WO1999006014A2

WO1999006014A2 - Combinations of sunscreens and compositions containing them

Info

Publication number: WO1999006014A2
Application number: PCT/EP1998/004518
Authority: WO
Inventors: Giuseppe Raspanti; Alverio Malpede
Original assignee: 3V Sigma S.P.A.
Priority date: 1997-07-30
Filing date: 1998-07-21
Publication date: 1999-02-11
Also published as: ITMI971823A1; AU8977898A; AU736477B2; WO1999006014A3; IT1293508B1

Abstract

Combinations of sunscreens which comprise at least one compound of formula (I), in combination with at least another sunscreen selected from benzylidenecamphor derivatives, dibenzoylmethane derivatives, alkoxycinnamic acid derivatives, triazinoaniline derivatives, benzophenone derivatives, diphenylcyanoacrylates, salicylic acid derivatives, benzymidazol-5-sulfonic acid derivatives, p-aminobenzoic acid derivatives, metal oxides having an atomic number ranging from 11 to 40. Compositions containing them, in particular cosmetic compositions capable of providing a sun protecting factor from the ultraviolet radiations not lower than 2.

Description

COMBINATIONS OF SUNSCREENS AND COMPOSITIONS CONTAINING THEM

The present invention relates to combinations of sunscreens and to the compositions containing them.

It is well known that sun radiations ranging from 280 to 400 nm are noxious for human skin; in particular those with a wavelength from 280 to 320 nm, the so- called UV-B radiation, cause erythema and cutaneous sunburns, whose severity depends on the kind of the skin and on the duration of the exposition to sunlight.

It has been ascertained that also radiations ranging from 320 to 400 nm, the so called UV-A radiations, which were considered innocuous and only responsible of skin tanning, are, as a matter of fact, harmful, in that they can cause damages to elastine and collagene, with consequent ageing of the skin as well as a number of phototoxic and photoallergic reactions.

A great number of substances are described in the patent and non-patent literature, which are capable of protecting skin from radiations, such substances belonging to a variety of chemical classes (benzophenones, dibenzoylmethane derivatives, benzylidenecamphor derivatives, salicylic acid derivatives, p-aminobenzoic acid derivatives, cyanocrylates, triazinoanilines , benzi idazoles , etc.). They exert their protective action more or less satisfactorily; however, the practical use thereof in cosmetic or dermatological compositions is not free from problems, due to the poor photostability of some of them (for example, dibenzoylmethane derivatives (Int. J. Cosm. Science, 10., 53, 1988)), to the poor absorbing power at certain wavelengths (for example, benzophenone derivatives show a poor absorption at 290 and 325 nm), and to problems of solubility in the oily or aqueous solvents used in cosmetics or in dermatology for the preparation of the relevant formulations.

Specific combinations of anti UV-A and anti UV-B sunscreens have been proposed in the attempt to prevent the photodegradation of the first ones, for example combinations of benzylidenecamphor derivatives or cyanocrylates (anti UV-B sunscreens) and dibenzoylmethane derivatives (anti UV-A sunscreens) are reported in GB 2,198,944, WO 91/11989 and WO 94/04131, and synergistic compositions of anti UV-B sunscreens are described in EP 0,689,828 and EP 0,685,224.

The kind of sunscreens and the amounts at which they are used, alone or in mixtures, are selected depending on the intended protection, as well as on the above mentioned remarks. In particular, an index of this protection is the so-called sun protection factor, (SPF), which is expressed as the ratio of the time of irradiation necessary to reach the erythematogenic threshold in the presence of the UV filter to the time necessary to reach the erythematogenic threshold in the absence of the UV filter.

There is, anyway, a demand for novel, more effective protection systems for those parts of the body which can be damaged by a more or less prolonged exposition to UV radiations, such as skin and hair, which demand is even more felt nowadays in view of the problems deriving from the holes in the ozone layer. Therefore, an object of the present invention are combinations of sunscreens for the protection from ultraviolet radiations, which comprise: a) at least one compound of formula I:

wherein :

R is a straight or branched (C^_₈) alkyl group, (^c _ 2^ cycloalkyl, optionally substituted with one or more straight or branched (C₁_₄) alkyl groups; X is an oxygen atom or the group -NH-; R^ has the same meanings as R, or is hydrogen, a monovalent metal ion, a quaternary ammonium group, or a group of formula II

in which A is a straight or branched (C^_₈) alkyl, (C^_ ₁₂) cycloalkyl, or (Cg_₁₀) aryl optionally substituted with one or more straight or branched (^cι_4) alkyl groups; R3 is hydrogen or methyl; n is an integer from 1 to 10; R₂ has the same meaning as R when X is -NH-, or has the same meanings as R^ when X is oxygen; in combination with at least one or more sunscreens selected from the following classes of compounds: b) benzylidenecamphor derivatives of formula Til:

wherein R^ is hydrogen, or the group SO3M, in which M is hydrogen, or a monovalent metal ion, or a quaternary ammonium group, and R^ is hydrogen, methyl, a group SO M wherein M is defined as above, or a group of formula IV or V

CH_

wherein R₄ is as defined above; c) dibenzoylmethane derivatives of formula VI

in which g and -, are selected independently from hydrogen, straight or branched (C_{* Q}) alkyl and straight or branched (C^_g) alkoxy; d) alkoxycinnamic acid esters of formula VII

wherein β- is a straight or branched (C^_^.) alkyl group, and R_q is selected from hydrogen, a straight or branched

(C_I -I_Q) alkyl group, a monovalent metal ion and a quaternary ammonium group; e) triazinoaniline derivatives of formula VIII

in which R , R_* and E, ^are def ined as above f or f or mula

( I ) f) benzophenone derivatives of formula IX

wheit-_'

( -_j__ ^_Q) alkyl group, R- is hydrogen or the group SO3Q, in which Q is hydrogen, a monovalent metal ion or a quaternary ammonium group, and R^₂ is hydrogen, hydroxy or straight or branched (C^_^) alkoxy; y) diphenylcyanoacrylates of formula X

COOR_l3

wherein 13 has I he same meanings as R., defined above; h) salicylic acid derivatives of formula XI

COOR₁

wherein

alkyl group, a benzyl group optionally substituted with a straight or branched (^cι__β) alkyl group, a 3,3,5- trimethylcyclohexyl residue, both as a racemate and as any optically active forms, or the group HN^CR^CR^OH^; i) benzimidazolesulfonic acid derivatives of formula XII

in which G is hydrogen, or a monovalent mo Lai ion, or a quaternary ammonium group; j) p-aminobenzoic acid (PABA) derivatives of formula

XIII

wherein R-,r and ^g are independently hydrogen or a straight or branched ( ^C _{~ Q} ) alkyl group, optionally substituted with a hydroxyl group, and R^γ is selected from hydrogen, a straight or branched (^cι_ιo) alkyl group, a monovalent metal ion and a quaternary ammonium group, or R^g is the group -(CH -CH2θ)_χH, R^g is the group -(CH₂-CH₂0) H and R₁₇ is the group -CH₂-CH₂-(OCH₂-

CH ) OC₂Ht_j, in which the sum of x, y and z is 25; k) metal oxides having atomic number ranging from 11 to 40.

It is evident from what stated above that the combinations of the present invention are, at least, binary combinations of a component as defined in a) with one of the components as defined in the classes b) to k). In the case of combinations of more than two components as defined in a) to k), two or more thereof can also be selected within the same class, provided at least one of the components present in the combination is as defined in a). The choice of the components of the combinations depends on the desired type and degree of protection, as well as on the chemico-physical and photostability characteristics of the selected components . Examples of alkyl group are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and isomers thereof.

Examples of cycloalkyl group are cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclododecyl. Examples of substitutions with alkyl groups are methyl, ethyl, propyl, butyl and isomers thereof at one or more positions of the cycloaliphatic ring.

Examples of monovalent metal ions are the sodium, potassium, lithium ions. Examples of aryl group are phenyl and naphthyl, optionally bearing one or more alkyl groups, such as methyl, ethyl, propyl, butyl and isomers thereof.

Examples of alkoxy group are methoxy, ethoxy, propoxy, butoxy and isomers thereof.

The preferred components of formula I are those in which R is methyl, 2 ,4,4-trimethyl-pent-2-yl, isopropyl or tert-butyl, R^ is 2-ethyl-hexyl, isopropyl or n- tetradecyl, R₂ is isopropyl or 2-ethyl-hexyl, and X is 0 or -NH-. Particularly preferred is the component in which R is tert-butyl, ^ and R₂ are both 2-ethyl-hexyl and X is oxygen, which will be referred to as component a) in the disclosure and examples. These components are described in EP 0,570,838.

Sunscreens of the classes b) to k) are anti UV-A sunscreens and/or anti UV-B sunscreens well-known in literature; many of them being commercial products.

Preferred components of the class b) are the compounds of formula III in which R^ is hydrogen and Rg is methyl or the group of formula IV, which are known under the trade names EUSOLEX™ 6300 and MEXORY ™ SO, respectively, and those in which R_* is the group SO3M, wherein M is hydrogen or a monovalent metal ion and R is the group of formula V in which R^ is defined as above , known under the trade name MEXORYL™ SX .

Preferred components of the class c) are those compounds of formula VI in which Rg is isopropyl or tert-butyl and ₇ is hydrogen or methoxy, known under the trade names EUSOLEX™ 8020 (Rg=(CH₃ )₂CH, R_?=H) and

PARSOL™ 1789 (Rg=(CH₃)₃C, R₇=OCH₃), respectively.

Preferred components of the class d) are those compounds of formula VII, in which Rg is methyl and R_g is 2-ethyl-hexyl or the group ⁺NH₂(CH₂CH₂OII)2 , known under the trade names PARSOL™ MCX and BERNEL™ HYDRO, respectively.

The preferred component of the class e) is the compound of formula VIII in which all of R, R^ and ₂ are 2-ethyl-hexyl, known under the trade name UVINUL™ T

150.

Preferred components of the class f) are those compounds of formula IX in which R^_Q is hydrogen or methyl, R^ is hydrogen or the group SO3Q, in which Q is hydrogen or a monovalent metal ion, and R^ is hydrogen, known under the trade names UVASORB™ 2QH

(R₁₀=R₁₁=R₁₂=H), UVASORB™ MET ( ₁₀=CH_3/ R₁₁=R₁₂=H),

UVASORB™ S5 (R₁₀=CH₃, R_1;L=S0₃Q wherein Q=H, R₁₂=H), respectively. The preferred component of the class g) is the compound of formula X in which R^₃ is 2-ethyl-hexyl, known under the trade name UVINUL™ N-539.

Preferred components of the class h) are those compounds of formula XI in which R₁₄ is 2-ethyl-hexyl, the residue ( + )-3 , 3, 5-trimethylcyclohexyl or the group

HN⁺(CH₂CH₂0H)₃, known under the trade names ESCALOL™

587, KEMESTER™ HMS and SUNAROME™ W, respectively.

Preferred components of the class i) are those compounds of formula XII in which G is hydrogen or a monovalent metal ion, known under the trade name

EUSOLEX™ 232.

Preferred components of the class j) are p- a inobenzoic acid as it is (formula XIII, ₁₅=R₁₆=R₁₇=H) , the compounds of formula XIII in which -_{j 5} and R^ are at the same time methyl or 2- hydroxypropyl, and R^₇ is ethyl or 2-ethyl-hexyl, known under the trade names UVASORB™ DMO (R₁₅= ₁₆=CH₃ , R_1?=2- ethyl-hexyl) and AMERSCREEN™ P (^Ri5^=Ri6^{= 2}" hydroxypropyl , R^₇=ethyl), respectively, and the compound of formula XIII in which R^₅ is the group -(- CH₂-CH₂0-)_χ-H, R₁₅ is the group (-CH₂-CH₂0-) H and R₁₇ is the group -CR^-CH^-OCR^-CH^-^O^Hg-, in which the sum of x, y and z is 25, known under the trade name

UVINUL™ P25.

Preferred components of the class k) are titanium dioxide (Ti0₂) and zinc oxide (ZnO). These oxides are preferably used in micronized form, in which the particles have a size not higher than about 100 nm as for Ti0₂, and ranging from about 15 to about 300 nm as for ZnO. Most preferably, the size of the Ti0_o particles ranges from about 5 to about 50 nm. Titanium dioxide can have an anatase, rutile or amorphous structure. For the purposes of the invention, these micronized metal oxides can be used either as they are or coated with other agents, such as A1₂0₃ or aluminium salts with C30-I8 aliphatic fatty acids. They are easily commercially available products. For example, micronized i0₂ is marketed under the trade name P25 (Degussa), whereas Ti0₂ coated with aluminium stearate is marketed as MT100T (Tayka Corp.), and that coated with A1₂0₃ is known as UFTR (Miyoshi). Micronized ZnO is, in its turn, available as Z-COTE™ ( sunSMART ) or as SPECTRAVEIL™ (Tioxide) .

Therefore, a preferred aspect of the present invention relates to sunscreens synergistic combinations which contain the component a) in combination with at least one or more of the sunscreens belonging to the classes b) to k) and defined above as the preferred ones. As already stated, when the combination comprises more than two sunscreens, the components, in addition to component a), can be selected from any of the different classes b) to k), or within the same class. This is also meant when an acidic sunscreen is used as a component : the combination can contain a mixture of the filter in the acidic form and in the εalified form with a monovalent metal, or with a quaternary ammonium group. Representative examples of these preferred combinations of sunscreens are those combinations which comprise the component a) with:

1) at least one preferred component of the class k), optionally together with one or more of the other preferred components according to the invention;

2) at least one preferred component of the class i), optionally together with a preferred component of the class k) and/or one or more of the other preferred components according to the invention; 3) at least one preferred component of the class c) and at least one preferred component of the class k), optionally together with one or more of the other preferred components according to the invention; 4) at least one preferred component of the class c), the preferred component of the class g), optionally together with a preferred component of the class k) and/or one or more of the other preferred components according to the invention; 5) at least one preferred component of the class c), the preferred component of the class g), at least one preferred component of the class i), optionally together with a preferred component of the class k) and/or one or more of the other preferred components according to the invention; 6) at least one preferred component of the class b) and at least one preferred component of the class k), optionally together with one or more of the other preferred components according to the invention; 7) at least one preferred component of the class b), at least one preferred component of the class i) and at least one preferred component of the class k), optionally together with one or more of the other preferred components according to the invention;

8) at least one preferred component of the class b), at least one preferred component of the class c), optionally together with a preferred component of the class k) and/or one or more of the other preferred components according to the invention;

9) at least one preferred component of the class c), at least one preferred component of the class f) and at least one preferred component of the class k), optionally together with one or more of the other preferred components according to the invention;

10) at least one preferred component of the class d), at least one preferred component of the class f), optionally together with a preferred component of the class k) and/or one of the other preferred components according to the invention; 11) at least one preferred component of the class e), optionally together with a preferred component of the class i) and/or one or more of the other preferred components according to the invention; 12) at least one preferred component of the class c) and at least one preferred component of the class d), optionally together with one or more of the other preferred components according to the invention; 13) at least one preferred component of the class c) and at least one preferred component of the class h), optionally together with one or more of the other preferred components according to the invention; 14) at least one preferred component of the class c) and at least one preferred component of the class j ) , optionally together with one or more of the other preferred components according to the invention. Other preferred combinations of sunscreens will be evident to those skilled in the art from the disclosure and examples.

The combinations of sunscreens of the present invention can be used both in the protection of human body from the harmful effects of UV radiations, and in the stabilization of the various compositions containing them, for example, cosmetic or dermatological compositions. This stabilizing effect has also been observed when including the above mentioned combinations in photosensitive compositions different from the cosmetic and dermatological ones, such as polymers. In said compositions, the combination used comprises at least one component a) in amounts ranging from about 0.05 to about 20% of the composition total weight, and at least one of the other components b) to k) in amounts ranging from about 0 to about 30%, calculated on the composition total weight, with the proviso that at least one of the components b) to k) is present in a percent amount different from zero. In general, the amount of the desired combination present in the composition ranges from about 0.1 to about 35% of the composition total weight. As stated above, the choice of the components of the combinations will depend on the desired type and degree of protection and stabilization, as well as on the chemico-physical and photostability characteristics of the selected components. The above indicated percentages and those reported in the following are percent by weight, and they are calculated on the composition total weight.

The preferred compositions are the cosmetic compositions, which, therefore, are a further object of the present invention.

In a preferred embodiment, the cosmetic compositions comprise a combination of sunscreens according to the invention in cos etically acceptable excipients, such as oil-in-water , water-in-oil, oil-water-oil, water-oil-water emulsions, oily solutions, lipid fusions, hydro-alcoholic or anhydrous aqueous gels, alcoholic or hydro-alcoholic solutions, and analogues. When an oily substance is necessary to dissolve or disperse one or more of the components of the selected combination, this substance is a compound advantageously selected from: i) hydrocarbons, such as paraffin, mineral oils, and analogs; ii) oils, butters and natural waxes, such as avocado oil, sunflower oil, almond oil, apricot-stone oil, karite butter, evening primrose oil, black currant oil, borage oil, jojoba oil, safflower oil, wheat germ oil, macadamia oil, rice bran oil, sesame oil, castor oil, coconut oil; unsaponifiable oils of olive, avocado, soya; cocoa butter, bees-wax, candelilla wax, carnauba wax, and analogs; iii) silicones oils such as dimethicones, cyclomethicones, dimethiconols, alkyldimethicones, and analogs; iv) esters of straight or branched, saturated or unsaturated aliphatic acids or of aromatic or alkylaromatic acids, having 1 to 25 carbon atoms, said acids being optionally hydroxylated and/or ethoxylated, with mono- or polyhydroxylated aliphatic alcohols, saturated or unsaturated, straight or branched, having 1 to 25 carbon atoms, such as octyldodecyl-neopentanoate, pentaery- thritol-dioleate, trimethylolpropan-trioleate, tri- isostearyl-citrate, diacetin, triacetin, 2-ethyl- hexyl acetate, neopentylglycol oleate, triethylene glycol diacetate, isopropyl myristate, isopropyl palmitate , bis-diglyceryl-caprylate/caprate/iso- stearate/stearate/hydroxystearate/adipate , dioctyl maleate, di-(2-ethγl-hexyl) malate, (C^^r^alkyl benzoates, cetylstearyl octanoate, cetylstearyl isononanoate, 2-ethyl-hexγl palmitate, 2-ethyl- hexyl stearate, Cg_ιo triglycerid, PEG-7 glyceryl coccoate and analogs; v) amides, such as those mentioned in EP 0,748,623, in particular N,N-diethylmethylbenzamides and ethyl 1- ( -acetyl-N-butyl )-propionate; vi) (^c6~^c35) alcohols, such as cetyl alcohol, stearyl alcohol, behenyl alcohol, octyldodecyl alcohol,

3,5,5-trimethylhexyl alcohol, 2-butoxyethanol, 2- phenoxyethanol , 2-ethyl-l,3-hexanediol and analogs; vii) ethers of (^c8^-c40^ fatty alcohols, such as di-n- octylether; viii) butyl ethers of glycols, such as propylene glycol tert-butyl ether, diethylene glycol butyl ether, a

(polypropylene glycol )₃_^ butyl ether, and analogs; ix) esters of (C^-g)alkyl ethers, such as diethylene glycol butyl ether acetate, propylene glycol methylether acetate, and analogs.

For the purposes of the present invention, the substances i) to ix), which are all easily commercially available, can be used either singularly or as mixtures thereof, such as the wax mixtures commercially known under the name CUTINA(^R) (Henkel). Generally, the oily component is used in amounts ranging from about 0.5 to 95% of the composition total weight.

A preferred group of oily components are the esters of saturated or unsaturated, straight or branched aliphatic acids, or of aromatic or alkylaromatic acids, having 1 to 25 carbon atoms, said acids being optionally hydroxylated and/or ethoxylated, with mono- or polyhydroxylated aliphatic alcohols, saturated or unsaturated, straight or branched, having 1 to 25 carbon atoms .

Another preferred group of oily components are the

N,N-diethyl-methylbenzamides and ethyl l-(N-acetyl-N- butyl )-propionate.

A third preferred group of oily components are the mixtures of esters of saturated or unsaturated, straight or branched aliphatic acids, or of aromatic or alkylaromatic acids, having 1 to 25 carbon atoms, said acids being optionally hydroxylated and/or ethoxylated, with mono- or polyhydroxylated aliphatic alcohols, saturated or unsaturated, straight or branched, having 1 to 25 carbon atoms, such as N,N-diethyl-methylbenzamides and/or ethyl l-(N-acetyl-N-butyl )-propionate . A fourth preferred group of oily components are the silicones oils.

The cosmetic compositions which comprise emulsions, such as those mentioned above, can also include one or more conventional, commercially available emulsifier. These can be anionic emulsifiers, such as soaps of fatty acids with alkali metals (for example, potassium stearate), alkaline-earth metals or aliphatic amines; alkylsulfate salts, such as sodium cetylstearyl sulfate (LANETTE™ E, Henkel); alkylphosphates salts, optionally ethoxylated, such as potassium cethylphoshate (AMPHISOL™ K, Givaudan); condensates of fatty acids with protein hydrolysates (LAMECREME™ LPM, Henkel); mono- and diglycerides anionic esters (GRINDTEK™ CA-P, Grindsted Products Ltd), and analogs. Amphoteric emulsifiers can be used as well, for example phospholipids such as lecithin, or also non ionic emulsifiers. The latter are, for example, ethoxylated compounds of natural oil derivatives, such as hydrogenated castor oil (7)OE (ARLACEL™ 989, ICI); mono- and diglycerides of fatty acids, optionally ethoxylated, such as glyceryl stearate (CUTINA™ GMS,

Henkel) and glyceryl( 20 )OE stearate (CUTINA™ E-24,

Henkel); sorbitan ethoxylated esters (TWEEN™, ICI and

CRILLET™, Croda) and non-ethoxylated esters (SPAN™,

ICI and CRILL™, Croda); polyglycerol esters with fatty acids, such as triglyceryl diisostearate (LAMEFORM™ TGI, Henkel) and triglyceryl distearate (CITHROL™ 2623, Croda); glucose, methylglucose and saccharose esters with ethoxylated and non-ethoxylated fatty acids, such as methylglucose dioleate (GLUCATE™ DO, Amerchol) and methylglucose ( 20 )OE sesquistearate (GLUCAMATE™ SS E-20. Amerchol); ethers of glucose and of its oligomers, optionally esterified with (C_1Q-_3Q )aliphatic acids, such as triglycerylmethylglucose distereate (TegoCare'^R' 450, Goldschmidt) and methyl glucose sesquistearate (TegoCare(^R) PS, Goldschmidt), or cetylstearyl glucoside (MONTANOV™ 68, Seppic ) ; ethoxylated fatty acids (MYRJ™, ICI); ethoxylated fatty alcohols (BRIJ™, ICI); lanolin and ethoxylated and non-ethoxylated derivatives, such as lanolin (30)OE (AQUALOSE™ L 30. Westbrook); alkylglycols/polyethylene glycols copolymers, such as the copolymer PEG-45/dodecylglycol (ELFACOS™ ST 9, Akzo); silicone emulsifiers (Silicone Fluid 3225 C, Dow Corning; ABIL™ W508 and Th. Goldschmidt AG); fluorinated emulsifiers (FOMBLIN(^R) - Ausimont); polymers of hydroxystearic acid esterified or etherified with polyethyleneglycols (PEG), polypropylene glycols (PPG) or copoly ers PEG/PPG; and analogs. Instead of these conventional emulsifiers, cross-linked copolymers can also advantageously be used, selected from a) cross- linked copolymers formed by i) acrylic or methacrylic acid, ii) vinyl esters of highly branched trialkylacetic acids of formula XIV

R

20 o

II ^R _{1 8}— ^c C— 0-CH = CH₂

| XIV

in which ^g, ^g and _2Q are straight alkyl residues, at least one them being methyl, the total sum of the carbon atoms of the acyl residue being preferably 10, and iii) a cross-linking agent such as pentaerythritol triallylether (STABYLEN 30, 3V SIGMA - Bergamo, Italy), and b) cross-linked copolymers formed by i) acrylic or methacrylic acid, ii) acrylates or inethacrylateε of

alkanolε, iii) a cross-linking agent like, for instance, the allyl ethers of saccharose or pentaerythritol, as an example, the products known under the trade name PEMULEN(^R) (B.F. Goodrich).

The amount of emulsifiers which can be used vary from about 0.1 to about 20% of the composition total weight. They can be used singularly or as mixtures thereof. Some of these emulsifiers can advantageously be employed as solvents for the combinations according to the invention. The cosmetics compositions of the invention can also comprise one or more vitamins, or their precursors, or their analogs. Specifically, the vitamins, or their precursors, or their analogs, which can advantageously be employed are selected from the group consisting of: i) vitamins of A group, including vitamin A₂ and retinal, and their possible esters with straight or branched, saturated or unsaturated (C₂_2₀)aliphatic onocarboxylic acids or (^c3_i2 )^alipha ic di- or tri- carboxyilic acids, said acids being optionally hydroxylated or alkoxylated with PEG, PPG, or copolymers PEG/PPG; or esters with nicotinic acids; ii) α- and β-carotene; iii) vitamins of the B group; iv) vitamin C, and its possible esters with straight or branched, saturated or unsaturated (C _₂o)^aliP^nat c monocarboxylic acids or (C _^₂)aliphatic di- or tri- carboxylic acids, said acids being optionally hydroxylated or alkoxylated with PEG, PPG, or copolymers PEG/PPG; or esters with nicotinic acid; v) the natural and synthetic tocopherols, including Vitamin E, as racemates, or in the form of their possible optically active isomers, and their possible esters with straight or branched, saturated or unsaturated (C₂_₂ø)aliphatic monocarboxylic acids or (C₃_₁₂)aliphatic di- or tri-carboxylic acids, said acids being optionally hydroxylated or alkoxylated with PEG, PPG, or copolymers PEG/PPG; or esters with nicotinic acid; vi) Essential Fatty Acids (EFA); vii) vitamin H; viii) vitamin P complex; and ix) vitamin PP. Generally, the amounts of vitamins, or their precursors, or their analogs, which can be employed, can vary within wide limits. Preferably, these amounts are comprised between about 0.02 and about 10% by weight, calculated on the composition total weight.

The cosmetic compositions comprising one or more of the above vitamins represent a further object of the present invention.

The cosmetic compositions of the invention can also comprise other conventional components, for example emulsion stabilizers such as sodium chloride or citrate, magnesium sulfate and analogs, in amounts ranging from about 0.1 to about 5% of the composition weight; wetting agents, such as glycerin, propylene glycol or 1,3- butylene glycol, in amounts from about 0.1 to about 30% of the composition weight; thickening agents, such as modified celluloses or acrylic acids polymers or copolymers, in amounts not above 4% of the composition weight; sequestering agents, such as EDTA salts, in amounts not higher than 1% of the composition weight; antioxidizers, such as tocopherols and the esters thereof, hydroxytoluene butoxide or butyl hydroxyanisol, in amounts not above 2% of the composition weight; emollients, such as mineral oils, polysiloxanes, almond oil, vaseline, isopropyl yristate or fatty acids triglycerids, in amounts from about 0.1 to about 95% of the composition weight; moisturizing agents in amounts not above 5% of the composition weight; agents for adjusting pH to the desired values, such as sodium or potassium citrate, sodium or potassium hydroxide, or citric acid onohydrate, in amounts not above 1% of the composition weight; film-forming agents, such as alkylated polyvinilpyrrolidones or high molecular weight waxes, in amounts not above 5% of the composition weight; preservatives, such as 2-bromo-2-nitro- propanediol, sodium dehydroacetate, isothiazolone, i idazolidinylurea, diazolidinylurea, parabens and hydantoin derivatives (GLYDANT™, Lonza), sorbic acid, benzoic acid and salts thereof, chlorhexidine and the salts thereof, phenoxyethanol, benzyl alcohol and analogs, in amounts not above 10% by composition weight.

Perfumes, antimicrobial agents, vegetal extracts such as, for instance, the green tea extracts or the walnut extract, depigmenting agents such as, for instance, magnesium ascorbil phosphate, and dyes can be added according to what known in the art. Moreover, the compositions of the invention can also contain artificial tanning agents such as dihydroxyacetone (DHA) and its derivatives, optionally in the presence of a iron salt, as described in EP-A- 0,688,203, in order to provide a less yellowish tan than that given by DHA alone. These artificial tanners can be present in amounts ranging from about 0.1 to about 10% of the composition weight.

The cosmetic compositions of the invention can be prepared according to the procedures known to those skilled in the art. Thus, for example, in the case of compositions in which the cosmetically acceptable carrier is an oil-in-water or water-in-oil emulsion, the two phases should preferably be prepared separately, dissolving or dispersing in any of them the desired components/lipophilic or hydrophilic ingredients, and subsequently mixed.

Examples of said compositions are sun-creams, day creams, moisturizing creams, sun-oils, ointments, lipsticks, solutions, lotions, gels, transparent gels, aerosol, foams and analogs. They contain a selected combination of the present invention together with the other ingredients in the above mentioned weight ratios, as well as any other compatible ingredient conventionally used in cosmetics. Generally speaking, said compositions will comprise a selected combination of the present invention so as to provide an SPF not lower than 2. The combinations of sunscreens of the present invention have often shown a synergistic effect.

The following examples further illustrate the invention. As mentioned above, the component a) is the compound of formula I in which R is tert-butyl , R^ and R₂ are both 2-ethyl-n.hexyl and X is oxygen. The amounts of the single components are expressed as weight percentages on the composition total weight. EXAMPLE 1

A face day-cream is prepared from

1. Cetylstearyl glucoside 4.0

2. Glyceryl stearate 1.0

3. Cetylstearyl alcohol 1.0 4. ^C12-15 ^alkylbenzoate 5.0

5. Octyl octanoate 5.0

6. Dimethicone 0.5

7. Component a) 1.0

8. Micronized zinc oxide-component k) 1.0 9. Demineralized water q.ε. to 100

10. Imidazolidinyl urea 0.3 11. Methyl p-hydroxybenzoate 0.2

12. Glycerin 3.0

13. Perfume 0.3

The mixture of components 1 to 6 is melted and heated to 70"C, then components 7 and 8 are added, under strong stirring (phase A). Separately_^ water is heated to 70°C (phase B). Phase A is added to phase B in a homogenizer. The mixture is cooled to room temperature, then glycerin, preservatives and perfume are added. EXAMPLE 2

A fluid oil-in-water emulsion is prepared from

1. Sorbitan(20)OE stearate 0.25

2. Avocado oil 3.0

3. Octyl palmitate 3.0 4. Mineral oil 3.0

5. Component a) 3.0

6. Micronized titanium dioxide-comp. k) 2.0

7. Demineralized water q.s. to 100

8. STABYLEN 30 (polymeric emulsifier 0.25 - 3V SIGMA, Bergamo, Italy)

9. 2-Phenylbenzimidazol-5-sulfonic- acid comp. i) 2.0

10. Sodium hydroxide q.s. to pH 7

11. Diazolidinyl urea 0.3 12. Isothiazolone 0.05

13. Propylene glycol 3.0

The mixture of components 1 to 4 is heated to 60"C then components 5 and 6 are added (phase A). Separately, component 8 is dispersed in about 90% of water, at 60 ^βC, under stirring (phase B). Subsequently, phase A is added to phase B in a homogenizer. Then, Component 9 is dissolved in the residual water at room temperature

(phase C), pH is adjusted to 7 with sodium hydroxide and phase C is added to phase A+B. The mixture is cooled to room temperature, then propylene glycol, preservatives and perfume are added.

EX MPLE 3

An anhydrous ointment is prepared from

1. Mineral oil q.s. to 100

2. Cetylstearyl isononanoate 30.0 3. ^c8-10 triglycerid 30.0 . Component a) 5.0

5. 4-tert-butyl-4 ' -methoxy-diben- zoylmethane component c) 1.0

6. Micronized titanium dioxide- component k) 2.0

7. Hydrogenated castor oil 1.5

8. Pyrogenic silica 1.5

9. Perfume 0.3

The mixture of components 1, 2 and 3 is heated to 60°C and components 4 and 5 are added, under stirring. Components 6, 7 and 8 are then dispersed in the above mixture, under strong stirring. The mixture is finally cooled to room temperature and added with the perfume. EXAMPLE 4 A fluid water-in-oil emulsion is prepared from

1. Hydrogenated castor oil(7)OE 7.5

2. Lanolin alcohols in mineral oil 2.5

3. Hydrogenated polyisobutene 5.0

4. Octyl octanoate 5.0 5 . ^c8-lθ ^triglY^{ce r}i^{d 3} - °

6 . Component a) 5 . 0 7. 4-tert-Butyl-4 ' -methoxy-diben- zoylmethane-component c) 2.0

8. 2-Cyano-3,3-diphenyl-acrylic acid 2-ethyl-hexyl ester component g) 5.0 9. Demineralized water q.s. to 100

10. Dimethyl-dimethylol-hydantoin 0.3

11. Phenoxyethanol and parabens 1.0

12. Glycerin 5.0

13. Perfume 0.3 The mixture of components 1 to 5 is heated to 70^βC and components 6 and 7 are added, under stirring (phase A) . Component 8 is then dispersed in phase A under strong stirring. Separately, water is heated to 70°C and added to phase A in a homogenizer. The mixture is cooled to room temperature, added with the preservatives mixed in glycerin and with the perfume. EXAMPLE 5

A high-protection water-in-oil cream is prepared front 1. Triglyceryl diisostearate 4.0

2. Bees-wax 2.0

3. Mineral oil 10.0

4. Octyl octanoate 5.0

5. Cyclomethicone 5.0 6. Component a) 5.0

7. 2-Cyano-3 ,3-diphenylacrylic acid 2-ethyl-hexyl ester component g) 5.0

8. 4-tert-Butyl-4 ' -methoxy-dibenzoyl- methane-component c) 2.0 9. Hydrogenated castor oil 0.5

10. Micronized titanium dioxide- component k) 5.0

11. Demineralized water q.s. to 100

12. 2-Phenylbenzimidazol-5-sulfonic acid - component i) 3.0 13. Triethanola ine q.s. tot pH 6.5

14. Sodium dehydroacetate 0.3

15. Phenoxyethanol and parabens 1.0

16. Glycerin 5.0

17. Perfume 0.3 The mixture of components 1 to 5 is melted at 60"C and, components 6, 7 and 8 are added, under stirring (phase A) . Components 9 and 10 are subsequently dispersed in this phase in a homogenizer. Separately, about 90% of water is heated to 60°C and added to phase A in a homogenizer. Then, cooling is started. Component 12 is dissolved in the reεidual water at room temperature, and the resulting solution is neutralized with 13 (phase C). Phase C is added to the above prepared emulsion, which is then cooled to room temperature and added with preservatives, glycerin and perfume. EXAMPLE 6

A fluid oil-in-water emulsion is prepared from 1. Stearic acid (100)OE 2.0 2. Cetylstearyl alcohol 1.0

3. Avocado oil 3.0

4. Jojoba oil 6.0

5. Karite butter 2.0

6. Butyl hydroxyanisol 0.1 7. Dimethicone and dimethiconol 1.0

8. Component a) 3.0 9. 3-(4-Methylbenzilydene)-camphor

- component b) 2.0

10. Micronized titanium dioxide - component k) 1.0 11. Demineralized water q.s. to 100

12. SYNTHALEN L (Carbomer 941 -

3V SIGMA, Bergamo, Italy) 0.5

13. Potassium cetylphosphate 1.0

14. Amino ethyl propanol 0.4 15. Imidazolidinyl urea 0.3

16. Potassium sorbate 0.5

17. EDTA disodium 0.1

18. Glycerin 3.0

19. Soluble collagene (1% sol.) 2.0 20. Perfume 0.3.

The mixture of components 1 to 6 is melted at 70°C and components 8, 9 and 10 are added, under strong stirring (phase A). Separately water is heated to 70°C and first component 12, then component 13 are dispersed, under stirring (phase B). Phase A is added to phase B in a homogenizer, and the resulting mixture is then neutralized (pH 7) with component 14. The mixture is cooled to room temperature and added with preservatives, glycerin, collagene and perfume. EXAMPLE 7

An oil-in-water cream is prepared from

1. Cetylstearyl alcohol(33 )OE 3.0

2. Glyceryl stearate(20)OE 2.0

3. Behenyl alcohol 2.0 4. Isohexadecane 10.0

5. Safflower oil 3.0 6 . Borage oil 2 . 0

7. Butyl hydroxyanisol 0.1

8. Copolymer PVP/eicosene 1.0

9. Component a) 3.0 10. 3-(4-Methylbenzilidene)-camphor - component b) 2.0

11. 2-Hydroxy-4-methoxy-benzophe- none - component f ) 1.0

12. Micronized zinc oxide - component k) 2.0

13. Demineralized water q.s. to 100

14. SYNTHALEN K (Carbomer 940 -

3V SIGMA, Bergamo, Italy) 0.15

15. Aminomethyl propanol 0.1 16. Imidazolidinyl urea 0.3

17. Phenoxyethanol and parabens 1.0

18. Butylene glycol 2.0

19. Perfume 0.3

The mixture of components 1 to 8 is melted at 70 "C and components 9 to 12 are added, under strong stirring

(phase A) . Separately, component 14 is dispersed in water at 70"C, under stirring (phase B). Phase A is then added to phase B in a homogenizer, and the resulting mixture is then neutralized (pH 7) with component 15. Finally, the mixture is cooled to room temperature and added with preservatives, butylene glycol and perfume. EXAMPLE 8

A water-in-oil cream is prepared from

1. Methylglucose dioleate 5.0 2. Copolymer PEG-45/dodecyl glycol 3.0

3. Mineral oil 10.0 4 . Paraf f in 1 . 0

5. Dioctyl aleate 5.0

6. Isopropyl myristate 5.0

7. Component a) 3.0 8. 3-(4-Methylbenzilidene)-camphor - component b) 3.0

9. 4-tert-Butyl-4 ' methoxy-dibenzoyl- ethane - component c) 1.0

10. Hydrogenated castor oil 0.5 11. Micronized titanium dioxide - component k) 2.0

12. Demineralized water q.s. to 100

13. Magnesium sulfate 0.5

14. 2-Bromo-2-nitro-propanediol 0.3 15. Phenoxyethanol and parabens 1.0

16. Propylene glycol 2.0

17. Tocopherol acetate 1.5

18. Perfume 0.3

The mixture of components 1 to 6 is melted at 60°C and components 7, 8 and 9 are added, under stirring. Components 10 and 11 are then dispersed in the fat mixture under strong stirring (phase A). Separately, water is heated to 70°C, component 13 is added thereto, and the resulting aqueous solution is added to phase A, in a homogenizer. The mixture is cooled to room temperature and added with preservatives, perfume, vitamin and propylene glycol. EXAMPLE 9

A silicon water-in-oil emulsion is prepared from 1. Cetyl Dimethicone Copolyol 3.0

2. Lanolin alcohols in mineral oil 2.5 3. Cyclomethicone 10.0

4. Di-( 2-ethyl-hexyl) malate 5.0

5. Octyldodecyl neopentanoate 5.0

6. Perfume 0.3 7. Component a) 3.0

8. 4-tert-Butyl-4 ' -methoxy-diben- zoylmethane - component c) 1.0

9. 2-Hydroxy-4-methoxy-benzophenone component f) 1.0 10. Micronized titanium dioxide comp. k) in isopropyl myristate 4.0

11. Demineralized water q.s. to 100

12. Sodium chloride 2.0

13. Chlorhexidine digluconate 0.3 14. Methyl paraben 0.2

15. Glycerin 5.0

A mixture of components 1 to 6 is prepared, components 7 , 8 and 9 are dissolved therein and subsequently, in the resulting mixture, component 10 is dispersed, at room temperature (phase A). Components 12 to 15 are dissolved in water, at room temperature (phase B), then phase B is slowly added to phase A, under stirring. Finally, the emulsion is made homogeneous in a homogenizer . EXAMPLE J.0

A sun-oil is prepared from

1. Dioctyl cyclohexane q.s. to 100

2. ^c8-10 triglycerid 20.0

3. Isopropyl palmitate 30.0 4. Cyclomethicone 10.0

5. Perfume 0.3 6. Component a) 3.0

7. Octyl salicylate - component h) 2.0

8. 4-tert-butyl-4 ^■ -methoxy-dibenzoyl- ethane component c) 1.0

The mixture of components 1, 2 and 3 is heated to 60^βC and components 6, 7 and 8 are added, under stirring. The resulting mixture is cooled to room temperature and added with components 4 and 5. EXAMPLE 11

An oil-in-water cream is prepared with

1. Cetylstearyl alcohol and cetylstearyl glucoside 3.50

2. Glyceryl stearate 1.00 3. Cetylstearyl alcohol 0.50

4. Propylene glycol dibenzoate 10.00

5. (C₁₂_i5)^alkγl benzoate 7.00

6. Dimethicone 1.00

7. Component a) 4.00 8. 4-tert-Butyl-4'-methoxy- dibenzoylmethane - component c) 2.00

9. De ineralized water q.s. to 100

10. SYNTHALEN K (Cabo er 940 -

3V SIGMA, Bergamo, Italy) 0.10 11. Potassium cetylphosphate 0.50

12. PEG-25 p-aminobenzoic acid - component j) 4.00

13. Aminomethyl propanol 0.05

14. Butylene glycol 1.50 15. Phenoxyethanol and parabens 1.00

16. Perfume 0.30 The mixture of components 1 to 6 is heated to 70°C and, under stirring, is added with components 7 and 8

(phase A). Separately, component 10 is dispersed into the water, previously heated to 70^βC, and the resulting dispersion is added with components 11 and 12 (phase B).

Then, phase A is added to phase B in a homogenizer, the obtained mixture is cooled at room temperature, subsequently neutralized with component 13, and finally added with components 14 to 16. EXAMPLE 12

An oil-in-water milk is prepared with

1. PEG-4 Polyglyceryl 2-laurate 2.00

2. Dicaprylyl ether 7.50

3. Propylene glycol dicaprylate/dicaprate 9.50 4. Cetyl lactate 3.00

5. Cetylstearyl alcohol 0.75

6. Dimethicone 0.50

7. α-tocopheryl acetate 1.50

8. Component a) 4.00 9. 4-tert-Butyl-4 ' -methoxy-dibenzoylmethane component c) 2.00

10. Demineralized water q.s. to 100

11. Stabylen 30 (3V SIGMA, Bergamo, Italy) 0.25

12. Trilauryl 40E phosphate 0.80 13. Aminomethyl propanol 0.20

14. Butylene glycol 2.00

15. Phenoxyethanol and parabens 1.00

16. Disodium EDTA 0.05

17. Perfume 0.30 The mixture of components 1 to 7 is heated to 70 °C and, under stirring, is added with components 8 and 9 (phase A). Separately, compound 11 is dispersed into the water, previously heated to 70°C, and the resulting dispersion is added with component 12 (phase B). Then phase A is added to phase B in a homogenizer, the obtained mixture is cooled to room temperature, subsequently neutralized with component 13, and finally added with components 14 to 17.

EXAMPLE 13

An oil-in-water cream is prepared with 1. PEG-100 Stearate 2.00

2. Glyceryl stearate 1.00

3. Cetearyl alcohol 2.50

4. Stearic acid 5.00

5. Propylene glycol dicaprylate/dicaprate 9.50 6. Caprylic/Capric triglyceride 3.00

7. Dimethicone 0.50

8. Ascorbyl palmitate 1.00

9. Component a) 4.00

10. Titanium dioxide MT100T (Taika Corp.) - component k) 4.00

11. Isohexadecane 5.00

12. Cyclomethycone 2.50

13. Demineralized water q.s. to 100

14. Potassium cetylphosphate 0.50 15. Stabylen 30 ( 3V SIGMA, Bergamo, Italy) 0.15

16. Butylene glycol 1.50

17. Imidazolidinyl urea 0.30

18. Methylparaben 0.20

19. Propylparaben 0.10 20. Perfume 0.30

The mixture of components 1 to 8 is heated to 70°C and subsequently added with component 9 under stirring.

Separately, component 10 is dispersed at room temperature in components 11 and 12, and the resulting dispersion is added to the hot mixture of components 1 to 8 (phase A). Component 15 is dispersed into the water, previously heated to 70°C, and the resulting dispersion is added with component 14 (phase B). Phase A is added to phase B in a homogenizer, the resulting mixture is cooled to room temperature and subsequently added with components 16 to 20.

EXAMPLE 14

An oil-in-water cream is prepared with

1. PEG-100 stearate 2.00

2. Gliceryl stearate 1.00 3. Cetearyl alcohol 2.50

4. Stearic acid 5.00

5. Propylene glycol dicaprylate/dicaprate 9.50

6. (C₁₈_₃g)acid glycol ester 2.00

7. Retinyl palmitate 1.00 8. α-tocopheryl acetate 1.00

9. Component a) 4.00

10. Titanium dioxide MT100T (Taika Corp.) component k) 4.00

11. Isohexadecane 5.00 12. Cyclomethicone 2.50

13. Demineralized water q.s. to 100

14. Potassium cetylphosphate 0.50

15. Stabylen 30 (3V SIGMA, Bergamo, Italy) 0.15

16. Butylene glycol 1.50 17. Green tea extract 1.00

18. Imidazolidinyl urea 0.30 19. Methylparaben 0.20

20. Propylparaben 0.10

21. Perfume 0.30 The mixture of components 1 to 8 is heated to 70"C and subsequently added with component 9 under stirring. Separately, component 10 is dispersed at room temperature in components 11 and 12, and the resulting dispersion is added to the hot mixture of components 1 to 8 (phase A). Component 15 is dispersed into the water, previously heated to 70°C, and the resulting dispersion is added with component 14 (phase B). Phase .A is added to phase B in a homogenizer, the resulting mixture is cooled to room temperature and subsequently added with components 16 to 21.

Claims

1. Combinations of sunscreens, which comprise: a) at least one compound of formula I:

wherein:

R is a straight or branched (C^__Q) alkyl group, (^c5_i2^ cycloalkyl, optionally substituted with one or more straight or branched (C^_^) alkyl groups; X is an oxygen atom or the group -NH-; R^ has the same meanings as R, or is hydrogen, a monovalent metal ion, a quaternary ammonium group, or a group of formula II

in which A is a straight or branched (C^_g) alkyl, (C^_ ^₂) cycloalkyl, or (C _^₀) ^a γl optionally substituted with one or more straight or branched (C₁_₄) alkyl groups; R₃ is hydrogen or methyl; n is an integer from 1 to 10; R₂ has the same meaning as R when X is -NH-, or has the same meanings as R^ when X is oxygen; in combination with at least one or more sunscreens selected from the following classes of compounds: b) benzylidenecamphor derivatives of formula III:

wherein R^ is hydrogen, or the group S0₃M, in which M is hydrogen, or a monovalent metal ion, or a quaternary ammonium group, and Rg is hydrogen, methyl, a group S0 M wherein M is defined as above, or a group of formula IV or V

CH.

wherein R₄ is as defined above; c) dibenzoylmethane derivatives of formula VI

in which and γ are selected independently from hydrogen, straight or branched (C^_g) alkyl and straight or branched (C^_₈) alkoxy; d) alkoxycinnamic acid esters of formula VII

R₈-0

wherein g is a straight or branched (C₁_₈) alkyl group, and R_Q is selected from hydrogen, a straight or branched (C^_₁₀) alkyl group, a monovalent metal ion and a quaternary ammonium group; e) triazinoaniline derivatives of formula VIII

in which R, R^ and R₂ are defined as above for formula

(I) f) benzophenone derivatives of formula IX

wherein R.._Q is hydrogen or a straight or branched (C^_ JΛ) alkyl group, R^ is hydrogen or the group S0₃Q, in which Q is hydrogen, a monovalent metal ion or a quaternary ammonium group, and R^₂ i hydrogen, hydroxy or straight or branched (C^..^) alkoxy; g) diphenylcyanoacrylates of formula X

<°\ C = C COORχ3

wherein R₁₃ has the same meanings as R., defined above, h) salicylic acid derivatives of formula XI

wherein R^ is a straight or branched (^cι_ιn) alkyl group, a benzyl group optionally substituted with a straight or branched (^cι_6) alkyl group, a 3,3,5- trimethylcyclohexyl residue, both as a racemate and as any optically active forms, or the group HN⁺(CH₂CH₂OH)₃; i) benzimidazolesulfonic acid derivatives of formula XII

in which G is hydrogen, or a monovalent metal ion, or a quaternary ammonium group; j) p-aminobenzoic acid (PABA) derivatives of formula XIII

wherein R^ and R^g are independently hydrogen or a straight or branched (^cι_6) alkyl group, optionally substituted with a hydroxyl group, and R^₇ is selected from hydrogen, a straight or branched (C^__1Q) alkyl group, a monovalent metal ion and a quaternary ammonium group, or R₁₅ is the group -(CH₂-CH₂0)_χH, R^ is the group -(CH₂-CH₂0) H and R^₇ is the group -CH₂-CH₂-(OCH₂-

CH₂)_zOC₂H₅, in which the sum of x, y and z is 25; k) metal oxides having atomic number ranging from 11 to 40.

2. A combination as claimed in claim 1, wherein compound a) is combined with a compound selected from groups b), c), d), e), f), g), h), i), j) and k) .

3. A combination as claimed in claim 1, wherein compound a) is combined with more compounds selected independently within and/or from groups b), c), d), e), f), g), h), i), j) and k) .

4. A combination as claimed in any one of claims 1-3, wherein in compounds of formula (I), R is selected from the group consisting of methyl, 2,4,4-trimethyl-pent-2- yl, isopropyl, tert-butyl; R^ is selected from the group consisting of 2-ethyl-hexyl, isopropyl and n-tetradecyl; R₂ is selected from isopropyl or 2-ethyl-hexyl; X is an oxygen atom or the group -NH-.

5. A combination as claimed in claim 4, wherein in compounds of formula (I), R is tert-butyl; R^ and R₂ are 2-ethyl-hexyl; X is an oxygen atom.

6. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (III), R₄ is hydrogen and R₅ is methyl or the group formula (IV), or R₄ is the group S0₃M, wherein M is hydrogen or a monovalent metal ion and R₅ is the group of formula (V) in which R₄ is as defined above.

7. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (VI), R_g is selected from isopropyl and tert-butyl, R₇ is selected from hydrogen and methoxy.

8. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (VII), Rg is methyl and Rg is 2-ethyl-hexyl or the group ⁺NH₂(CH₂CH₂OH)₂.

9. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (VIII), R, R^ and R₂ are 2-ethyl-hexyl.

10. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (IX), R₁₀ is selected from hydrogen and methyl; R^ is selected from hydrogen and the group S0₃Q, in which Q is hydrogen or a monovalent metal ion; R^₂ is hydrogen.

11. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (X), R₁₃ is 2-ethyl- hexyl.

12. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (XI), -^ is selected from 2-ethyl-hexyl, the residue (+)-3,3,5- trimethylcyclohexyl and the group NH(CH₂CH₂OH)₃.

13. A combination as claimed in any one of claims 1-5, wherein in compounds of formula (XII), G is selected from hydrogen or a monovalent metal ion.

14. A combination as claimed in any one of claims 1-5, wherein compound of formula (XIII) is selected from those in which:

^R15' ^R16 ^{and R}17 ^are hydrogen;

R^g and R^g are at the same time methyl or 2- hydroxypropyl and R₁₇ is ethyl or 2-hetylhexyl; R₁₅ is the group -(-CH₂-CH₂-0-)_χ-H, R₁₆ is the group -(-CH₂-CH₂-0-)_y-H, R_1? is the group -CH₂-CH₂-(-0-CH₂- CH₂-)_z-OC₂H₅, in which the sum of x, y and z is 25.

15. A combination as claimed in any one of claims 1-5, wherein the compound of group k) is selected from titanium dioxide in the micronized form, with particles of size not higher than about 100 nm, and zinc oxide in the micronized form, with particles of size from about 15 nm to about 300 nm, said oxides being optionally coated.

16. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 15.

17. A combination as claimed in any one of claims 1-5, or claim 16, wherein the combined compound is at least one compound as claimed in claim 13.

18. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 7 and at least one compound as claimed in claim 15.

19. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 7, the compound of claim 11, and optionally at least one compound as claimed in claim 15.

20. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 7, the compound of claim 11, at least one compound as claimed in claim 13, and optionally at least one compound as claimed in claim 15.

21. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 6 and at least one compound as claimed in claim 15.

22. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 6, at least one compound as claimed in claim 13, and optionally at least one compound as claimed in claim 15.

23. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 6, at least one compound as claimed in claim 7, and optionally at least one compound as claimed in claim 15.

24. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 7, at least one compound as claimed in claim 10, and at least one compound as claimed in claim 15.

25. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 8 at least one compound as claimed in claim 10, and optionally at least one compound as claimed in claim 15.

26. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound as claimed in claim 9, and optionally at least one compound as claimed in claim 13.

27. A combination as claimed in any of the claims 1-5, wherein the combined compound is at least one compound as claimed in claim 7, and at least one compound as claimed in claim 8.

28. A combination as claimed in any one of claims 1-5, wherein the combined compound is at least one compound aε claimed in claim 7 and at least one compound as claimed in claim 12.

29. A combination as claimed in any one of claims 1-5, wherein the combined compound is at. least one compound as claimed in claim 7 and at least one compound as claimed in claim 14.

30. Cosmetic or dermatological compositions containing a combination as claimed in any one of claims 1-29, in an amount ranging from about 0.1 to 35% by weight on the composition total weight.

31. Compositions as claimed in claim 30, wherein component a) is present in an amount ranging from about 0.05 to about 20% of the composition total weight and at least one of the other components b) to k) is present in an amount ranging from about 0 to 30% by weight on the composition total weight, with the proviso that at least one of the components b) to k) is present in amounts different from 0.

32. Cosmetic compositions as claimed in claims 30 and

31. which are oil-in- water, water-in-oil, oil-water- oil, water-oil-water emulsions, oily solutions, lipid fusions, hydro-alcoholic or anhydrous aqueous gels, alcoholic or hydro-alcoholic solutions.

33. Cosmetic compositions as claimed in any one of claims 30 to 32, in which the solvent or dispersant of the oily phase is selected from hydrocarbons; oils, butters and natural waxes; silicones oils; esters of straight or branched, saturated or unsaturated aliphatic acids or of aromatic or alkylaromatic acids, having 1 to 25 carbon atoms, said acids being optionally hydroxylated and/or ethoxylated, with mono- or polyhydroxylated aliphatic alcohols, saturated or unsaturated, straight or^" branched, having 1 to 25 carbon atoms; amides; alcohols containing 6 to 35 carbon atoms; ethers of fatty alcohols having 8 to 40 carbon atoms; butyl ethers of glycols or esters of (C^_g)alkyl ethers.

34. Cosmetic compositions as claimed in any one of claims 30 to 33, in which the solvent or dispersant of the oily phase is selected from esters of straight or branched, saturated or unsaturated aliphatic acids or of aromatic or alkylaromatic acids, having 1 to 25 carbon atoms, said acids being optionally hydroxylated and/or ethoxylated, with mono- or polyhydroxylated aliphatic alcohols, saturated or unsaturated, straight or branched, having 1 to 25 carbon atoms, N,N-diethyl- methyl-benzamides or ethyl l-(N-acetyl-N- butyl )propionate, or mixtures thereof.

35. Cosmetic compositions as claimed in any one of claims 30 to 33, in which the solvent or dispersant of the oily phase is a silicones oil.

36. Cosmetic compositions as claimed in any one of claims 30 to 35, in which the solvent or dispersant of the oily phase is used in amounts ranging from about 0.5 to about 95% of the composition total weight.

37. Cosmetic compositions as claimed in any one of claims 28 to 33, which comprise an emulsifier selected from anionic, a photeric or non-ionic emulsifiers, or emulsifiers selected from a cross-linked copolymer consisting of i) acrylic or methacrylic acid, ii) vinyl esters of highly branched trialkylacetic acids of formula XIV

in which

nd R_2Q are straight alkyl residues, at least one them being methyl, the total sum of the carbon atoms of the acyl residue being preferably 10, and iii) a cross-linking agent, and b) cross-linked copolymers formed by i) acrylic or methacrylic acid, ii) acrylates or methacrylates of (C₁₀_₃₀)aliphatic alkanolε, iii) a cross-linking agent.

38. Compositions as claimed in any one of claims 30-37, further comprising vitamins, or their precursors, or their analogs, selected from the group consisting of: i) vitamins of A group, including vitamin A₂ and retinal, and their possible esters with straight or branched, saturated or unsaturated (C₂_₂₀)aliphatic monocarboxylic acids or (C₃_^₂)aliphatic di- or tri- carboxylic acids, said acids being optionally hydroxylated or alkoxylated with PEG, PPG, or copolymers PEG/PPG; or esters with nicotinic acid; ii) α- and β-carotene; iii) vitamins of the B group; iv) vitamin C, and its possible esters with straight or branched, saturated or unsaturated (C₂_ _Q )aliphatic monocarboxylic acids or

di- or tri- carboxylic acids, said acids being optionally hydroxylated or alkoxylated with PEG, PPG, or copolymers PEG/PPG; or esters with nicotinic acid; v) the natural and synthetic tocopherols, as racemates or in the form of their possible optically active isomers, and their possible esters with straight or branched, saturated or unsaturated (C₂_2o)^al ⁿ tic monocarboxylic acids or

di- or tri- carboxylic acids, said acids being optionally hydroxylated or alkoxylated with PEG, PPG, or copolymers

PEG/PPG; or esters with nicotinic acid; vi) Essential Fatty Acids (EFA); vii) vitamin H; viii) vitamin P complex; and ix) vitamin PP.

39. Compositions as claimed in claim 38, wherein the vitamins are employed in amounts comprised between about 0.02 and about 10% by weight, calculated on the composition total weight.

40. Composition as claimed in any one of claims 30 or 31, having a sun protecting factor (SPF) not lower than 2.

41. The use of a combination as claimed in any one of claims 1 to 29 for the preparation of a dermatological or cosmetic composition useful for protecting human skin from sun radiations.

42. A method for the stabilization of a photosensitive composition, which comprises including a combination of any one of claims 1-29.

43. A method as claimed in claim 42, wherein said composition is a cosmetic or dermatological composition.

44. A method as claimed in claim 42, wherein said composition is a composition of one or more polymers.