Stabilizer or stabilizer composition for stabilizing dihydroavenanthramide d

Abstract

The present invention relates to the use of a stabilizer or a stabilizer composition for stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenanthramide D and to a mixture comprising Dihydroavenanthramide D and a stabilizer, as well as to a cosmetic preparation comprising such a mixture.

Description

[0001] Stabilizer or stabilizer composition for stabilizing Dihydroavenanthramide D

[0002] The present invention relates to the use of a stabilizer or a stabilizer composition for stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenanthramide D and to a mixture comprising Dihydroavenanthramide D and a stabilizer, as well as to a cosmetic preparation comprising such a mixture. Dihydroavenanthramide D is a compound with particular importance in the cosmetic industry. Dihydroavenanthramide D belongs to the family of Avenanthramides, i.e. anthranilic acid amides, and is also described as hydroxyphenyl propamidobenzoic acid. Dihydroavenanthramide D is described by the CAS number 697235-49-7 (as listed by the European Chemicals Agency) and corresponds to the following chemical structure:

[0003] Dihydroavenanthramide D Dihydroavenanthramide D has been described for several cosmetic applications. For example, WO 2006 / 134013 A1 describes an application of Dihydroavenanthramide D for alleviating itching and / or for reducing skin reddening.

[0004] US 2006 / 089413 A1 describes that Dihydroavenanthramide D can be used forthe inhibition of the substance P-induced release of histamine from mast cells. In this way, pruritus, skin reddening, weal development or allergic skin reactions may be prevented.

[0005] Typically, Dihydroavenanthramide D is formulated in a cosmetic composition including further substances. One challenge for using Dihydroavenanthramide D is to provide and maintain its colour stability in a cosmetic composition. If no or only insufficient colour stability of Dihydroavenanthramide D in a cosmetic composition is provided, it starts to cause a discoloration of the cosmetic composition. In such cases, the cosmetic compositions will change to a yellow to brownish colour, which increases with decreased colour stabilization of Dihydroavenanthramide D.

[0006] Compositions with such discoloration are not accepted by the consumers of cosmetic compositions, irrespective of the functionality of such a composition.

[0007] Thus, Dihydroavenanthramide D is typically stabilized in cosmetic compositions. The stabilizer ascorbyl palmitate ascorbyl palmitate is widely used in such compositions. Ascorbyl palmitate is frequently added as a colour stabilizer for Dihydroavenanthramide in a cosmetic composition. It was found that ascorbyl palmitate is able to stabilize Dihydroavenanthramide D in cosmetic compositions. However, it was found that this function of ascorbyl palmitate is limited, since a reduced colour stability of Dihydroavenanthramide D was observed after long-term storage of cosmetic com- positions comprising Dihydroavenanthramide D. Even though the stabilizer ascorbyl palmitate was added, the compositions showed a discoloration, often yellow to brownish discoloration, after storage for some months and / or under conditions promoting the instability of compounds in a composition, such as increased temperature (e.g. 40 °C or higher or 50 °C or higher).

[0008] Thus, a need for further, preferably improved, colour stabilizers for Dihydroavenanthramide D in cosmetic compositions remains.

[0009] Furthermore, discussions regarding the stabilizer ascorbyl palmitate have recently started. It is (controversially) discussed that ascorbyl palmitate provides a comedogenic activity, i.e. promotes the formation of comedones.

[0010] Comedones are clogged hair follicles in the skin, which occur as a result of increased oil production in the sebaceous glands. Comedones are visible as darkened spots on the skin and occur mostly on the face, neck, upper chest, shoulders, and back of a subject, wherein they represent an exclusively cosmetic condition.

[0011] Frequently, those areas treated with cosmetic compositions are visible in daily life and represent those areas which shall provide a groomed appearance. Thus, comedones need to be prevented in these areas.

[0012] Consequently, there is a need for further colour stabilizers for Dihydroavenanthramide D in cosmetic compositions, which preferably show an improved colour stabilizing ability.

[0013] The primary object of the present invention was thus to provide stabilizers for Dihydroavenanthramide D, preferably with improved colour stabilization compared to ascorbyl palmitate.

[0014] The primary object of the present invention is solved by the use of a stabilizer or a stabilizer composition, wherein the stabilizer or, respectively, the or one or all stabilizers) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringyli- dene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof, for stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenanthramide D, wherein the stabilization is characterized by reduced discoloration and / or malodour formation.

[0015] It was surprisingly found that the stabilizers) used according to the invention provide a particular advantageous colour stabilization of Dihydroavenanthramide D. It was surprisingly found that a particularly low discoloration is observed when such a stabilizer or stabilizer composition is used, compared to the typically used stabilizer for Dihydroavenan- thramde D, i.e. ascorbyl palmitate, or tocopherol acetate, which is another frequently used stabilizer.

[0016] Moreover, it was surprisingly found that a particularly low malodour formation occurs when such a stabilizer or stabilizer composition is used, compared to the typically used stabilizer for Dihydroavenanthramde D, i.e. ascorbyl palmitate, or tocopherol acetate, which is another frequently used stabilizer.

[0017] Diethylhexyl syringylidene malonate is also known as Oxynex ST and is preferably described by the CAS number 444811-29-4 (as listed by the European Chemicals Agency) and is preferably described as Propanedioic acid, 2-[(4-hydroxy-3,5-dimethoxy- phenyl)methylene]-, 1 ,3-bis(2-ethylhexyl) ester.

[0018] Tocopheryl acetate, preferably alpha-tocopherol acetate, is preferably described by the CAS number 52225-20-4 (as listed by the European Chemicals Agency) and is preferably described as [2R*(4R*,8R*)]-(±)-3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyl- tridecyl)-2H-benzopyran-6-yl acetate.

[0019] Sodium metabisulfite is preferably described by the CAS number 7681-57-4 (as listed by the European Chemicals Agency) and is preferably described as Disodium disulphite.

[0020] Tris(tetramethylhydroxypiperidinol) citrate is preferably described by the CAS number 220410-74-2 (as listed by the European Chemicals Agency) and is preferably described as 1 ,4-dihydroxy-2,2,6,6-tetramethyl piperidinium-2-hydroxy-1 ,2,3-propanetricarboxylate.

[0021] Advantageously, no comedogenic activity is described for diethylhexyl syringylidene malonate, sodium metabisulfite or Tris(tetramethylhydroxypiperidinol) citrate. The term “stabilizer composition” as used herein describes a composition comprising one or more stabilizer(s). In case the composition comprises more than one stabilizer, two, three or more or all stabilizers may be mixed.

[0022] Preferably for stabilizing Dihydroavenanthramide D, the stabilizer or, respectively, stabilizer composition is mixed with Dihydroavenanthramide D. In case of a stabilizer composition, the respective stabilizers, in case more than one stabilizer is present in the stabilizer composition, may be mixed with Dihydroavenanthramide D separately. In case of a stabilizer composition, the respective stabilizers, in case more than one stabilizer is present in the stabilizer composition, may be mixed with each other first and then be mixed with Dihydroavenanthramide. In case of a stabilizer composition, two, three or more of the respective stabilizers, in case more than one stabilizer is present in the stabilizer composition, may be mixed with each other first and then be mixed with Dihydroavenanthramide D and one, two, three or more of the of the respective stabilizers, in case more than one stabilizer is present in the stabilizer composition, may be mixed with Dihydroavenanthramide D separately. Typically, before mixing a or the stabilizers) with Dihydroavenanthramide D, the, one or more or all stabilizers) are dissolved in a solvent. Additionally or alternatively, before mixing a or the stabilizer(s) with Dihydroavenanthramide D, Dihydroavenanthramide D is typically dissolved in a solvent.

[0023] Preferably, the term “stabilizer”, as used herein, refers to a compound reducing or preventing the discoloration and / or malodour formation of Dihydroavenanthramide D or, respectively, a mixture comprising Dihydroavenanthramide D.

[0024] The term “stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenanthramide D” preferably refers to the prevention or reduction of discoloration of the mixture. The discoloration may be measured by comparing the CIE L*a*b* Coordinates of two samples, which is well known to a skilled person.

[0025] Additionally or alternatively, the term “stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenanthramide D” preferably refers to the prevention or reduction of malodour formation. The formation of malodour may be tested by sensorical evaluation, e.g. by panellists.

[0026] Preferably, the term “reduction of discoloration” or “reduction of malodour formation”, as used herein, describes a comparison of a mixture comprising a stabilizer with the same mixture but without the stabilizer. Preferably, the discoloration may be measured by determining the AL* value, preferably wherein a AL* value (i.e. the absolute value) of higherthan 1.5, preferably higher than 1.75, particularly preferably higher than 2, further preferably higher than 2.25, more preferably higher than 2.5, even further preferably higher than 2.75, most preferably higher than 3 is considered as a discoloration.

[0027] Preferably, the discoloration may be measured by determining the Aa* value, preferably wherein a Aa* value (i.e. the absolute value) of higherthan 1.5, preferably higher than 1.75, particularly preferably higher than 2, further preferably higher than 2.25, more preferably higher than 2.5, even further preferably higher than 2.75, most preferably higher than 3 is considered as a discoloration.

[0028] Preferably, the discoloration may be measured by determining the Ab* value, preferably wherein a Ab* value (i.e. the absolute value) of higherthan 1.5, preferably higher than 1.75, particularly preferably higher than 2, further preferably higher than 2.25, more preferably higher than 2.5, even further preferably higher than 2.75, most preferably higher than 3 is considered as a discoloration.

[0029] Preferably, the discoloration may be measured by determining the AE* value, preferably wherein a AE* value (i.e. the absolute value) of higher than 1.5, preferably higher than 1.75, particularly preferably higher than 2, further preferably higher than 2.25, more preferably higher than 2.5, even further preferably higher than 2.75, most preferably higher than 3 is considered as a discoloration. Preferably, the AE* is determined according to the following formula:

[0030] Preferably, the stabilizer or, respectively, the or one or all stabilizer(s) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringylidene malonate, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0031] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is diethylhexyl syringylidene malonate.

[0032] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is sodium metabisulfite. Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is Tris(tetramethylhydroxypiperidinol) citrate.

[0033] Preferably, the mixture comprising Dihydroavenanthramide D comprises i) Dihydroavenanthramide D, and ii) one or more alkane diol(s).

[0034] Preferably the, one, two, three or more or all alkane diol(s) is / are selected from the group consisting of 1 ,2-alkane diols, 1 ,3-alkane diols, 2,3-alkane diols, and mixtures thereof.

[0035] Preferably the, one, two, three or more or all alkane diol(s) is / are selected from the group consisting of 1 ,2-propane diol, 1 ,2-butane diol, 1 ,2-pentane diol, 1 ,2-hexane diol, 1 ,2-hep- tane diol, 1 ,2-octane diol, 1 ,2-nonane diol, 1 ,2-decane diol, 1 ,2-undecane diol, 1 ,2-dodec- ane diol and 1 ,2-tridecane diol, 1 ,3-propane diol, 1 ,3-butane diol, 1 ,3-pentane diol, 1 ,3- hexane diol, 1 ,3-heptane diol, 1 ,3-octane diol, 1 ,3-nonane diol, 1 ,3-decane diol, 1 ,3-un- decane diol, 1 ,3-dodecane diol and 1 ,3-tridecane diol, 2-methyl-2,4-pentan diol, 2,3-butane diol, 2,3-pentane diol, 2,3-hexane diol, 2,3-heptane diol, 2,3-octane diol, 2,3-nonane diol, 2,3-decane diol, 2,3-undecane diol, 2,3-dodecane diol, 2,3-tridecane diol, and mixtures thereof.

[0036] Preferably, the, one or two alkane diols is / are selected from the group consisting of 1 ,3- butylene glycol, 1 ,2-pentylene glycol, and mixtures thereof.

[0037] Thus, it is preferred that the mixture comprising Dihydroavenanthramide D comprises i) Dihydroavenanthramide D, ii.a) 1 ,3-butylene glycol, and ii.b) pentylene glycol.

[0038] It is preferred that the stabilizer or, respectively, stabilizer composition is mixed with the mixture comprising Dihydroavenanthramide D to obtain a stabilized mixture, wherein the obtained stabilized mixture comprises 0.01 to 7.5 wt.-%, preferably 0.05 to 5 wt.-%, preferably 0.1 to 2.5 wt.-% of diethylhexyl syringylidene malonate, based on the total weight of the stabilized mixture, and / or wherein the obtained stabilized mixture comprises 0.001 to 2.5 wt.-%, preferably 0.005 to 1 wt.-%, preferably 0.01 to 0.5 wt.-% of sodium metabisulfite, based on the total weight of the stabilized mixture, and / or wherein the obtained stabilized mixture comprises 0.005 to 2.5 wt.-%, preferably 0.01 to 1.5 wt.-%, preferably 0.05 to 1 wt.-% of Tris(tetramethylhydroxypiperidinol) citrate, based on the total weight of the stabilized mixture.

[0039] Preferably, the term “stabilized mixture” refers to a mixture comprising the stabilizer or, respectively, stabilizer composition and Dihydroavenanthramide D and optionally further components, as described herein, preferably one or more solvents. The term “stabilized” refers to the stabilization of Dihydroavenanthramide D, as described herein, i.e. to reduced discoloration and / or malodour formation.

[0040] Preferably, the obtained stabilized mixture comprises 0.1 to 20 wt.-%, preferably 0.5 to 15 wt.-%, preferably 1 to 10 wt.-%, preferably 2.5 to 7.5 wt.-% of Dihydroavenanthramide D, based on the total weight of the stabilized mixture.

[0041] It is preferred that the weight ratio of Dihydroavenanthramide D to diethylhexyl syringylidene malonate in the (stabilized) mixture is in a range of from 1 .000:1 to 1 :1 .000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0042] It is preferred that the weight ratio of Dihydroavenanthramide D to sodium metabisulfite in the (stabilized) mixture is in range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1. It is preferred that the weight ratio of Dihydroavenanthramide D to Tris(tetramethylhydrox- ypiperidinol) citrate in the (stabilized) mixture is in a range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0043] It is preferred that the weight ratio of Dihydroavenanthramide D to the summed weight of diethylhexyl syringylidene malonate, sodium metabisulfite and Tris(tetramethylhydroxypi- peridinol) citrate in the (stabilized) mixture is in a range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1. In case one or more of diethylhexyl syringylidene malonate, sodium metabisulfite and Tris(tetramethylhydroxypiperidinol) citrate is not present in the (stabilized) mixture, its weight is considered as 0 for calculating the summed weight.

[0044] The present invention further relates to a method for stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenanthramide D, comprising the steps a) providing a mixture comprising Dihydroavenanthramide D, b) providing a stabilizer or a stabilizer composition, wherein the stabilizer or, respectively, the or one or all stabilizer(s) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof, c) mixing the components provided in step a) and in step b).

[0045] Preferably, providing the stabilizer or stabilizer composition in step b) includes dissolving the stabilizer or stabilizer composition or the, one, two, three or more or all stabilizer(s) of a stabilizer composition in a solvent.

[0046] What was said above with regard to the use according to the invention applies accordingly.

[0047] Particularly, what was said above with regard to the stabilizer or stabilizer composition or with regard to a stabilization applies accordingly. Preferably, the stabilizer or, respectively, the or one or all stabilizer(s) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringylidene malonate, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0048] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is diethylhexyl syringylidene malonate.

[0049] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is sodium metabisulfite.

[0050] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is Tris(tetramethylhydroxypiperidinol) citrate.

[0051] Preferably, the mixture provided in step a) comprises i) Dihydroavenanthramide D, ii) one or more alkane diol(s).

[0052] What was said above with regard to the alkane diol(s) applies accordingly.

[0053] Particularly preferably, the mixture provided in step a) comprises i) Dihydroavenanthramide D, ii.a) 1 ,3-butylene glycol, and ii.b) pentylene glycol.

[0054] Furthermore, it is preferred that after the mixing in step c), a stabilized mixture is obtained, wherein the obtained stabilized mixture comprises 0.01 to 7.5 wt.-%, preferably 0.05 to 5 wt.-%, preferably 0.1 to 2.5 wt.-% of diethylhexyl syringylidene malonate, based on the total weight of the stabilized mixture, and / or wherein the obtained stabilized mixture comprises 0.001 to 2.5 wt.-%, preferably 0.005 to 1 wt.-%, preferably 0.01 to 0.5 wt.-% of sodium metabisulfite, based on the total weight of the stabilized mixture, and / or wherein the obtained stabilized mixture comprises 0.005 to 2.5 wt.-%, preferably 0.01 to 1.5 wt.-%, preferably 0.05 to 1 wt.-% of Tris(tetramethylhydroxypiperidinol) citrate, based on the total weight of the stabilized mixture.

[0055] Preferably, the term “stabilized mixture” refers to a mixture comprising the stabilizer or, respectively, stabilizer composition and Dihydroavenanthramide D and optionally further components, as described herein, preferably one or more solvents. The term “stabilized” refers to the stabilization of Dihydroavenanthramide D, as described herein, i.e. to reduced discoloration and / or malodour formation.

[0056] Preferably, the obtained stabilized mixture comprises 0.1 to 20 wt.-%, preferably 0.5 to 15 wt.-%, preferably 1 to 10 wt.-%, preferably 2.5 to 7.5 wt.-% of Dihydroavenanthramide D, based on the total weight of the (stabilized) mixture.

[0057] It is preferred that the weight ratio of Dihydroavenanthramide D to diethylhexyl syringyli- dene malonate in the (stabilized) mixture is in a range of from 1 .000:1 to 1 :1 .000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0058] It is preferred that the weight ratio of Dihydroavenanthramide D to sodium metabisulfite in the (stabilized) mixture is in range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0059] It is preferred that the weight ratio of Dihydroavenanthramide D to Tris(tetramethylhydrox- ypiperidinol) citrate in the (stabilized) mixture is in a range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0060] It is preferred that the weight ratio of Dihydroavenanthramide D to the summed weight of diethylhexyl syringylidene malonate, sodium metabisulfite and Tris(tetramethylhydroxypi- peridinol) citrate in the stabilized mixture is in a range of from 1 .000:1 to 1 :1 .000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1. In case one or more of diethylhexyl syringylidene malonate, sodium metabisulfite and Tris(tetramethylhydroxypiperidinol) citrate is not present in the (stabilized) mixture, its weight is considered as 0 for calculating the summed weight.

[0061] The present invention further relates to a mixture comprising i) Dihydroavenanthramide D, ii) one or more alkane diol(s), and iii) a stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0062] What was said above with regard to the use and / or method according to the invention applies accordingly.

[0063] Preferably, the mixture according to the invention is a stabilized mixture, wherein Dihydroavenanthramide D is stabilized in the mixture.

[0064] Preferably, the mixture according to the invention is a stabilized mixture as described herein, wherein Dihydroavenanthramide D is stabilized in the mixture.

[0065] Particularly, what was said above with regard to the stabilizer or stabilizer composition or with regard to a stabilization applies accordingly. Preferably, the stabilizer or, respectively, the or one or all stabilizer(s) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringylidene malonate, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0066] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is diethylhexyl syringylidene malonate.

[0067] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is sodium metabisulfite.

[0068] Preferably, the stabilizer or, respectively, the or one stabilizer of the stabilizer composition is Tris(tetramethylhydroxypiperidinol) citrate.

[0069] Particularly, what was said above with regard to the alkane diol(s) applies accordingly.

[0070] It is thus preferred that the mixture comprises i) Dihydroavenanthramide D, ii.a) 1 ,3-butylene glycol, ii.b) pentylene glycol, and iii) a stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0071] Preferably, the mixture comprises

[0072] 0.01 to 7.5 wt.-%, preferably 0.05 to 5 wt.-%, preferably 0.1 to 2.5 wt.-% of diethylhexyl syringylidene malonate, based on the total weight of the stabilized mixture, and / or

[0073] 0.001 to 2.5 wt.-%, preferably 0.005 to 1 wt.-%, preferably 0.01 to 0.5 wt.-% of sodium metabisulfite, based on the total weight of the stabilized mixture, and / or 0.005 to 2.5 wt.-%, preferably 0.01 to 1.5 wt.-%, preferably 0.05 to 1 wt.-% of Tris(tet- ramethylhydroxypiperidinol) citrate, based on the total weight of the stabilized mixture.

[0074] Preferably, the mixture comprises 0.1 to 20 wt.-%, preferably 0.5 to 15 wt.-%, preferably 1 to 10 wt.-%, preferably 2.5 to 7.5 wt.-% of Dihydroavenanthramide D, based on the total weight of the mixture.

[0075] It is preferred that the weight ratio of Dihydroavenanthramide D to diethylhexyl syringyli- dene malonate in the mixture is in a range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0076] It is preferred that the weight ratio of Dihydroavenanthramide D to sodium metabisulfite in the mixture is in range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1 .

[0077] It is preferred that the weight ratio of Dihydroavenanthramide D to Tris(tetramethylhydrox- ypiperidinol) citrate in the mixture is in a range of from 1.000:1 to 1 :1.000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1.

[0078] It is preferred that the weight ratio of Dihydroavenanthramide D to the summed weight of diethylhexyl syringylidene malonate, sodium metabisulfite and Tris(tetramethylhydroxypi- peridinol) citrate in the mixture is in a range of from 1 .000:1 to 1 :1 .000, preferably in a range of from 500:1 to 1 :250, further preferably in a range of from 400:1 to 1 :100, especially preferably in a range of from 300:1 to 1 :25, even further preferably in a range of from 200:1 to 1 :1 , more preferably in a range of from 175:1 to 2:1 , particularly preferably in a range of from 150:1 to 5:1. In case one or more of diethylhexyl syringylidene malonate, sodium metabisulfite and Tris(tetramethylhydroxypiperidinol) citrate is not present in the mixture, its weight is considered as 0 for calculating the summed weight. The present invention further relates to a cosmetic preparation comprising a mixture according to the invention.

[0079] Cosmetic preparations, as described herein, are in particular preparations, which are suitable for topical application to the skin of a human, in particular to achieve a cosmetic effect.

[0080] Cosmetic preparations, as described herein, may further comprise one, two, three or more or all substances selected from the group consisting of odoriferous substances, perfume oils, fatty oils, fatty acids, ceramides, pseudoceramides, sterols, hydrocarbons phytosterols, anti-acne active ingredients, antidandruff active ingredients, antimicrobial active ingredients, preservatives, antiperspirants, anti-irritants, pruritus-relieving active ingredients, cooling active ingredients, antiaging active ingredients, skin-lightening and skin-tanning active ingredients, skin moisture regulators, osmolytes, enzyme inhibitors, odour absorbers, dyes, abrasives, anti-acne agents, anti-cellulitis agents, antidandruff agents, anti-inflammatory agents, irritation-preventing agents, irritation-inhibiting agents, antioxidants, astringents, perspiration-inhibiting agents, antiseptic agents, ant-statics, binders, buffers, carrier materials, chelating agents, cell stimulants, cleansing agents, care agents, depilatory agents, surface-active substances, deodorizing agents, antiperspirants, softeners, emulsifiers, enzymes, essential oils, fibres, film-forming agents, fixatives, foam-forming agents, foam stabilizers, substances for preventing foaming, foam boosters, gelling agents, gelforming agents, hair care agents, hair-setting agents, hair-straightening agents, moisturedonating agents, moisturizing substances moisture-retaining substances, bleaching agents, strengthening agents, stain-removing agents, optically brightening agents, impregnating agents, dirtrepellent agents, friction-reducing agents, lubricants, moisturizing creams, ointments, opacifying agents, plasticizing agents, covering agents, polish, gloss agents, polymers, powders, proteins, re-oiling agents, abrading agents, silicones, skinsoothing agents, skin-cleansing agents, skin care agents, skin-healing agents, skin-lightening agents, skin-protecting agents, skin-softening agents, hair promotion agents, cooling agents, skin-cooling agents, warming agents, skin-warming agents, stabilizers, UV- absorbing agents, UV filters, detergents, fabric conditioning agents, suspending agents, skin-tanning agents, thickeners, vitamins, oils, waxes, fats, phospholipids, saturated fatty acids, mono- or polyunsaturated fatty acids, a-hydroxy acids, polyhydroxyfatty acids, liquefiers, dyestuffs, colour-protecting agents, pigments, anticorrosives, aromas, flavouring substances, odoriferous substances, polyols, surfactants, electrolytes, organic solvents, and silicone derivatives. Preferably, the amount of Dihydroavenanthramide D in the preparation according to the invention is in the range of from 0.000005 to 2.5 wt.-%, preferably in the range of from 0.0000075 to 2 wt.-%, further preferably in the range of from 0.00001 to 1.5 wt.-%, especially preferably in the range of from 0.000025 to 1 .25 wt.-%, even further preferably in the range of from 0.00005 to 1 wt.-%, more preferably in the range of from 0.000075 to 0.75 wt.-%, particularly preferably in the range of from 0.0001 to 0.5 wt.-%, even more preferably in the range of from 0.00025 to 0.25 wt.-%, most preferably in the range of from 0.0005 to 0.1 wt.-%, based on the total weight of the preparation.

[0081] Preferably, the summed weight of Dihydroavenanthramide D and the stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof in the preparation is in a range of from 0.01 to 4 wt.-%, preferably in a range of from 0.05 to 3 wt.-%, further preferably in a range of from 0.1 to 2 wt.%, based on the total weight of the cosmetic preparation. In case one or more of the above compounds is not present in the mixture, its weight is considered as 0 for calculating the summed weight.

[0082] Preferably, the summed weight of Dihydroavenanthramide D and the stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof, and alkane diol(s) in the preparation is in a range of from 0.01 to 4 wt.-%, preferably in a range of from 0.05 to 3 wt.- %, further preferably in a range of from 0.1 to 2 wt.%, based on the total weight of the cosmetic preparation. In case one or more of the above compounds is not present in the mixture, its weight is considered as 0 for calculating the summed weight.

[0083] Preferably, the cosmetic preparation according to the invention is a rinse-off preparation.

[0084] Preferably, the cosmetic preparation according to the invention is a leave-on preparation.

[0085] What was said above with regard to the use and / or method and / or mixture according to the invention applies accordingly. Particularly, what was said above with regard to the stabilizer or stabilizer composition or with regard to a stabilization applies accordingly. Particularly, what was said above with regard to the alkane diol(s) applies accordingly.

[0086] Further aspects and advantages of the invention result from the subsequent description of preferred examples. Examples

[0087] Example 1 : Comparing different stabilizers - discoloration

[0088] Compositions A-M were prepared as described below and stored at 40°C and 50°C for 1 month. Composition A serves as a comparative sample.

[0089] The color of all samples were measured by using chromametry (L*a*b* values) at test-start and after 1 month storage at the different temperatures. Based on this numbers, the overall discoloration (AE) was calculated.

[0090] The following stabilizing ingredients were used: - Ascorbyl palmitate (Composition B)

[0091] Oxynex ST liquid (INCI: Diethylhexyl Syringylidene Malonate, Caprylic / Capric / Tri- glycerides, 90% AS) (Compositions C and D)

[0092] Tinogard TT (INCI Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate) (Compositions E and F) - Tocopherol Acetate (Compositions G and H)

[0093] Covastyle MBS (INCI Sodium Metabisulfite) (Compositions I and K)

[0094] Tinogard Q (INCI Tris(Tetramethylhydroxypiperidinol) Citrate) (Compositions L and M)

[0095] Table 1

[0096] Table 1 (continued) Production Method (compositions A to M)

[0097] Heat Butylene Glycol and Pentylene Glycol up to maximum 70°C and blend both ingredients by stirring. Add respective stabilizer at 65 °C - 80°C and stir for 5 minutes at this temperature. Add Dihydroavenanthramide D at 60°C. stir for 30 min. Color determination (Lico 690 ex Hach Lange)

[0098] The color of the samples were measured by using chromametry (L*a*b* values) at teststart and after 1 month storage at the different temperatures.

[0099] Bases on this numbers the overall discoloration (AE) was calculated according to the following formula: Color determination of samples E and F (containing Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate) was not possible due to recrystallization directly after production. These samples were not stored, no further evaluation was performed.

[0100] The following results were obtained: The above data reveal that compositions C and D (including diethylhexyl syringylidene malonate), I and K (including sodium metabisulfite), and L and M (including Tris(tetramethylhy- droxypiperidinol) citrate) provided much lower discoloration after 1 month of storage, indicating much more stable compositions than composition B (including ascorbyl palmitate), composition G and H (including tocopherol acetate) or composition A (including no stabilizer).

[0101] Example 2: Comparing different stabilizers - malodour formation

[0102] Compositions A, B, C, G, I, and L were prepared as described in Example 1 .

[0103] The compositions were stored at 22 °C for 1 month.

[0104] Subsequently, the malodour intensity was evaluated by a trained panel of 4 panellists (P1 to P4), using a scale from 0 to 10 with 0 = no malodour and 10 = intense malodour.

[0105] The following results were obtained:

[0106] The above data reveal that compositions C (including diethylhexyl syringylidene malonate), I (including sodium metabisulfite), and L (including Tris(tetramethylhydroxypiperidinol) citrate) provided much lower malodour formation after 1 month of storage, indicating much more stable compositions than composition B (including ascorbyl palmitate), composition G and H (including tocopherol acetate) or composition A (including no stabilizer).

[0107] A particularly low malodour formation was observed for compositions C (including diethylhexyl syringylidene malonate), and L (including Tris(tetramethylhydroxypiperidinol) citrate). Application Examples:

[0108] PERFUME OILS

[0109] Table 2: Composition of perfume oil 1 (PO1 , Amounts in %o b.w.)

[0110]

[0111] Table 3: Composition of perfume oil 2 (PO2, Amounts in %o b.w.)

[0112]

[0113] Table 4: Composition of perfume oil 3 (PO3, Amounts in %o b.w.)

[0114]

[0115] Table 5: Composition of perfume oil 4 (PO4, Amounts in %o b.w.)

[0116]

[0117] Table 6: Composition of perfume oil 5 (PO5, Amounts in %o b.w.)

[0118]

[0119] The perfume oils PO1, PO2, PO3, PO4, or PO5 from the above examples were separately added into the formulations as presented below.

[0120] Cosmetic formulations (compositions) - amounts are indicated as % by weight for all formulations.

[0121] Energy Concentrate Natural Beauty Enhancer (Solid concentrate)

[0122] Solid Body Oil Sensi-SCALP (Green Solid Shampoo)

[0123] Advanced Lifting serum

[0124] Perfect Hand with exp. SPF 15, UVA / UVB Balanced

[0125] Warming Mineral Mask

[0126] Sheet mask | Citric acid 50% sol | Aqua, Citric acid | 0.12 ]

[0127] After Shave Tonic

[0128] After Sun Refreshing Gel

[0129] Flash SOS Aloe Gelee

[0130] Intimate Sensi-Gel

[0131] Mild feminine wash

[0132] Intimate Rescue Gel

[0133] Men After Shave Fluid

[0134] Anti-Wrinkle Night Emulsion

[0135] Essential Care Face& Body Cream

[0136] Natural Night Cream Aloe

[0137] Revitalizing CONDITIONER

[0138] Refreshing Conditioning Foam

[0139] Dandruff Control Shampoo

[0140] Shampoo Sulfate-Free

[0141] Mild Conditioning Shampoo for Kids / Babies

Claims

Claims1 . Use of a stabilizer or a stabilizer composition, wherein the stabilizer or, respectively, the or one or all stabilizers) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof, for stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroavenan- thramide D.

2. Use according to claim 1 , wherein the mixture comprising Dihydroavenanthramide D comprises i) Dihydroavenanthramide D, and ii) one or more alkane diol(s).

3. Use according to any one of the preceding claims, wherein the mixture comprising Dihydroavenanthramide D comprises i) Dihydroavenanthramide D, ii.a) 1 ,3-butylene glycol, and ii.b) pentylene glycol.

4. Use according to any one of the preceding claims, wherein the stabilizer or, respectively, stabilizer composition is mixed with the mixture comprising Dihydroavenanthramide D to obtain a stabilized mixture, wherein the obtained stabilized mixture comprises 0.01 to 7.5 wt.-%, preferably 0.05 to 5 wt.-%, preferably 0.1 to 2.5 wt.-% of diethylhexyl syringylidene malonate, based on the total weight of the stabilized mixture, and / or wherein the obtained stabilized mixture comprises 0.001 to 2.5 wt.-%, preferably 0.005 to 1 wt.-%, preferably 0.01 to 0.5 wt.-% of sodium metabisulfite, based on the total weight of the stabilized mixture, and / orwherein the obtained stabilized mixture comprises 0.005 to 2.5 wt.-%, preferably 0.01 to 1 .5 wt.-%, preferably 0.05 to 1 wt.-% of Tris(tetramethylhydroxy- piperidinol) citrate, based on the total weight of the stabilized mixture.

5. Method for stabilizing Dihydroavenanthramide D in a mixture comprising Dihydroav- enanthramide D, comprising the steps a) providing a mixture comprising Dihydroavenanthramide D, b) providing a stabilizer or a stabilizer composition, wherein the stabilizer or, respectively, the or one or all stabilizer(s) of the stabilizer composition is / are selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof, c) mixing the components provided in step a) and in step b).

6. Method according to claim 5, wherein the mixture provided in step a) comprises i) Dihydroavenanthramide D, ii) one or more alkane diol(s).

7. Method according to claim 5 or 6, wherein the mixture provided in step a) comprises i) Dihydroavenanthramide D, ii.a) 1 ,3-butylene glycol, and ii.b) pentylene glycol.

8. Method according to any one of claims 5 to 7, wherein after the mixing in step c), a stabilized mixture is obtained, wherein the obtained stabilized mixture comprises 0.01 to 7.5 wt.-%, preferably 0.05 to 5 wt.-%, preferably 0.1 to 2.5 wt.-% of diethylhexyl syringylidene malonate, based on the total weight of the stabilized mixture, and / orwherein the obtained stabilized mixture comprises 0.001 to 2.5 wt.-%, preferably 0.005 to 1 wt.-%, preferably 0.01 to 0.5 wt.-% of sodium metabisulfite, based on the total weight of the stabilized mixture, and / or wherein the obtained stabilized mixture comprises 0.005 to 2.5 wt.-%, preferably 0.01 to 1 .5 wt.-%, preferably 0.05 to 1 wt.-% of Tris(tetramethylhydroxy- piperidinol) citrate, based on the total weight of the stabilized mixture.

9. Mixture comprising i) Dihydroavenanthramide D, ii) one or more alkane diol(s), and iii) a stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

10. Mixture according to claim 9, comprising i) Dihydroavenanthramide D, ii.a) 1 ,3-butylene glycol, ii.b) pentylene glycol, and iii) a stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.11 . Mixture according to claim 9 or 10, wherein the mixture comprises0.01 to 7.5 wt.-%, preferably 0.05 to 5 wt.-%, preferably 0.1 to 2.5 wt.-% of diethylhexyl syringylidene malonate, based on the total weight of the stabilized mixture, and / or0.001 to 2.5 wt.-%, preferably 0.005 to 1 wt.-%, preferably 0.01 to 0.5 wt.-% of sodium metabisulfite, based on the total weight of the stabilized mixture, and / or0.005 to 2.5 wt.-%, preferably 0.01 to 1 .5 wt.-%, preferably 0.05 to 1 wt.-% of Tris(tetramethylhydroxypiperidinol) citrate, based on the total weight of the stabilized mixture.

12. Cosmetic preparation comprising a mixture according to any one of claims 9 to 11 .

13. Cosmetic preparation according to claim 12, wherein the summed weight of Dihy- droavenanthramide D and the stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxypiper- idinol) citrate, and mixtures thereof in the preparation is in a range of from 0.01 to 4 wt.-%, preferably in a range of from 0.05 to 3 wt.-%, further preferably in a range of from 0.1 to 2 wt.%, based on the total weight of the cosmetic preparation.

14. Cosmetic preparation according to claims 12 or 13, wherein the summed weight of Dihydroavenanthramide D and the stabilizer selected from the group consisting of diethylhexyl syringylidene malonate, sodium metabisulfite, Tris(tetramethylhydroxy- piperidinol) citrate, and mixtures thereof, and alkane diol(s) in the preparation is in a range of from 0.01 to 4 wt.-%, preferably in a range of from 0.05 to 3 wt.-%, further preferably in a range of from 0.1 to 2 wt.%, based on the total weight of the cosmetic preparation.

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