Title of Invention

SUN SCREEN FORMULATIONS

Abstract

This Invention relates to sun screen formulation, comprising (a) 0.5 to 10% of a microns organic insoluble UV absorber selected from a triaging, a benzotriazole, a vinyl group-containing amide, a canals acid amide or a suffocated benzimidazole; and (b) a cosmetically acceptable carrier, Wherein the microns organic UV absorber is present in the oil phase of the formulation. The sunscreen formulation of the invention provides excellent protection of the human skin against the damaging effects of sunlight, while permitting safe tanning of the skin.

Full Text

Sun Screen Formulations The present invention relates to new formulations and, in particular, to new UV-protection formulations which comprise a micronised UV absorber, wherein the micronised UV absorber is present in the oil phase of the formulation. It has long been known that prolonged exposure to UV radiation which reaches the surface of the earth can lead to the formation of erythemas or light dermatoses, as well as to an increased incidence of skin cancers, or accelerated skin ageing. Various sunscreen formulations have been proposed which include a material which is intended to counteract UV radiation, thereby inhibiting the said undesired effects on the skin. A great number of compounds has been proposed for use as UV protectants in sunscreen formulations, especially soluble organic UV absorbers and insoluble micronised inorganic compounds, in particular zinc oxide and titanium dioxide. With respect to the use in sunscreen formulations of soluble organic UV absorbers, they have the disadvantages that their effectiveness as UV protectants in terms of SPF (Sun Protection Factor) in a sunscreen formulation is often too low for commercial purposes; as a result of their solubility, they exhibit relatively high allergenic potential; and that as a result of intrinsic photochemical lability, the duration of the protective effect is often too low. The high specific weight of insoluble inorganic compounds, such as titanium dioxide leads to a reduced stability of fomiulations containing them. Moreover, such inorganic compounds have been claimed to generate toxic radicals under the influence of light and water ("Redox Mechanisms in Heterogeneous Photocatalysis", Serpone et a/, Electrochemistry in Colloids and Dispersions, Editors Mackay and Texter, VCH Publishers Inc.. NewYork 1992). In GB-A-2303549, there is described a method of producing micronised, insoluble organic UV absorbers, as well as a sunscreen composition comprising a) 0,1 to 15%. preferably 0.5 to 10% by weight, based on the total composition of a micronised formulation of an insoluble organic UV absorber, produced according to the said method; and optionally b) a cosmetically acceptable carrier. Micronised, insoluble organic UV absorbers so obtained, when used in sunscreen formulations, provide excellent UV protection and have at least as high an SPF rating as corresponding sunscreen formulations containing a known inorganic UV absorber. Unlike the latter UV absorbers, micronised, insoluble organic UV absorbers show no tendency, under the influence of light, to generate radicals which could damage or sensitise human skin. In a further development of the concept disclosed in GB-A-2303549, it has now been found that, micronised. insoluble organic UV absorbers which are present in the oil phase of the sun screen formulation surprisingly show a significant improvement in sun protection. Accordingly, the present invention provides, as a first aspect, a sun screen formulation, which is especially suitable for use in pharmaceutical or cosmetic applications, comprising (a) a micronised organic UV absoriDer; and (b) a cosmetically acceptable carrier, wherein the micronised organic UV absorber is present in the oil phase of the formulation. The micronised organic UV absorber may be incorporated into the oil phase with different methods. In a preferred incorporation method the micronised organic UV absorber may be incorporated as powder. For this purpose the micronised organic UV absorber may be subjected to known powdering processes like solvent precipitation, vacuum spraying from solvents etc.. These powders have a particle size of 0.1 nm to 2 µm. In order to prevent agglomeration processes the micronised organic UV absorber may be coated before powdering with a surface active agent like nonionic, anionic, cationic or amphoteric surfactants like phospholipids or known polymers, for example PVP, acrylates etc. As example, a water-soluble surfactant or emulsifier is added to the aqueous suspension of the micronised organic UV absorber. The mixture is then spray-dried. During the spray-drying process the surfactant or emulsifier sheathes the micro-particles in form of a thin film and inhibits aggregation or facilitates the re-dispersion to the desired particle size in the oil phase. In another preferred method the micronised organic UV absorber may be transferred to the oil phase during the preparation of the sun screen formulation: when mixing the micronised organic UV absorber which was produced by aqueous grinding with the oil phase of the sun screen formulation the water will be removed by known methods like vacuum removal. By this measure the micronised organic UV absorber will be transferred to the oil phase of the formulation. Furthermore, it was observed that the micronised organic UV absorber which is present in the aqueous phase of the sun screen composition will migrate into the oil phase after a couple of days or weeks. Therefore, another aspect the present invention refers to a method of preparation of the sunscreen composition by micronising the organic UV absorber in the first step as aqueous suspension, mixing the micronised organic UV absorber with the oil phase of the sunscreen composition in a second step and storing the formulation for at least three weeks in a final step. Suitable organic UV absorber may be. e.g., a triazine, a benzotriazole, a vinyl group-containing amide, a cinnamic acid amide or a sulfonated benzimidazole UV absorber. A preferred class of triazine compounds is that having the formula R13 is C1-C5alkyl; Ti is hydrogen; or C1-C8alkyI; m1, m2 and m3. independently of one another, are 1 to 4; P1 is 0 or a number from 1 to 5; A1 is a radical of the formula Very particularly preferred in this case are triazine compounds of the fomiuia (2e) - (2h), in which R17 and R18 have the same meaning. Furthermore , interesting triazines correspond to the formula as well as 2,4,6-tris(diisobutyl-4'-aminoben2almalonate)-s-triazine and 2,4-bis(diisobutyl-4-aminobenzalmalonate)-6-{4'-aminobenzyiidenecamphor)-s-triazine. Particularly preferred compounds of formula (1) are those having the formula: In relation to the compounds of formula (25), when R26 is an alkali metal it is preferably potassium or. especially sodium; when R26 is a group N(R27)4 in which R27 has its previous significance, it is preferably a mono-, di- or tri-CrC4alkylammonium salt, a mono-, di- or tri-C2-C4alkanolammonium salt or a C1--C3alkyI ester thereof; when R27 is a C1-C3alkyI group, it is preferably a C1-C2 alkyl group, more preferably a methyl group; and when R27 is polyoxyethylene group, this preferably contains from 2-6 ethylene oxide units. Further preferred classes of micronised or mioronisable UV absorbers used for the present invention: - p-aminobenzoic acid derivatives, typically 2-ethylhexyl"4-dimethylaminobenzoate - salicylic acid derivatives, typically 2-ethylhexyl salicylate; homosalates; and isopropyl sylicylates; - benzophenone derivatives, typically 2-hydroxy-4-methoxybenzophenone; - dibenzoylmethane derivatives, typically 1 •(4-tert-butylphenyl)-3-(4-methoxyphenyl>- propane-1,3"dione; - diphenylacrylates, typically 2-ethylhexyl-2-cyano-3,3"diphenylacrylate and 3-{benzo-furanyl)-2-cyanoacryiate; - 3-imidazol-4-yl-acrylic acid and 3-imidazol-4-yl-acrylate; - benzofuran derivatives, preferably 2-{p-aminophenyl)benzofuran derivatives, disclosed in EP-A-582 189. US-A-5 338 539, US-A-5 518 713 and EP-A-613 893; - polymeric UV absorbers, such as the benzylidenemalonate derivatives described, inter alia, in EPA-709 080; - cinnamic acid derivatives, typically the 2-ethylhexyl-4-methoxycinnamate or isoamylate or cinnamic acid derivatives disclosed, inter alia, in US-A-5 601 811 and WO 97/00851; - camphor derivatives, typically 3-(4'-methyl)ben2ylidenebornan-2-one, 3-benzylidene-bornan-2-one, N-[2(and 4)-2-oxyborn-3-ylidenemethyl)ben2yl]acrylamide polymer, 3-(4'-trimethylammonium)benzylidenebornan-2-one methylsulfate, 3.3'-(1.4-phenylenedime-thine)-bis(7.7-dimethyl-2-oxobicyclo-[2.2.1]heptane-1-methanesulfonic acid) and the salts thereof, 3-(4'-suifo)benzylldenebornan-2-one and the salts thereof; - 2-phenylbenzimidazole-5-sulfonic acids and the salts thereof; and - menthyl-o-aminobenzoate. In the compounds of formula (1) to (30), C1-C12 alkyl groups may be methyl, ethyl, n-propyl or isopropyl, butyl, pentyi, hexyl, heptyi, octyl, isooctyl, nonyl, decyl undecyl, dodecyl, methyl being preferred; and Ci-C3alkoxy groups include methoxy, ethoxy, propoxy and isopropoxy, methoxy and ethoxy being preferred, C2-C4carboxyalkyl includes carboxymethyl, carboxyethyl, carboxypropyl and carboxyisopropyl, carboxymethyl being preferred. Cs-Cscycloalkyi includes cyclopentyl, cyclohexyl and cyclooctyl. The compounds of formula (1) to (30) are known. Preferably, the micronised organic UV absorber, component (a) of the new sun screen agent, has a mean particle size in the range of from 0.01 to 2, more preferably from 0.02 to 1.5, especially from 0.05 to 1.0|j.. The sun screen formulation may also comprise as optional component an oil-soluble organic UV absorber which is not micronized. This may be any known oil-soluble organic UV absorber, especially those which are already approved and marketed for cosmetic use. Such oil-soluble organic UV absorbers are described, for instance, in "Sunscreens", Development, Evaluation and Regulatory Aspects, Eds.:N.J.Lowe and N.A.Shaath. M.Dekker Inc, New York and Basel. 1990; and Ken Klein, Encyclopedia of UV absorbers for sunscreen products, Cosmetics & Toiletries 107 45-64 (1992). The oil-soluble, non-micronised UV absorber may be, for example, a p-aminobenzoic acid derivative such as an ester, salt or an amine-modified derivative of p-aminobenzoic acid; a salicylic acid derivative such as an ester or salt thereof; a benzophenone derivative; a dibenzoylmethane derivative; a diphenylacrylate derivative; a benzofuran derivative; a polymeric UV absorber containing one or more silico-organic residues; a cinnamate ester; a camphor derivative; phenylbenzimidazole sulfonic acid and its salts; urocanic acid (3-imidazol-4-yl-acrylic acid) or its ethyl ester; or amenthyl anthranilate. Specific examples of benzophenone derivatives include ben2ophenone-3-(2-hydroxy-4-methoxybenzophenone), benzophenone-4(2-hydroxy-4-methoxyben2ophenone-5-sulfonic acid) and benzophenone-8-(2,2'-diliydroxy-4-methoxybenzGphenone). A specific example of a dibenzoylmethane derivative is butyl metlioxydibenzoylmethane [1-(4-tert.-butyl)-3-{4-methoxyphenyl)propane-1,3-dione]. Specific examples of a diphenylacrylate derivative include octocrylene (2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate) and etocrylene (ethyl-2-cyano-3,3'-diphenyl acrylate). Specific examples of a benzofuran derivative include the 3-(benzofuranyl)-2-cyanoacrylates described in US 5338539 or EP 582189, especially the compounds having the formula Specific examples of a cinnamate ester include octyl methoxy cinnamate (4-methoxy-cinnamic acid 2-ethylhexyl ester), diethanolamine methoxy cinnamate (diethanolamine salt of 4-methoxycinnamic acid), isoamyl p-methoxycinnamate (4-methoxycinnamic acid 2-isoamyl ester), 2,5-diisopropyl methyl cinnamate, the cinnamido derivatives disclosed in US 5601811 and the derivatives described in WO 97/00851. Specific examples of camphor derivatives are 4-methyl-benzylidene camphor [3-(4'-methyl)benzylidene-bornan-2-one], 3-benzylidene camphor (3-benzylidene-bornan-2-one), polyacrylamidomethyl benzylidene camphor {N-[2(and 4)-2-oxyborn-3-yliden-methyl)benzyl]acrylamide polymer}, trimonium benzylidene camphor sulfate [3-(4'-trimethylammonium)-benzylidene-bornan-2-one methyl sulfate], terephthalydene dicamphor sulfonic acid {3,3'-(1,4-phenylenedimethine)-bis-(7.7-dimethyl-2-oxo-bicyclo-[2.2.1]heptan-1-methanesulfonic acid} and salts thereof and benzylidene camphor sulfonic acid [3-(4'-sulfo)benzylidene-bornan-2-one] and salts thereof. Specific examples of trianilino-s-triazine derivatives include octyl triazine [2,4,6-trianilino-(p-carbo-2'-ethyl-1'-oxy)-1,3,5-tria2ine, the trianilino-s-triazine derivatives disclosed in US 5332568, the trianilino-s-triazine derivatives described in EP 517104, trianilino-s-triazine derivatives disclosed in EP 570838, the trianilino-s-triazine derivatives described in US 5252323, the trianilino-s-triazine derivatives described in WO 93/17002-A1 and the trianilino-s-triazine derivatives disclosed in WO 97/03642-A1. A specific example of a benzotriazole is 2-(2-hydroxy-5-methyl-phenyl)benzotriazole. Specific examples of hydroxyphenyltriazine derivatives include, e.g, those described EP-A1-775.698, such as 2,4-bis-{[4-{2-ethyl-hexyloxy)-2-hydroxy]-phenyl}-6-(4-methoxyphenyl)-1.3,5-triazine. Specific examples of bis-resorcinol-dialkylaminotriazines are, e.g., those described in EP-A1-780,382. The sunscreen composition of the invention may be formulated as a water-in oil or an oil-in- r>^ water dispersion, an oil or oil-alcohol lotion, a vesicular dispersion of an ionic or nonionic amphiphilic lipid, a gel, a solid stick or an aerosol formulation. When formulated as a water-in oil or an oiI,-in-water dispersion, the cosmetically acceptable carrier preferably comprises 5 to 50% of an oil phase, 5 to 20% of an emulsifier and 30 to 90% of water, each by weight based on the total weight of the carrier. The oil phase may comprise any oil conventionally used in cosmetic formulations, especially an emollient e.g., one or more of a fatty alcohol; hydrocarbon oil; a natural or synthetic triglyceride; a wax including esters of long-chain acids and alcohols as well as compounds having wax-like properties; a silicone oil; a fatty acid ester or a fatty alcohol; and lanoline-containing products. Examples of fatty alcohols include cetyl alcohol, stearyl alcohol, octyldodecanol. cetearyl alcohol and oleyl alcohol; examples of hydrocarbon oils are, e.g., mineral oil (light or heavy), petrolatum (yellow or white), polyethylene, paraffin, squalane, microcrystalline wax, ceresin, polybutene and hydrogenated polyisobutene; examples of a natural or synthetic triglyceride include castor oil. caprylic/capric triglyceride, Japan wax, hydrogenated vegetable oil, sweet almond oil, wheat germ oil, sesame oil, hydrogenated cottonseed oil, coconut oil, wheat germ glycerides, avocado oil, com oil, trilaurin, hydrogenated castor oil, shea butter, cocoa butter, soybean oil, mink oil, sunflower oil, safflower oil, macadamia nut oil, olive oil, hydrogenated tallow, apricot kernel oil, hazelnut oil and borage oil; examples of a wax including esters of long-chain acids and alcohols as well as compounds having wax-like properties are, e.g., carnauba wax, beeswax (white or yellow), lanolin, candelellila wax. ozokerite, lanolin oil, paraffin. Japan wax, microcrystalline wax. ceresin, jojoba oil, cetearyl esters wax, synthetic jojoba oil, synthetic beeswax and lanolin wax; a silicone oil is e.g. dimethicone or cyclomethicone; examples of a fatty acid ester or a fatty alcohol include isopropyl myristate, isopropyl palmitate, octyl palmitate, isopropyl lanolate, acetylated lanolin alcohol, the benzoate of Ci2-Ci5alcohols, cetearyl octanoate, cetyl palmitate, myristyl myristate, myristyl lactate, cetyl acetate, propylene glycol dicaprylate/caprate, decyl oleate, acetylated lanolin, stearyl heptanoate. diisostearyl malate, octyl hydroxystearate, octyl hydroxystearate and isopropyl isostearate; and examples of lanoline-containing products include lanolin, lanolin oil, isopropyl lanolate, acetylated lanolin alcohol, acetylated lanolin, hydroxylated lanolin, hydrogenated lanolin and lanolin wax. The emulsifier may comprise any emulsifier conventionally used in cosmetic formulations, e.g., one or more of an ethoxylated ester of a natural oil derivative such as a polyethoxylated ester of hydrogenated castor oil; a silicone oil emulsifier such as a silicone polyol; an optionally ethoxylated fatty acid soap; an ethoxylated fatty alcohol; an optionally ethoxylated sorbitan ester; an ethoxylated fatty acid; or an ethoxylated glyceride. The sunscreen composition of the invention may also comprise further components which are known to perform a useful function in a sunscreen corhposition. Examples of such further components include, e.g.. emollients, skin moisturisers, skin tanning accelerators, antioxidants, emulsion stabilisers, thickening agents such as xanthan, moisture-retention agents such as glycerine, film formers, preservatives, perfumes and colourants. The sunscreen composition of the invention provides excellent protection of the human against the damaging effects of sunlight, while pemiitting safe tanning of the skin. Moreover, the sunscreen composition of the invention has a skin waterproofing effect. The following Examples further Illustrate the present invention. Parts and percentages shown therein are by weight unless othenwise stated. The micronised organic UV absorber prepared by aqueous grinding (D) is added to the oil phase (A). Water is removed under vacuum so that the microparticles will transfer into the oil phase. Then, the homogenised oil phase (A) and the aqueous phase (B) are heated to 80°C each and stirred together. Then phase (C) is added and-homogenised intensively-After cooling down to room temperature under stirring the emulsion is adjusted to pH 6.5-7 with 10%NaOH-solution. The SPF (in vitro: SPF-analyser 290) of the emulsion is 34. If the emulsion is prepared in the manner, that the aqueous suspension of the micronised UV absorber is added as additional phase either to the aqueous phase or separately at the end of the emulsifying process thein-vitro-SPF is only 12. Example 2: 0/W sunprotection lotion Dry micronised 2.2'-methylen-bis-[6-(2H-benztriazol-2-yl)-4-(1.1,3,3-tetramethylbutyl)-phenoi (D) is suspended intensively in the oil phase by mixing and using supersonics. Then phase (A) and (B) are heated separately to 80**C and mixed without stirring. After addition of (C) it is homogenised intensively and cooled down to room temperature with stirring. At the end the desired pH is adjusted with (E). The phases (A) and (B) are separately warmed up to 80°C and added together without stirring. After addition of (C) the formulation is homogenised intensively. After stirring the mixture is cooled down to room temperature. Phase (D) is adjusted with citric acid to pH 5.5 and additionally stin-ed for 15 minutes. At the end, the desired pH is adjusted with (E). Immediate after preparation the Iin-vitro-SPF of 12 is determined which will rise to SPF of 37 after three weeks of storing. The presence of the micro-particles in the oil phase is detected microscopic. Example 4: 0/W sunscreen lotion Ingredients (% b.w.): 2.4-Bis{[4-(2-ethylhexyloxy)-2-hydroxylDhenyl}-6-(4-methoxyphenyl)-1,3.5-triazineis dissolved in octyl methoxycinnamate and added to the oil phase (A). The phases (A) and (B) are heated separately to 80°C and added together without stirring. After addition of (C) the mixture is homogenised intensively. Under stirring the mixture is cooled down to room temperature. Phase (D) is adjusted to pH 5.5 with citric acid and added portionwise with cautious stirring. After additional stirring for ca. 15 minutes the desired pH is adjusted with (E). Immediate after preparation the in-vitro-SPF of about 23 is detemiined which will rise to SPF of 54 after three weeks of storing. The presence of the micro-particles in the oil phase is detected microscopic. This nanodispersion is further worKed up to a W/0 emulsion of the following composition: 20 g nanodispersion 2 (comprising 6 % of the compound of formula (101)) 5g polyglyceryl-2-dipolyhydroxystearate 1 g glyceryl oleate 6 g caprylic/capric triglyceride 6 g octyldodecanol 5 g cetearyl isononanoate 1 g tocopheryl acetate 1.2 g beewax 49.3 g water 5 g glycerine 0.5 g preservative The SPF (in vitro: SPF analyser 290) is 20.2. Example 6: If 1,5 g 2-ethylhexyl-p-methoxycinnamate at the expense of water is added to the nano- dispersion 2 of Example 5 an unexpected high SPF of 36.2 is obtained. 20 g nanodispersion 2 (comprising 6% of the compound of foRmula (101)) 5 g polyglyceryl-2-dipolyhydroxystearate 1 g glyceryl oleate 6 g capryiic/capric triglyceride 6 g octyldodecanol 5 g cetearyl Isononanoate 1 g tocopheryl acetate 1,2 g beewax 1.5 g 2-ethylhexyUp-methoxycinnamate 47.8 g water 5 g Glycerin 0.5 g preservative WE CLAIM: 1. A sun screen formulation, comprising (a) 0.5 to 10% of a micronised organic insoluble UV absorber selected from a triazine, a benzotriazole, a vinyl group-containing amide, a cinnamic acid amide or a sulfonated benzimidazole; and (b) a cosmetically acceptable carrier, wherein the micronised organic UV absorber is present in the oil phase of the formulation. 2. The sun screen formulation as claimed in claim 1, in which the triazine UV absorber has the formula in which R1, R2 and R3. independently, are H; OH; C1C3alkoxy; NH2; NH-R4; N(R4)2; OR4, wherein R4 is C1-C3 alkyi; phenyl; phenoxy; anilino; pyrrolo, in which the respective phenyl, phenoxy or aniline, or pyrrolo moieties are not substituted or substituted by one, two or three substitutents selected from OH. carboxy, CO-NH2, C1C3alkyl, C1-C3alkoxy. a methylidenecamphor group, a group -(CH=CH)mC(=O)-OR4, a group di- or tri-Ci-C4alkylammonium, mono-, di- or tri-C2-C4alkanolammonium salts, or the C1-C3alkyl esters thereof, a radical of formula (1a) R', R" and R'" are each independently of the others CrC^alkyl that is unsubstituted or substituted by one or more OH groups; Re is hydrogen; M; Ci-CsalkyI; or a radical of the formula -{CH2)m2 -O-T1 ; M is a metal cation; T1 is hydrogen; or Ci-CsalkyI; m is 0 or 1; m1 is from 1 to 5; m2 is from 1 to 4; m3 is from 2 to 14. 3. The sun screen formulation as claimed in claim 1 or 2, in which the triazine UV absorber has the formula R7 and R8, independently of one another, are C1-C18alkyI; C2-C18alkenyl; a radical of the formula -CH2-CH(-O H)-CH2-O-T1 ; or; a radical of the M is a metal cation;and n1 is 1-16. 4. The sun screen formulation as claimed in claim 1, in which the triazine compound has the formula (25) in which the individual radicals R26 are the same or different and each is hydrogen; an alkali metal; an ammonium group N(R27)4 in which R27 is hydrogen or an organic radical; C1-C3al-kyl; or a polyoxyethylene radical which contains from 1 to 10 ethylene oxide units and the terminal OH group of which may be etherified by a c1-C3alcohol. 5. The sun screen formulation as claimed In claim 1, in which the triazole organic UV absorber has the formula in which T1 is d-Csalkyl or hydrogen; and T2 is C1C4alkyl. 6. The sun screen formulation as claimed in claim 1, in which the benzotriazole organic UV absorber has the formula (28) in which T2 is hydrogen, C1-C12alkyl or C1-C4alkyl substituted by phenyl. 7. The sun screen formulation as claimed in claim 6, in which T2 is t-butyl. 8. The sun screen formulation as claimed in claim 1, in which the vinyl group-containing amide organic UV absorber has the formula (29) R28-(Y)m-CO-C(R29)=C{R3o)-N(R31)(R32), in which R28 is C1-C3alkyI, phenyl or phenyl substituted by one, two or three substituents selected from OH, C1-C3alkyI, CrCaalkoxy or CO-OR33, R33 C1-C3alkyl; R29, R30- R31 and R32 are the same or different and each is C1-C3alkyl or hydrogen; Y is -NH- or -O-; and m is 0 or 1. ^ 9. The sun screen formulation as claimed in claim 1, in which the cinnamjc acid amide organic UV absorber has the formula R33 is hydroxy or C1-C4alkoxy, R34 is hydrogen or C1-C4alkyl, and R35 is -(CONH)m-phenyl in which m is 0 or 1 and the phenyl group is optionally substituted by one, two or three substituents selected from OH, C1-C3alkyI, C1C3alkoxy or CO- OR4 in which R4 is C1-C4alkyL 10. The sun screen formulation as claimed in claim 1, in which the sulfonated benzimidazole organic UV absorber has the formula M is hydrogen or an alkali metal, an alkaline earth metal or zinc. 11. The sun screen formulation as claimed in any of the preceding claims in which the micronised organic UV absorber, component (a), has a mean particle size in the range of from 0.01 to 2u, 12. The sun screen formulation as claimed in any of the preceding claims wherein the sun screen formulation additionally comprises an oil-soluble organic UV absorber selected from a p-aminobenzoic acid derivative; a salicylic acid derivative; a benzophenone derivative; a dibenzoylmethane derivative; a diphenylacrylate derivative; a benzofuran derivative; a polymeric UV absorber containing one or more siiico-organic residues; a cinnamate ester; a camphor derivative; a trianilino-s-triazine derivative; phenylbenzimidazole sulfonic acid or one of its salts; urocanic acid (3~imidazol-4-yl-acry!ic acid) or its ethyl ester; menthyl anthranilate; a benzotriazole; a hydroxyphenyltriazine derivative; and a bis-resorcinol-dialkylaminotriazine. 13. The sun screen formulation as claimed in any of the preceding claims which is formulated as a water-in oil or an oil-ln-water dispersion, an oil or oil-alcohol lotion, a vesicular dispersion of an ionic or nonionic amphiphilic lipid, an oil-alcohol or alcohol gel, a solid stick or an aerosol formulation.

Documents:

in-pct-2000-833-che-abstract.pdf

in-pct-2000-833-che-claims.pdf

in-pct-2000-833-che-correspondence others.pdf

in-pct-2000-833-che-correspondence po.pdf

in-pct-2000-833-che-description complete.pdf

in-pct-2000-833-che-form 1.pdf

in-pct-2000-833-che-form 26.pdf

in-pct-2000-833-che-form 3.pdf

in-pct-2000-833-che-form 5.pdf

in-pct-2000-833-che-other documents.pdf

in-pct-2000-833-che-pct.pdf