid (hereinafter also referred to as CLA) comprises a group of positional and geometric isomers of linoleic acid, in which several configurations of cis and trans double bonds at positions (6,8), ( 7.9), (8, 10), (9, 1 1), (10, 1 2) u (1 1, 13) are possible. In this way, there are twenty-four different isomers of CLA. The invention also includes derivatives of the free acid, which thus comprises portions of conjugated linoleic acid. Preferred derivatives include those derived from substitution of the carboxyl group of the acid, such as esters (for example, retinyl esters, triglyceride esters, monoglyceride esters, diglyceride esters, phosphoesters), amides (e.g., ceramide derivatives), sales (for example, alkali metal and alkaline earth metal salts, ammonium salts), and / or those substituted for the C18 carbon chain, such as alpha hydroxy and / or beta hydroxy derivatives. In the case of triglyceride ester derivatives, all positional isomers of CLA substituents in the glycerol backbone are included. Triglycerides must contain at least a portion of CLA. For example, of the three esterifiable positions in the glycerol backbone, positions 1 and 2 can be esterified with CLA and another lipid in position 3 or as an alternative, the glycerol backbone could be esterified by CLA in positions 1 and 3 with another lipid in position 2. Whenever the term "conjugated linoleic acid" or "CLA" is used in this specification it will be understood that derivatives thereof comprising portions of CLA are also included. "Portions of CLA" refers to the fatty acyl portion (s) of CLA of a CLA derivative. The isomers of greatest interest in the present cosmetic compositions are cis linoleic acid, trans 1 1 and trans linoleic acid 10, cis 12. Hereinafter, the term "9,11-linoleic acid" or "acid 10, 12 -linoleic "should preferably mean these two main isomers, but will include smaller amounts of the remaining isomers, in particular when they are obtained or derived from a natural source. According to the present invention, linoleic acid 9, linoleic acid and linoleic acid 10, 12 are formulated in cosmetic preparations and either as the free acid, as individual chemical derivatives, or as combinations of free acid and derivative. By "CLA enriched with isomer c9, t1 1 and t1 0, c1 2" means that at least 30% by weight of the total CLA (and / or portions of CLA) present in the composition is in the form of the cis-isomers. , trans 1 1 and trans 1 0, cis 1 2. Preferably, at least 40%, most preferably at least 50%, by weight of the total CLA and / or portions of CLA present in the composition, is in the form of isomers mentioned above. The amount of the CLA present in emulsions of this invention can vary from about 0.1 to about 10% by weight of the composition. More preferably, the amount is from about 0.5% to about 5%, and most preferably from about 1% to about 3%. The mixed isomers of CLA are prepared by treatment of high temperature alkali and safflower oil, generating CLA with equal amounts of the C C, T1 1 and t1 0, c1 isomers. CLA enriched in CLA c9, 11 1 is separated from the mixture by selective esterification with lauryl alcohol using Geotrichunm Candidum as a catalyst. CLA c9, 11 1 enriched is hydrolyzed and converted to triglyceride. After the step of esterification and separation of the remaining CLA acids, they are enriched in CLA t1 0, c1 2. Commercially, the CLA is available as Clarinol® A-80 and A- 95 from Loders-Croklaan, Channahon, Illinois and Neobee® CLA 80 and 90 from Stepan, North Field, Illinois.

Water-in-oil surfactant A wide variety of silicone surfactants are useful herein. These silicones are usually organopolysiloxane organically modified, such as dimethicone copolyols. Non-limiting examples of dimethicone copolyols and other silicone surfactants useful herein include copolymers of polydimethylsiloxane polyether with pendant polyethylene oxide side chains, polydimethylsiloxane polyether copolymers with pendant polypropylene oxide side chains, polydimethylsiloxane polyether copolymers with side chains of polyethylene oxide and polypropylene oxide mixed slopes, copolymers of polydimethylsiloxane polyether with side chains of mixed poly (ethylene) (propylene) oxide slopes, copolymers of polydimethylsiloxane polyether with pendant organobetaine side chains, copolymers of polydimethylsiloxane polyether with carboxylate side chains earrings, polydimethylsiloxane polyether copolymers with quaternary ammonium side chains; and also further modifications of the foregoing copolymers, containing linear, branched or cyclic C2-3 alkyl or pendant portions. Examples of commercially available dimethicone copolyols useful herein sold by Dow Corning Corporation are Dow Corning® 190, 1 93, Q2-5220, 2501 Was, 2-5324 Fluid and 3225C (being sold the latter material as a mixture with cyclomethicone). The copolyol of cetyl dimethicone is commercially available as a mixture with polyglyceryl-4-isostearate and hexyl laurate and is sold under the tradename Abil® WE-09 (available from Goldschmidt). Copolyol cetyl dimethicone is also commercially available as a mixture with hexyl laurate and polyglyceryl-3 oleate sold under the tradename Abil® WS-08 (also available from Goldschmidt). Other non-limiting examples of dimethicone copolyols include lauryl dimethicone copolyol, dimethicone copolyol acetate, dimethicone copolyol adipate, dimethicone copolyol amine, dimethicone copolyol behenate, dimethicone copolyol butyl ether, dimethicone copolyol hydroxy stearate, dimethicone copolyol isostearate, dimethicone copolyol laurate, dimethicone copolyol methyl ether, dimethicone copolyol phosphate, dimethicone copolyol sulfosuccinate and dimethicone copolyol stearate. PEG-1 0 Dimethicone available from Shin-Etsu is very preferred. The amounts of the silicone surfactant can vary from about 0.1 to about 30%, preferably from about 1 to about 10%, optimally from about 1.5 to about 5% by weight of the composition.

Titanium Dioxide Particles The compositions of this invention will contain ultrathin titanium dioxide in a form, which can be either a dispersible form in water or an oil dispersible form. By "ultrathin titanium dioxide" is meant titanium dioxide having an average particle size of less than 1 00 nm, preferably from about 90 to about 1 nm, more preferably from about 60 to about 5 nm, even more preferably from about 30 to about 10 nm, and optimally from about 25 to about 1 5 nm. The titanium dioxide dispersible in water is an ultrafine titanium dioxide whose particles are uncoated or which are coated with a material to impart a hydrophilic surface property to the particles. Examples of such materials include aluminum oxide, silica and aluminum silicate. The oil-dispersible titanium dioxide is ultra-fine titanium dioxide, the particles of which exhibit a hydrophobic surface property, and which for this purpose can be coated with hydrophobic materials including metal soaps, such as, aluminum stearate, laurate aluminum or zinc stearate, or with organosilicon compounds, such as dimethicones and dimethiconols. Other useful coatings include polyols, such as butylene glycols, polyethylene glycol and glycerin; natural and synthetic esters including castor oil, caprylic / capric triglyceride, octyl dodecyl neopentanoate, isopropyl myristate, octyl palmitate, C12-C5 alkyl benzoate and mixtures thereof; and combinations of organic liquids with inorganic powders. The most preferred are dioxides of titanium dispersible in oil. The amounts of the titanium dioxide solar filter agent can vary from about 0.1 to about 30%, preferably from about 0.5 to about 15%, more preferably from about 1 to about 10% by weight of the final composition.

Disperse Aqueous Phase The compositions of the present invention comprise from about 5% to about 90%, more preferably from about 30% to about 75%, and even more preferably from about 45% to about 60% of a dispersed aqueous phase. In emulsion technology, the term "dispersed phase" means that the phase exists as small particles or droplets suspended in and surrounded by a continuous phase. The dispersed phase is also known as the internal or discontinuous phase. The dispersed aqueous phase is a dispersion of small aqueous particles or droplets suspended in and surrounded by the continuous silicone phase described hereinabove. The water phase can be water, or a combination of water and one or more ingredients soluble or dispersible in water. Non-limiting examples of such optional ingredients include thickeners, acids, bases, salts, chelants, gums, alcohols and water soluble or dispersible polyols, buffers, preservatives and dyes.

Optional Components The composition of the present invention may contain a variety of other ingredients that are conventionally used in given product types as long as they do not unacceptably alter the benefits for the invention. A component of the present invention can be a crosslinked silicone elastomer (organopolysiloxane). There is no specific restriction as to the type of curable organopolysiloxane composition that can serve as the starting material for the cross-linked silicone elastomer. Examples in this regard are organopolysiloxane curing compositions by addition reaction, which cure under platinum metal catalysis by the addition reaction between diorganopolysiloxane containing SiH and organopolysiloxane having vinyl groups attached to silicon; condensation-curing organopolysiloxane compositions, which cure in the presence of an organotin compound by a dehydrogenation reaction between hydroxyl-terminated diorganopolysiloxane and diorganopolysiloxane containing SiH; condensation-curing organopolysiloxane compositions, which cure in the presence of an organotin compound or a titanate ester, by a condensation reaction between a hydroxyl-terminated diorganopolysiloxane and a hydrolyzable organosilane (this condensation reaction is exemplified by reactions of dehydration, alcohol release, oxime release, amine release, amide release, carboxyl release and ketone release); compositions of organopolysiloxane of peroxide curing, which cure thermally in the presence of an organoperoxide catalyst and organopolysiloxane compositions, which are cured by high energy radiation, such as by gamma rays, ultraviolet radiation or electron beams. Organopolysiloxane curing compositions by addition reaction are preferred for their fast curing rates and excellent curing uniformity. An organopolysloxane curative composition by particularly preferred addition reaction is prepared from: an organopolysiloxane having at least 2 lower alkenyl groups in each molecule; an organopolysiloxane having at least two hydrogen atoms attached to silicon in each molecule; and a platinum-type catalyst. The cross-linked siloxane elastomer may be either an emulsifying or non-emulsifying cross-linked organopolysiloxane elastomer or combinations thereof. The term "non-emulsifying", as used herein, defines a cross-linked organopolysiloxane elastomer from which polyoxyalkylene units are absent. The term "emulsifier", as used herein, means cross-linked organopolysiloxane elastomer having at least one polyoxyalkylene unit (eg, polyoxyethylene or polyoxypropylene). Particularly useful emulsifying elastomers are elastomers modified with polyoxyalkylene formed from divi or lo compounds, in particular siloxane polymers with at least two free vinyl groups, which react with Si-H bonds in a polysiloxane skeleton. Preferably, the elastomers are dimethyl polysiloxanes crosslinked by Si-H sites in a molecularly spherical MQ resin. Preferred silicone elastomers are organopolysiloxane compositions available under the INCI names of dimethicone / vinyl dimethicone cross-linked polymer, dimethicone cross-linked polymer and Polysilicone-1 1. Ordinarily these materials are provided as a 1-30% crosslinked silicone elastomer dissolved or suspended in a dimethicone fluid (usually cyclomethicone). For purposes of definition, "cross-linked silicone elastomer" refers to the elastomer alone in place of the total commercial compositions, which also include a solvent carrier (eg, dimethicone). Crossed dimethicone / vinyl dimethicone polymers and cross-linked dimethicone polymers are available from a variety of suppliers including Dow Corngin (9040, 9041, 9045, 9506 and 9509), General Electric (SFE 839), Shin-Etsu (KSG-1 5, 16, 18 [dimethicone / phenyl vinyl dimethicone cross-linked polymer]) and Grant Industries (GransilM R material line) , and cross-linked lauryl dimethicone / vinyl dimethicone polymers provided by Shin-Etsu (eg, KSG-31, KSG-32, KSG-41, KSG-42, KSG-43 and KSG-44). Other suitable commercially available silicone elastomer powders include vinyl dimethicone / methicone cross-linked polymers Silesquioxane from Shin-Etsu sold as KSP-100, KSP-101, KSP-102, KSP-103, KSP-104, KSP-105 and hybrid silicone powders containing a fluoroalkyl group or a phenyl group sold by Shin-Etsu as KSP-200 and KSP-300 respectively. Also used is Dow Corning 5-7070, an amino silicone elastomer emulsion named INCI of quaternium-16 silicon cross-linked polymer / glycidoxy dimethicone (and) tridecet-12. The crosslinked silicone elastomers can vary in concentration from about 0.01 to about 30%, preferably from about 0.1 to about 10%, optimally from about 0.5 to about 2% by weight of the cosmetic composition. These weight values exclude any solvent, such as cyclomethicone found in commercial "elastomer" silicones, such as, the Dow Corning 9040 and 9045 products. For example, the amount of silicone elastomer crosslinked at 9040 and 9045 is between 1 2 and 1 3% by weight. More preferred is the silicone elastomer DC 9045, which has a particle size of swollen elastomer of cyclomethicone D5 (based on volume and calculated as spherical particles), which averages about 38 microns and can vary from about 25 to about approximately 55 microns. The compositions may include from about 1% to about 80% by weight of the composition, of a suitable carrier for the organopolysiloxane elastomer component. reticulated described above. The carrier, when combined with the crosslinked organopolysiloxane elastomer particles serves to suspend and swell the elastomer particles to provide a gel-like, elastic matrix or network. The carrier for the cross-linked siloxane elastomer is liquid under ambient conditions, and preferably has a low viscosity to provide improved spreading on the skin. Carrier concentrations may vary from about 5% to about 60%, more preferably from about 5% to about 40%, by weight of the composition. These liquid carriers may be organic, silicone-containing or fluorine-containing, volatile or non-volatile, polar or non-polar, provided that the liquid carrier forms a solution or other homogeneous liquid or liquid dispersion with the selected cross-linked siloxane elastomer at the elastomer concentration of selected siloxane at a temperature of from about 28 ° C to about 250 ° C, preferably from about 28 ° C to about 78 ° C. The term "non-polar" usually means that the material has a solubility parameter below 6.5 (cal / cm3) 0 5. The non-polar volatile oil tends to impart highly desirable aesthetic properties to the compositions of the present invention. Consequently, non-polar volatile oils are preferably used at a high bastane level. Volatile non-polar oils particularly used in the present invention are silicone oils; hydrocarbons; and mixtures thereof. Examples of preferred non-polar volatile hydrocarbons include polydecanes, such as isododecane and isodecane (for example, Permethyl-99A, which is available from Presperse I nc.) And the isoprafines of C7-8 to C1 2- is (such as the series Isopar available from Exxon Chemicals). Particularly preferred volatile silicone oils are cyclic volatile silicones, wherein the repeating unit ranges from about 3 to about 5; and linear silicones wherein the repeating unit ranges from about 1 to about 7. Highly preferred examples of volatile silicone oils include cyclomethicones of varying viscosities, eg, Dow Corning 200, Dow Corning 244, Dow Corning 245, Dow Corning 344 and Dow Corning 345, (commercially available from Dow Corning Corp.); SF-1204 and SF-1202 Silicone Fluids, GE 7207 and 71 58 (commercially available from G.E. Silicones) and SWS-03314 (commercially available from SWS Silicones Corp). The compositions of the present invention may also contain C1- or alpha- and beta-hydroxy carboxylic acids and salts thereof. The salts are preferably alkali metal, ammonium and d, 2 alkanolammonium salts and mixtures thereof. The term "alpha-hydroxycarboxylic acids" includes not only hydroxy acids but also alpha-keto acids and related compounds of hydroxy acid polymer forms. Alpha-hydroxy acids are organic carboxylic acids, in which a hydroxyl group is attached to the alpha carbon adjacent to the carboxyl group. The generic structure is as follows: (Ra) (Rb) C (OH) COOH where Ra and Rb are H, F, Cl, Br, alkyl, aralkyl or aryl group of straight or branched chain, isomeric or nonisomeric, saturated or unsaturated or cyclic form, having 1 to 25 carbon atoms, and in addition Ra and Rb it can carry OH, CHO, COOH and alkoxy groups having 1 to 9 carbon atoms. The alpha-hydroxy acids may be present as a free acid or in lactone form, or in a salt form with an organic base or an inorganic alkali. Alpha-hydroxy acids can exist as stereoisomers as D, L and DL forms, when Ra and Rb are not identical. Normal alkyl, aralkyl and aryl groups for Ra and Rb include methyl, ethyl, propyl, isopropyl, butyl, pentyl, octyl, lauryl, stearyl, benzyl and phenyl. Among the most preferred alpha-hydroxy acids are glycolic acid, lactic acid, alpha-hydroxycaprilic acid, gluconolactone and combinations thereof. Among the beta-hydroxycarboxylic acids, the most prominent and useful is salicylic acid. The amounts of the hydroxycarboxylic acids can vary from about 0.01 to about 1.5%, preferably from about 0.1 to about 125%, more preferably from about 1 to about 8%, optimally from about 2 to about 8% by weight of the total cosmetic composition. The humectant can be incorporated into compositions of the present invention. The humectants are usually polyols. Representative polyols include glycerin, diglycerin, polyalkylene glycols and more preferably alkylene polyols and their derivatives including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,2-butylene glycol, 1, 2,6- hexanetriol, isoprene glycol, 2-methyl-1,3-propanediol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. Amounts of the humectant can vary from about 0.01 to about 30%, preferably from about 0.1 to about 15%, optimally from about 2 to 10% by weight of the composition. The emollients can be formulated in the compositions.

These emollients can be selected from hydrocarbons, silicones, fatty alcohols, fatty acids, synthetic or natural esters and combinations thereof. The amounts of the emollients can vary from about 0.01 to about 30%, preferably from about 0.1 to about 10%, optimally from about 0.5 to about 5% by weight of the composition. The hydrocarbons include mineral oil, polyalphaolefins and isoparaffins. Among the ester emollients are: Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms, examples of which include isoaraquidyl neopentanoate, isononyl isononanoate, oleyl myristate, oleyl stearate, octyl stearate and oleyl oleate; Ether esters, such as esters of fatty acids of ethoxylated fatty alcohols; Esters of polyhydric alcohols, such as esters of ethylene glycol mono- and di-fatty acids, esters of diethylene glycol mono- and di-fatty acids, esters of polyethylene glycol mono- and di-fatty acids (200-6000), esters of mono- and di-fatty acids of propylene glycol, polypropylene glycol monooleate 2000, polypropylene glycol monostearate 2000, ethoxylated proethylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol polyglyceryl esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; Wax esters, such as, beeswax, spermaceti, myristyl myristate, stearyl stearate; Ester of mono-, di- and triglycerides, such as caprylic / capric triglyceride of PEG-8; and esterols of sterols, of which fatty acid esters of cholesterol are examples thereof. Most preferred is glycerol monostearate, available from Kessco Corporation and Sterols sold under the trademark Generol 122®. Natural esters which can be employed as emollients include olive oil, sunflower seed oil, safflower oil, cottonseed oil, rape seed oil, palm kernel oil, palm oil and mixtures thereof. The fatty alcohols can also serve as emollients. These are usually formed from 10 to 30 carbon atoms and include cetyl, myristyl, palmityl, stearyl, isostearyl, hydroxystearyl, oleyl, linoleyl, behenyl alcohol and mixtures thereof. Fatty acids having from 10 to 30 carbon atoms can also be included in the compositions of this invention. Pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erucic acids are illustrative of this category. The amounts can vary from about 0.1 to about 20%, preferably from about 1 to about 10%, optimally from about 2 to about 5% by weight. The compositions of the present invention may comprise a skin lightening agent. When used, the compositions preferably comprise from about 0.1% to about 10%, more preferably from about 0.2% to about 5% by weight of the composition, of a skin lightening agent. Skin lightening agents Suitable include niacinamide, kojic acid, arbutin, tranexamic acid, ethyl resorcinol, placental extract, ascorbic acid and derivatives thereof (eg, ascorbyl magnesium phosphate, ascorbyl sodium phosphate, ascorbyl glucoside and ascorbyl tetraisopalmitates). Other skin lightening materials suitable for use herein include Actiwhite® (Cognis), Emblica® (Roña), Azeloglycine (Sinerga) and extracts (for example, blackberry extract). The preservatives may be desirably incorporated into the cosmetic compositions of this invention to protect against the growth of potentially useful microorganisms. Traditional preservatives for compositions of this invention are alkyl esters of para-hydroxybenzoic acid. Other preservatives that have entered more recently into use include hydantoin derivatives, propionate salts and a variety of quaternary ammonium compounds. Cosmetic chemists are familiar with the appropriate preservatives and choose them routinely to satisfy the conservative challenge test and to provide product stability. Particularly preferred preservatives are phenoxyethanol, methyl paraben, propyl paraben, imidazolidinyl urea, sodium dehydroacetate and benzyl alcohol. Conservatives should be selected taking into consideration the use of the composition and possible incompatibilities between conservatives and other ingredients in the composition. The most preferred is iodopropynyl butylcarbamate available from Lonza Corporation under the trademarks Glydant Plus and Glycasil L. The preservatives are preferably used in amounts ranging from 0.001% to 2% by weight of the composition. The compositions of the present invention may also include herbal extracts. Illustrative extracts include extracts of Centella Asiatica, Ginseng, Citrus Unshui, Ginko Biloba, chamomile, green tea, Scullcap, nettle root, Japonic Swertia, fennel and Aloe Vera and combinations thereof. The amounts of each of the extracts in an active base can vary from about 0.00001 to about 1%, preferably from about 0.001 to about 0.5%, optimally from about 0.005 to about 0.2% by weight of the composition. Minor auxiliary ingredients may also be present in the compositions. Among these may be vitamins, such as, vitamin E esters, vitamin C, panthenol and any of the vitamin B complexes (for example, niacinamide and vtimain B6). Retinoids can be employed including retinol, retinyl linoleate, retinyl acetate, retinoic acid and combinations thereof. Anti-irritant agents may also be present including those of steviosides, alpha-bisabolol and glycyrrhizinate salts. Each vitamin, retinoid or anti-irritant agent may be present in amounts ranging from about 0.0001 to about 1.0%, preferably from about 0.001 to about 0.5%, optimally from about 0.01 to about 0.3% by weight of the composition. The cosmetic compositions may exhibit pH properties ranging from pH 2 to 1 0. A preferred embodiment has pH varying from about 4.5 to about 7.0. The compositions of the present invention may comprise one or more thickening agents, preferably from about 0.05% to about 10%, more preferably from about 0.1% to about 5%, and even more preferably from about 0.25% to about 4%, in weight for the composition. Non-limiting classes of thickening agents include those selected from the group consisting of: a. 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 acrylic acids and the substituted acrylic acids, wherein the crosslinking agent contains two or more double carbon bonds. carbon and is derived from a polyhydric alcohol. Examples of commercially available carboxylic acid polymers useful herein include Carbomers, which are homopolymers of acrylic acid cross-linked with allyl ethers of sucrose or pentaerythritol. Carbomers are available as the Carbopol® 900 series from Noveon Corporation (eg, Carbopol® 954). In addition, other suitable carboxylic acid polymeric agents include C1 0-3 copolymers or alkyl acrylates with one or more monomers of acrylic acid, methacrylic acid or one of its short chain esters (ie, C1-4 alcohol), wherein the crosslinking agent is an allyl ether of sucrose or pentaeritriotol. These copolymers are known as Acrylate / C10-3 alkyl acrylate crosspolymers and are commercially available as Carbopol® 1 342, Carbopol® 1 382, Ultrez® 21, Pemulen® TR-1 and Pemulen® TR-2, from Noveon Corporation. b. Taurate Polymers The compositions of the present invention may optionally comprise crosslinked taurate polymers useful as thickening or gelling agents including anionic, cationic and nonionic polymers. Examples include hydroxyethyl acrylate / sodium acryloyldimethyl taurate (eg, Simulgel® NS and INS 100), sodium acrylate / acryloyldimethyl taurate (eg, Simulgel® EG), sodium acryloyldimethyl taurate (eg, Simulgel® 800) and Ammonium acryloyldimethyl taurate / vinyl pyrrolidone (For example, Aristoflex® AVC). c. Polyacrylamide Polymers The compositions of the present invention may optionally comprise polyacrylamide polymers, especially nonionic polyacrylamide polymers including unbranched or branched substituted polymers. Preferred among these polyacrylamide polymers is the nonionic polymer given the designation CTFA polyacrylamide and isoparaffin and laureth-7, available under the tradename Sepigel® 305 from Seppic Corporation. Other polyacrylamide polymers useful herein include copolymers of multiple blocks of acrylamides and acrylamides substituted with acrylic acids and substituted acrylic acids. Commercially available examples of these multi-block copolymers include Hypan SR150H, SS500V, SS500W and SSSA100H from Lipo Chemicals, Inc. d. Polysaccharides A wide variety of polysaccharides are useful herein.

"Polysaccharides" refers to gelling agenes that contain a skeleton of repeating sugar units (ie, carbohydrate). Non-limiting examples of polysaccharide gelling agenes include those selected from the group consisting of cellulose, carboxymethyl hydroxyethyl cellulose, hydroxyethyl cellulose, hydroxyethyl ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, methyl hydroxyethyl cellulose, microcrystalline cellulose, sodium cellulose sulfate and mixtures thereof. and. Gums and clays Other thickening and gelling agents useful herein include materials that are derived primarily from natural sources. Non-limiting examples include materials selected from the group consisting of acacia, aga, algin, alginic acid, ammonium alginate, amylopectin, calcium alginate, calcium carrageenan, carnitine, carrageenan, dextrin, gelatin, gelana gum, guar gum, guar hydroxypropyltrimonium chloride, hectorite, laponite, bentonite, hyaluronic acid, hydrated silica, hydroxypropyl chitosan, hydroxypropyl guar, karaya gum, kelp, locust bean gum, natto gum, potassium carrageenan, propylene glycol alginate, sclerotium gum, sodium carboxymethyl dextran, sodium carrageenan, gum tragacanth, gum xanthan and mixtures thereof. Another optional ingredient may be an organic sunscreen agent. Sunscreen agents have at least one chromophoric group that absorbs within ultraviolet light ranging from 290 to 400 nm. The chromophoric organic sunscreen agents can be divided into the following categories (with specific examples) including: p-aminobenzoic acid, its salts and its derivatives (ethyl esters, isobutyl and glyceryl and p-dimethylaminobenzoic acid); anthranilates, (o-aminobenzoates, methyl, menthyl, phenyl, benzyl, phenylethyl, linalyl, ter-phenyl, and cyclohexenyl esters); salicylates (octyl, amyl, phenyl, benzyl, menthyl, glyceryl and dipropylene glycol esters); cinnamic acid derivatives (menthyl and benzyl ester, alpha-phenyl cinnamonitrile and butyl cinnamoyl pyruvate); dihydroxycinnamic acid derivatives (umbelliferone, methylumbelliferone and methylacetoumbeliferone); trihydroxycinnamic acid derivatives (esculetin, methylesculetin, daphnetin and the glucosides, esculin and daphnin); hydrocarbons (diphenylbutadiene and stilbene); dibenzalacetone and benzalacetophenone; naphtholsulfonates (sodium salts of 2-naphthol-3,6-disulfonic acids); dihydroxy naphthoic acid and its salts; o- and p-hydroxybiphenyldisulfonates; coumarin derivatives (7-hydroxy, 7-methyl and 3-phenyl); diazoles (2-acetyl-3-bromoindazole, phenyl benzoxazole, methyl naphthoxazole and various aryl benzothiazoles); quinine salts (bisulfate, sulfate, chloride, oleate and tannate); quinoline derivatives (salts of 8-hydroxyquinoline and 2-phenylquinoline); hydroxy- or methoxy-substituted benzophenones; uric and vilouric acids; tannic acid and its derivatives (for example, hexaethyl ether); (butyl carbitil) (6-propyl) piperonyl) ether; hydroquinone; benzophenones (oxybenzone, sulisobenzone, dioxybenzone, benzoresorcinol, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and octabenzone); 4-isopropyldibenzoylmethane; Butylmethoxydibenzoylmethane; etocrylene; and 4-isopropyl-dibenzoylmethane. Particularly useful are: 2-ethylhexyl p-methoxycinnamate, 4,4'-t-butyl methoxydibenzoylmethane, 2-hydroxy-4-methoxybenzophenone, octyldimethyl p-aminobenzoic acid, digalioltrioleate, 2,2-dihydroxy-4-methoxybenzophenone, ethyl 4- [bis (hydroxypropyl)] aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate, glyceryl p-aminobenzoate, 3,3,5-trimethylcyclohexylsalicylate, methylanthranilate, p-dimethylaminobenzoic acid or aminobenzoate, 2- ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2- (p-dimethylaminophenyl) -5-sulfoniumbenzoxazoic acid, 4-methylbenzylidene camphor, bis-ethylhexyloxyphenol methoxyphenol triazine, methylene bis-benzotriazolyl tetramethylbutylphenol, dimethicodiethylbenzal malonate, isoamyl methoxycinnamate, octyl triazone, terephthalimide dialkanol sulfonic acid and mixtures thereof. The amounts may vary from about 0.1 to about 10%, preferably from about 1 to about 5% by weight of the composition. Except that in the operation and comparison examples, or where explicitly stated otherwise, all figures in this description indicating quantities of material should be understood as modified by the word "approximately".

The term "comprises" means that it is not limited to any element subsequently declared but covers unspecified elements of greater or lesser functional importance. In other words, the listed steps, elements or options do not need to be exhaustive. Whenever the words "include" or "have" are used, these terms mean that they are equivalent to "comprises" as defined above. All documents referred to herein, including all patents, patent applications and printed publications, are hereby incorporated by reference in their entirety in this disclosure. 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 l-V A series of sunscreen formulations according to the present invention are reported in these examples. The resulting creams have the following components.

Includes: vitamin E acetate, vitamin A palmitate, ceramide 3 and 6, bisabolol, borage oil, cylinder seed oil, lactate, sodium ascorbyl phosphate, betula alba extract (white birch), DL-panthenol, Sodium PCA (50%), hydrolyzed milk protein, pomegranate extract, cholesterol and stearic acid.

EXAMPLE VI A series of color stability experiments were conducted to evaluate the effect of CLA to prevent discoloration on the aging of continuous oil emulsions. The following details the components of the four compositions (A-D) used for this study. (2) Herbal extracts / nutrients included only in zinc oxide formulas.

Color comparison test The color was evaluated by the Hunter Lab method. Intrinsic optical properties of the formulas were tested using a Hunter Lab LabScan XE (H unter Associates Laboratory, I nc. Reston, Vi rginia) using a port plate standard sample cup. The equipment adjustments used were: Spectrum performance: Wavelength range: 400-700 nm Internal wavelength: 10 nm Bandpass: 1 0 nm triangular equivalent Photometric range: 0-150% The LabScan XE 0/45 spectrophotometer in the port orientation above is then configured for an area of 1.75 in view with UV filter set to nominal. Once the instrument is standardized following the procedure specified in the commercially available instrument and software program manual, the sample is prepared for color measurement (a *, b * and L *). The black plastic ring is placed inside the sample cup which is then filled with product at a level above the ring. The ceramic disc is then placed on top of the sample with the white portion that looks at the sample until it rests firmly on the top of the plastic ring. This disc provides a white background to direct light that has traveled through the sample back to the detector. The objective is to have the sample appear soft and opaque through the bottom of the sample cup. Next, the sample is placed on the sample cup port plate and covered with the opaque cover. This cover provides a light trap to exclude external light interference in the sample measurements. The average of three readings is used for a simple color measurement that represents the color of the lot. The color lab is preset by the color space Hunter lab a *, b * and L *.

The term a * is green-red space, the term b * is the blue-yellow space and the term L * is black-white space. For example, a large L * value means more white and the smaller b * value means more blue. The overall color difference from the standard sample is then determined by the value of dE *. dE * can be obtained when configuring the instrument to display it when its settings are specified or can be calculated as follows: dE * = V (dL) 2 + (da) 2 + (db) 2 where: dL - L sample - L - reference sample a = a * estra sample reference sample db - bb * sample - mu benchmark the greater the value of dE, the greater the degree of color change of the control. Adversely, low values of dE indicate that the overall color of the sample is closer to that of the control.

Results The results of the color study are reported in the tables below. Formula with zinc oxide (the results are reported for formulas held for 2 months at 43 ° C. Changes in the value of E are relative to the formula of 0% CLA stored at 22 ° C for 2 months) The formula with titanium dioxide (the results are reported for formulas held for 1 month at 50 ° C. Changes in the value of E are relative to the formula of 0% CLA stored at 4 ° C for 1 month).

In the presence of zinc oxide, the addition of CLA reused in an ever-increasing color problem. For comparison, the replacement of zinc oxide with titanium dioxide resulted in a stable formula, where CLA prevented discoloration.

EXAMPLE VII Another property that manifests stability is that of viscosity. The sunscreen compositions with zinc oxide were compared to the identical ones where titanium dioxide replaced zinc oxide. These compositions are reported in the table in example VI. The compositions were placed in storage for a period of one month at 50 ° C. The viscosities were measured using a Brookfield RVT viscometer at 23 ° C, T-spindles (-B, -C or -E) at 5 rpm. The results are recorded in the tables below.

Formula with zinc oxide (Storage at 50 ° C) Formula with titanium dioxide (storage at 50 ° C) Zinc oxide formulas exhibited a change in viscosity increased with the addition of small CLA contents. In contrast, replacement of zinc oxide with titanium dioxide decreased the viscosity but only to a relatively small degree. As CLA increased from 1% to 3%, the change in viscosity became lower. It is evident that CLA is effective to stabilize formulas with titanium dioxide in a continuous oil system.

Claims (9)

REIVI N DICACIONES

1 . A cosmetic composition, which is a water-in-oil emulsion, comprising: (i) from 0.1 to 30% by weight of a water-in-oil emulsifying silicone surfactant; (ii) from 0. 1 to 30% by weight of a titanium dioxide solar filter agent; and (Mi) from 0.1 to 10% of a conjugated li noleic acid.

2. The composition according to claim 1, wherein the water-in-oil surfactant is a silicone copolyol.

3. The composition according to claim 1, wherein the titanium dioxide is present in an amount of from 1 to 10% by weight of the composition.

4. The composition according to claim 1, wherein the conjugated linoleic acid is present in an amount from 1 to 3% by weight of the composition.

5. The composition according to claim 1, wherein the conjugated li noleic acid consists of essentially at least 30% by weight of total conjugated linoleic acid present in the composition of a mixture of cis-9 linoleic acids, trans- 1 1 and trans-1 0, cis-12.

6. The composition according to claim 5, wherein the conjugated linoleic acid consists essentially of at least 40% by weight of total conjugated linoleic acid present in the composition of a mixture of linoleic acids cis-9, trans-1 and trans1 0, cis-12.

7. The composition according to claim 1, wherein the titanium dioxide has a particle size ranging from 5 to 100 nm. The composition according to claim 1, wherein the titanium dioxide has a particle size ranging from 10 to 60 nm. 9. The composition according to claim 1, wherein the titanium dioxide is a titanium dioxide dispersible in oil. SUMMARY A water-in-oil cosmetic composition is provided, which includes a water-in-oil emulsifying silicone surfactant, an ultra-fine titanium dioxide and conjugated li noleic acid. The presence of conjugated linoleic acid stabilizes the composition against color degradation and also maintains an approximately stable viscosity.