WO2016082209A1

WO2016082209A1 - Oil in water composition comprising cyclodextrin, dihydroflavonol and/or stereoisomer thereof, and surfactants

Info

Publication number: WO2016082209A1
Application number: PCT/CN2014/092552
Authority: WO
Inventors: Xuanhui ZHANG; Xinrong LIN
Original assignee: L'oreal
Priority date: 2014-11-28
Filing date: 2014-11-28
Publication date: 2016-06-02
Also published as: CN107001311B; CN107001311A

Abstract

Provided is an oil in water composition, which comprising: a) at least one cyclodextrin and/or its derivative, b) at least one dihydroflavonol according to formula (I), and/or stereoisomer thereof, wherein, R ₁ and R ₂ are, same or different, selected from hydrogen, hydroxyl group, C ₁-C ₆ alkoxy, or C ₁-C ₆ alkyl, R ₃ is Rhamonose, glucose, or arabinose, and c) at least one surfactant chosen from esters of C ₁₆-C ₂₂ fatty acid and of sorbitan, esters of C ₁₆-C ₂₂ fatty acid and of glycerol, ester of C ₁₆-C ₂₀ fatty acid and of polyethylene glycol, or a mixture thereof.

Description

An oil in water composition comprising cyclodextrin， dihydroflavonol and/or stereoisomer thereof， and surfactants

Field of the invention

The present invention relates to cosmetic and/or dermatological field. In particular， the present invention relates to a composition comprising a cyclodextrin and a dihydroflavonol and/or stereoisomer thereof， in particular in aqueous medium， and preparation method thereof.

Background of the invention

Flavonoids have drawn more and more attention of cosmetic industry for its potential in whitening， anti-aging， and antioxidant fields. Among which， dihydroflavonols are found to be highly effective on whitening. However， they have very poor solubility in water and most oils， and they are unstable at high pH and high temperature. Solubilisers and organic solvents have been used for the solubilization of dihydroflavonols， but they still degrade a lot after 2 months at 45℃ (＞20％degradation) in formulas. Cyclodextrin has been disclosed for solubilizing and stabilizing dihydroflavonols， especially astilbins in aqueous solution， i.e.， in water， under low pH， for example， 3.5， see in “Aqueous Solubility and Stability Enhancement of Astilbin through Complexation with Cyclodextrins” ， Qing-Feng Zhang， et. al.， Agric. Food Chem. 201 3， 61， 151-156. However， none of the above mentioned prior arts disClosed dihydroflavonols in a more complex composition， i.e.， an oil in water composition， and maintains a good solubility and/or stability， especially under higher temperature (for example 45℃) ， and which does not require a strict low pH.

Therefore， how to solve the solubility and stability issue of dihydroflavonols in an oil in water composition is a challenge for formulators in cosmetic and dermatological field.

Summary of the invention

The major problem to be solved by the present application is to solubilize and/or stabilize dihydroflavonols and/or stereoisomer thereof in an oil in water composition.

According to one aspect of the present invention， there is provided an oil in water composition comprising：

a) at least one cyclodextrin and/or its derivative，

b) at least one dihydroflavonol according to formula (I) ， and/or stereoisomer thereof：

wherein，

R₁ and R₂ are， same or different， selected from hydrogen， hydroxyl group， C₁-C₆ alkoxy， or C₁-C₆ alkyl，

R₃ is rhamonose， glucose， or arabinose， and

c) at least one surfactant chosen from esters of C₁₆-C₂₂ fatty acid and of sorbitan， esters of C₁₆-C₂₂ fatty acid and of glycerol， ester of C₁₆-C₂₀ fatty acid and of polyethylene glycol， or a mixture thereof.

According to another aspect， there is provided a method for preparing a composition according to the present invention comprising mixing at least one cyclodextrin， at least one dihydroflavonol according to formula (I) mentioned above， and/or stereoisomer thereof， and at least one surfactant chosen from esters of C₁₆-C₂₂ fatty acid and of sorbitan， esters of C₁₆-C₂₂ fatty acid and of glycerol， ester of C16-C20 fatty acid and of polyethylene glycol， or a mixture thereof.

According to yet another aspect， there is provided use of the composition of the present invention in caring for and/or making up the keratin materials， comprising applying to the keratin materials， especially the skin， the composition of the present invention. The composition according to the present invention can be used as whitening， anti-oxidation， and/or anti-aging products to the keratin materials， especially the skin. The composition is stable after two months storage， especially at 45℃.

Advantageously， the composition of the present invention can be used as a skin-care composition.

Brief description of the drawing

While the specification concludes with claims distinctly pointing out the subject matter that applicant regards as his invention， it is believed that the invention will be better understood when taken in connection with the accompanying drawing in which：

Figure 1 shows the amount of HPCD vs. that of Engelhardtia chrysolespis leaf extract comprising 80％of astilbin (the product under the trade name ENGELHARDTIA ROXBURGHIANA WALL. P. E. by Layn) in water.

Detailed description of the invention

The present invention is based on an unexpected finding that cyclodextrin can substantially improve solubilization and/or stabilization of dihydroflavonol in an oil in water composition， and in particular at high temperature (for example 45℃) .

a) at least one cyclodextrin and/or its derivative，

wherein，

R₁ and R₂ are， same or different， selected from hydrogen， hydroxyl group，

C₁-C₆ alkoxy， or C₁-C₆ alkyl，

R₃ is rhamonose， glucose， or arabinose， and

The composition is for topical application.

Cyclodextrins and derivatives thereof

Cyclodextrins (CDs) are cyclic oligosaccharides constituted of (α-1， 4) α-D-glucopyranose units with a lipophilic central cavity and a hydrophilic outer surface

KH， Szejtli J： ″Cyclodextrins in pharmacy″ ， Kluwer Academic Publishers， Dordrecht， 1994) .

Cyclodextrins are known to increase the solubility of some molecules by forming a ″cage″ -shaped structure having an external hydrophilic part and an internal hydrophobic part. Cyclodextrins may thus form inclusion complexes with many molecules by accepting the whole molecule， or more commonly the lipophilic part of the molecule， inside the cavity.

The most abundant natural cyclodextrins are α-cyclodextrins， β-cyclodextrins and γ-cyclodextrins.

α-Cyclodextrins (also known under the name Schardinger′s α-dextrin，cyclomaltohexaose， cyclohexaglucan， cyclohexaamylose， α-CD， ACD， C6A) comprise 6 glucopyranose units. β-Cyclodextrins (also known under the name Schardinger′s β-dextrin， cyclomaltoheptaose， cycloheptaglucan， cycloheptaamylose， β-CD， BCD， C7A) comprise 7 glucopyranose units and γ-cyclodextrins (also known under the name Schardinger’s γ-dextrin， cyclomaltooctaose， cyclooctaglucan， cyclooctaamylose， γ-CD， GCD， C8A) comprise 8 glucopyranose units.

Among these three types of CDs， β-cyclodextrins appear to be the most useful due to the size of their cavity， their availability， their properties and their low cost.

According to Dr J. Szejtli (″Cyclodextrins″ ， in Encyclopedia of Supramolecular Chemistry， Eds. Marcel Dekker， 2004) cyclodextrins are advantageous but also have limiting factors that restrict the application of cyclodextrins to certain types of products.

Furthermore， not all compounds are suitable for complexing with cyclodextrins. Many products cannot be complexed or else complexing does not provide any fundamental advantage. Inorganic compounds are generally unsuitable for complexing with cyclodextrins.

Cyclodextrin derivatives can also be used in the present invention. In cyclodextrins， each glucopyranose unit has three free hydroxyl groups that differ in their function and their reactivity.

The term ″cyclodextrin derivative″ is understood to mean a cyclodextrin of which all or some of the hydroxyl groups have been modified by substitution of the hydroxyl group or of the hydrogen atom.

Ester， ether， anhydro， deoxy-， acidic， basic， etc. derivatives may be prepared by chemical or enzymatic reactions well known to a person skilled in the art.

For example， in β-CDs， 21 hydroxyl groups may be modified by substituting the hydrogen atom or the hydroxyl group with a wide variety of groups such as alkyl， hydroxyalkyl， carboxyalkyl， amino， thio， tosyl， glucosyl， maltosyl， etc. groups.

Among preferred derivatives， mention may be made of the derivatives of α-cyclodextrins， β-cyclodextrins， γ-cyclodextrins preferably β-cyclodextrins and in particular the methyl derivatives of cyclodextrins such as TRIMEB (heptakis (2， 3， 6-trimethyl) -β-CD) ， DIMEB (heptakis (2， 6-dimethyl) -β-CD) or else RAMEB (Randomly Methylated β-cyclodextrin) ； 2-hydroxyl (C1-C6) alkyl-β-CDs preferably 2-hydroxyl (C1-C4) alkyl-β-CDs for example 2-hydroxymethyl-β-CD， 2-hydroxyethyl-β-cyclodextrin， 2-hydroxypropyl-β-cyclodextrin (HPCD) and hydroxybutyl-β-CD. In particular， mention may be made of the HPCD sold especially under the name Kleptose

by Roquette and the

W7 HP sold by Wacker Chimie.

According to a preferred embodiment， the amount of cyclodextrin (s) or the derivative (s) therefore in the compositions of the invention preferably ranges from 0.1％to 20％by weight， more preferably from 1％to 15％by weight， relative to the total weight of the composition.

Dihydroflavonol and stereoisomer thereof

Dihydroflavonols are polyphenolic compounds present in many fruits， vegetables， and herbs， such as Smilax glabra Roxb， Smilax china L. ， Sarchandra gardn， Engelhardtia roxburghiana， or grapes.

The composition of the present invention comprises at least one dihydroflavonol according to formula (I) ， and/or stereoisomer thereof：

In a embodiment， in formula (I) ：

R₃ is rhamonose， glucose， or arabinose..

Mentions may be made of such dihydroflavonols， such as 2R， 3R-isomer， for example， Astilbin， Engeletin； 2R， 3S-isomer， for example， Isoastilbin， Isoengeletin； 2S， 3R-isomer， for example， Neoastilbin， Neoengeletin； and 2R， 3S-isomer， for example， Neoisoastilbin， Neoisoengeletin.

In a more preferred embodiment， R₁ and R₂ are hydroxyl， and R₃ is rhamonose. Such compounds may be chosen from astilbin， isoastilbin， neoastilbin， neoisoastilbin， or a mixture thereof.

Most preferably， mention may be made to astilbin， according to the present invention.

Advantageously， the dihydroflavonols and stereoisomer thereof may exist in form of compounds with more than 80％purity， or of the extract from botanical sources like Smilax glabra Roxb， Smilax china L. ， Sarchandra gardn， Engelhardtia roxburghiana， or grapes. These extracts contain different level of Astilbin and/or its derivatives， which can range from 0.001％to 90％by weight， relative to the total weight of the extract.

Engelhardtia chrysolepis leaf extract with at least 80％by weight， relative to the total weight of the extract， of Astilbin， is preferred to be used in the present invention. Such products are， for example， the one sold under the name ENGELHARDTIA ROXBURGHIANA WALL. P. E. by Layn.

According to a preferred embodiment， the amount of the dihydroflavonol according to formula (I) ， and/or stereoisomer thereof in the compositions of the invention ranges from 0.001％to 5％by weight， preferably from 0.01％to 4％by weight， and more preferably from 0.1％to 3％by weight， relative to the total weight of the composition.

Surfactants

According to the present invention， the composition comprises at least one surfactant chosen from esters of C₁₆-C₂₂ fatty acid and of sorbitan， esters of C₁₆-C₂₂ fatty acid and of glycerol， ester of C16-C20 fatty acid and of polyethylene glycol， or a mixture thereof.

According to a first embodiment of the invention， the composition comprises an ester of C₁₆-C₂₂ fatty acid and of sorbitan.

The esters of C₁₆-C₂₂ fatty acid and of sorbitan are formed by esterification， with sorbitol， of at least one fatty acid comprising at least one saturated or unsaturated linear alkyl chain respectively having from 16 to 22 carbon atoms. These esters can be chosen in particular from sorbitan stearates， behenates， arachidates， palmitates or oleates， and their mixtures. Use is preferably made of sorbitan stearates and palmitates and preferentially sorbitan stearates.

The ester of C₁₆-C₂₂ fatty acid and of sorbitan present in the composition according to the invention is advantageously solid at a temperature of less than or equal to 45℃. Mention may be made， as examples of sorbitan ester which can be used in the composition according to the invention， of the sorbitan monostearate (CTFA name： Sorbitan stearate) sold by Croda under the name Span 60， the sorbitan tristearate sold by Croda under the name Span 65 V， the sorbitan monopalmitate (CTFA name： Sorbitan palmitate) sold by Croda under the name Span 40， the sorbitan monooleate sold by Croda under the name Span 80 V or the sorbitan trioleate sold by Uniqema under the name Span 85 V. Preferably， the sorbitan ester used is sorbitan tristearate. The ester of glycerol and of fatty acid can be obtained in particular from an acidcomprising a saturated linear alkyl chain having from 16 to 22 carbon atoms. Mention may in particular be made， as ester of glycerol and of fatty acid， of glyceryl stearate (glyceryl mono-， di-and/or tristearate) (CTFA name： Glyceryl stearate) ， glyceryl ricinoleate and their mixtures. Preferably， the ester of glycerol and of fatty acid used is chosen from glyceryl stearates.

The composition of the invention can comprise in particular a mixture of glyceryl stearate and of polyethylene glycol 100 EO monostearate and in particular that comprising such a mixture in proportions by weight of 50/50 sold under the name Arlacel^TM 165 by Croda.

The ester of C₁₆-C₂₂ fatty acid and of polyethylene glycol is preferably comprising from 8 to 100 ethylene oxide units.

The fatty chain of the esters can be chosen in particular from stearyl， behenyl， arachidyl， palmityl or cetyl units and their mixtures， such as cetearyl， and preferably a stearyl chain.

The number of ethylene oxide units can range from 8 to 100， preferably from 10 to 80 and better still from 10 to 50. According to a specific embodiment of the invention， this number can range from 20 to 40.

Mention may be made， as examples of ester of fatty acid and of polyethylene glycol， of stearic acid esters respectively comprising 20， 30， 40， 50 or 100 ethylene oxide units， such as the products respectively sold under the names Myrj^TM 49 P (polyethylene glycol 20 EO stearate； CTFA name： PEG-20 stearate) ， Myrj^TM 51， Myrj^TM 52 P (polyethylene glycol 40 EO stearate； CTFA name： PEG-40 stearate) ， Myrj^TM 53 and Myrj^TM 59 P by Croda.

According to a preferred invention， the surfactant is chosen from esters of C₁₆-C₂₂ fatty acid and of glycerol， ester of C₁₆-C₂₂ fatty acid and of polyethylene glycol， or a mixture thereof.

More particularly， the surfactant is chosen from glyceryl stearate， polyethylene glycol 20 EO stearate， polyethylene glycol 100 EO monosterate， or a mixture thereof.

According to a preferred embodiment， the surfactant (s) is present in the composition of the present invention ranging from 0.01％to 30％by weight， preferably 0.1％to 10％by weight， and more preferably 1％to 5％by weight， relative to the total weight of the composition.

According to a preferred embodiment， the composition of the present invention has a pH value of 2 to 6， preferably 3 to 5， more preferably 3.9 to 4.1， and still preferably 4.

Waxes

According to the present invention， the composition may further comprise waxes. More preferably， the composition comprises at least one wax with a melting point greater than or equal to 60℃.

The wax under consideration in the context of the present invention is generally a lipophilic compound that is solid at room temperature (25℃) ， with a solid/liquid reversible change of state， having a melting point of greater than or equal to 60℃， which may be up to 200℃ and in particular up to 120℃.

As illustrations of waxes that are suitable for the invention， mention may be made especially of hydrocarbon-based waxes， for instance beeswax， lanolin wax， Chinese insect waxes， rice bran wax， carnauba wax， candelilla wax， ouricury wax， esparto grass wax， berry wax， shellac wax， Japan wax and sumach wax； montan wax， orange wax and lemon wax， microcrystalline waxes， paraffins and ozokerite； polyethylene waxes， the waxes obtained by Fischer-Tropsch synthesis and waxy copolymers， and also esters thereof， fatty acids or esters obtained by catalytic hydrogenation of animal or plant oils containing linear or branched C₈-C₃₂ fatty chains， preferably C₁₆ to C₁₈ chains， silicone waxes and fluoro waxes， or a mixture thereof.

Mentions may be made of polyethylene which， for example， is sold under the tradename Performalene 500-L Polyethylene by the company New Phase Technologies.

Mention may also be made of fatty acids obtained by catalytic hydrogenation of animal or plant oils containing linear or branched C₈-C₃₂ fatty chains， preferably C₁₆ to C₁₈ chains. Among these compounds， mention may be made especially of stearic acid， palmitic acid， or a mixture thereof. The fatty acids used in the current invention are commercially available under the trade names， for example， AEC Stearic Acid sold by A & E Connock (Perfumery & Cosmetics) Ltd. ， Pristerene^TM 9559 Flakes sold by Uniqema (Croda) ， Emersol sold by Emery Oleochemical LLC， Palmitic Acid PC sold by Protameen Chemicals， Inc.

As for esters obtained by catalytic hydrogenation of animal or plant oils， mention may be made to the waxes obtained by hydrogenation of castor oil esterified with cetyl alcohol， sold under the names Phytowax ricin

and

by the company Sophim， may also be used. Such waxes are described in patent application FR-A-2 792 190.

The waxes obtained by hydrogenation of olive oil esterified with C₁₂ to C₁₈ chain fatty alcohols such as those sold by the company SOPHIM under the brand names Phytowax Olive 12L44， 14L48， 16L55 and 18L57， are also convenient.

A wax that may be used is a C₂₀-C₄₀ alkyl (hydroxystearyloxy) stearate (the alkyl group containing from 20 to 40 carbon atoms) ， alone or as a mixture. Such a wax is especially sold under the names Kester Wax K

Hydroxypolyester K

and Kester Wax K

by the company Koster Keunen.

Preferably， the composition according to the invention further comprises waxes chosen from hydrocarbon-based waxes， such as beeswax， fatty acids obtained by catalytic hydrogenation of animal or plant oils containing linear or branched C₈-C₃₂ fatty chains， preferably C₁₆ to C₁₈ chains， and a mixture thereof.

More preferably， the composition according to the invention further comprises waxes chosen from beeswax， stearic acid， and a mixture thereof.

Advantageously， a composition of the invention may comprise from 0.01％to 20％by weight and preferably from 0.1％to 10％by weight and more preferably from 1％to 5％by weight of wax (es) relative to the total weight of the said composition.

Fatty alcohol

Advantageously， the composition according to the invention comprises at least one fatty alcohol.

For the purposes of the invention， the fatty alcohols are linear， and saturated or unsaturated， and comprise from 12 to 26 carbon atoms and preferably from 14 to 22 carbon atoms.

Preferably， for the purposes of the invention， the fatty alcohols are solid.

The fatty alcohol (s) that are suitable for use in the invention are preferably chosen from the group comprising cetyl alcohol， stearyl alcohol， cetylstearyl alcohol， myristyl alcohol， lauryl alcohol， tridecyl alcohol， pentadecyl alcohol， hexadecyl alcohol， arachidyl alcohol， behenyl alcohol and myricyl alcohol； they are preferably chosen from cetyl alcohol， stearyl alcohol and cetylstearyl alcohol.

As cetyl alcohols that may be most particularly suitable for use in the invention， use may be made， for example， of the products sold under the names

16/98 F and

16/98 P sold by the company Ecogreen Oleochemicals，

16 sold by the company Evonik Goldschmidt，

16 sold by the company Cognis，

1698 sold by the company VVF，

1698 P sold by the company Oxiteno， Cetyl Alcohol 98％Min sold by the company Emery Oleochemicals，

16 (98％) sold by the company Godrej Industries，

16-98 sold by the company Sasol，

6098 sold by the company Kao， and

16 sold by the company Aegis Chemical.

As stearyl alcohols that are most particularly suitable for use in the invention， use may be made， for example， of those sold under the names

18 sold by the company Evonik Goldschmidt，

18/98 F and

18/98 P sold by the company Ecogreen Oleochemicals，

18 sold by the company Cognis，

8098 sold by the company Kao，

18 sold by the company Aegis Chemical，

18-98 sold by the company Sasol and

45 sold by the company Nihon Yushi.

As cetylstearyl alcohols that are most particularly suitable for use in the invention， use may be made， for example， of those sold under the names

68/50 F and

68/50 P sold by the company Ecogreen Oleochemicals，

O OR and

O OR Flakes sold by the company Cognis，

1618 C50 P sold by the company Oxiteno，

16-18 EN sold by the company Sasol， Alcohol Cetoestearilico 50/50 sold by the company Industria Quimica Del Centro，

30 CK sold by the company New Japan Chemical， Cetylstearyl Alcohol 50∶50 sold by the company Evonik Goldschmidt，

6850 sold by the company Kao，

1618 (50∶50) sold by the company VVF and

1618 50∶50 OR sold by the company Godrej Industries.

According to one preferred embodiment， the composition according to the invention comprises a content of fatty alcohol (s) ranging from 0.01％to 20％by weight， preferably 0.1％to 10％by weight， more preferably 1％to 5％by weight， relative to the total weight of the composition.

Hydrophilic thickeners

The composition of the present invention may further comprises at least one hydrophilic thickener.

The hydrophilic thickeners that may be mentioned include carboxyvinyl polymers such as the Carbopol products (carbomers) and the Pemulen products (acrylate/C10-30-alkylacrylate copolymer) ； polyacrylamides， for instance the crosslinked copolymers marketed under the name “Sepigel^TM 305” (CTFA name： polyacrylamide/C_13-14 isoparaffin/Laureth 7) or “Simulgel 600” (CTFA name： acrylamide/sodium acryloyldimethyltaurate copolymer/isohexadecane/polysorbate 80) by SEPPIC； 2-acrylamido-2-methylpropanesulfonic acid polymers and copolymers， which are optionally crosslinked and/or neutralized， for instance the poly (2-acrylamido-2-methylpropanesulfonic acid) marketed by Hoechst under the name″

AMPS″ (CTFA name： ammonium polyacryldimethyltauramide) ； cellulose-based derivatives such as hydroxyethylcellulose； polysaccharides and especially gums such as xanthan gum； and mixtures thereof.

Preferably， the hydrophilic thickener of the present invention is polyacrylamide.

More preferably， the composition according to the invention comprises a content of hydrophilic thickener (s) ranging from 0.5％to 2％by weight relative to the total weight of the composition.

Additives

In a particular embodiment， a composition according to the invention further comprises at least one compound chosen from hydrophilic solvents， lipophilic solvents， oils， and mixtures thereof.

A composition according to the invention may also comprise any additive usually used in the field under consideration， chosen， for example， from additional gums， additional anionic， cationic， amphoteric or nonionic surfactants， silicone surfactants， resins， lipophilic thickeners， dispersants， antioxidants， essential oils， preserving agents， fragrances， neutralizers， UV-screening agents， cosmetic active agents， such as vitamins， moisturizers， emollients or anti-wrinkle agents， colorants， pH adjusters， and mixtures thereof.

It is a matter of routine operations for a person skilled in the art to adjust the nature and amount of the additives present in the compositions in accordance with the invention such that the desired cosmetic properties and stability properties thereof are not thereby affected.

The composition according to the invention may be prepared in a conventional manner.

The examples that follow are given as nonlimiting illustrations of the present invention.

The percentages are weight percentages.

The composition of the invention has good whitening and antioxidant effect.

The composition is stable under room temperature (25℃， 2 months) and 45℃ (2 months) .

According to another aspect of the present invention， there is provided a method for preparing a composition according to the present invention comprising mixing at least one cyclodextrin， at least one dihydroflavonol according to formula (I) ， and/or stereoisomer thereof， and at least one surfactant chosen from esters of C₁₆-C₂₂ fatty acid and of sorbitan， esters of C₁₆-C₂₂ fatty acid and of glycerol， ester of C₁₆-C₂₀ fatty acid and of polyethylene glycol， or a mixture thereof.

According to one aspect of the present invention， there is provided use of the composition of the present invention in caring for and/or making up the keratin materials， comprising applying to the keratin materials， especially the skin， the composition of the invention.

Galenical form

A composition according to the invention may be in the form of makeup compositions and/or care compositions for keratin materials， in particular for the skin.

Particularly， a composition according to the invention may be a cream， essence， water， lotion or gel， preferably in the form of face skincare cream.

In a preferred embodiment， a composition according to the present invention is a non-rinsing composition： the composition is not intended to be rinsed after application on the skin.

These compositions are prepared according to the usual methods.

The compositions of this type may be in the form of a facial and/or body care or makeup product， and may be conditioned， for example， in the form of cream in a jar or of fluid in a tube.

Preferably， the compositions of the present invention are emulsions， notably oil in water emulsions.

In yet another preferred embodiment， the compositions of the invention are gelified compositions and in particular gelified oil in water emulsions.

The oil in water composition of the present invention comprises at least one aqueous phase and at least one fatty phase.

Preferably， the aqueous phase is a continuous phase， and the fatty phase is a dispersed phase.

Aqueous phase

The composition according to the invention comprises an aqueous phase.

The aqueous phase comprises water.

The aqueous phase may also comprise water-miscible organic solvents (at room temperature： 25℃) ， for instance monoalcohols containing from 2 to 6 carbon atoms， such as ethanol or isopropanol； polyols especially containing from 2 to 20 carbon atoms， preferably containing from 2 to 10 carbon atoms and preferentially containing from 2 to 6 carbon atoms， such as glycerol， propylene glycol， butylene glycol， pentylene glycol， hexylene glycol， dipropylene glycol or diethylene glycol； glycol ethers (especially containing from 3 to 16 carbon atoms) such as mono-， di-or tripropylene glycol (C₁-C₄) alkyl ethers， mono-， di-or triethylene glycol (C₁-C₄)alkyl ethers， and mixtures thereof.

The aqueous phase may also comprise stabilizers， for example sodium chloride， magnesium dichloride or magnesium sulfate.

The aqueous phase may also comprise any water-soluble or water-dispersible compound that is compatible with an aqueous phase， such as gelling agents， film-forming polymers， thickeners or additional surfactants， and mixtures thereof. In particular， a composition of the invention may comprise an aqueous phase in a content ranging from 1％to 90％by weight， especially from 5％to 90％and more particularly from 50％to 90％by weight relative to the total weight of the composition.

Fatty phase

A composition in accordance with the present invention may comprise at least one liquid and/or solid fatty phase.

In particular， a composition of the invention may comprise at least one liquid fatty phase， especially at least one oil as mentioned below.

The term “oil” means any fatty substance that is in liquid form at room temperature (20-25℃) and at atmospheric pressure.

The fatty phase that is suitable for preparing the cosmetic compositions according to the invention may comprise hydrocarbon-based oils， silicone oils， fluoro oils or non-fluoro oils， or mixtures thereof.

The oils may be volatile or non-volatile.

They may be of animal， plant， mineral or synthetic origin.

The term ″non-volatile oil″ means an oil that remains on the skin or the keratin fibre at room temperature and atmospheric pressure. More specifically， a non-volatile oil has an evaporation rate strictly less than 0.01 mg/cm2/min.

To measure this evaporation rate， 15 g of oil or of oil mixture to be tested are placed in a crystallizing dish 7 cm in diameter， which is placed on a balance in a large chamber of about 0.3 m3 that is temperature-regulated， at a temperature of 25℃， and hygrometry-regulated， at a relative humidity of 50％. The liquid is allowed to evaporate freely， without stirring it， while providing ventilation by means of a fan (Papst-Motoren， reference 8550 N， rotating at 2700 rpm) placed in a vertical position above the crystallizing dish containing said oil or said mixture， the blades being directed towards the crystallizing dish， 20 cm away from the bottom of the crystallizing dish. The mass of oil remaining in the crystallizing dish is measured at regular intervals. The evaporation rates are expressed in mg of oil evaporated per unit of area (cm2) and per unit of time (minutes) .

The term ″volatile oil″ means any non-aqueous medium that is capable of evaporating on contact with the skin or the lips in less than one hour， at room temperature and atmospheric pressure. The volatile oil is a cosmetic volatile oil， which is liquid at room temperature. More specifically， a volatile oil has an evaporation rate of between 0.01 and 200 mg/cm2/min， limits included.

For the purposes of the present invention， the term “silicone oil” means an oil comprising at least one silicon atom， and especially at least one Si-O group.

The term “fluoro oil” means an oil comprising at least one fluorine atom.

The term “hydrocarbon-based oil” means an oil mainly containing hydrogen and carbon atoms.

The oils may optionally comprise oxygen， nitrogen， sulfur and/or phosphorus atoms， for example in the form of hydroxyl or acid radicals.

A composition of the invention may comprise a liquid fatty phase in a content ranging from 1％to 90％， in particular from 5％to 80％， in particular from 10％to 50％and more particularly weight relative to the total weight of the composition.

Preferred is oil in water emulsion with the amount of the aqueous phase of greater than or equal to 70％by weight， relative to the total weight of the composition.

Preferably， the oil in water composition of the present invention has the amount of water greater than or equal to 70％by weight， relative to the total weight of the composition.

In addition， the compositions according to the invention may be more or less fluid and may have the appearance of a white or coloured cream， an ointment， a milk， a lotion， a serum.

In an embodiment， the composition is a skin-care product， such as lotions， milks， creams of thicker or thinner consistency.

Unless otherwise indicated， all numbers expressing quantities of ingredients， reaction conditions， and so forth used in the specification and claims are to be understood as being modified in all instances by the term ″about. ″

Accordingly， unless indicated to the contrary， the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations， the numerical values set forth in the specific examples are reported as precisely as possible.

Any numerical value， however， inherently contain certain errors necessarily resulting from the standard deviation found in their respective measurements. The following examples are intended to illustrate the invention without limiting the scope as a result. The percentages are given on a weight basis.

The invention will now be illustrated by means of the following non-limiting examples.

The amounts of the ingredients in the following formulation examples are expressed as ％by weight relative to the entire formulation.

Examples

Example 1-3： Preparation examples

The following formulations were prepared as follows：

Components for phase A were mixed and heated to 75℃ until totally solubilized.

Components for phase B were mixed and heated to 80℃. Phase B was added to A and stirred at 75℃ for 10min， then component (s) for phase C were added at 50-55℃ and stirred for 10min. Components for phase D were added and stirred for 10 min. The mixture was cooled to room temperature (25℃) and pH was adjusted to 4 with components for phase E.

Ex. 3 is comparative example without 2-Hydroxypropyl-β-Cyclodextrin.

Example 4： Evaluation of stability of formulations

Evaluation of stability of each of the examples 1， 2 and 3 was performed and demonstrated by the following tests.

Decreasing percentage of the Engelhardtia Chrysolepis leaf extract

The samples of formulations from examples 1， 2 and 3 were kept under 45℃ for 2 months. The content (％by weight relative to the total weight of the example) of the Engelhardtia Chrysolepis leaf extract used in the examples 1， 2， and 3 were measured at T_0M (after formulation) ， T_1M (after 1 month) ， and T_2M (after 2 months) . The decreasing percentage was calculated using the following equation：

％(1 month decrease) ＝ (T_0M-T_1M) /T_0M

％(2 months decrease) ＝ (T_0M-T_2M) /T_0M

The results were as follows：

Microscope

The examples 1， 2， and 3 after 2 months under 45℃ were evaluated using the microscope Leica DMI 3000B produced by Laica to observe the homogeneity of the emulsion.

pH change

pH values of the examples 1， 2， and 3 after2 months under45℃ were measured in order to observe the change of pH.

The less the change of pH value， more stable the formula is.

Appearance

Finally， the appearances of the examples 1， 2， and 3 after 2 months under 45℃ were observed by 5 experts.

Scores were given to the results of the microscope， pH change， and appearance， respectively：

1 (not acceptable) ： very loose emulsion， crystals formed； significant change on pH value； inhomogeneous appearance， significant change on color or texture (darkened color) ；

2 (acceptable) ： fine emulsion， no crystals formed； no significant change on pH value； homogeneous appearance， no significant change on color or texture；

3 (very good) ： fine emulsion with pleasant thick texture， no crystals formed， no change or slight change on pH value； homogeneous appearance， no change on the color or texture.

The results were as follow：

It was observed from the results above， that invention examples 1 and 2 had much lower decrease on the content of the active ingredient， i.e.， Engelhardtia Chrysolepis leaf extract， comparing to the comparative example 3.

Besides， the invention examples 1 and 2 were more stable comparing to the comparative example 3 in terms of emulsion homogeneity， change of pH， and the appearance.

In conclusion， the invention examples 1 and 2 had an improved stability， in particular under 45℃， comparing to the comparative example 3.

Example 5： evaluation of solubility of dihydroflavonol in water

Solubility of Engelhardtia chrysolepis leaf extract with 80％Astilbin in water (ENGELHARDTIA ROXBURGHIANA WALL.P.E. from Layn) was tested with the increasing amount of 2-hydroxypropyl-β-CD (

W7 HP from Wacker Chimie) . The solubility of Engelhardtia chrysolepis leaf extract in water vs. the amount of 2-hydroxypropyl-β-CD was showed in FIG. 1.

FIG. 1 shows that the solubility of Engelhardtia chrysolepis leaf extract in water is increasing with the increase of amount of 2-hydroxypropyl-β-CD， i.e. the solubility of Engelhardtia chrysolepis leaf extract in water is improved by 2-hydroxypropyl-β-CD.

While illustrative examples of the invention have been described above， it is， of course， understood that many and various modifications will be apparent to those of ordinary skill in the relevant art， or may become apparent as the art develops， in the light of the foregoing description. Such modifications are contemplated as being within the spirit and scope of the invention or inventions disclosed in this specification.

Claims

An oil in water composition comprising:

a) at least one cyclodextrin and/or its derivative,

b) at least one dihydroflavonol according to formula (I) , and/or stereoisomer thereof:

wherein,

R₁ and R₂ are, same or different, selected from hydrogen, hydroxyl group, C₁-C₆ alkoxy, or C₁-C₆ alkyl,

R₃ is Rhamonose, glucose, or arabinose, and

c) at least one surfactant chosen from esters of C₁₆-C₂₂ fatty acid and of sorbitan, esters of C₁₆-C₂₂ fatty acid and of glycerol, ester of C₁₆-C₂₀ fatty acid and of polyethylene glycol, or a mixture thereof.
The composition according to claim 1, wherein the cyclodextrin is selected from α-cyclodextrins， β-cyclodextrins， γ-cyclodextrins, or a mixture thereof； preferably selected from 2-hydroxyl (C₁-C₆) alkyl-β-cyclodextrins, more preferably selected from 2-hydroxymethyl-β-cyclodextrins, 2-hydroxyethyl-β-cyclodextrins, 2-hydroxypropyl-β-cyclodextrins, 2-hydroxybutyl-β-cyclodextrins, or a mixture thereof.
The composition of claim 1 or 2, wherein the cyclodextrin is 2-hydroxypropyl-β-cyclodextrins.
The composition according to any one of the claims 1 to 3, wherein the cyclodextrin and/or its derivative is present ranging from 0.1％ to 20％ by weight, preferably 1％ to 15％ by weight, relative to the total weight of the composition.
The composition according to any one of the claims 1 to 4, wherein in formula (I) , R₁ and R₂ are independently from each other, selected from hydrogen and hydroxyl, and R₃ is selected from Rhamonose, preferably, both R₁ and R₂ are hydroxyl, and R₃ is Rhamonose, more preferably the dihydroflavonol is chosen from astilbin, isoastilbin, neoastilbin, neoisoastilbin, or a mixture thereof.
The composition according to any one of the preceding claims 1 to 5, wherein the dihydroflavonol is astilbin.
The composition according to any of claims 1 to 6, wherein the dihydroflavonol of formula (I) and/or stereoisomer thereof is present ranging from 0.001％ to 5％ by weight, preferably from 0.01％ to 4％ by weight, and more preferably from 0.1％ to 3％by weight, relative to the total weight of the composition.
The composition according to any one of the preceding claims 1 to 7, wherein the surfactant is chosen from sorbitan monostearate, sorbitan tristearate, sorbitan monopalmitate, sorbitan monooleate, sorbitan trioleate, glyceryl stearate, glyceryl ricinoleate, stearic acid esters comprising 20, 30, 40, 50, or 100 ethylene oxide units, or a mixture thereof； preferably chosen from glyceryl stearate, polyethylene glycol 20 EO stearate, polyethylene glycol 100 EO monosterate, or a mixture thereof.
The composition according to any one of the preceding claims 1to 8, wherein the surfactant is present ranging from 0.01％ to 30％ by weight, preferably from 0.1％ to 10％ by weight, more preferably from 1％ to 5％ by weight, relative to the total weight of the composition.
The composition according to any one of the preceding claims 1 to 9, wherein thepH value is from 2 to 6, preferably from 3 to 5, more preferably from 3.9 to 4.1, and still preferably 4.
The composition according to any one of the preceding claims 1 to 10 further comprising at least one wax chosen from hydrocarbon-based waxes, fatty acids or esters obtained by catalytic hydrogenation of animal or plant oils containing linear or branched C₈-C₃₂ chains, silicone waxes and fluoro waxes, or a mixture thereof； preferably chosen from beeswax, stearic acid, or a mixture thereof.
The composition according to any one of the preceding claims 1 to 11, wherein the wax is present ranging from 0.01％ to 20％ by weight, preferably from 0.1％ to 10％ by weight, more preferably from 1％ to 5％ by weight, relative to the total weight of the composition.
The composition according to any one of the preceding claims 1 to 12 further comprising at least one fatty alcohol, preferably solid fatty alcohol, chosen from cetyl alcohol, stearyl alcohol, cetylstearyl alcohol, miyristyl alcohol, lauryl alcohol, tridecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, arachidyl alchol, behenyl alcohol, myricyl alcohol, or a mixture thereof； more preferably chosen from cetyl alcohol, stearyl alcohol, cetylstearyl alcohol, or a mixture thereof.
The composition according to any one of the preceding claims 1 to 13, wherein the fatty alcohol is present ranging from 0.01％ to 20％ by weight, preferably from 0.1％ to 10％ by weight, more preferably from 1％ to 5％ by weight, relative to the total weight of the composition.
The composition according to any one of the preceding claims 1 to 14 further comprising at least one hydrophilic thickener chosen from carboxyvinyl polymers, polyacrylamides, 2-acrylamido-2-methylpropanesulfonic acid polymers and copolymers, or a mixture thereof； preferably polyacrylamides； more preferably polyacrylamide/C_13-14 isoparafin/laureth 7.
Method of preparation of the composition according to any one of the claims 1 to 15, comprising mixing at least one cyclodextrin, at least one dihydroflavonol according to formula (I) , and/or stereoisomer thereof, and at least one surfactant chosen from esters of C₁₆-C₂₂ fatty acid and of sorbitan, esters of C₁₆-C₂₂ fatty acid and of glycerol, ester of C₁₆-C₂₀ fatty acid and of polyethylene glycol, or a mixture thereof as defined in any one of claims 1-15.
Use of the composition according to any one of the preceding claims 1 to 15 in caring for and/ormaking up the keratin materials, comprising applying to the keratin materials, especially the skin, the composition according to any one of the preceding claims 1 to 15.