Cosmetic containing pyridoxine

Abstract

The purpose of the present invention is to provide a cosmetic that has exceptional stability and usability while containing pyridoxine.　A cosmetic according to the present invention is characterized by containing: (A) pyridoxine, or a salt or a derivative thereof; (B) ethyl ascorbic acid; and (C) a higher fatty acid or a higher alcohol that is liquid at 25°C.

Description

Cosmetics containing pyridoxine

[0001] The present invention relates to a cosmetic preparation that contains pyridoxine, a salt or a derivative thereof, and yet has excellent stability and ease of use.

[0002] Pyridoxine, a water-soluble vitamin that is a member of the vitamin B6 group, and its salts or derivatives (hereinafter sometimes referred to as "pyridoxines") are known to have a sebum-suppressing effect and are used in a variety of cosmetics, such as skin care products, makeup bases, sunscreens, and makeup, to alleviate sebum problems such as oily skin, stickiness, and acne. However, pyridoxines are easily decomposed over time when exposed to light, causing discoloration in cosmetics, and therefore there is a need to improve their stability in cosmetics.

[0003] In an attempt to improve the stability of pyridoxine compounds in cosmetics, for example, Patent Document 1 proposes blending a dehydrochlorinated product of pyridoxine hydrochloride with an acidic compound such as ascorbic acid or a derivative thereof. Table 2-1 shows that discoloration is suppressed and stability is improved by combining a dehydrochlorinated product of pyridoxine hydrochloride with ascorbic acid, ascorbic acid glucoside, or 3-O-ethyl ascorbic acid. Table 2-2 also shows that stability is further improved by adding sodium pyrosulfite or sodium citrate as a stability improver.

[0004] However, cosmetics containing pyridoxines tend to be sticky during application, not blend well with the skin, sticky when drying, and leave a squeaky or coated feeling after application. Furthermore, when ascorbic acid or its derivatives, which improve the stability of pyridoxines, are added, the usability may be significantly impaired.

[0005] JP 2017-123833 A

[0006] An object of the present invention is to provide a cosmetic preparation that contains pyridoxines and yet has excellent stability and ease of use.

[0007] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors discovered that by blending ethyl ascorbic acid and a higher fatty acid or higher alcohol that is liquid at 25°C with a cosmetic preparation containing pyridoxines, it is possible to obtain a cosmetic preparation that stably retains pyridoxines while also being easy to use, and thus completed the present invention.

[0008] That is, the gist of the present invention is a cosmetic comprising: (A) pyridoxine, a salt or derivative thereof; (B) ethyl ascorbic acid; and (C) a higher fatty acid or a higher alcohol that is liquid at 25°C.

[0009] By adopting the above-described constitution, the cosmetic according to the present invention can stably retain pyridoxines and can also be realized as a cosmetic that is easy to use.

[0010] The cosmetic of the present invention is characterized by containing (A) pyridoxine, a salt or derivative thereof, (B) ethyl ascorbic acid, and (C) a higher fatty acid or higher alcohol that is liquid at 25° C. Each component constituting the cosmetic of the present invention will be described in detail below.

[0011] <(A) Pyridoxine, its salt, or derivative> The pyridoxine, its salt, or derivative (A) used in the present invention may be used alone or in any combination of two or more. The salt of pyridoxine is not particularly limited as long as it is pharmaceutically, pharmacologically (pharmaceutical), or physiologically acceptable, and examples thereof include the following compounds: (i) organic acid salts: monocarboxylates (acetate, trifluoroacetate, butyrate, palmitate, stearate, etc.), polycarboxylates (fumarate, maleate, succinate, malonate, etc.), hydroxycarboxylates (lactate, tartrate, citrate, etc.), organic sulfonates (methanesulfonate, toluenesulfonate, tosylate, etc.), (ii) inorganic acid salts: hydrochloride, sulfate, nitrate, hydrobromide, phosphate, etc., (iii) salts with organic bases: salts with organic amines such as methylamine, triethylamine, triethanolamine, morpholine, piperazine, pyrrolidine, tripyridine, picoline, etc., (iv) salts with inorganic bases: ammonium salts, salts with alkali metals (sodium, potassium, etc.), salts with alkaline earth metals (calcium, magnesium, etc.), and salts with metals such as aluminum. Among these, inorganic acid salts of pyridoxine are preferred, pyridoxine hydrochloride or phosphate is more preferred, and pyridoxine hydrochloride is even more preferred. Pyridoxine derivatives, some of which are included in the above-mentioned salts, are in particular those which have pyridoxine activity and have been stabilized and fat-soluble by phosphorylation, esterification, etc., and examples thereof include pyridoxine cyclic phosphate, pyridoxine glycyrrhetinate, pyridoxine dicaprylate, pyridoxine dipalmitate, pyridoxine trishexyldecanoate, pyridoxine tripalmitate, etc., but are not limited to these.

[0012] The blending amount of (A) pyridoxine, its salt, or derivative is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the cosmetic. Therefore, the blending amount range may be 0.001 to 10% by mass, or 0.01 to 5% by mass, etc. Within this range, the sebum-suppressing effect of (A) pyridoxine, its salt, or derivative can be fully exerted.

[0013] <(B) Ethyl Ascorbic Acid> The (B) ethyl ascorbic acid (2-O-ethyl ascorbic acid) used in the present invention is a type of ascorbic acid derivative with improved stability, and similar to ascorbic acid, has various physiologically active effects. (B) Ethyl ascorbic acid is known to have antioxidant effects, whitening effects, and effects of promoting the production of collagen and hyaluronic acid, and is widely used as an active ingredient in cosmetics and topical skin preparations.

[0014] The blending amount of (B) ethyl ascorbic acid is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and preferably 1% by mass or less, more preferably 0.5% by mass or less, based on the total amount of the cosmetic. Therefore, the blending amount range may be 0.001 to 1% by mass, or 0.01 to 0.5% by mass, etc. Within this range, the stability of (A) pyridoxines can be sufficiently improved without significantly impairing the usability of the cosmetic.

[0015] <(C) Higher Fatty Acid or Higher Alcohol Liquid at 25° C.> The (C) higher fatty acid or higher alcohol liquid at 25° C. used in the present invention is not particularly limited as long as it is liquid at 25° C., and one type may be used alone, or two or more types may be used in combination. Examples of higher alcohols that are liquid at 25° C. include 2-ethylhexanol, 6-methyl-2-heptanol, isononyl alcohol, isodecyl alcohol, isoundecyl alcohol, isododecyl alcohol, 2-butyloctanol, isotridecyl alcohol, isotetradecyl alcohol, isopentadecyl alcohol, isohexadecyl alcohol, 2-hexyldecanol, isoheptadecyl alcohol, isostearyl alcohol, isononadecyl alcohol, isoeicosanol, octyldodecanol, isoheneicosanol, 18-methyleicosanol, isodocosanol, and 2-decyltetradecanol.

[0016] Examples of higher fatty acids that are liquid at 25°C include isononanoic acid, isodecanoic acid, dimethyloctanoic acid, isoundecanoic acid, isododecanoic acid, isotridecanoic acid, isotetradecanoic acid, isopentadecanoic acid, isohexadecanoic acid, isoheptadecanoic acid, isostearic acid, isononadecanoic acid, isoicosanoic acid, 2-ethylhexanoic acid, 2-butyloctanoic acid, 2-hexyldecanoic acid, 2-octyldodecanoic acid, 2-decyltetradecanoic acid, 2-dodecylhexadecanoic acid, 2-tetradecyloctadecanoic acid, 2-hexadecylic eicosanoic acid, undecenoic acid, myristoleic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, gadoleic acid, eicosapentaenoic acid, docosahexaenoic acid, erucic acid, brassidic acid, and arachidonic acid.

[0017] Among these, isostearic acid, oleic acid, isostearyl alcohol, and octyldodecanol are particularly preferred because they have a significant effect of improving ease of use.

[0018] The blending amount of (C) the higher fatty acid or higher alcohol that is liquid at 25°C is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less, based on the total amount of the cosmetic. There is no particular lower limit to the blending amount, but it is preferably 0.001% by mass or more, and more preferably 0.005% by mass or more. Therefore, examples of the blending amount range include 0.001 to 0.5% by mass and 0.005 to 0.3% by mass. Within this range, the usability of the cosmetic can be sufficiently improved without impairing the stability of (A) the pyridoxine.

[0019] <(A) / (B) Ratio> In the cosmetic of the present invention, the blending mass ratio of (A) pyridoxine, a salt or a derivative thereof to (B) ethyl ascorbic acid ((A) / (B) ratio) is preferably less than 3, more preferably 2.5 or less, and even more preferably 2 or less. By adjusting the (A) / (B) ratio to be less than 3, sufficiently excellent effects can be obtained in both the stability of (A) pyridoxines and the usability of the cosmetic.

[0020] <(C) / Total Oil Ratio> The cosmetic of the present invention may contain (C) an oil other than a higher fatty acid or higher alcohol that is liquid at 25°C, but the blending mass ratio of component (C) to the total oil including component (C) ((C) / total oil ratio) is preferably 10 mass% or more, more preferably 20 mass% or more. Within this range, usability can be sufficiently improved even when (A) a pyridoxine and (B) ethyl ascorbic acid are blended.

[0021] <Optional Components> In addition to the components (A) to (C) described above, the cosmetic of the present invention may contain components that are commonly used in cosmetics, as long as they do not impair the effects of the present invention. For example, oils other than component (C), aqueous solvents, and moisturizers, as well as antioxidants, chelating agents, preservatives, fragrances, etc. may be appropriately blended as needed.

[0022] The oil component is not particularly limited as long as it is an oil component other than component (C) that is typically blended in cosmetics, and examples thereof include silicone oil, hydrocarbon oil, and ester oil.

[0023] Examples of silicone oils include linear and cyclic polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, decamethylpolysiloxane, dodecamethylpolysiloxane, tetramethyltetrahydrogenpolysiloxane, cyclotetradimethylsiloxane, and cyclopentadimethylsiloxane.

[0024] Examples of hydrocarbon oils include liquid paraffin, isohexadecane, ozokerite, pristane, paraffin, isoparaffin, ceresin, petrolatum, microcrystalline wax, hydrogenated polyisobutene, olefin oligomers, and volatile hydrocarbon oils (e.g., isododecane, undecane, and tridecane).

[0025] Examples of ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, isocetyl stearate, isocetyl isostearate, cholesteryl hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane triethylhexanoate, and triisostearate. trimethylolpropane, pentaerythrityl tetraethylhexanoate, glyceryl tri-2-ethylhexanoate, cetyl ethylhexanoate, ethylhexyl palmitate, glyceryl trimyristate, glyceryl tri-2-heptylundecanoate, castor oil fatty acid methyl esters, oleyl oleate, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, di-2-heptylundecyl adipate, ethyl laurate, diethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, diethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, and triethyl citrate.

[0026] In the cosmetic of the present invention, the blending amount of the total oil content including component (C) is preferably 0.001% by mass or more and 2% by mass or less, based on the total amount of the cosmetic. Therefore, the blending amount range is, for example, 0.001 to 2% by mass.

[0027] Examples of aqueous solvents include water (purified water, ion-exchanged water, tap water, etc.), lower alcohols, and mixtures thereof.

[0028] Examples of moisturizing agents include polyoxyalkylene-polyoxyethylene copolymer dialkyl ether, 1,3-butylene glycol (BG), polyethylene glycol (PEG), propylene glycol, dipropylene glycol (DPG), hexylene glycol, glycerin, diglycerin, xylitol, maltitol, maltose, and D-mannite.

[0029] In particular, blending polyethylene glycol (PEG) with a molecular weight of 300 to 2000 can improve skin compatibility and reduce stickiness, further improving the usability of the cosmetic. The molecular weight of the polyethylene glycol is preferably 300 or more, and preferably 2000 or less, and more preferably 1500 or less. Here, the molecular weight refers to the weight-average molecular weight of the compound, and can be measured, for example, by GPC (gel permeation chromatography). When blending polyethylene glycol with a molecular weight of 300 to 2000, the amount is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and preferably 5% by mass or less, and more preferably 2% by mass or less, based on the total amount of the cosmetic. Therefore, examples of the blending amount range include 0.01 to 5% by mass and 0.1 to 2% by mass.

[0030] <Uses and Forms> The cosmetic of the present invention can be applied to a cosmetic that suppresses sebum secretion because it can stably incorporate pyridoxine (A). The form of the cosmetic of the present invention is not particularly limited, and it can be widely applied to any form used in cosmetics, such as lotion, serum, emulsion, cream, and gel. Generally, pyridoxine (A) is kept relatively stable in cosmetics with a high oil content, such as emulsion, but the present invention can stably incorporate pyridoxine (A) even in lotions, serums, and the like that cannot incorporate a high amount of oil.

[0031] The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the blending amounts are expressed in mass % relative to the cosmetic. Before describing each example in detail, the evaluation methods used will be described.

[0032] <Stability of pyridoxine> Each cosmetic was placed in a light-shielding glass screw tube, and the amount of pyridoxine after storage at 0°C for one month and after storage at 50°C for one month was measured according to the liquid chromatography method in the general testing method of the Quasi-drug Ingredients Standards 2006, and the stability was evaluated by calculating the residual rate (%) of pyridoxine ([amount of pyridoxine after storage at 50°C for one month] / [amount of pyridoxine after storage at 0°C for one month] × 100).

[0033] <Usability> Each cosmetic was applied to the skin, and the usability was examined from the viewpoints of (i) absence of stickiness during application, (ii) goodness of absorption, (iii) absence of stickiness when drying, (iv) absence of squeaky feeling after application, and (v) absence of film-like feeling, and rated according to the following criteria. [Rating criteria] A: Very good B: Good C: Fully acceptable D: Poor

[0034] <Reference Example> The cosmetics shown in Table 1 below were prepared and evaluated for stability based on the evaluation method and criteria described above. The purpose of this Reference Example is to investigate the extent to which (B) ethyl ascorbic acid and other antioxidants affect the stability of (A) pyridoxines when component (C) is not blended. The evaluation results are also shown.

[0035]

[0036] As shown in Table 1, among the antioxidants widely used in cosmetics, (B) ethyl ascorbic acid showed the best stability of pyridoxine.

[0037] <Production Examples> The cosmetics shown in Tables 2A to 2C below were prepared and evaluated based on the evaluation methods and criteria described above. The evaluation results are also shown.

[0038]

[0039]

[0040]

[0041] As shown in Tables 2A to 2C, when (C) higher fatty acids or higher alcohols that are liquid at 25°C were not included, all evaluations of usability were poor, both when (A) pyridoxine was used alone and when (A) pyridoxine was used in combination with (B) ethyl ascorbic acid (Production Examples 1 and 2). Furthermore, when only oils that are liquid at 25°C but do not fall under the category of higher fatty acids or higher alcohols were added, usability could not be sufficiently improved (Production Examples 3 to 7). On the other hand, it was confirmed that usability was improved by adding (C) components that are liquid at 25°C and fall under the category of higher fatty acids or higher alcohols (isostearic acid, isostearyl alcohol, oleic acid, and octyldodecanol) (Production Examples 8 to 27). Furthermore, it was confirmed that good usability could be maintained even when other oils were blended in addition to component (C) (Production Examples 18 to 25), and that the mass ratio of (A) pyridoxine to (B) ethyl ascorbic acid ((A) / (B) ratio) was preferably less than 3 (Production Examples 8, 26, and 27).

[0042] The cosmetics shown in Table 3 below were prepared, and the usability of the cosmetics was evaluated relative to Production Example 8 as a control, and judged according to the following criteria. The evaluation results are also shown. [Judgment criteria] +2: Very good +1: Good 0: Equal -1: Slightly poor -2: Poor

[0043]

[0044] As shown in Table 3, when polyethylene glycol with a molecular weight in the range of 300 to 2000 was added, all or any of the following characteristics were improved compared to the cosmetic of Production Example 8: non-stickiness during application, good compatibility, and non-stickiness upon drying (Production Examples 29 to 33). On the other hand, when polyethylene glycol with a molecular weight of 20,000 was added, the sticky feeling during application became more noticeable, and it was found that usability was actually reduced (Production Example 28).

Claims

1. A cosmetic comprising (A) pyridoxine, its salt or derivative, (B) ethyl ascorbic acid, and (C) a higher fatty acid or a higher alcohol that is liquid at 25°C.

2. The cosmetic according to claim 1, wherein the higher fatty acid or the higher alcohol that is liquid at 25°C in (C) is at least one selected from isostearic acid, oleic acid, isostearyl alcohol, and octyldodecanol.

3. The cosmetic according to claim 1, wherein the blending mass ratio ((A) / (B) ratio) of (A) pyridoxine, its salt or derivative to (B) ethyl ascorbic acid is less than 3.

4. The cosmetic according to claim 1, wherein the blending amount of (B) ethyl ascorbic acid relative to the total amount of the cosmetic is 0.001 to 1% by mass.

5. The cosmetic according to claim 1, wherein the blending amount of the higher fatty acid or the higher alcohol that is liquid at 25°C in (C) relative to the total amount of the cosmetic is 0.5% by mass or less.

6. The cosmetic according to claim 1, wherein the blending amount of the total oil component containing the higher fatty acid or the higher alcohol that is liquid at 25°C in (C) is 0.001 to 2% by mass relative to the total amount of the cosmetic.

7. The cosmetic according to claim 1, wherein the blending mass ratio ((C) / total oil component ratio) of the component (C) to the total oil component containing the higher fatty acid or the higher alcohol that is liquid at 25°C in (C) is 10% by mass or more.

8. The cosmetic according to claim 1, further comprising polyethylene glycol having a molecular weight of 300 to 2000.

9. The cosmetic according to claim 1, wherein the cosmetic is a sebum secretion-inhibiting cosmetic.

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