Aqueous composition based on a sennoside and weak base

Abstract

Aqueous composition based on an e sennoside and a weak base The present invention relates to a cosmetic composition comprising at least one compound of formula (I) as defined below, or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or solvates such as hydrates, at least one weak base, and water, said composition having a pH of between 6.0 and 6.5. Figure for the abstract: none

Description

Title of the invention: Aqueous composition based on a sennoside and weak base

[0001] The present invention relates to a cosmetic composition comprising: a. at least one compound of formula (I) as defined below, or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or solvated such as hydrates, b. at least one weak base, and c. water,

[0002] said composition having a pH between 6.0 and 6.5.

[0003] Human skin is made up of two compartments, namely a deep compartment, the dermis, and a superficial compartment, the epidermis. The epidermis is in contact with the external environment, and its role is in particular to protect the body from dehydration and from external, chemical or mechanical attacks.

[0004] There is always a need for new cosmetic compositions having interesting properties, particularly on the skin.

[0005] Sennosides can be interesting active ingredients for this purpose. Indeed, this type of active ingredient is known in cosmetics, for example from application JP2002-255733.

[0006] However, sennosides are partially soluble in certain solvents such as methanol or acetone (which are not cosmetically acceptable solvents), and are not soluble in water, particularly at room temperature. They therefore do not allow, as such, the formulation of stable cosmetic compositions applicable to the skin.

[0007] The formulator is therefore looking for compositions comprising a sennoside such as sennoside A which are stable and applicable in particular topically (i.e. on the skin and / or mucous membranes).

[0008] Such compositions must further comprise a certain amount of water, in order to be able to formulate a sennoside such as sennoside A in a wide range of cosmetic carriers including lotions, gels or emulsions.

[0009] In this context, the inventors have surprisingly discovered that particular bases allow the solubilization of a sennoside such as sennoside A, and are compatible with a formulation in an aqueous medium at a given pH.

[0010] The invention therefore aims to provide a cosmetic composition which responds to all these problems.

[0011] Indeed, in this case, sennoside A is insoluble in water at its native pH, i.e. around 4.3. It is known that by raising the pH of a molecule beyond its last pKa, it becomes soluble. However, since sennoside A has 4 pKa and its last pKa is equal to 8.2, such a pH leads to the formulation of sennoside A beyond 8.3, which is incompatible with topical cosmetic application, particularly on the skin and / or mucous membranes. Indeed, topical cosmetic compositions, particularly those applicable to the skin and / or mucous membranes, must have an acceptable physiological pH, i.e. between 5.0 and 7.0.

[0012] Surprisingly, as demonstrated in examples, the Applicant has discovered that by adjusting the pH directly with a weak base, it is possible to obtain a clear solution, whereas this is not the case with a strong base.

[0013] Thus, the present invention relates to a cosmetic composition comprising: a. at least one compound of formula (I) or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or its solvates such as hydrates, b. at least one weak base, and c. water,

[0014] said composition having a pH between 6.0 and 6.5.

[0015] Preferably, the present invention relates to a cosmetic composition consisting of: a. at least one compound of formula (I) or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or its solvates such as hydrates, b. at least one weak base, and c. water,

[0016] said composition having a pH between 6.0 and 6.5.

[0017] For the purposes of the present invention, and unless otherwise indicated: - an “alkyl” radical is a saturated, linear or branched hydrocarbon radical, in particular C1-C6, preferably C1-C4; - a "sugar" radical is a monosaccharide or disaccharide radical. Examples of sugar radicals include: sucrose (or saccharose), glucose, galactose, ribose, fucose, maltose, fructose, mannose, arabinose, xylose or lactose; - by "monosaccharide" is meant a monosaccharide sugar comprising at least 5 carbon atoms of formula CX(H2O)X, with x being an integer greater than or equal to 5, preferably x is greater than or equal to 6, in particular x is inclusively between 5 and 7, preferably x = 6. They may be of D or L configuration, and of alpha or beta anomer, as well as one of their salts or their solvates such as hydrates; - by "disaccharide" is meant a di-osidic sugar which is a compound consisting of two oses linked together by O-osidic bonds, said compounds being composed of two monosaccharides (also called mono-osidics) as defined above, said monosaccharide units comprising at least 5 carbon atoms, preferably 6, particularly the mono-osidic units are linked together in 1,4 or 1,6, in anomer α (alpha) or [3 (beta), each osidic unit being able to be of L or D configuration, as well as one of its salts or its solvates such as hydrates. A disaccharide is more particularly a polymer formed from two oses (or monosaccharides) having the general formula: -[Cx(H2O)y)]2- or -[(CH2O)X]2-, with x being an integer greater than or equal to 5, preferably x is greater than or equal to 6, in particular x is inclusively between 5 and 7, preferably x = 6, and y is an integer which represents x - 1; - by “organic or mineral base salt” we mean a salt of a base or alkaline agent such as alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, ammonia, amines, alkanolamines or salts of so-called “basic” amino acids such as lysine or arginine; - by “skin” we mean the skin of the face and / or body, the scalp; - by "annexes" we mean eyelashes, eyebrows, nails, and hair, in especially eyelashes and hair; - in what follows, and unless otherwise indicated, the limits of a domain of values ​​are included in this domain, in particular in the expressions “between” and “ranging from ... to ..."; - furthermore, the expression “at least one” used in this description is equivalent to the expression “one or more”.

[0018] The invention also relates to a method for caring for the skin and / or mucous membranes comprising the application of the composition according to the invention to the skin and / or mucous membranes.

[0019] The invention also relates to the use of a composition according to the invention for the care of the skin and / or mucous membranes.

[0020] The invention also relates to a final cosmetic composition comprising, in a cosmetically acceptable medium, at least 50% by weight, preferably from 60% to 99%, and more preferably from 70% to 95% relative to the total weight of the composition of a composition as described above (i.e. comprising ingredients a) to c)). This final composition corresponds in particular to the final commercialized cosmetic product. Compound of formula (I) (compound (a))

[0021] The composition according to the invention comprises at least one compound of formula (I) or one of its optical isomers, cis-trans isomers (such as an alpha or beta anomer), tautomers or one of its salts, in particular of organic or mineral base, or one of its solvates such as hydrates:

[0022] [Chem.l]

[0023] in which:

[0024] - R' and R' ' are identical or different, preferably identical, and represent a H or a monosaccharide or a polysaccharide comprising up to 20 sugar units, preferably up to 6 sugar units, in pyranose and / or furanose form and of L and / or D series, said mono- or polysaccharide possibly being substituted by a hydroxyl group which must be free, and optionally one or more amine function(s) which may be protected, and said monosaccharide or polysaccharide being optionally substituted on its -CH2OH group by a -C(O)-CO2 H group;

[0025] - R represents H or -C-(O)-O-Ri or -Alk-X-Rl, preferably -C-(O)-O-Ri or Alk- O-Ri,

[0026] with X being O, S or -NRi, preferably O; Ri being H or a saturated or unsaturated hydrocarbon chain, preferably saturated in C1-C6, more preferably RI corresponds to H, and Alk corresponds to a C1-C6 alkylene group, preferably -CH2-,

[0027] Advantageously, R' and R” are identical or different and represent a monosaccharide or a polysaccharide containing up to 6 sugar units, in pyranose and / or furanose form and of L and / or D series, said mono- or polysaccharide having at least one hydroxyl function which is obligatorily free and / or optionally one or more amine functions which are obligatorily protected.

[0028] Advantageously, the monosaccharide is chosen from D-glucose, D-galactose, D-mannose, D-xylose, D-lyxose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-iduronic acid, N-acetyl-D-glucosamine and N-acetyl-D-galactosamine. The monosaccharide advantageously denotes D-glucose, L-rhamnose, D-xylose, N-acetyl-D-glucosamine or L-fucose, and more preferably D-glucose.

[0029] Advantageously, the polysaccharide containing up to 6 sugar units is chosen from D-maltose, D-lactose, D-cellobiose, D-maltotriose, a disaccharide combining a uronic acid chosen from D-iduronic acid or D-glucuronic acid with a hexosamine chosen from D-galactosamine, D-glucosamine, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, a disaccharide combining L-rhamnose and D-galactose, an oligosaccharide containing at least one xylose which may be advantageously chosen from xylobiose, methyl-[3-xylobioside, xylotriose, xylotetraose, xylopentaose and xylohexaose and in particular xylobiose which is composed of two xylose molecules linked by a 1-4 bond.

[0030] More preferably, R' and R' ' are identical and represent a monosaccharide chosen from D-glucose, D-xylose, L-fucose, L-rhamnose, D-galactose and D-maltose, preferably D-glucose.

[0031] The monosaccharide or polysaccharide of R' and / or R” may be substituted on one or more hydroxymethyl residue(s) by a -C(O)-COOH group.

[0032] Preferably, the compound of formula (I) or one of its optical isomers, cis-trans isomers (such as an alpha or beta anomer), tautomers or one of its salts, in particular of organic or mineral base or one of its solvates such as hydrates, is chosen from sennosides A, B, C, D, E and F, preferentially it is chosen from sennosides A and B, even more preferentially the compound of formula (I) is sennoside A or one of its salts.

[0033] The compound of formula (I) or one of its optical isomers, cis-trans isomers (such as an alpha or beta anomer), tautomers or one of its salts, in particular of organic or mineral base or one of its solvates such as hydrates, preferably sennoside A or one of its salts is present in solubilized form in the composition. By "in solubilized form" is meant that said compound does not form crystals visible to the naked eye in the composition.

[0034] Sennoside A (C42H38O20) (or acid (9R)-9-[(9R)-2-carboxy-4-hydroxy-10-oxo-5-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(h ydroxymethyl)oxan-2-yl]oxy-9H-anthracen-9-yl]-4-hydroxy-10-oxo-5-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-9H-anthracene-2-carboxylic acid (IUP AC) is the chemical compound of formula (I') below:

[0035] [Chem.2]

[0036] Its CAS number is 81-27-6. It is a derivative of anthraquinone, found in plants of the genus Senna. It typically appears as a very hygroscopic yellow powder.

[0037] Sennoside A has 4 pKa, whose values ​​are pKal = 3.3, pKa2 = 3.9, pKa3 = 7.5 and its last pKa (pKa4) is equal to 8.2.

[0038] The compound of formula (I), preferably sennoside A, may also be in salt form. By "salt" is meant a cosmetically acceptable salt, i.e. compatible with application to the skin, mucous membranes and / or appendages. The salt of the compound of formula (I), preferably the salt of sennosides A, may be an alkali or alkaline earth metal salt, preferably a calcium, magnesium, sodium or potassium salt.

[0039] Typically, the salt of the compound of formula (I), preferably the sennoside salt such as sennoside A salt, may exist once the compound is introduced into the composition. Indeed, the compound of formula (I) is introduced in non-salified form into the composition.

[0040] Sennoside A is for example marketed by INTERCHIM under the name Sennoside A.

[0041] Preferably, the composition comprises between 0.1 and 5% by weight of the compound of formula (I) or one of its optical isomers, cis-trans isomers (such as an alpha or beta anomer), tautomers or one of its salts, in particular of organic or mineral base or one of its solvates such as hydrates, relative to the total weight of the composition, preferably between 0.2 and 4% by weight, preferably between 0.3 and 3% by weight, preferably between 0.4 and 1% by weight.

[0042] Preferably, the composition comprises between 0.1 and 10% by weight of sennoside A or one of its salts relative to the total weight of the composition, preferably between 0.2 and 5% by weight, preferably between 0.3 and 3% by weight, preferably between 0.4 and 1% by weight. Weak base (compound (b))

[0043] The composition according to the invention comprises at least one weak base. A weak base is a base which does not completely dissociate in water.

[0044] By “weak base” is meant a base belonging to an acid-base pair with a pKa between 0 and 14.

[0045] The weak base can be mineral or organic.

[0046] As weak mineral bases, we can cite ammonia or aluminum hydroxide.

[0047] Preferably, the weak base is chosen from organic weak bases, preferably from alpha-amino acids.

[0048] Alpha-amino acids have the formula H2N-HCR-COOH, where R is the side chain identifying the alpha-amino acid. Preferably, alpha-amino acids are proteinogenic.

[0049] Preferably, the alpha-amino acid is selected from L-arginine, L-alanine, L-asparagine, L-aspartate, L-cysteine, L-glutamate, L-glutamine, L-glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine and L-valine.

[0050] Preferably, the weak base is arginine (or L-arginine).

[0051] The composition according to the invention may comprise at least one low base with an active material content ranging from 0.01% to 5% by weight, relative to the total weight of the composition, in particular from 0.1% to 1% by weight, preferably ranging from 0.15% to 0.6% by weight. Water (compound (c))

[0052] The composition according to the invention comprises water.

[0053] The water used may be sterile demineralized water and / or a floral water such as rose water, cornflower water, chamomile water or linden water, and / or a natural thermal or mineral water such as VITTEL water, LUCAS water or LA ROCHE POSAY water.

[0054] The composition preferably comprises at least 30% by weight of water relative to the total weight of the composition, preferably at least 50% by weight, preferably at least 60% by weight, preferably at least 70% by weight.

[0055] The composition preferably comprises from 30% to 98% by weight of water relative to the total weight of the composition, more preferably from 50% to 97% by weight, even more preferably from 70% to 95% by weight. pH of the composition

[0056] The composition according to the invention has a pH between 6.0 and 6.5.

[0057] The weak base is used to adjust the final pH of the composition between 6.0 and 6.5.

[0058] Preferably, the composition according to the invention is substantially free of strong base. By "substantially free of strong base" is meant that the composition comprises less than 1% by weight, preferably less than 0.5% by weight, preferably less than 0.01% by weight relative to the total weight of the composition of strong base. Preferably, the composition according to the invention is completely free of strong base.

[0059] Preferably, the present invention relates to a cosmetic composition comprising: a. sennoside A or one of its salts, b. arginine, and c. water,

[0060] said composition having a pH between 6.0 and 6.5.

[0061] Preferably, the present invention relates to a cosmetic composition consisting of: a. sennoside A or one of its salts, b. arginine, and c. water,

[0062] said composition having a pH between 6.0 and 6.5.

[0063] The composition according to the invention may also contain ingredients usual in the cosmetic field, such as preservatives, perfumes, fillers, oils, waxes, pasty fatty substances, sun protection filters or UV filters, odor absorbers, coloring materials, basic agents, sequestering agents or active ingredients.

[0064] The quantities of these different ingredients are those conventionally used in the field considered, and for example from 0.01 to 20% of the total weight of the composition. These ingredients, depending on their nature, can be introduced into the fatty phase and / or into the aqueous phase.

[0065] Of course, those skilled in the art will take care to choose the possible compound(s) to be added to the composition according to the invention and their quantities in such a way that the advantageous properties intrinsically attached to the composition in accordance with the invention are not, or not substantially, altered by the envisaged addition.

[0066] The composition in accordance with the invention can be obtained in a conventional manner by a person skilled in the art.

[0067] The invention also relates to a final cosmetic composition comprising, in a cosmetically acceptable medium, at least 50% by weight relative to the total weight of the composition of a composition as described previously (i.e. comprising ingredients a) to c)), preferably from 60 to 99% by weight, more preferably initially from 70 to 95% by weight. The final composition corresponds in particular to the final commercialized cosmetic product, based on sennoside. By cosmetically acceptable medium, we mean a medium compatible with the skin and / or its appendages.

[0068] The invention also relates to a method for caring for the skin and / or mucous membranes comprising the application of the composition according to the invention or of the final composition according to the invention to the skin and / or mucous membranes.

[0069] The invention also relates to the use of a composition according to the invention or of the final composition according to the invention for the care of the skin and / or mucous membranes.

[0070] The following examples will allow a better understanding of the invention, without however being limiting in nature. The raw materials are named by their chemical or INCI name. The quantities indicated are in % by weight of raw materials relative to the total weight of the composition (% w / w), unless otherwise stated. Examples

[0071] Example 1: preparation of a composition according to the invention and evaluation by report to comparative compositions

[0072] A composition according to the invention is compared with counterexamples. Operating mode

[0073] The composition according to the invention of Table 1 below is prepared as follows:

[0074] In a beaker under magnetic stirrer, the powdered sennoside A is put then the water, the mixture is not homogeneous. The pH is then adjusted drop by drop with the arginine. Stirring is left for a while to stabilize the pH.

[0075] In the case of counterexamples:

[0076] The same method is used in counterexamples 1 and 2 with a strong base (NaOH). But the pH adjustment is extremely difficult to achieve: when the pH is for example 5.8 (counterexample 1), sennoside A is not completely solubilized. A very small pH variation, for example 0.1 to obtain solubilization (counterexample 2), does not allow reproducibility.

[0077] [Tables 1] Ingredients (% w / w) Example 1 according to the invention Counter-example (without base) Counter-example 1 Counter-example 2 Sennoside A 0.5 0.5 0.5 0.5 NaOH (strong base) - - 0.035 0.0403 Arginine 0.178 - - - Water Qsp 100 Qsp 100 Qsp 100 Qsp 100 PH 6 4.3 5.8 5.9 Observation Clear transparent solution Opaque yellow dispersion Cloudy color always pale yellow Clear transparent But not reproducible

[0078] Sennoside A is completely insoluble in water at native pH (4.3); the dispersion (counterexample without base) is opaque yellow.

[0079] It is possible to obtain a perfect and stable solubility over time of sennoside A at 0.5% by weight by varying the pH of this solution with a weak base such as arginine. Indeed, at a pH between 6.0 and 6.5, the solution (example 1 according to the invention) is clear and without recrystallization over time.

[0080] Obtaining the sennoside A solution by going directly to a pH of 6.0 is easier than with a strong base, where the introduction rates are low, i.e. of the order of 102 to 103 (counter-examples 1 and 2).

Claims

Claims

1. Cosmetic composition comprising: (a) at least one compound of formula (I) or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or its solvates such as hydrates: [Chem.l] (I) in which: - R' and R' ' are identical or different, preferably identical, and represent an H or a monosaccharide or a polysaccharide comprising up to 20 sugar units, preferably up to 6 sugar units, in pyranose and / or furanose form and of L and / or D series, said mono- or polysaccharide possibly being substituted by a hydroxyl group which must be free, and optionally one or more amine function(s) which may be protected, and said monosaccharide or polysaccharide being optionally substituted on its -CH2OH group by a -C(O)-CO2H group; - R represents H or -C-(O)-O-Ri or -Alk-X-Rl, preferably -C-(O)-OR! or Alk-O-Rj, with X being O, S or -NRb, preferably O; RI being H or a saturated or unsaturated hydrocarbon chain, preferably saturated in C1-C6, more preferably RI corresponds to H, and Alk corresponds to a C1-C6 alkylene group, preferably -CH2-, a. at least one weak base, and b. water, said composition having a pH between 6.0 and 6.

5.

2. Composition according to claim 1, wherein the compound of formula (I) is such that R' and R' ' are identical and represent a monosaccharide chosen from D-glucose, D-galactose, D-mannose, D-xylose, D-lyxose, L-fucose, L-arabinose, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-iduronic acid, N-acetyl-D-glucosamine and N-acetyl-D-galactosamine, preferably chosen from D-glucose, L-rhamnose, D-xylose, N-acetyl-D-glucosamine and L-fucose, and more preferably D-glucose; preferably the compound of formula (I) or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or one of its solvates such as hydrates, is chosen from sennosides A, B, C, D, E and F, preferentially it is chosen from sennosides A and B.

3. Composition according to one of the preceding claims, in which the compound of formula (I) is sennoside A or one of its salts.

4. Composition according to one of the preceding claims which comprises between 0.1 and 10% by weight of compound of formula (I) relative to the total weight of the composition, preferably between 0.2 and 5% by weight, preferably between 0.3 and 3% by weight, preferably between 0.4 and 1% by weight.

5. Composition according to one of the preceding claims, in which the weak base is mineral or organic, preferably chosen from ammonia, aluminum hydroxide and alpha-amino acids, preferably from alpha-amino acids.

6. Composition according to one of the preceding claims, in which the weak base is arginine.

7. Composition according to one of the preceding claims, in which the weak base is present in an active material content ranging from 0.01% to 5% by weight, relative to the total weight of the composition, in particular from 0.1% to 1% by weight, preferably ranging from 0.15% to 0.6% by weight.

8. Composition according to one of the preceding claims, which comprises at least 30% by weight of water relative to the total weight of the composition, preferably at least 50% by weight, preferably at least 60% by weight, preferably at least 70% by weight; preferably comprises from 30% to 98% by weight of water relative to the total weight of the composition, more preferably from 50% to 97% by weight, still more preferably from 70% to 95% by weight.

9. Composition according to one of the preceding claims, which consists of: a. at least one compound of formula (I) or one of its optical isomers, cis-trans isomers, tautomers or one of its salts, in particular of organic or mineral base or its solvates such as hydrates, b. at least one weak base, and c. water, said composition having a pH of between 6.0 and 6.

5.

10. A composition according to any preceding claim, which is substantially free of strong base, preferably which is completely free of strong base.

11. Final cosmetic composition comprising, in a cosmetically acceptable medium, at least 50% by weight, preferably from 60 to 99% by weight, more preferably from 70 to 95% by weight relative to the total weight of the composition of a composition according to one of claims 1 to 10.

12. A method of caring for the skin and / or mucous membranes comprising the application of the composition according to one of the preceding claims to the skin and / or mucous membranes.

13. Use of a composition according to one of claims 1 to 10 or 11 for the care of the skin and / or mucous membranes.