Stabilizer or stabilizer composition for stabilizing dihydrooat alkaloid D

Abstract

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

Description

Technical Field

[0001] The present invention relates to the use of a stabilizer or stabilizer composition for stabilizing dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D, a mixture containing dihydrooat alkaloid D and a stabilizer, and a cosmetic preparation containing such a mixture. Background Art

[0002] Dihydrooat alkaloid D is a particularly important compound in the cosmetic industry. Dihydrooat alkaloid D belongs to the avenanthramide family, i.e., anthranilic acid amides, also known as hydroxyphenylpropionamide benzoic acid. The CAS number of dihydrooat alkaloid D is 697235-49-7 (registered by the European Chemicals Agency), and its chemical structure is as follows:

[0003]

[0004] In the prior art, dihydrooat alkaloid D has been used in a variety of cosmetic applications. For example, WO 2006 / 134013A1 describes the use of dihydrooat alkaloid D for reducing itching and / or for reducing skin redness.

[0005] US2006 / 089413 A1 describes that dihydrooat alkaloid D can be used to inhibit the release of histamine from mast cells induced by substance P. In this way, itching, skin redness, scar spread or skin allergic reactions can be prevented.

[0006] Generally, dihydrooat alkaloid D is formulated with other substances into a cosmetic composition. One challenge in using dihydrooat alkaloid D is how to ensure and maintain its color stability in the cosmetic composition. If dihydrooat alkaloid D does not have sufficient color stability in the cosmetic composition, or even has no color stability at all, it will cause the cosmetic composition to change color. In this case, the cosmetic composition will turn yellow to light brown, and this phenomenon will become more serious as the color stability of dihydrooat alkaloid D decreases.

[0007] Consumers are often difficult to accept such a discolored cosmetic composition, regardless of the function of this composition.

[0008] Therefore, dihydrooat alkaloid D is usually stabilized in the cosmetic composition. The stabilizer ascorbyl palmitate is widely used in cosmetic compositions.

[0009]

[0010] Ascorbic acid palmitate is often added to cosmetic compositions as a color stabilizer for dihydrooat alkaloids. It has been found that ascorbic acid palmitate can stabilize dihydrooat alkaloid D in cosmetic compositions. However, it has further been found that this function of ascorbic acid palmitate has limitations, since a decrease in the color stability of dihydrooat alkaloid D is observed after long-term storage of a cosmetic composition containing dihydrooat alkaloid D. Even when the stabilizer ascorbic acid palmitate is added, the composition still shows discoloration, usually changing color from yellow to light brown, after storage for several months and / or under conditions that promote the instability of the compounds in the composition, such as at high temperatures (e.g., above 40 °C or above 50 °C).

[0011] Therefore, dihydrooat alkaloid D in cosmetic compositions still requires further, preferably improved, color stabilizers.

[0012] In addition, discussions about the stabilizer ascorbic acid palmitate have recently begun. It is (controversially) discussed that ascorbic acid palmitate has comedogenic activity, i.e., it promotes the formation of acne.

[0013] Acne is the blockage of skin hair follicles caused by increased sebum secretion from sebaceous glands. Acne is the visible blackheads on the skin, mainly appearing on the face, neck, upper chest, shoulders and back, and is a simple skin appearance condition.

[0014] Generally, the areas treated with cosmetic compositions are visible in daily life, and these areas need to present a neat appearance. Therefore, it is necessary to prevent acne from appearing in these areas.

[0015] Therefore, dihydrooat alkaloid D in cosmetic compositions requires further color stabilizers, which preferably have stronger color stabilizing ability. SUMMARY OF THE INVENTION

[0016] In view of this, the main object of the present invention is to provide a stabilizer for dihydrooat alkaloid D, which preferably has stronger color stabilizing ability than ascorbic acid palmitate.

[0017] The main object of the present invention is solved by using a stabilizer or a stabilizer composition to stabilize dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D, wherein the said or one or all of the stabilizers in the stabilizer or stabilizer composition are respectively selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate and mixtures thereof,

[0018] wherein the above-mentioned stabilization is characterized by reducing discoloration and / or the formation of off-odors.

[0019] Surprisingly, it has been found that the stabilizers used according to the present invention are particularly advantageous for the color stability of dihydrooat alkaloid D. Surprisingly, a particularly low degree of discoloration is observed when using such stabilizers or stabilizer compositions as compared to the stabilizers commonly used for dihydrooat alkaloid D, namely ascorbyl palmitate or tocopheryl acetate, another commonly used stabilizer.

[0020] Furthermore, surprisingly, less off-odor formation occurs when using such stabilizers or stabilizer compositions as compared to the stabilizers commonly used for dihydrooat alkaloid D, namely ascorbyl palmitate or tocopheryl acetate, another commonly used stabilizer.

[0021] Diethylhexyl syringylmalonate, also known as Oxynex ST, is preferably described by the CAS number 444811-29-4 (registered by the European Chemicals Agency) and is preferably described as malonic acid, 2-[(4-hydroxy-3,5-dimethoxyphenyl)methylene]-, 1,3-bis(2-ethylhexyl) ester.

[0022] Tocopheryl acetate, preferably α-tocopheryl acetate, is preferably described by the CAS number 52225-20-4 (registered 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-trimethyltridecyl)-2H-benzopyran-6-yl acetate.

[0023] Sodium metabisulfite is preferably described by the CAS number 7681-57-4 (registered by the European Chemicals Agency) and is preferably described as disodium disulfite.

[0024] Tris(tetramethylhydroxypiperidinol) citrate is preferably described by the CAS number 220410-74-2 (registered by the European Chemicals Agency) and is preferably described as 1,4-dihydroxy-2,2,6,6-tetramethylpiperidinium-2-hydroxy-1,2,3-propanetricarboxylate.

[0025] Advantageously, diethylhexyl syringylmalonate, sodium metabisulfite or tris(tetramethylhydroxypiperidinol) citrate are not described as having comedogenic activity.

[0026] As used herein, the term "stabilizer composition" refers to a composition comprising one or more stabilizers. If the composition comprises a plurality of stabilizers, two, three or more or all of the stabilizers may be mixed.

[0027] Preferably, in order to stabilize dihydrooat alkaloid D, a stabilizer or a stabilizer composition is mixed with dihydrooat alkaloid D respectively. In the case of a stabilizer composition, if there are multiple stabilizers in the stabilizer composition, each stabilizer can be mixed with dihydrooat alkaloid D individually. In the case of a stabilizer composition, if there are multiple stabilizers in the stabilizer composition, the individual stabilizers can be first mixed with each other and then mixed with dihydrooat alkaloid D. In the case of a stabilizer composition, if there are multiple stabilizers in the stabilizer composition, two, three or more of the individual stabilizers can be first mixed with each other and then mixed with dihydrooat alkaloid D, and if there are multiple stabilizers in the stabilizer composition, one, two, three or more of the individual stabilizers can be mixed with dihydrooat alkaloid D individually. Generally, before mixing one or the said (multiple) stabilizers with dihydrooat alkaloid D, the said or one or more or all of the stabilizers are dissolved in a solvent. Additionally or alternatively, before mixing one or the said (multiple) stabilizers with dihydrooat alkaloid D, dihydrooat alkaloid D is generally dissolved in a solvent.

[0028] Preferably, as used herein, the term "stabilizer" refers to a compound that reduces or prevents discoloration and / or the formation of off-odor of dihydrooat alkaloid D or a mixture containing dihydrooat alkaloid D respectively.

[0029] The term "stabilize dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D" preferably refers to preventing or reducing the discoloration of the mixture. Discoloration can be measured by comparing the CIE L*a*b* coordinates of two samples, which is a method well-known to those skilled in the art.

[0030] Additionally or alternatively, the term "stabilize dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D" preferably refers to preventing or reducing the formation of off-odor. The formation of off-odor can be tested by sensory evaluation, for example, by panelists.

[0031] Preferably, as used herein, the terms "reduction of discoloration" or "reduction of off-odor formation" describe a comparison of a mixture containing a stabilizer with the same mixture without a stabilizer.

[0032] Preferably, discoloration can be measured by determining the ΔL* value, preferably, where when ΔL* (i.e., the absolute value) is greater than 1.5, preferably greater than 1.75, particularly preferably greater than 2, further preferably greater than 2.25, more preferably greater than 2.5, even further preferably greater than 2.75, and most preferably greater than 3, discoloration can be considered to have occurred.

[0033] Preferably, color change can be measured by determining the Δa* value, preferably, where when the Δa* value (i.e., the absolute value) is greater than 1.5, preferably greater than 1.75, particularly preferably greater than 2, further preferably greater than 2.25, more preferably greater than 2.5, even further preferably greater than 2.75, and most preferably greater than 3, color change can be considered to have occurred.

[0034] Preferably, color change can be measured by determining the Δb* value, preferably, where when the Δb* value (i.e., the absolute value) is greater than 1.5, preferably greater than 1.75, particularly preferably greater than 2, further preferably greater than 2.25, more preferably greater than 2.5, even further preferably greater than 2.75, and most preferably greater than 3, color change can be considered to have occurred.

[0035] Preferably, color change can be measured by determining the ΔE* value, preferably, where when the ΔE* value (i.e., the absolute value) is greater than 1.5, preferably greater than 1.75, particularly preferably greater than 2, further preferably greater than 2.25, more preferably greater than 2.5, even further preferably greater than 2.75, and most preferably greater than 3, color change can be considered to have occurred. Preferably, ΔE* is determined according to the following formula:

[0036]

[0037] Preferably, the said or one or all stabilizers in the stabilizer or stabilizer composition are respectively selected from the group consisting of diethylhexyl syringylmalonate, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0038] Preferably, the said or one stabilizer in the stabilizer or stabilizer composition is respectively diethylhexyl syringylmalonate.

[0039] Preferably, the said or one stabilizer in the stabilizer or stabilizer composition is respectively sodium metabisulfite.

[0040] Preferably, the said or one stabilizer in the stabilizer or stabilizer composition is respectively tris(tetramethylhydroxypiperidinol) citrate.

[0041] Preferably, the mixture containing dihydrooat alkaloid D contains:

[0042] i) Dihydrooat alkaloid D; and

[0043] ii) One or more alkylene diols.

[0044] Preferably, one, two, three or more or all of the alkylene diols are selected from the group consisting of 1,2-alkylene diols, 1,3-alkylene diols, 2,3-alkylene diols, and mixtures thereof.

[0045] Preferably, one, two, three or more or all of the alkanediols are selected from the group consisting of 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2-nonanediol, 1,2-decanediol, 1,2-undecanediol, 1,2-dodecanediol and 1,2-tridecanediol; 1,3-propanediol, 1,3-butanediol, 1,3-pentanediol, 1,3-hexanediol, 1,3-heptanediol, 1,3-octanediol, 1,3-nonanediol, 1,3-decanediol, 1,3-undecanediol, 1,3-dodecanediol and 1,3-tridecanediol; 2-methyl-2,4-pentanediol, 2,3-butanediol, 2,3-pentanediol, 2,3-hexanediol, 2,3-heptanediol, 2,3-octanediol, 2,3-nonanediol, 2,3-decanediol, 2,3-undecanediol, 2,3-dodecanediol, 2,3-tridecanediol; and mixtures thereof.

[0046] Preferably, one or two alkanediols are selected from the group consisting of 1,3-butanediol, 1,2-pentanediol and mixtures thereof.

[0047] Accordingly, preferably, the mixture comprising dihydrooat alkaloid D comprises:

[0048] i) dihydrooat alkaloid D;

[0049] ii.a) 1,3-butanediol; and

[0050] ii.b) pentanediol.

[0051] Preferably, a stabilizer or a stabilizer composition is separately mixed with the mixture comprising dihydrooat alkaloid D to obtain a stable mixture,

[0052] wherein, based on the total weight of the resulting stable mixture, the stable mixture comprises 0.01 wt.-% to 7.5 wt.-%, preferably 0.05 wt.-% to 5 wt.-%, preferably 0.1 wt.-% to 2.5 wt.-% of diethylhexyl syringylmalonate, and / or

[0053] wherein, based on the total weight of the resulting stable mixture, the stable mixture comprises 0.001 wt.-% to 2.5 wt.-%, preferably 0.005 wt.-% to 1 wt.-%, preferably 0.01 wt.-% to 0.5 wt.-% of sodium metabisulfite, and / or

[0054] Based on the total weight of the resulting stable mixture, the stable mixture comprises 0.005 wt.-% to 2.5 wt.-%, preferably 0.01 wt.-% to 1.5 wt.-%, preferably 0.05 wt.-% to 1 wt.-% of tris(tetramethylhydroxypiperidinol) citrate.

[0055] Preferably, the term "stable mixture" refers to a mixture comprising a stabilizer or stabilizer composition and dihydrooat alkaloid D and optionally other components, said other components being preferably one or more solvents as described herein. The term "stable" refers to the stabilization of dihydrooat alkaloid D, as described herein, i.e., reducing discoloration and / or odor formation.

[0056] Preferably, based on the total weight of the resulting stable mixture, the stable mixture comprises 0.1 wt.-% to 20 wt.-%, preferably 0.5 wt.-% to 15 wt.-%, preferably 1 wt.-% to 10 wt.-%, preferably 2.5 wt.-% to 7.5 wt.-% of dihydrooat alkaloid D.

[0057] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to diethylhexyl syringylmalonate is in the range of 1,000:1 to 1:1,000, preferably in the range of 500:1 to 1:250, further preferably in the range of 400:1 to 1:100, particularly preferably in the range of 300:1 to 1:25, even further preferably in the range of 200:1 to 1:1, more preferably in the range of 175:1 to 2:1, and especially preferably in the range of 150:1 to 5:1.

[0058] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to sodium metabisulfite is in the range of 1,000:1 to 1:1,000, preferably in the range of 500:1 to 1:250, further preferably in the range of 400:1 to 1:100, particularly preferably in the range of 300:1 to 1:25, even further preferably in the range of 200:1 to 1:1, more preferably in the range of 175:1 to 2:1, and especially preferably in the range of 150:1 to 5:1.

[0059] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to tris(tetramethylhydroxypiperidinol) citrate is in the range of 1,000:1 to 1:1,000, preferably in the range of 500:1 to 1:250, further preferably in the range of 400:1 to 1:100, particularly preferably in the range of 300:1 to 1:25, even further preferably in the range of 200:1 to 1:1, more preferably in the range of 175:1 to 2:1, and especially preferably in the range of 150:1 to 5:1.

[0060] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to the total weight of diethylhexyl syringylmalonate, sodium metabisulfite, and tris(tetramethylhydroxypiperidinol) citrate is in the range of 1,000:1 to 1:1,000, preferably in the range of 500:1 to 1:250, more preferably in the range of 400:1 to 1:100, particularly preferably in the range of 300:1 to 1:25, even more preferably in the range of 200:1 to 1:1, still more preferably in the range of 175:1 to 2:1, and especially preferably in the range of 150:1 to 5:1. If one or more of diethylhexyl syringylmalonate, sodium metabisulfite, and tris(tetramethylhydroxypiperidinol) citrate are absent from the (stable) mixture, their weight is considered 0 for calculating the total weight.

[0061] The present invention also relates to a method for stabilizing dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D, comprising the following steps:

[0062] a) providing a mixture containing dihydrooat alkaloid D;

[0063] b) providing a stabilizer or a stabilizer composition, wherein the or one or all of the stabilizers in the stabilizer or stabilizer composition are respectively selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof;

[0064] c) mixing the components provided in step a) and step b).

[0065] Preferably, providing the stabilizer or stabilizer composition in step b) includes dissolving the stabilizer or stabilizer composition or one, two, three, or more or all of the stabilizers in the stabilizer composition in a solvent.

[0066] The above-mentioned content regarding the use according to the present invention applies accordingly.

[0067] In particular, the above-mentioned content regarding the stabilizer or stabilizer composition or regarding stabilization applies accordingly.

[0068] Preferably, the or one or all of the stabilizers in the stabilizer or stabilizer composition are respectively selected from the group consisting of diethylhexyl syringylmalonate, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0069] Preferably, the or one stabilizer in the stabilizer or stabilizer composition is respectively diethylhexyl syringylmalonate.

[0070] Preferably, the or one stabilizer in the stabilizer or stabilizer composition is respectively sodium metabisulfite.

[0071] Preferably, the stabilizer or a stabilizer in the stabilizer composition is tris(tetramethylhydroxypiperidinol) citrate, respectively.

[0072] Preferably, the mixture provided in step a) comprises:

[0073] i) Dihydroavenanthramide D;

[0074] ii) One or more alkanediols.

[0075] The content described above regarding alkanediols applies accordingly.

[0076] Particularly preferably, the mixture provided in step a) comprises:

[0077] i) Dihydroavenanthramide D;

[0078] ii.a) 1,3-Butanediol; and

[0079] ii.b) Pentanediol.

[0080] Furthermore, preferably, after mixing in step c), a stable mixture is obtained,

[0081] wherein, based on the total weight of the resulting stable mixture, the stable mixture comprises 0.01 wt.-% to 7.5 wt.-%, preferably 0.05 wt.-% to 5 wt.-%, preferably 0.1 wt.-% to 2.5 wt.-% of diethylhexyl sublactate, and / or

[0082] wherein, based on the total weight of the resulting stable mixture, the stable mixture comprises 0.001 wt.-% to 2.5 wt.-%, preferably 0.005 wt.-% to 1 wt.-%, preferably 0.01 wt.-% to 0.5 wt.-% of sodium metabisulfite, and / or

[0083] wherein, based on the total weight of the resulting stable mixture, the stable mixture comprises 0.005 wt.-% to 2.5 wt.-%, preferably 0.01 wt.-% to 1.5 wt.-%, preferably 0.05 wt.-% to 1 wt.-% of tris(tetramethylhydroxypiperidinol) citrate.

[0084] Preferably, the term "stable mixture" refers to a mixture comprising a stabilizer or a stabilizer composition and dihydroavenanthramide D and optionally other components, and the other components are preferably one or more solvents as described herein. The term "stable" refers to the stabilization of dihydroavenanthramide D, as described herein, i.e., reducing discoloration and / or odor formation.

[0085] Preferably, based on the total weight of the resulting (stable) mixture, the stable mixture comprises from 0.1 wt.-% to 20 wt.-%, preferably from 0.5 wt.-% to 15 wt.-%, preferably from 1 wt.-% to 10 wt.-%, preferably from 2.5 wt.-% to 7.5 wt.-% of dihydrooat alkaloid D.

[0086] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to diethylhexyl syringylmalonate is in the range from 1,000:1 to 1:1,000, preferably in the range from 500:1 to 1:250, more preferably in the range from 400:1 to 1:100, particularly preferably in the range from 300:1 to 1:25, even more preferably in the range from 200:1 to 1:1, more preferably in the range from 175:1 to 2:1, and especially preferably in the range from 150:1 to 5:1.

[0087] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to sodium metabisulfite is in the range from 1,000:1 to 1:1,000, preferably in the range from 500:1 to 1:250, more preferably in the range from 400:1 to 1:100, particularly preferably in the range from 300:1 to 1:25, even more preferably in the range from 200:1 to 1:1, more preferably in the range from 175:1 to 2:1, and especially preferably in the range from 150:1 to 5:1.

[0088] Preferably, in the (stable) mixture, the weight ratio of dihydrooat alkaloid D to tris(tetramethylhydroxypiperidinol) citrate is in the range from 1,000:1 to 1:1,000, preferably in the range from 500:1 to 1:250, more preferably in the range from 400:1 to 1:100, particularly preferably in the range from 300:1 to 1:25, even more preferably in the range from 200:1 to 1:1, more preferably in the range from 175:1 to 2:1, and especially preferably in the range from 150:1 to 5:1.

[0089] Preferably, in the stable mixture, the weight ratio of dihydrooat alkaloid D to the total weight of diethylhexyl syringylmalonate, sodium metabisulfite, and tris(tetramethylhydroxypiperidinol) citrate is in the range of 1,000:1 to 1:1,000, preferably in the range of 500:1 to 1:250, more preferably in the range of 400:1 to 1:100, particularly preferably in the range of 300:1 to 1:25, even more preferably in the range of 200:1 to 1:1, still more preferably in the range of 175:1 to 2:1, and most preferably in the range of 150:1 to 5:1. If one or more of diethylhexyl syringylmalonate, sodium metabisulfite, and tris(tetramethylhydroxypiperidinol) citrate are absent from the (stable) mixture, their weight is regarded as 0 for calculating the total weight.

[0090] The present invention also relates to a mixture comprising:

[0091] i) dihydrooat alkaloid D;

[0092] ii) one or more alkanediols; and

[0093] iii) a stabilizer selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0094] The above-mentioned content regarding the use and / or method according to the present invention applies accordingly.

[0095] Preferably, the mixture according to the present invention is a stable mixture in which dihydrooat alkaloid D is stable in the mixture.

[0096] Preferably, the mixture according to the present invention is the stable mixture as described herein, in which dihydrooat alkaloid D is stable in the mixture.

[0097] In particular, the above-mentioned content regarding the stabilizer or stabilizer composition or regarding stabilization applies accordingly.

[0098] Preferably, the said or one or all of the stabilizers in the stabilizer or stabilizer composition are respectively selected from the group consisting of diethylhexyl syringylmalonate, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0099] Preferably, the said or one stabilizer in the stabilizer or stabilizer composition is diethylhexyl syringylmalonate respectively.

[0100] Preferably, the said or one stabilizer in the stabilizer or stabilizer composition is sodium metabisulfite respectively.

[0101] Preferably, the stabilizer or each stabilizer in the stabilizer composition is tris(tetramethylhydroxypiperidinol) citrate respectively.

[0102] In particular, the above-mentioned content regarding alkylene glycols applies correspondingly.

[0103] Therefore, it is preferred that the mixture comprises:

[0104] i) Dihydroxyoat alkaloid D;

[0105] ii.a) 1,3-Butanediol;

[0106] ii.b) Pentylene glycol; and

[0107] iii) A stabilizer selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

[0108] Preferably,

[0109] Based on the total weight of the stabilizing mixture, the mixture comprises 0.01 wt.-% to 7.5 wt.-%, preferably 0.05 wt.-% to 5 wt.-%, preferably 0.1 wt.-% to 2.5 wt.-% of diethylhexyl syringylmalonate, and / or

[0110] Based on the total weight of the stabilizing mixture, the mixture comprises 0.001 wt.-% to 2.5 wt.-%, preferably 0.005 wt.-% to 1 wt.-%, preferably 0.01 wt.-% to 0.5 wt.-% of sodium metabisulfite, and / or

[0111] Based on the total weight of the stabilizing mixture, the mixture comprises 0.005 wt.-% to 2.5 wt.-%, preferably 0.01 wt.-% to 1.5 wt.-%, preferably 0.05 wt.-% to 1 wt.-% of tris(tetramethylhydroxypiperidinol) citrate.

[0112] Preferably, based on the total weight of the mixture, the mixture comprises 0.1 wt.-% to 20 wt.-%, preferably 0.5 wt.-% to 15 wt.-%, preferably 1 wt.-% to 10 wt.-%, preferably 2.5 wt.-% to 7.5 wt.-% of dihydroxyoat alkaloid D.

[0113] Preferably, in the mixture, the weight ratio of dihydrooat alkaloid D to diethylhexyl syringylmalonate ranges from 1,000:1 to 1:1,000, preferably from 500:1 to 1:250, more preferably from 400:1 to 1:100, particularly preferably from 300:1 to 1:25, even more preferably from 200:1 to 1:1, still more preferably from 175:1 to 2:1, and most preferably from 150:1 to 5:1.

[0114] Preferably, in the mixture, the weight ratio of dihydrooat alkaloid D to sodium metabisulfite ranges from 1,000:1 to 1:1,000, preferably from 500:1 to 1:250, more preferably from 400:1 to 1:100, particularly preferably from 300:1 to 1:25, even more preferably from 200:1 to 1:1, still more preferably from 175:1 to 2:1, and most preferably from 150:1 to 5:1.

[0115] Preferably, in the mixture, the weight ratio of dihydrooat alkaloid D to tris(tetramethylhydroxypiperidinol) citrate ranges from 1,000:1 to 1:1,000, preferably from 500:1 to 1:250, more preferably from 400:1 to 1:100, particularly preferably from 300:1 to 1:25, even more preferably from 200:1 to 1:1, still more preferably from 175:1 to 2:1, and most preferably from 150:1 to 5:1.

[0116] Preferably, in the mixture, the weight ratio of dihydrooat alkaloid D to the total weight of diethylhexyl syringylmalonate, sodium metabisulfite, and tris(tetramethylhydroxypiperidinol) citrate ranges from 1,000:1 to 1:1,000, preferably from 500:1 to 1:250, more preferably from 400:1 to 1:100, particularly preferably from 300:1 to 1:25, even more preferably from 200:1 to 1:1, still more preferably from 175:1 to 2:1, and most preferably from 150:1 to 5:1. If one or more of diethylhexyl syringylmalonate, sodium metabisulfite, and tris(tetramethylhydroxypiperidinol) citrate are absent from the mixture, their weight is considered 0 for calculating the total weight.

[0117] The present invention also relates to a cosmetic preparation comprising the mixture according to the present invention.

[0118] As described herein, a cosmetic preparation is a preparation particularly suitable for topical application to the human skin, especially for achieving a cosmetic effect.

[0119] As described herein, the cosmetic preparation may further comprise one, two, three or more or all of the substances of the group consisting of: odorants, perfume oils, fatty oils, fatty acids, ceramides, ceramide-like substances, sterols, phytosterols, hydrocarbons, anti-acne active ingredients, anti-dandruff active ingredients, anti-microbial active ingredients, preservatives, antiperspirants, anti-irritants, anti-itching active ingredients, cooling active ingredients, anti-aging active ingredients, skin brightening and skin tanning active ingredients, skin moisturizing regulators, penetrants, enzyme inhibitors, odor absorbers, dyes, abrasives, anti-acne agents, anti-cellulitis agents, anti-dandruff agents, anti-inflammatory agents, irritation preventives, irritation inhibitors, antioxidants, astringents, antiperspirants, antibacterial agents, antistatic agents, adhesives, buffers, carrier materials, chelating agents, cell stimulants, detergents, care agents, depilatory agents, surface active substances, deodorants, antiperspirants, softeners, emulsifiers, enzymes, essential oils, fibers, film formers, fixatives, foaming agents, foam stabilizers, foam preventing substances, foam promoters, gelling agents, gel formers, hair care agents, hair styling agents, hair straightening agents, wetting agents, moisturizing substances, bleaching agents, enhancers, detergents, optical brighteners, impregnating agents, soil repellents, friction reducing agents, lubricants, moisturizing creams, ointments, opacifiers, plasticizers, finishing agents, polishers, brighteners, polymers, powders, proteins, re-oiling agents, abrasives, silicones, skin soothers, skin detergents, skin care agents, skin healing agents, skin brighteners, skin protectors, skin softeners, hair quality improvers, cooling agents, skin cooling agents, warming agents, skin warming agents, stabilizers, UV absorbers, UV filters, detergents, fabric conditioners, suspending agents, skin tanning agents, thickeners, vitamins, oils, waxes, fats, phospholipids, saturated fatty acids, mono-unsaturated or poly-unsaturated fatty acids, alpha-hydroxy acids, polyhydroxy fatty acids, liquefiers, colorants, color fixatives, pigments, corrosion preventives, aromatic fragrances, flavoring substances, odorants, polyols, surfactants, electrolytes, organic solvents and silicone derivatives.

[0120] Preferably, based on the total weight of the preparation, the amount of dihydrooat alkaloid D in the preparation according to the invention ranges from 0.000005 wt.-% to 2.5 wt.-%, preferably from 0.0000075 wt.-% to 2 wt.-%, more preferably from 0.00001 wt.-% to 1.5 wt.-%, particularly preferably from 0.000025 wt.-% to 1.25 wt.-%, even more preferably from 0.00005 wt.-% to 1 wt.-%, still more preferably from 0.000075 wt.-% to 0.75 wt.-%, especially preferably from 0.0001 wt.-% to 0.5 wt.-%, even more preferably from 0.00025 wt.-% to 0.25 wt.-%, and most preferably from 0.0005 wt.-% to 0.1 wt.-%.

[0121] Preferably, based on the total weight of the cosmetic preparation, the total weight of dihydrooat alkaloid D and a stabilizer selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof in the preparation ranges from 0.01 wt.-% to 4 wt.-%, preferably from 0.05 wt.-% to 3 wt.-%, and more preferably from 0.1 wt.-% to 2 wt.-%. If one or more of the above compounds are not present in the mixture, their weight is considered 0 for calculating the total weight.

[0122] Preferably, based on the total weight of the cosmetic preparation, the total weight of dihydrooat alkaloid D, a stabilizer selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof, and an alkanediol in the preparation ranges from 0.01 wt.-% to 4 wt.-%, preferably from 0.05 wt.-% to 3 wt.-%, and more preferably from 0.1 wt.-% to 2 wt.-%. If one or more of the above compounds are not present in the mixture, their weight is considered 0 for calculating the total weight.

[0123] Preferably, the cosmetic preparation according to the invention is a rinse-off preparation.

[0124] Preferably, the cosmetic preparation according to the invention is a leave-on preparation.

[0125] What has been said above regarding the uses and / or methods and / or mixtures according to the invention applies accordingly. In particular, what has been said above regarding the stabilizer or stabilizer composition or regarding stabilization applies accordingly. In particular, what has been said above regarding the alkanediol applies accordingly. Detailed Description

[0126] Other aspects and advantages of the present invention come from the description of the following preferred embodiments.

[0127] Example

[0128] Example 1: Comparing different stabilizers - discoloration

[0129] Compositions A - M were prepared as described below and stored at 40 °C and 50 °C for 1 month.

[0130] Composition A was used as a comparative sample.

[0131] At the start of the test and after storage at different temperatures for 1 month, the color of all samples was measured using colorimetry (L*a*b* values). Based on these values, the overall degree of color change (ΔE) was calculated.

[0132] The following stabilizing ingredients were used:

[0133] Ascorbyl palmitate (Composition B)

[0134] Oxynex ST Liquid (International Nomenclature of Cosmetic Ingredients (INCI): Diethylhexyl syringylidenemalonate, Caprylic / Capric / Triglyceride, 90% AS) (Compositions C and D)

[0135] Tinogard TT (INCI: Pentaerythrityl tetra - (di - tert - butyl hydroxyhydrocinnamate)) (Compositions E and F)

[0136] Tocopheryl acetate (Compositions G and H)

[0137] Covastyle MBS (INCI: Sodium metabisulfite) (Compositions I and K)

[0138] Tinogard Q (INCI: Tris(tetramethylhydroxypiperidinol) citrate) (Compositions L and M)

[0139] Table 1

[0140]

[0141] Table 1 (continued)

[0142]

[0143] Preparation method (Compositions A to M)

[0144] Heat butylene glycol and pentylene glycol to a maximum of 70 °C, then mix the two ingredients by stirring. Add each stabilizer at 65 °C - 80 °C and stir at this temperature for 5 minutes. Add dihydro - avenanthramide D at 60 °C and stir for 30 minutes.

[0145] Color determination (Lico 690 (Hach Lange))

[0146] At the start of the test and after storage at different temperatures for 1 month, the color of the samples was measured using colorimetry (L*a*b* values).

[0147] Based on these values, the overall color change degree (ΔE) was calculated according to the following formula:

[0148]

[0149] Since recrystallization was carried out immediately after preparation, color determination could not be performed on Samples E and F (containing pentaerythritol tetra(bis-tert-butyl hydroxydrocinnamate)). These samples were not stored and were not further evaluated.

[0150] The following results were obtained:

[0151]

[0152]

[0153] The above data show that Compositions C and D (containing diethylhexyl syringylmalonate), I and K (containing sodium metabisulfite), and L and M (containing tris(tetramethylhydroxypiperidinol) citrate) had a very low degree of color change after 1 month of storage, indicating that these compositions were much more stable than Composition B (containing ascorbyl palmitate), Compositions G and H (containing tocopheryl acetate), or Composition A (without stabilizer).

[0154] Example 2: Comparing different stabilizers - odor formation

[0155] Compositions A, B, C, G, I, and L were prepared as described in Example 1.

[0156] The compositions were stored at 22 °C for 1 month.

[0157] Subsequently, 4 experienced panelists (P1 to P4) evaluated the intensity of off-odor using a scale from 0 to 10, where 0 = no off-odor and 10 = strong off-odor.

[0158] The following results were obtained:

[0159] Team members A B C G I L P1 5 5 2 2 4 1 P2 3 3 2 3 2 1 P3 4 3 4 4 4 3 P4 4 4 2 3 3 2 Average value 4.0 3.75 2.5 3.0 3.25 1.75

[0160] The above data show that compositions C (containing diethylhexyl syringylmalonate), I (containing sodium metabisulfite), and L (containing tris(tetramethylhydroxypiperidinol) citrate) form less off-odor after 1 month of storage, indicating that these compositions are much more stable than composition B (containing ascorbyl palmitate), compositions G and H (containing tocopheryl acetate), or composition A (without stabilizer).

[0161] For compositions C (containing diethylhexyl syringylmalonate) and L (containing tris(tetramethylhydroxypiperidinol) citrate), particularly low off-odor formation was observed.

[0162] Application example:

[0163] Perfume oil 1

[0164] Table 2: Components of perfume oil 1 (PO1, amounts in ‰ b.w.)

[0165]

[0166]

[0167] Table 3: Components of perfume oil 2 (PO2, amounts in ‰ b.w.)

[0168]

[0169]

[0170] Table 4: Components of perfume oil 3 (PO3, amounts in ‰ b.w.)

[0171]

[0172] Table 5: Components of perfume oil 4 (PO4, amounts in ‰ b.w.)

[0173]

[0174]

[0175]

[0176] Table 6: Components of perfume oil 5 (PO5, amounts in ‰ b.w.)

[0177]

[0178]

[0179] The perfume oils PO1, PO2, PO3, PO4, or PO5 in the above embodiments are added to the formulation individually, as follows.

[0180] Cosmetic formulation (composition) - all amounts of the formulations are expressed in weight percentages.

[0181] Energy concentrate

[0182]

[0183]

[0184] Natural beauty enhancer (solid concentrate)

[0185]

[0186] Solid body care oil

[0187]

[0188] Sensi SCALP (green solid shampoo)

[0189]

[0190]

[0191] Advanced lifting essence

[0192]

[0193]

[0194] Hand care product (Perfect Hand), SPF 15, UVA / UVB balanced

[0195]

[0196]

[0197] Warm mineral mask

[0198]

[0199]

[0200] Sheet mask

[0201]

[0202] Aftershave lotion

[0203]

[0204]

[0205] After-sun Refreshing Gel

[0206]

[0207]

[0208] Flash SOS Aloe Gel

[0209]

[0210]

[0211] Intimate Sensi-Gel

[0212]

[0213]

[0214] Gentle Feminine Wash

[0215]

[0216]

[0217] Intimate Rescue Gel

[0218]

[0219]

[0220] Men's Aftershave

[0221]

[0222] Anti-Wrinkle Night Cream

[0223]

[0224]

[0225]

[0226] Basic Care Face Cream and Body Lotion

[0227]

[0228]

[0229] Natural Aloe Night Cream

[0230]

[0231]

[0232] Repair Hair Conditioner

[0233]

[0234]

[0235] Refreshing Conditioning Foam

[0236]

[0237] Anti-dandruff Shampoo

[0238]

[0239]

[0240] Sulfate-free Shampoo

[0241]

[0242]

[0243] Gentle Conditioning Shampoo for Children / Babies

[0244]

[0245]

Claims

1. Use of a stabilizer or stabilizer composition for stabilizing dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D, wherein the stabilizer or each or one or all of the stabilizers in the stabilizer composition are respectively selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

2. The use according to claim 1, wherein the mixture containing dihydrooat alkaloid D comprises: i) dihydrooat alkaloid D; and ii) one or more alkylene glycols.

3. The use according to any one of the preceding claims, wherein the mixture containing dihydrooat alkaloid D comprises: i) dihydrooat alkaloid D; ii.a) 1,3 - butanediol; and ii.b) pentanediol.

4. The use according to any one of the preceding claims, wherein the stabilizer or stabilizer composition is respectively mixed with the mixture containing dihydrooat alkaloid D to obtain a stable mixture, wherein based on the total weight of the resulting stable mixture, the stable mixture comprises 0.01 wt.-% to 7.5 wt.-%, preferably 0.05 wt.-% to 5 wt.-%, preferably 0.1 wt.-% to 2.5 wt.-% of diethylhexyl syringylmalonate, and / or wherein based on the total weight of the resulting stable mixture, the stable mixture comprises 0.001 wt.-% to 2.5 wt.-%, preferably 0.005 wt.-% to 1 wt.-%, preferably 0.01 wt.-% to 0.5 wt.-% of sodium metabisulfite, and / or wherein based on the total weight of the resulting stable mixture, the stable mixture comprises 0.005 wt.-% to 2.5 wt.-%, preferably 0.01 wt.-% to 1.5 wt.-%, preferably 0.05 wt.-% to 1 wt.-% of tris(tetramethylhydroxypiperidinol) citrate.

5. A method for stabilizing dihydrooat alkaloid D in a mixture containing dihydrooat alkaloid D, comprising the following steps: a) Provide a mixture comprising dihydrooat alkaloid D; b) Provide a stabilizer or a stabilizer composition, wherein the stabilizer or each or one or all of the stabilizers in the stabilizer composition are independently selected from the group consisting of diethylhexyl syringylidenemalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof; c) Mix the components provided in step a) and step b).

6. The method according to claim 5, wherein the mixture provided in step a) comprises: i) dihydrooat alkaloid D; ii) one or more alkylene diols.

7. The method according to claim 5 or 6, wherein the mixture provided in step a) comprises: i) dihydrooat alkaloid D; ii.a) 1,3 - butanediol; and ii.b) pentylene glycol.

8. The method according to any one of claims 5 to 7, wherein after mixing in step c), a stable mixture is obtained, wherein based on the total weight of the resulting stable mixture, the stable mixture comprises 0.01 wt.-% to 7.5 wt.-%, preferably 0.05 wt.-% to 5 wt.-%, preferably 0.1 wt.-% to 2.5 wt.-% of diethylhexyl sublactate, and / or wherein based on the total weight of the resulting stable mixture, the stable mixture comprises 0.001 wt.-% to 2.5 wt.-%, preferably 0.005 wt.-% to 1 wt.-%, preferably 0.01 wt.-% to 0.5 wt.-% of sodium metabisulfite, and / or wherein based on the total weight of the resulting stable mixture, the stable mixture comprises 0.005 wt.-% to 2.5 wt.-%, preferably 0.01 wt.-% to 1.5 wt.-%, preferably 0.05 wt.-% to 1 wt.-% of tris(tetramethylhydroxypiperidinol) citrate.

9. A mixture comprising: i) dihydrooat alkaloid D; ii) one or more alkylene diols; and iii) a stabilizer selected from the group consisting of diethylhexyl sublactate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

10. The mixture according to claim 9, comprising: i) dihydrooat alkaloid D; ii.a) 1,3 - butanediol; ii.b) pentylene glycol; and iii) a stabilizer selected from the group consisting of diethylhexyl sublactate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate, and mixtures thereof.

11. The mixture according to claim 9 or 10, wherein: Based on the total weight of the stable mixture, the mixture comprises from 0.01 wt.-% to 7.5 wt.-%, preferably from 0.05 wt.-% to 5 wt.-%, preferably from 0.1 wt.-% to 2.5 wt.-% of diethylhexyl syringylidenemalonate, and / or Based on the total weight of the stable mixture, the mixture comprises from 0.001 wt.-% to 2.5 wt.-%, preferably from 0.005 wt.-% to 1 wt.-%, preferably from 0.01 wt.-% to 0.5 wt.-% of sodium metabisulfite, and / or Based on the total weight of the stable mixture, the mixture comprises from 0.005 wt.-% to 2.5 wt.-%, preferably from 0.01 wt.-% to 1.5 wt.-%, preferably from 0.05 wt.-% to 1 wt.-% of tris(tetramethylhydroxypiperidinol) citrate.

12. A cosmetic preparation comprising the mixture according to any one of claims 9 to 11.

13. The cosmetic preparation according to claim 12, wherein based on the total weight of the cosmetic preparation, the total weight of dihydrooat alkaloid D and the stabilizer selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate and mixtures thereof in the preparation is in the range of 0.01 wt.-% to 4 wt.-%, preferably in the range of 0.05 wt.-% to 3 wt.-%, more preferably in the range of 0.1 wt.-% to 2 wt.-%.

14. The cosmetic preparation according to claim 12 or 13, wherein based on the total weight of the cosmetic preparation, the total weight of dihydrooat alkaloid D, the stabilizer selected from the group consisting of diethylhexyl syringylmalonate, sodium metabisulfite, tris(tetramethylhydroxypiperidinol) citrate and mixtures thereof and alkylene glycol in the preparation is in the range of 0.01 wt.-% to 4 wt.-%, preferably in the range of 0.05 wt.-% to 3 wt.-%, more preferably in the range of 0.1 wt.-% to 2 wt.-%.

Images