EP0966259A1

EP0966259A1 - Triple emulsion containing a solar protecting system

Info

Publication number: EP0966259A1
Application number: EP98942807A
Authority: EP
Inventors: Delphine Allard
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 1997-09-16
Filing date: 1998-09-01
Publication date: 1999-12-29
Also published as: JP2000506547A; US6174518B1; AR012517A1; AU9080298A; FR2768337A1; FR2768337B1; WO1999013853A1

Abstract

The invention concerns a cosmetic or dermatological emulsion of the water/oil/water type (E/H/E), characterised in that it comprises: (a) an outer aqueous phase and (b) a discontinuous fatty phase constituting with an inner aqueous phase a primary water/oil emulsion (E/H), said fatty phase containing as lipophilic emulsifier at least a copolymer block consisting of a polymer sequence derived from a monohydroxycarboxylic acid and of a polymer sequence derived from an alkylglycol or from a polyalkyleneglycol; (c) at least a solar protection system capable of filtering UV rays (UV-A and/or UV-B). The invention also concerns uses of said emulsion in and for preparing cosmetic or dermatological compositions for solar protection of the skin or of the hair.

Description

TRIPLE EMULSIONS CONTAINING A PHOTOPROTECTIVE SYSTEM

The present invention relates to triple cosmetic / dermatological emulsions of the water / oil / water type comprising a discontinuous fatty phase containing as water / oil emulsifier at least one block copolymer consisting of a polymer sequence derived from a monohydroxycarboxylic acid and d '' a polymer sequence derived from an alkyl glycol or a polyalkylene glycol and a photoprotective system capable of filtering UV rays (UV-A and / or UV-B)

We know that the light radigtions of wavelengths between 280 nm and 400 nm allow the browning of the human epidermis and that the rays of wavelengths between 280 nm and 320 nm, known under the name of UV -B, cause erythema and skin burns which can affect the development of natural tanning; this UV-B radiation must therefore be filtered.

It is also known that UV-A rays, of wavelengths between 320 nm and 400 nm, which cause browning of the skin, are capable of inducing an alteration of the latter, in particular in the case of a sensitive skin or skin continuously exposed to solar radiation. UV-A rays cause in particular a loss of elasticity in the skin and the appearance of wrinkles, leading to premature aging. They promote the triggering of the erythematous reaction or amplify this reaction in certain subjects and can even be the cause of phototoxic or photoallergic reactions. It is therefore desirable to also filter UV-A radiation.

According to the invention, the term “photoprotective system capable of filtering UV radiation” is generally intended to denote any compound or any combination of compounds which, by known mechanisms of absorption and / or reflection and / or diffusion of UV-A and / or UV-B radiation, makes it possible to prevent, or at least limit, the contacting of said radiation with a surface (skin, hair,) on which this or these compounds have been applied. In other words, the compounds targeted by the present invention are both organic UV-absorbing photoprotective filters and

(nano) UV diffusing and / or reflecting mineral pigments, as well as their mixtures.

Many cosmetic and / or dermatological compositions intended for the photoprotection (UV-A and / or UV-B) of the skin have been proposed to date.

These sunscreen compositions are quite often in the form of an emulsion, of the oil-in-water type (that is to say a cosmetically and / or dermatologically acceptable support consisting of a continuous aqueous dispersing phase and a discontinuous dispersed fatty phase) or water-in-oil (aqueous phase dispersed in a continuous fatty phase), which contains, at various concentrations, one or more conventional organic filters, lipophilic and / or hydrophilic, capable of selectively absorbing radiation Harmful UV rays, these filters (and their quantities) being selected according to the sun protection factor sought (the sun protection factor (SPF) expressed mathematically by the ratio of the irradiation time necessary to reach the erythematogenic threshold with the filter UV at the time necessary to reach the erythematogenic threshold without UV filter). In such emulsions, hydrophilic filters are present in the aqueous phase and lipophilic filters are present in the fatty phase.

The sunscreen compositions in the form of an oil-in-water or water-in-oil emulsion may contain pigments and / or mineral nanopigments (that is to say pigments with an average size of the primary particles generally does not exceed 100 nm) based on metal oxides, and in particular titanium oxide. They are more and more sought after taking into account the fact that the latter substances, when they are associated with conventional UV filters (mainly organic compounds capable of absorbing harmful radiation) make it possible to obtain very high protection indices. These nanopigments can be present both in the aqueous phase of the emulsion and in its fatty phase.

Oil-in-water emulsions are, in general, more appreciated by the consumer than water-in-oil emulsions, in particular because of their pleasant feel (close to water) and their presentation in the form of non-fat milk or cream; however, they also more easily lose their effectiveness in UV protection when they come into contact with water; in fact, hydrophilic filters, particularly acid filters, disappear in water, by swimming in the sea or in a swimming pool, in the shower or during the practice of water sports; thus, the sun compositions which contain them, alone or combined with lipophilic filters, no longer provide the initial protection sought when the substrate (skin or hair) on which they have been applied comes into contact with water, this loss in protection index by elimination of the hydrophilic filter with water, being all the more marked when the lipophilic-hydrophilic filtering association, present in the composition, is synergistic at the level of the sun protection factor.

Sunscreen compositions having improved SPF and water resistance can be available by using water-in-oil emulsions. Indeed, a hydrophilic filter is more persistent in water in a water-in-oil emulsion than in an oil-in-water emulsion. However, as indicated above, such compositions are not yet entirely satisfactory insofar as they leave after application an impression of fat which is particularly unpleasant for the user.

Thus, the need still remains as to be able to have sunscreen compositions which can contain both hydrophilic filters, lipophilic filters, as well as nanopigments whose SPF would be high, stable in the time and water resistant, whatever the hydrophilic and / or epophilic filters and / or the nanopigments used and whose cosmetic performance would be comparable to that obtained with conventional oil / water emulsions

Other types of emulsions known as multiples of the water / oil / water (W / O / W) or oil / water / oil (O / W / O) type are known in the prior art. Among the multiple emulsions, preferably emulsions with an external aqueous phase, namely W / O / W emulsions, which combine the advantages of freshness with application, provided by the water present in the external aqueous phase, and the comfort provided by a quantity relatively large oil In particular, it was proposed in document WO-A-94/224 4 a process for preparing multiple W / O / W emulsions consisting in preparing a W / O emulsion containing as W / O emulsifier a fatty acid and glyceryl ester, and in dispersing this emulsion in an aqueous phase in the presence of an O / W emulsifier chosen from oxyethylenated fatty alcohols and oxyethylenated sterols

By W / O emulsifier is meant, within the meaning of the present invention and in the text which follows, any compound having emulsifying properties making it possible to produce water-in-oil emulsions

By O / W emulsifier is understood, within the meaning of the present invention and in the text which follows, any compound having emulsifying properties making it possible to produce oil-in-water emulsions

Unfortunately, the stability of the emulsions obtained according to this document is not sufficient to meet the requirements of the products sold and in particular for storage at high temperatures, for example above 40 ° C. Such instability can lead to a W / O emulsion, leading to a loss of the qualities of the multiple emulsion, in particular its quality of freshness on application since the external phase is no longer an aqueous phase This multiple emulsion can also transform into an O / W emulsion, often unstable with oil and water phase shift. In addition, these emulsions require a choice of particular oils in large quantities which are not very emollient and are not always well tolerated by the skin and can cause irritation.

EP-A-691839 also discloses triple emulsions

W / O / W cosmetics comprising a primary W / O emulsion containing in the discontinuous fatty phase as a W / O emulsifier a polyoxyethylenated derivative

(2.5 moles of ethylene oxide) and polyoxypropylene (1.5 moles of propylene oxide) of a mixture of glycerol esters and sorbitol of hydroxystearic and isostearic acids sold under the trade name ARLACEL 780 by the Company HERE.

The Applicant has found that this type of emulsion could not be used in the field of protecting the skin and the hair against UV radiation, in particular against solar radiation insofar as they were unstable on storage in the presence of hydrophilic filters and / or lipophilic filters and / or nanopigments based on metal oxides in their composition.

The Applicant has surprisingly and unexpectedly discovered that certain multiple W / O / W emulsions comprising in the external aqueous phase a primary W / O emulsion containing in the discontinuous fatty phase as W / O emulsifier a block copolymer consisting of a polymer sequence derived from a monohydroxycarboxylic acid and a polymer sequence derived from an alkylglycol or a polyalkyleneglycol, on the one hand could contain hydrophilic filters, lipophilic filters as well as nanopigments without presenting the problems of stability mentioned above and on the other hand could lead to high and stable SPF over time, whatever the hydrophilic (s) and / or lipophilic (s) filters and / or the nanopigments used. The Applicant has also discovered that these same specific multiple W / O / W emulsions not only made it possible to obtain sunscreen compositions whose cosmetic performance was comparable to those generally obtained with a conventional sunscreen composition in the form of an oil / water emulsion but also exhibited improved water retention.

The Applicant has also discovered that these same multiple W / O / W emulsions could contain a wide variety of oils constituting the fatty phase of said emulsions, well tolerated by the skin, not causing irritation and providing the cosmetic advantages of emulsion with external aqueous phase.

These discoveries are at the origin of the present invention.

The subject of the present invention is a triple cosmetic / dermatological emulsion of the W / O / W type, characterized in that it comprises:

(a) an aqueous external phase and

(b) a discontinuous fatty phase constituting with an internal aqueous phase a W / O primary emulsion, said fatty phase containing as W / O emulsifier at least one block copolymer consisting of a polymer sequence derived from a monohydroxycarboxylic acid and from a polymer sequence derived from an alkyl glycol or a polyalkylene glycol;

(c) at least one photoprotective system capable of filtering UV rays (UV-A and / or UV-B).

By cosmetic or dermatological emulsion, within the meaning of the present invention and in the following text, is meant any emulsion in which the external and internal aqueous phases and the discontinuous fatty phase consist of cosmetically or dermatologically acceptable substances for topical application to materials human keratin including skin, hair, eyelashes, eyebrows, lips, nails or mucous membranes. The present invention also relates to a cosmetic treatment method for protecting the skin and / or hair against ultraviolet radiation, in particular solar radiation, consisting in applying to the latter an effective amount of a composition as defined above.

The present invention also relates to the use of the composition as defined above as, or for the manufacture of cosmetic compositions for the protection of the skin and / or the hair against ultraviolet radiation, in particular solar radiation.

Other characteristics, aspects and advantages of the present invention will appear on reading the detailed description which follows.

According to the present invention, the W / O emulsifiers of the block copolymer type consisting of a polymer block derived from a monohydroxycarboxylic acid and a polymer block derived from an alkyl glycol or a polyalkyleneglycol correspond to the following general formula: ABA (I)

in which :

A denotes an oil-soluble monohydroxycarboxylic acid residue having a molecular weight of at least 500 of the following formula:

in which :

R is hydrogen or a substituted or unsubstituted monovalent hydrocarbon group

R is hydrogen or a monovalent hydrocarbon group at CC ₂₄ ;

R ₂ a divalent C _r C ₂₄ hydrocarbon group; p is a number from 1 to 200; B denotes a divalent residue of an alkyl glycol or of a polyalkylene glycol having a molecular weight of at least 500 and corresponding to the following formula:

HO- - ((III)

in which: the radicals R ₃ , identical or different, represent hydrogen, an alkyl radical in CC ₄ ; q is a number from 1 to 100; s is a number from 1 to 17.

Preferably, R denotes a linear or branched alkyl radical containing up to 25 carbon atoms and more preferably a linear chain a linear chain comprising from 12 to 24 carbon atoms, preferably from 14 to 20 carbon atoms, for example derived from oleic, palmitic or stearic acid.

Preferably, the units containing the radicals R 1 and R ₂ constitute a linear chain comprising from 12 to 24 carbon atoms, preferably from 14 to 20 carbon atoms and can denote a residue of hydroxyoleic, hydroxy palmitic acid. or hydroxy stearic acid.

The alkylene glycol and / or polyalkylene glycol groups can be chosen, for example, from ethylene glycol, propylene glycol, other C ₄ -C ₅ alkyl glycols. B more particularly denotes a residue of polyethylene glycol or of 1,4-butanediol.

The block copolymers of formula (I) are known per se and are described in particular in patents GB1469591, US4203877 and patent application WO96 / 07689. These same documents describe their preparation methods. According to a particularly preferred embodiment of the invention, a block copolymer corresponding to formula (I) in which A denotes the remainder of a poly- chain will be used in the discontinuous fatty phase in multiple emulsions.

(12-hydroxy-stearic acid) ending in a stearic acid group and B denotes a residue of polyethylene glycol; the polyethylene glycol blocks of said emulsifying copolymer comprise from 4 to 50 moles of ethylene oxide, and more preferably from 20 to 40 moles of ethylene oxide.

The block copolymer sold under the name ARLACEL P135 by the company ICI, the name INCI of which is PEG-30 Dipolyhydroxystearate, will be used more particularly.

According to the invention, the W / O block copolymer emulsifier is preferably present in an amount ranging from 0.5 to 10% by weight, preferably from 2 to 5% by weight.

The discontinuous fatty phase of multiple emulsions according to the invention consists of fatty substances chosen from oils, waxes, gums or silicone resins and their mixtures usually used for the preparation of emulsions used in sunscreen compositions.

By oil is meant a compound which is liquid at room temperature. The term “wax” is intended to mean a compound which is solid or substantially solid at room temperature, and the melting point of which is generally greater than 35 ° C.

As oils, mention may, for example, be made of mineral oils such as isoparaffins; vegetable oils (sweet almond oil, macadamia oil, blackcurrant seed, jojoba); synthetics such as perhydrosqualene, alcohols, fatty acids or esters (octyl paimitate, isopropyl lanolate, triglycerides including those of capric / caprylic acids), fatty esters and ethers oxyethylenated or oxypropylenated; silicone oils (cyclomethicone, polydimethysiloxanes or PDMS) or fluorinated oils; poly-alpha-olefins such as hydrogenated or not hydrogenated polydecenes, hydrogenated or not hydrogenated polyisobutylenes.

As waxy compounds, there may be mentioned paraffin, carnauba wax, beeswax, hydrogenated castor oil.

Advantageously, the discontinuous fatty phase is present in an amount ranging from 5 to 40% by weight and more preferably from 10 to 30% by weight relative to the total weight of the triple emulsion.

The primary W / O emulsion according to the invention is preferably present in an amount ranging from 40 to 80% by weight and more preferably from 50 to 80% by weight relative to the total weight of the triple emulsion.

According to the invention, the external aqueous phase preferably contains one or more O / W emulsifiers. Mention may be made of those comprising an oxyethylenated group such as oxyethylenated fatty alcohols, oxyethylenated sterols and their mixtures. Other types of O / W emulsifiers could be used and in particular those having an HLB (“Hydrophilic Lipophilic Balance”) greater than 10 such as oxyethylenated nonyphenols, oxyethylenated and / or oxypropylenated block polymers such as Poloxamers, fatty esters sorbitan.

The oxyethylenated fatty alcohols advantageously have a fatty chain comprising from 16 to 22 carbon atoms and preferably contain from 20 to 50, and better still from 20 to 30 moles of ethylene oxide. As oxyethylenated fatty alcohols which can be used according to the invention, there may be mentioned for example the mixture of cetyl / stearyl alcohol, oxyethylenated with 30 moles of ethylene oxide (CTFA name: Ceteareth-30).

The oxyethylenated sterols preferably contain from 10 to 40, and better still from 25 to 30 moles of ethylene oxide. As oxyethylenated sterols, mention may be made of: example soybean sterol oxyethylenated with 25 moles of ethylene oxide (name

CFTA: PEG-25 Soya sterol).

The polyoxyethylene / polyoxypropylene block copolymer known under the name CTFA POLXAMER 407 and sold under the trade name SYNPERONIC PE / F127 by the company ICI will be used more particularly.

The O / W emulsifiers are preferably present in an amount ranging from 0.1 to 10% by weight and preferably from 0.5 to 5% by weight relative to the total weight of the emulsion.

The process used to prepare the multiple emulsion according to the invention is identical to the process described in document WO-A-94/22414. It consists in mixing the oil or oils and the W / O emulsifier and in introducing into the mixture the internal aqueous phase with vigorous stirring then in introducing the primary emulsion obtained with stirring into the external aqueous phase preferably containing at least one emulsifier O / W until the W / O / W emulsion is obtained.

According to the invention, the photo protective system consists of one or more organic hydrophilic UV absorbing filters and / or one or more organic lipophilic UV absorbing filters and / or one or more (nano) mineral pigments.

According to the invention, the hydrophilic organic filters can be incorporated in the internal aqueous phase of the primary W / O emulsion and / or in the external aqueous phase of the triple emulsion. They are in particular chosen from benzophenone derivatives, p-aminobenzoic acid derivatives, camphor derivatives or also from benzimidazole derivatives.

As hydrophilic organic filters particularly usable in the present invention, there may be mentioned benzene acid 1, 4-di (3-methylidene-10- camphorsulfonic acid) and 2-phenylbenzimidazole-5-sulfonic acid sold under the trade name "Eusolex 232" by the company Merck.

The hydrophilic organic filter or filters can be present in the final composition according to the invention at a content which can vary from 0.1 to 20%, preferably from 0.2 to 10%, by weight, relative to the total weight of the composition.

According to the invention, the lipophilic organic filters can be present in the discontinuous fatty phase of the triple emulsion. They can be chosen from dibenzoylmethane derivatives, benzimidazole derivatives, cinnamic derivatives, salicylic derivatives, camphor derivatives, triazine derivatives, benzophenone derivatives, β, β-diphenylacrylate derivatives, derivatives p-aminobenzoic acid, the screening polymers and the screening silicones described in applications WO-93/04665 and WO-94/06404. Other examples of organic filters are given in patent application EP-A-0487404.

As lipophilic organic filters which can be particularly used in the present invention, mention may be made of 4-tert-butyl-4'-methoxydibenzoylmethane sold under the trade name "PARSOL 1789" by the company GIVAUDAN, octylmethoxycinnamate sold under the trade name "PARSOL MCX By GIVAUDAN and 2-ethylhexyl -cyano-β, β-diphenylacrylate sold under the trade name "UVINUL N539" by the company BASF.

The lipophilic organic filter or filters may be present in the final composition according to the invention at a content which can vary from 0.5 to 30%, preferably from 0.5 to 20%, by weight, relative to the total weight of the composition. A second category of photoprotective agents which are particularly suitable for multiple emulsions according to the invention is that of pigments. Preferably, nanopigments are used (average size of the primary particles: generally between 5 nm and 100 nm, preferably between 10 and 50 nm) metallic oxide minerals coated or not, such as for example titanium oxide nanopigments (amorphous or crystallized in rutile form and or anatase), iron, zinc, zirconium or cerium which are all well known photoprotective agents acting by physical blocking

(reflection and or diffusion) of UV radiation. Conventional coating agents are moreover alumina and / or aluminum stearate or else silicones. Such nanopigments of metallic oxides, coated or uncoated, are in particular described in patent applications

EP-A-0518772 and EP-A-0518773.

The mineral (nano) pigment (s) may be present in the compositions according to the invention at a content of between 0.1% and 30%, preferably from 0.5% to 10%, by weight, relative to the total weight of composition.

The compositions according to the invention can also contain thickeners.

The thickeners can be chosen in particular from crosslinked polyacrylic acids, fatty chain polyacrylic acids, guar gums and modified or unmodified celluloses such as hydroxypropylated guar gum, methylhydroxyethylcellulose and hydroxypropylmethyl cellulose.

The thickener (s) may be present in the final composition according to the invention at a content which can range from 0.1 to 10%, preferably from 0.1 to 5%, by weight, relative to the total weight of the composition. The compositions according to the invention may also contain artificial tanning and / or browning agents for the skin (self-tanning agents), such as for example dihydroxyacetone (DHA).

The compositions in accordance with the present invention may also comprise conventional cosmetic and / or dermatological adjuvants in particular chosen from organic solvents, softeners, antioxidants, anti-free radical agents, opacifiers, stabilizers, emollients, α- hydroxy acids, anti-foaming agents, hydrating agents, vitamins, perfumes, preservatives, surfactants, fillers, sequestrants, polymers, propellants, alkalizing or acidifying agents, dyes, or any other ingredient usually used in the cosmetic and / or dermatological field, in particular for the manufacture of sunscreen compositions in the form of emulsions.

Of course, those skilled in the art will take care to choose the optional compound (s) mentioned above and / or their quantities in such a way that the advantageous properties intrinsically attached to the multiple emulsions in accordance with the invention are not, or not substantially, altered by the planned addition (s).

Concrete, but in no way limiting, examples illustrating the invention will now be given.

EXAMPLES

EXAMPLE 1 Sunscreen composition in the form of a W / O / W emulsion

Discontinuous fatty phase:

- Block copolymer of formula (I) sold under the name ARLACEL P135 by HERE 2.4% by weight

- Isohexadecane 6.6% - Stearyl alcohol oxypropylenated with 15 moles of propylene oxide 3.3%

- Mixture of triglycerides of capric acid and caprylic acid 3.3% - Octyl methoxycinnamate sold under the name "Parsoi MCX" by GIVAUDAN 5.0%

Internal aqueous phase:

- Benzene acid 1, 4-di (3-methylidene-10-camphosulfonic) 1% - Triethanolamine 0.56%

- Preservatives 0.72%

- Water 37.12%

External aqueous phase: - Benzene acid 1, 4-di (3-methylidene-10-camphosulfonic) 1%

- POE / POP block copolymer (CTFA name: Poloxamer 407) sold under the name SYMPERONIC PE / F 127 by HERE 2.0%

- Triethanolamine 0.56%

- Thickener 0.7% - Preservatives 1, 2%

- Water qs 100%

The composition obtained remains stable on storage after 2 months at room temperature and at temperatures above 40 ° C.

EXAMPLE 2 (COMPARATIVE: Excluding invention)

A sunscreen emulsion of the W / O / W type identical to that of the example is prepared but in which the product ARLACEL P135 has been replaced by a polyoxyethylenated derivative (2.5 moles of ethylene oxide) and polyoxypropylenated (1, 5 moles of propylene oxide) of a mixture of glycerol esters and sorbitol of hydroxystearic and isosteahic acids sold under the name ARLACEL 780 by ICI. The concentration of the W / O emulsifier is identical to that used in Example 1.

It is observed that the emulsion is unstable.

EXAMPLE 3 (COMPARATIVE: Excluding invention):

A conventional sunscreen O / W emulsion is prepared having the following composition:

- ARLACEL 165 (emulsifier) 2% - Classic co-emulsifiers 3.75%

- Silicone 10.5%

- Classic fatty substances 10.5%

- Moisturizing 8%

- Thickener / gelling agent 0.4% - PARSOL MCX 5%

- Benzene acid 1, 4-di-3-methylidene-10-camphosulfonic) 2%

- Triethanolamine 1, 82%

- Preservative, water qs 100%

1 / Evaluation of the water persistence of the compositions of Examples 1 and 3:

For each of the formulations of Examples 1 and 3 thus prepared, the resistance to water of the sun protection factor (SPF) which is attached to it was then determined.

The measurement of the sun protection factor was carried out according to the following method (in vivo): these formulations were applied, at a rate of 2 mg of product / cm ² of skin, on the back of 5 human models, then we subjected simultaneously the protected areas and the unprotected areas of skin with the action of a solar simulator marketed under the name of "Xenon Multiport WG 320-UG 1 1"; the sun protection factor (SPF) was then calculated mathematically by the ratio of the irradiation time that was necessary to reach the erythematogenic threshold with the UV filter (protected area) at the time that was necessary to reach the erythematogenic threshold without filter

UV (unprotected area).

According to this method, the SPF of each formulation is determined on areas of skin treated with each of them and which have not undergone a bath.

At the same time, the SPF of each formulation is also determined on areas of skin treated with each of them and having undergone two baths; each bath for 20 minutes and the two baths being spaced 20 minutes apart.

The variation of the SPF of each formulation (expressed as a percentage) with bath and without bath is then calculated, which corresponds to the percentage of water persistence.

The results are given with a 95% confidence interval in the table below:

These% remanence results show Example (invention) 76.8 ± 15.8 clearly Example 3 (comparative) 46.9 ± 14.2 that, with identical filtering system, the triple W / O / W emulsion of Example 1 in accordance with the present invention, exhibits better water persistence than the conventional O / W emulsion of Example 3.

2 / Evaluation of the cosmetic properties of the compositions of Examples 1 and 3:

A sensory test is carried out on a panel of 10 people by applying each of the emulsions of Examples 1 and 3 at a rate of 0.2 g to the skin of each forearm. The following criteria were studied: - Ease of application

- Bold

- Tights

- Quick drying - Softness

The 10 people judged that the triple W / O / W emulsion of Example 1 in accordance with the invention provided cosmetic properties similar to that of the conventional W / O emulsion of Example 3.

Claims

1. Triple emulsion of the water / oil / water (W / O / W) type, cosmetic or dermatological, characterized in that it comprises:

(a) an aqueous external phase and

(b) a discontinuous fatty phase constituting with an internal aqueous phase a primary water / oil (W / O) emulsion, said fatty phase containing as W / O emulsifier at least one block copolymer consisting of a polymer block derived from a monohydroxycarboxylic acid and a polymer sequence derived from an alkyl glycol or a polyalkylene glycol;

2. Emulsion according to claim 1, according to which the W / O emulsifier of the block copolymer type consisting of a polymer block derived from a monohydroxycarboxylic acid and a polymer block derived from an alkyl glycol or a polyalkyleneglycol corresponds to the following general formula: ABA (I) in which:

A denotes an oleoluble monohydroxycarboxylic acid residue having a molecular weight of at least 500 of the following formula:

in which :

R is hydrogen or a substituted or unsubstituted monovalent hydrocarbon group;

R ₁ is hydrogen or a monovalent hydrocarbon group at CC ₂₄ ;

R ₂ a divalent hydrocarbon group at CC ₂₄ ; p is a number from 1 to 200; B denotes a divalent residue of an alkyl glycol or of a polyalkylene glycol having a molecular weight of at least 500 and corresponding to the following formula:

3. Emulsion according to claim 2, according to which in formula (I), A denotes the remainder of a poly (12-hydroxy-stearic acid) chain ending in a stearic acid group and B denotes a residue of polyethylene glycol.

4. An emulsion according to claim 3, wherein the polyethylene glycol blocks of said emulsifying copolymer comprise from 4 to 50 moles of ethylene oxide, and more preferably from 20 to 40 moles of ethylene oxide.

5. Emulsion according to any one of claims 1 to 4, according to which the W / O emulsifier is present in an amount ranging from 0.5 to 10% by weight, preferably from 2 to 5% by weight.

6. Emulsion according to any one of claims 1 to 5, according to which the discontinuous fatty phase is present in an amount ranging from 5 to 40% by weight and more preferably from 10 to 30% by weight relative to the total weight of l 'emulsion.

7. Emulsion according to any one of claims 1 to 6, according to which the primary W / O emulsion is present in an amount ranging from 40 to 80% by weight and more preferably from 50 to 80% by weight relative to the total weight of the emulsion.

8. Emulsion according to any one of claims 1 to 7, according to which the external aqueous phase contains at least one O / W emulsifier.

9. Emulsion according to any one of claims 1 to 8, according to which said photo-protective system consists of one or more organic filters absorbing UV hydrophilic and / or one or more organic filters absorbing UV lipophilic and or one or several (nano) mineral pigments.

10. Emulsion according to claim 9, according to which the organic hydrophilic UV absorbers filters are chosen from benzophenone derivatives, p-aminobenzoic acid derivatives, camphor derivatives or also from benzimidazole derivatives.

1 1. Emulsion according to Claim 10, characterized in that the organic hydrophilic UV absorbing filters are chosen from camphor derivatives.

12. Emulsion according to claim 1 1, characterized in that the hydrophilic UV absorber filter is benzene acid 1, 4-di (3-methylidene-10-camphosulfonic).

13. Emulsion according to claim 9, characterized in that the organic hydrophilic UV absorbing filters are chosen from benzimidazole derivatives.

14. Emulsion according to claim 13, characterized in that the hydrophilic UV absorber filter is 2-phenylbenzimidazole-5-sulfonic acid.

15. Emulsion according to any one of claims 9 to 13, characterized in that the organic hydrophilic UV absorbers filters are present in the composition at a content which can range from 0.1 to 20%, by weight, relative to the total weight of the emulsion.

16. Emulsion according to claim 9, characterized in that the organic lipophilic UV absorbers filters are chosen from dibenzoymethane derivatives, benzimidazole derivatives, cinnamic derivatives, salicylic derivatives, camphor derivatives, derivatives of triazine, benzophenone derivatives, β, β-diphenyiacrylate derivatives, p-aminobenzoic acid derivatives, filter polymers and filter silicones.

17. Emulsion according to Claim 16, characterized in that the organic lipophilic UV absorbing filters are chosen from dibenzoylmethane derivatives.

18. Emulsion according to Claim 17, characterized in that the organic lipophilic UV-absorbing filter is 4-tert-butyl-4'-methoxydibenzoyl-methane.

19. Emulsion according to Claim 16, characterized in that the organic lipophilic UV-absorbing filter is octylmethoxycinnamate

20. Emulsion according to claim 16, characterized in that the organic lipophilic UV-absorbing filters are chosen from β, β-diphenylacrylate derivatives.

21. An emulsion according to claim 16, characterized in that the organic lipophilic UV absorber filter lipophilic filter is 2-ethylhexyl α-cyano-β, β-diphenylacrylate.

22. Emulsion according to any one of Claims 9 to 16, characterized in that the organic lipophilic UV-absorbing filters are present in the composition at a content which can range from 0.5 to 30%, by weight, relative to the total weight of the emulsion.

23. Emulsion according to claim 9, characterized in that the (nano) mineral pigments are nanopigments of metallic oxides coated or not.

24. Emulsion according to claim 23, characterized in that the mineral nanopigments of metal oxides are chosen from those of titanium oxide, iron, zinc, zirconium or cerium coated or not.

25. An emulsion according to claim 16, 23 or 24, characterized in that the (nano) mineral pigments are present at a content of between 0.1% and 30%, preferably from 0.5% to 10%, in weight, relative to the total weight of the emulsion.

26. Cosmetic treatment method for protecting the skin and / or hair against ultraviolet radiation, in particular solar radiation, characterized in that it consists in applying to the latter an effective amount of a triple E emulsion / O / W as defined in any one of claims 1 to 25.

27. Use of the triple W / O / W emulsion defined in any one of claims 1 to 25 as, or for the manufacture of, cosmetic compositions for the protection of the skin and / or the hair against ultraviolet radiation, especially solar radiation.