COSMETIC PROCESS FOR ATTENUATING WRINKLES

Abstract

The invention relates to a cosmetic process for caring for the skin, more particularly facial skin, in particular wrinkled skin, comprising the topical application to the skin of a cosmetic composition comprising a grafted polysaccharide polymer (I) and exposure of the treated skin to light radiation, polymer (I) being of formula:

PS—(CO—NH-L-X).sub.a(COOH)b

in which PS denotes the basic backbone of the polysaccharide bearing the carboxylic acid groups;
L is a divalent hydrocarbon-based group containing from 1 to 20 carbon atoms;
X denotes a photoactive group of azide or diazirine type;
a denotes the content of COOH groups substituted with the group —NH-L-X;
b denotes the content of unsubstituted free COOH groups;
a being between 0.01 and 0.8; b being between 0.2 and 0.99;
a+b=1

The invention also relates to the polymers (I) bearing a photoactive group X of diazirine type and to a composition comprising such a polymer in a physiologically acceptable medium.

Claims

1. Cosmetic process for caring for the skin comprising: (i) a step consisting in applying to the skin a cosmetic composition, comprising, in a physiologically acceptable medium, at least 0.3% by weight, relative to the total weight of the composition, of a grafted polysaccharide polymer of formula (I):
PS—(CO—NH-L-X)a(COOH)b in which PS denotes the basic backbone of a polysaccharide bearing the carboxylic acid groups; L is a linear, branched or cyclic, saturated or unsaturated divalent hydrocarbon-based group comprising from 1 to 20 carbon atoms which may be interrupted with one or more non-adjacent heteroatoms chosen from sulfur, oxygen, or an —NH—, —COO—, —CONH—, —O—CO—NH— or —NH—CO—NH— group, said divalent group being optionally substituted with one or more groups chosen from hydroxyl, amine, thiol, carboxylic acid, amide and cyano groups; X denotes a photoactive group of azide or diazirine type; a denoting the content of COOH groups substituted with the group —NH-L-X; b denoting the content of unsubstituted free COOH groups; a being between 0.01 and 0.8; b being between 0.2 and 0.99 a+b=1 (ii) a step comprising exposing the skin to light radiation.

2. Process according to the claim 1, wherein the polysaccharide comprises one or more base units chosen from uronic acid, glucuronic acid and mannuronic acid.

3. Process according to claim 1, wherein the polysaccharide is chosen from hyaluronic acid, chondroitin, chondroitin sulfate, alginic acid, heparin, heparin sulfate and xanthan gum.

4. Process according to claim 1, wherein the polysaccharide is hyaluronic acid.

5. Process according to claim 1, wherein a is between 0.1 and 0.6 and b is between 0.4 and 0.9.

6. Process according to claim 1, wherein L is chosen from the following groups: ##STR00018##

7. Process according to claim 1, wherein photoactive group X is chosen from the following groups: ##STR00019##

8. Process according to claim 1, wherein the group X-L- is chosen from: ##STR00020## ##STR00021## ##STR00022##

9. Process according to claim 1, wherein the grafted polysaccharide polymer (I) has a weight-average molecular weight ranging from 5000 to 1 000 000 daltons.

10. Process according to claim 1, wherein the grafted polysaccharide polymer is present in the composition in a content ranging from 0.3% to 10% by weight, relative to the total weight of the composition.

11. Process according to claim 10, in which the step consisting in applying light radiation is performed after or at the same time as (simultaneously with) the step comprising applying the cosmetic composition comprising the grafted polysaccharide (I).

12. Process according to claim 10, in which step (ii) consisting in applying light radiation is performed after step (i) comprising applying the cosmetic composition comprising the grafted polysaccharide (I).

13. Process according to claim 1, wherein the light radiation is natural light or artificial light with a wavelength of between 360 and 600 nm.

14. Process according to claim 1, in which the light radiation has a source chosen from arc lamps; fluorescent lamps; incandescent lamps; LEDs and lasers.

15. Process according to claim 1, in which the exposure time to the light radiation is at least 5 seconds.

16. Process according to claim 1, wherein the composition is in the form of an O/W emulsion or an aqueous gel.

17. Process according to claim 1, which is intended for attenuating wrinkles.

18. Grafted polysaccharide polymer of formula (I′) below:
PS—(CO—NH-L-X)a(COOH)b in which PS denotes the basic backbone of a polysaccharide bearing the carboxylic acid groups; L is a linear, branched or cyclic, saturated or unsaturated divalent hydrocarbon-based group comprising from 1 to 20 carbon atoms which may be interrupted with one or more non-adjacent heteroatoms chosen from sulfur, oxygen, or —NH—, —COO—, —O—CO—NH— or —NH—CO—NH— groups, said divalent group being optionally substituted with one or more groups chosen from hydroxyl, amine, thiol, carboxylic acid, amide and cyano groups; X denotes a photoactive group of diazirine type a denotes the content of COOH groups substituted with the group —NH-L-X b denotes the content of unsubstituted free COOH groups a being between 0.01 and 0.8; b being between 0.2 and 0.99 a+b=1.

19. Polymer according to claim 18, wherein the polysaccharide comprises one or more base units chosen from uronic acid, glucuronic acid and mannuronic acid.

20. Polymer according to claim 18, wherein the polysaccharide is chosen from hyaluronic acid, chondroitin, chondroitin sulfate, alginic acid, heparin, heparin sulfate and xanthan gum.

21. Polymer according to claim 18, wherein the polysaccharide is hyaluronic acid.

22. Polymer according to claim 18, wherein a is between 0.1 and 0.6 and b is between 0.4 and 0.9.

23. Polymer according to claim 18, wherein L is chosen from the following groups: ##STR00023##

24. Polymer according to claim 18, wherein photoactive group X may be chosen from the following groups: ##STR00024##

25. Polymer according to claim 18, wherein the group X-L- is chosen from: ##STR00025## ##STR00026##

26. Polymer according to claim 18, wherein it has a weight-average molecular weight ranging from 5000 to 1 000 000 daltons.

27. Composition comprising, in a physiologically acceptable medium, a polymer (I′) according to claim 18.

28. Composition according to claim 27, wherein polymer (I′) is present in a content ranging from 0.3% to 10% by weight, relative to the total weight of the composition.

29. Composition according to claim 27, which comprises a cosmetic adjuvant chosen from water, emulsifiers, preserving agents, sequestrants, fragrances, thickeners, oils, waxes and film-forming polymers.

30. Composition according to claim 28, which is in the form of an O/W emulsion or an aqueous gel.

Description

EXAMPLE 1: DEMONSTRATION OF THE TENSIONING EFFECT OF POLYMERS 1 AND 2

[0107] The following compositions were prepared:

[0108] Composition 1: aqueous solution containing 5% by weight of AM of hyaluronic acid (Hyacare® 50 from Evonik)

[0109] Composition 2: aqueous solution containing 2.5% by weight of AM of hyaluronic acid (Hyacare® 50 from Evonik)

[0110] Composition 3: aqueous solution containing 1.25% by weight of AM of hyaluronic acid (Hyacare® 50 from Evonik)

[0111] Composition 4: aqueous solution containing 0.25% by weight of AM of hyaluronic acid (Hyacare® 50 from Evonik)

[0112] Composition 5: aqueous solution containing 5% by weight of AM of polymer 1

[0113] Composition 6: aqueous solution containing 2.5% by weight of AM of polymer 1

[0114] Composition 7: aqueous solution containing 1.25% by weight of AM of polymer 1

[0115] Composition 8: aqueous solution containing 0.25% by weight of AM of polymer 1

[0116] Composition 9: aqueous solution containing 2.5% by weight of AM of polymer 2

[0117] Composition REF: aqueous composition of Hybridur® 875 polymer dispersion from Air Products (aqueous dispersion containing 40% by weight of particles of an interpenetrated network of polyurethane and acrylic polymers) at 7% AM.

[0118] The tensioning power of polymers 1 and 2 was compared in vitro with a reference tensioning polymer: Hybridur® 875 polymer dispersion from Air Products (aqueous dispersion containing 40% by weight of particles of an interpenetrated network of polyurethane and acrylic polymers) and also with reference to hyaluronic acid (Hyacare® 50 from Evonik).

[0119] The tensioning effect is measured by an in vitro retraction test. This test consists in quantifying in vitro the tensioning power of a material deposited on an elastomeric substrate (Kimtech nitrile reference 90627 from Kimberley Clark) having a modulus of about 20 MPa and a thickness of 100 μm.

[0120] 26 μl of each polymer composition were deposited on a rectangular specimen (9×40 mm) of elastomer. Some of the treated specimens were irradiated for 1 minute with an Oriel sun simulator machine from the company Oriel-Lot.

[0121] After 3 hours of drying at 22±3° C. and 40±10% relative humidity, the tensioning effect exerted by the polymer deposited on the specimen is directly linked to the decrease in width at the centre of the specimen. The tensioning effect (TE1) may then be quantified in the following manner:

tensioning effect (TE1) in %=(L.sub.0−L.sub.1/L.sub.0)×100

[0122] L.sub.0=initial width 9 mm

[0123] and L.sub.1=width after 3 hours of drying

[0124] The persistence with respect to water of the observed tensioning effect was then evaluated.

[0125] The deposits were rinsed by spraying onto the strip, at a distance of 5 cm, 10 μl of aqueous 0.9 M NaCl solution (synthetic sweat).

[0126] The deposits were dried for 3 hours at 22±3° C. and 40±10% relative humidity, and the tensioning effect after washing (TE2) was measured again by measuring the width L.sub.2 of the specimen.

Tensioning effect (TE2) in %=(L.sub.0−L.sub.2/L.sub.0)×100

[0127] with L.sub.2=width of the specimen after rinsing and 3 hours of drying.

[0128] The following results were obtained:

TABLE-US-00002 Tensioning Tensioning effect (TE1) effect (TE2) Irradiated (before (after Example Composition Polymer (yes/no) washing) washing) A 1 Hyaluronic acid No 33% 11% B 2 Hyaluronic acid No 22% 0% C 3 Hyaluronic acid No 0% 0% D 4 Hyaluronic acid No 0% 0% E 5 Polymer 1 No 33% 11% F 6 Polymer 1 No 22% 0% G 7 Polymer 1 No 0% 0% H 8 Polymer 1 No 0% 0% I 5 Polymer 1 Yes 77% 77% J 6 Polymer 1 Yes 77% 77% K 7 Polymer 1 Yes 44% 44% L 8 Polymer 1 Yes 0% 0% M 9 Polymer 2 No 33% 11% N 9 Polymer 2 Yes 77% 77% O REF Hybridur ® 875 No 55% 22% polymer dispersion

[0129] The results obtained show that the polymer of Example 1 and that of Example 2 according to the invention, after irradiation of the deposit (Examples I to L and N), make it possible to obtain a good tensioning effect before and after washing. The tensioning effect obtained thus shows good persistence with respect to water.

SYNTHESIS EXAMPLE 3 (POLYMER 3): HYALURONIC ACID FUNCTIONALIZED WITH 16% DIAZIRINE

[0130] ##STR00016##

[0131] 12.8 g (34.7 mmol) of hyaluronic acid (Hyacare® 50 from Evonik) were dissolved in 1 litre of distilled water in a round-bottomed flask covered with aluminium foil to prevent exposure to light. 9.4 g (34.7 mmol) of N-{4-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenyl}ethane-1,2-diamine were dissolved in 500 ml of distilled water and then added to the round-bottomed flask containing the hyaluronic acid. The pH was adjusted to 6.5 with hydrochloric acid (2M) and 12.5 g (52 mmol) of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) were then added. The reaction mixture was stirred for 16 hours while maintaining the pH at 6.5 with hydrochloric acid (2M) or sodium bicarbonate (2M). 12.5 g (52 mmol) of DMTMM were added. The reaction mixture was stirred for 24 hours while maintaining the pH at 6.5 with hydrochloric acid (2M) or sodium bicarbonate (2M). The reaction mixture was placed in dialysis tubes (Spectra/Por Dialysis Membrane MWCO 3500) and then dialysed with distilled water (2 litres) for 48 hours. The water was changed 4 times during the 48 hours. The content of the tubes was lyophilized to generate a solid residue. The solid residue was then triturated twice with acetone (500 mL), filtered off for 5 minutes and then dried under vacuum at room temperature for 12 hours. 16 g of a beige-coloured solid product (powder) were thus obtained.

[0132] The product was stored in an amber-coloured flask at −20° C.

[0133] The .sub.1H NMR analysis in deuterated water: 16% grafting

EXAMPLE 2: DEMONSTRATION OF THE TENSIONING EFFECT OF POLYMER 3

[0134] The following composition was prepared:

[0135] Composition 10: aqueous solution containing 2.5% by weight of AM of polymer 3

[0136] The tensioning effect was evaluated according to the procedure as described in Example 1, using the amounts indicated below.

[0137] The following results were obtained:

TABLE-US-00003 Tensioning Tensioning effect (TE1) effect (TE2) Ex- Com- Irradiated (before (after ample position Polymer (yes/no) washing) washing) P 10 (30 μl) Polymer 3 No 44% 22% Q 10 (30 μl) Polymer 3 Yes 66% 66% R 10 (60 μl) Polymer 3 Yes 77% 77%

[0138] The results obtained show that the polymer 3, after irradiation, has a good tensioning effect which is persistent with respect to water.

SYNTHESIS EXAMPLE 4 (POLYMER 4): ALGINIC ACID FUNCTIONALIZED WITH 10% DIAZIRINE

[0139] ##STR00017##

[0140] 0.65 g of alginic acid (Protanal PH 6160 from the company FMC Corporation) was dissolved in 33 ml of water. The pH was adjusted to 3.5 with hydrochloric acid solution (0.2M, 10 mL). Next, a solution of 0.71 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride in 3 ml of water was added, with stirring at room temperature (25° C.). After 5 minutes of stirring, 0.8 g of N-hydroxysulfosuccinimide was added, the reaction mixture was stirred for 5 minutes at room temperature, and 1 g of N-{4-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenyl}ethane-1,2-diamine was then added. After 5 minutes, the pH was adjusted to 4.7 with hydrochloric acid solution (0.4M). The reaction mixture was stirred for 40 hours at room temperature and protected from light. Next, the reaction mixture was poured into acetone (300 ml), stirred for 1 hour at room temperature and then filtered to recover a white solid. The solid was placed in water (40 mL) and then dialysed with water for 3 days, the water being changed each day. The product was obtained by lyophilization. 0.6 g of a beige-coloured solid product (powder) was thus obtained.

[0141] The product was stored in an amber-coloured flask at −20° C.

[0142] The .sub.1H NMR analysis in deuterated water: 10% grafting

SYNTHESIS EXAMPLE 5 (POLYMER 5): ALGINIC ACID FUNCTIONALIZED WITH 6% DIAZIRINE

[0143] The polymer was prepared according to the procedure described in Synthesis Example 4, using:

[0144] 0.65 g of alginic acid in 33 ml of water

[0145] 0.5 g of N-{4-[3-(trifluoromethyl)-3H-diazirin-3-yl]phenyl}ethane-1,2-diamine

[0146] 0.4 g of N-hydroxysulfosuccinimide

[0147] 0.36 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. hydrochloride in 3 mL of water

[0148] 0.57 g of a beige-coloured product (powder) was obtained.

[0149] The product was stored in an amber-coloured flask at −20° C.

[0150] The .sub.1H NMR analysis in deuterated water: 6% grafting

EXAMPLE 3: DEMONSTRATION OF THE TENSIONING EFFECT OF POLYMERS 4 AND 5

[0151] The following composition was prepared:

[0152] Composition 11: aqueous solution containing 1% by weight of AM of polymer 4

[0153] Composition 12: aqueous solution containing 1% by weight of AM of polymer 5

[0154] The tensioning effect was evaluated according to the procedure as described in Example 1, using the amounts indicated below.

[0155] The following results were obtained:

TABLE-US-00004 Tensioning Tensioning effect (TE1) effect (TE2) Ex- Com- Irradiated (before (after ample position Polymer (yes/no) washing) washing) S 11 (30 μl) Polymer 4 No 55% 11% T 11 (30 μl) Polymer 4 Yes 55% 55% U 12 (30 μl) Polymer 5 No 55% 11% V 12 (30 μl) Polymer 5 Yes 66% 55%

[0156] The results obtained show that the polymers 4 and 5, after irradiation, have a good tensioning effect which is persistent with respect to water.

EXAMPLE 4

[0157] An antiwrinkle gel having the following composition is prepared:

TABLE-US-00005 polymer of Example 1 1 g hydroxyethylcellulose (Natrosol ® 250 0.5 g HHR CS from Ashland) Preserving agents qs Water qs 100 g

[0158] The composition obtained is applied to the face and the surface of the treated skin is then irradiated with white light (Lite-Pad lamp from the company Reicorp) for 3 minutes. The treatment applied makes it possible to effectively smooth out the wrinkles.

EXAMPLE 5

[0159] An antiwrinkle gel having the following composition is prepared:

TABLE-US-00006 Polymer of Example 2 1 g Hydroxyethylcellulose (Natrosol ® 250 0.5 g HHR CS from Ashland) Preserving agents qs Water qs 100 g

[0160] The composition obtained is applied to the face and the surface of the treated skin is then irradiated with white light (Lite-Pad lamp from the company Reicorp) for 10 minutes. The treatment applied makes it possible to effectively smooth out the wrinkles.

EXAMPLE 6

[0161] An antiwrinkle gel having the following composition is prepared:

TABLE-US-00007 polymer of Example 3 1 g hydroxyethylcellulose (Natrosol ® 250 0.5 g HHR CS from Ashland) Preserving agents qs Water qs 100 g

[0162] The composition obtained is applied to the face and the surface of the treated skin is then irradiated with white light (Lite-Pad lamp from the company Reicorp) for 10 minutes. The treatment applied makes it possible to effectively smooth out the wrinkles.

EXAMPLE 7

[0163] An antiwrinkle gel having the following composition is prepared:

TABLE-US-00008 polymer of Example 4 1 g hydroxyethylcellulose (Natrosol ® 250 0.3 g HHR CS from Ashland) Preserving agents qs Water qs 100 g

[0164] The composition obtained is applied to the face and the surface of the treated skin is then irradiated with blue light (goLITE BLU from the company Philips) for 15 minutes. The treatment applied makes it possible to effectively smooth out the wrinkles.

EXAMPLE 8

[0165] An antiwrinkle gel having the following composition is prepared:

TABLE-US-00009 polymer of Example 5 1.5 g hydroxyethylcellulose (Natrosol ® 250 0.2 g HHR CS from Ashland) Preserving agents qs Water qs 100 g

[0166] The composition obtained is applied to the face and the surface of the treated skin is then irradiated with blue light (Camag Box 3 lamp from the company Camag) for 5 minutes. The treatment applied makes it possible to effectively smooth out the wrinkles.