Surfactant, and an emulsion-type cosmetic composition and a liposome containing said surfactant

Abstract

The invention provides a surfactant comprising at least one trehalose-6-fatty acid ester selected from those represented by the following formula: 1

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a surfactant which has excellent surface activity and safety.

[0002] The invention also relates to a detergent with excellent safety, containing the surfactant.

[0003] The invention further relates to an emulsion-type cosmetic composition with excellent emulsion stability, safety to skin and sensory properties, containing the surfactant.

BACKGROUND OF THE INVENTION

[0004] A number of compounds are known as surfactants and used in many applications. However, most of those surfactants irritate skin when they are used in cosmetics, such as shampoos, rinses, soaps and other cosmetic compositions, which contact with a human body directly. Therefore, lower irritating surfactants have been desired.

[0005] In many emulsions use is made of nonionic surfactants having a polyoxyethylene chain, anionic surfactants such as fatty acid soaps, cationic surfactants or ampholytic surfactants. However, there was a problem that emulsion-type cosmetic compositions with those synthetic surfactants generally tend to irritate skin. Also, even with nonionic surfactants which are said to be less irritating, most of them fit poorly to skin because of their polyoxyethylene chains.

[0006] On the other hand, alkylesterified sugars are nonionic surfactants which have been used widely in foods, cosmetics and the like. Among others, sucrose alkylesters in which sucrose constitutes a sugar skeleton are used widely and seen in many publications (Japanese Patent Application Laid Open No. 56-55306/1981). However, those are insufficient in sensory properties and long-term storage stability. Also, it is known to use, as a surfactant, trehalose-6,6′-dialkylester in which a trehalose derivative constitutes a sugar skeleton (Japanese Patent Application Laid Open Nos. 60-25819/1985 and 62-91236/1987). Those are insufficient in emulsifiability.

[0007] Synthesis of trehalose fatty acid ester are reported in Chem. Phar. Bull., 30 (4) pp1169-1174, (1982), where synthesis of 6-stearoyl-trehalose and 6,6′-distearoyl-trehalose and the analysis of them using NMR, etc. are described. Those esters are reported to have anti-tumor activity against Ehrlich ascites tumor in mice. There is no description or suggestion that they show properties as a surfactant. An emulsion-type anti-tumor agent is known in which a specific emulsifier composition is combined with trehalose-6,6′-difatty acid ester as an anti-tumor agent in order to solve a disadvantage that the ester is difficult to dissolve in water (Japanese Patent Application Laid Open No. 61-289038/1986).

[0008] In consideration of surface activity, foamability, washing ability and so forth for a surfactant, the presence of a single lipophilic moiety is said to be preferred. For example, glucose fatty acid monoester is reported in Japanese Patent Application Laid Open No. 03-157349/1991. However, this has a disadvantage that a stable emulsion can not be obtained due to its weak hydrophilicity.

DISCLOSURE OF THE INVENTION

[0009] A purpose of the invention is to provide a surfactant that has excellent surface activity and safety.

[0010] Another purpose of the invention is to provide a detergent that has excellent safety.

[0011] A further purpose of the invention is to provide an emulsion-type cosmetic that has low irritation to skin, long-term storage stability, excellent sensory properties and beautiful appearance with fine surface texture.

[0012] The present invention is a surfactant containing one or more of trehalose-6-fatty acid esters represented by the following formula: 2

[0013] wherein R represents a saturated or unsaturated acyl group having 8-22 carbon atoms, and may have substituents such as a hydroxyl group.

[0014] One preferred embodiment of the invention is a surfactant containing 6-(10-undecylenyl)-trehalose represented by the following formula: 3

[0015] Another preferred embodiment of the invention is a surfactant containing 6-lauroyl-trehalose.

[0016] Further, another preferred embodiment of the invention is a surfactant containing 6-stearoyl-trehalose.

[0017] Also, the invention is a detergent characterized in that it contains a surfactant containing one or more of trehalose-6-fatty acid esters represented by the following formula: 4

[0018] wherein R is a saturated or unsaturated acyl group having 8-22 carbon atoms, and may have substituents such as a hydroxyl group.

[0019] Further, the invention is an emulsion-type cosmetic composition characterized in that it contains one or more of trehalose-6-fatty acid esters represented by the following formula: 5

[0020] wherein R is a saturated or unsaturated acyl group having 8-22 carbon atoms, and may have substituents such as a hydroxyl; and

[0021] a water-soluble polymer.

BEST MODE OF THE INVENTION

[0022] The trehalose-6-fatty acid ester of the invention can be obtained by a condensation reaction of trehalose with a fatty acid or by an ester interchange reaction between trehalose and a fatty acid ester.

[0023] Examples of the fatty acid or fatty acid ester which can be used in the invention include synthetic fatty acids and esters thereof, natural fatty acids, such as soybean fatty acid, beef tallow, cotton seed oil, olive oil, palm oil and so forth, and fatty acid esters thereof with lower alkyl groups, which esters are obtained in any conventional method.

[0024] Trehalose which can be used in the invention may be α, α-trehalose, α,β-trehalose, β,β-trehalose or mixtures thereof.

[0025] The trehalose-6-fatty acid of the invention can be obtained in any usual method of producing sucrose alkyl esters, as described in U.S. Pat. Nos. 2,893,990 and 3,963,699, Japanese Patent Application Laid Open laid Nos. 36-21717/1961 and 53-6130/1978, all of which are incorporated herein by reference.

[0026] The trehalose-6-fatty acid ester is obtained as a main reaction product in these methods. In some cases, there are contained small amounts of unreacted trehalose and trehalose-6,6′-fatty acid diester as a side-reaction product. The trehalose-6-fatty acid ester may be purified in a conventional manner before used, if desired. However, the trehalose-6-fatty acid may be used together with small amounts of unreacted trehalose and trehalose-6,6′-fatty acid diester, because the trehalose-6-fatty acid can exhibit surface activity even in the presence of them.

[0027] The trehalose-6-fatty acid ester used in the invention is preferably those in which a fatty acid radical, i.e. an acyl group, has a linear or branched, saturated alkyl or alkenyl group having 8-22 carbon atoms. Examples of those include trehalose monocaprylate, trehalose monononanoate, trehalose monocaprate, trehalose monoundecanoate, trehalose monolaurate, trehalose monomyristate, trehalose monopalmitate, trehalose monostearate, trehalose monoarachidate, trehalose monobehenate, trehalose monoundecylenate, trehalose monooleate, trehalose monolinoleate, trehalose monolinolenate, trehalose monoisostearate, trehalose monohydroxystearate, and trehalose monoricinoleate. One or more from these trehalose-6-fatty acid esters can be used in the invention.

[0028] The surfactant of the invention preferably contains one or more selected from 6-(10-undecylenyl)-trehalose, 6-lauroyl-trehalose and 6-stearoyl-trehalose.

[0029] The surfactant of the invention has excellent surface activity and safety to skin and also may be used as an emulsifier in foods.

[0030] The skin or hair washing agent detergent of the invention preferably contains one or more of the trehalose-6-fatty acid ester in an amount of 1-50 wt. %, particularly 10-35 wt. %. It may further contain other surfactants.

[0031] The cosmetic composition of the invention contains one or more of the above trehalose-6-fatty acid ester and a water-soluble polymer. The content of the above trehalose-6-fatty acid ester in the cosmetic composition is preferably 0.01-20 wt. %, particularly 0.1-10 wt. %, based on the total weight of the cosmetic composition. If the content is less than 0.01 wt. %, the emulsion stability of the cosmetic composition tends to decrease during its storage. On the other hand, if it is more than 20 wt. %, it is difficult to obtain fine feeling in use.

[0032] The water-soluble polymer used in the invention may be generally any of those used in cosmetic compositions or pharmaceutical bases. Examples of the water-soluble polymer include guar gum, roastbean gum, queensseed, carageenan, galactan, arabic gum, tragacanth, pectin, mannan, starch, xanthan gum, dextrin, succinoglucan, curdlan, gelatin, casein, albumin, collagen, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, methylhydroxypropyl cellulose, soluble starch, carboxymethyl starch, methyl starch, propyleneglycol alginate, salts of alginic acid, polyvinylalcohol, polyvinylpyrrolidone, polyvinylmethylether, carboxyvinyl polymers, sodium polyacrylate, polyethyleneglycol, ethylene oxide/propylene oxide copolymers, cationated cellulose, sodium chondroitin sulfate, and sodium hyaluronate. These water-soluble polymers may be used alone or in combination.

[0033] The content of the above water-soluble polymer is preferably 0.001-40 wt. %, particularly 0.01-20 wt. %, on the basis of the total weight of the cosmetic composition. If the content is less than 0.001 wt. %, the emulsion stability of the cosmetic composition tends to decrease during its storage. On the other hand, if it is more than 40 wt. %, it is difficult to obtain fine feeling in use.

[0034] The cosmetic composition of the invention may contain one or more oil substances that can usually be used in cosmetic compositions or pharmaceutical bases, if necessary, such as hydrocarbons, such as liquid paraffin, squalane, vaseline and microcrystalline wax; ester oils, such as isopropylmyristate, cetyl-2-ethylhexalate, glyceryl-tri-2-ethylhexanoate, vitamin C palmitate, vitamin C stearate, vitamin C sulfate and vitamin E acetate; waxes, such as beeswax and spermaceti; vegetable oils, such as avocado oil, almond oil, rice bran oil, olive oil, castor oil, rapeseed oil, saffron oil, corn oil, wheat germ oil, soybean oil, cotton-seed oil, tea-seed oil and jojoba oil; animal oils, such as turtle oil, mink oil and yolk oil; higher alcohols, such as cetyl alcohol, stearyl alcohol, oleyl alcohol, octyldodecanol and behenyl alcohol; higher fatty acids, such as laurylic acid, myristic acid, palmitic acid, stearic acid, oleic acid, linolic acid, linolenic acid, ricinoleic acid and isostearic acid; silicone oils, such as dimethylsilicone, methylphenylsilicone and cyclic silicone; other silicone resins and silicone polymers.

[0035] The cosmetic composition of the invention may contain polyvalent alcohols, such as ethyleneglycol, propyleneglycol, 1,3-butyleneglycol, dipropyleneglycol, glycerin, and polyglycerins such as diglycerin, triglycerin, tetraglycerin, pentaglycerin and hexaglycerin; trimethylolpropane, 1,2,6-hexatriol, glucose, maltose, maltitol, sucrose, fructose, xylitol, mannitol, sorbitol, maltotriose, threitol, sorbitan, starch-decomposed sugar and starch decompoed reducing alcohol, alone or in combination thereof.

[0036] The cosmetic composition of the invention may contain any ingredients customarily used in cosmetics and pharmaceutical bases, such as humectants, active ingredients, fragrances, preservatives, colorants, UV absorbents, astringents, synthetic surfactants, pigments (e.g., kaolin, mica, sericite, talc, yellow iron oxide, red iron oxide and titanium oxide) and water.

[0037] The cosmetic composition of the invention includes massage creams, cleansing creams, skin creams, foundation creams, makeup bases, hair creams, massage jellys, and medicinal jellys, but is not limited to those.

[0038] The invention will be explained further in detail in reference to the following Examples, but shall not be limited to those.

Preparation of trehalose-6-fatty Acid Ester

EXAMPLE 1

Preparation of 6-(10-undecylenyl)-trehalose

[0039] a) One hundred grams of α,α-trehalose were dissolved in 400 ml of dimethylformamide, to which added were 52.4 g of methyl 10-undecylenate and 1.0 g of potassium hydroxide, heated to 100° C. and then stirred for 12 hours. After this reaction solution was cooled, unreacted methyl 10-undecylenate was removed by extracting the solution with 400 ml of hexane three times. The dimethylformamide solution containing the desired substance was concentrated to about 200 ml in vacuum, to which, then, 1,000 ml of acetone was added to precipitate unreacted trehalose which was subsequently filtered out. The precipitate were washed with 100 ml of n-butanol, and the washing liquid was combined with the above filtrate. The filtrate was distilled in vacuum to obtain a yellowish viscous syrup. This viscous syrup was subjected to silica gel chromatography (developing solvent: chloroform/methanol=4/1) so as to remove remaining unreacted substances. A fraction containing the desired substance was distilled in vacuum to obtain 24.3 g of a yellowish viscous syrup.

[0040] b) The resultant syrup was analyzed by 13C-NMR spectroscopy. Signals were confirmed for a carbonyl group at 175.5 ppm, terminal methylene group at 140.11 and 114.73 ppm, and 6- and 6′-positions of trehalose at 64.4 and 62.64 ppm. This indicates the formation of 6-(10-undecylenyl)-trehalose.

EXAMPLE 2

Preparation of 6-lauroyl-trehalose

[0041] The procedures of Example 1a) were repeated with the exception that 62.5 g of methyl laurate was used instead of 52.4 g of methyl 10-undecylenate. 27.3 g of a white solid were obtained.

[0042] The resultant white solid was analyzed by 13C-NMR spectroscopy. Signals were confirmed for a carbonyl group at 175.5 ppm, and 6- and 6′-positions of trehalose at 64.4 and 62.64 ppm. The solid was analyzed by FAB-MS spectrometry with NaI and a peak at 547(M(molecular weight of the parent peak)+23) was confirmed. These indicate the formation of 6-lauroyl-trehalose.

EXAMPLE 3

Preparation of 6-stearoyl-trehalose

[0043] The procedures of Example 1a) were repeated with the exception that 87.1 g of methyl stearate was used instead of 52.4 g of methyl 10-undecylenate. 32.1 g of a white solid was obtained. The resultant white solid was analyzed by FAB-MS spectrometry with NaI and a peak at 631(M(molecular weight of the parent peak)+23) was confirmed. This indicates the formation of 6-stearoyl-trehalose.

EXAMPLE 4

Preparation of trehalose-6-soybean Fatty Acid Ester

[0044] One hundred grams of α,α-trehalose were dissolved in 400 ml of dimethylformamide. To this solution added were 60 g of a methyester of soybean fatty acid and 1.0 g of potassium hydroxide, heated to 100° C., and then stirred for 18 hours. After this reaction solution was cooled, the unreacted methylester of soybean fatty acid was removed by extracting the reaction solution with 400 ml of hexane five times. The dimethylformamide solution containing the desired substance was concentrated to about 200 ml in vacuum, to which 1,500 ml of acetone was added to precipitate unreacted trehalose which was subsequently filtered off. The precipitates were washed with 100 ml of n-butanol, and the washing liquid was combined with the above filtrate. The filtrate was distilled in vacuum to obtain 41.6 g of trehalose-6-soybean fatty acid ester as a yellowish viscous syrup, which contained 6-linoleyl-trehalose as a primary component.

EXAMPLE 5

Preparation of trehalose-6-palm Oil Fatty Acid Ester

[0045] The procedures of Example 4 were repeated with the exception that 60 g of a methylester of palm oil fatty acid were used instead of 60 g of methylester of soybean fatty acid to obtain 34.9 g of trehalose-6-palm oil fatty acid ester as a yellowish viscous syrup, which contained 6-lauroyl-trehalose as a primary component.

[0046] Safety Test

[0047] As a safety test on the above trehalose-6-fatty acid esters, irritation to skin was examinaed in accordance with the following procedures.

[0048] An adhesive plaster for patch test which had been impregnated with 1 ml of a 0.2% solution of the surfactant was put on 20 subjects for 24 hours. Irritaion was evaluated 24 hours after removing the patch. The result was rated by percentage of positive subjects who showed an clear erythema. The results are as shown in Table 1. Sodium laurylphosphate used as a control is a surfactant which is usually used in shampoos, body shampoos and the like.

TABLE 1
Irritation to skin,
positive, %
Sample (0.1% solution)
6-(10-Undecylenyl)-trehalose     0
6-Lauroyl-trehalose              0
6-Stearoyl-trehalose             0
Trehalose-6-soybean fatty acid ester 0
Trehalose-6-palm fatty acid ester 0
Control
(Monosodium lauryl phosphate)    0.5

[0049] As seen from Table 1, the trehalose-6-fatty acid ester of the invention has no irritation to skin and has excellent safety to skin.

EXAMPLES 6-8

Preparation of a Skin Washing Agent

[0050] Liquid skin washing agents having the compositions shown in Table 2 were prepared using the 6-(10-undecylenyl)-trehalose, 6-laurolyl-trehalose, trehalose-6-palm oil fatty acid ester prepared above. These washing agents were used to wash face. Soil was removed completely and the feeling was fine.

TABLE 2
	Example 6	Example 7	Example 8
Component	wt. %	wt. %	wt. %
6-(1-Undecylenyl)-	25.0	—	—
trehalose
6-Lauroyl-trehalose	—	15.0	—
Trehalose-6-palm oil	—	—	25.0
fatty acid ester
Miranol C2M	5.0	5.0	5.0
(Miranol)
Glycerine	10.0	10.0	10.0
Carboxyvinyl polymer	0.6	0.6	0.6
Perfume (citrus	0.4	0.4	0.4
type composition)
Water	59.0	69.0	59.0

EXAMPLES 9 AND 10

Preparation of a Hair Washing Agent

Claims

1. A surfactant comprising at least one trehalose-6-fatty acid ester represented by the following formula:

2. A surfactant comprising at least one trehalose-6-fatty acid esters selected from the group consisting of 6-(10-undecylenyl)-trehalose, 6-lauroyl-trehalose, 6-stearoyl-trehalose, trehalose monoisostearate, trehalose monodocosanate, trehalose monolinolenate, trehalose monocaprate, and trehalose monomyristate.

3. A washing agent comprising the surfactant as claimed in claim 1.

4. The washing agent as claimed in claim 3, wherein the washing agent is a hair or skin washing agent.

5. The washing agent as claimed in claim 3, wherein a content of said trehalose-6-fatty acid ester is 1-50 wt. %, preferably 10-35 wt. %.

6. An emulsion-type cosmetic composition comprising at least one water-soluble polymer selected from trehalose-6-fatty acid esters represented by the following formula:

7. An emulsion-type cosmetic composition comprising at least one trehalose-6-fatty acid ester selected from the group consisting of 6-(10-undecylenyl)-trehalose, 6-lauroyl-trehalose, 6-stearoyl-trehalose, trehalose monoisostearate, trehalose monodocosanate, trehalose monolinolenate, trehalose monocaprate, and trehalose monomyristate, and a water-soluble polymer.

8. The emulsion-type cosmetic composition as claimed in claim 6, wherein said water-soluble polymer is one or more of water-soluble polymers selected from the group consisting of guar gum, roastbean gum, queensseed, carageenan, galactan, arabic gum, tragacanth, pectin, mannan, starch, xanthan gum, dextrin, succinoglucan, curdlan, gelatin, casein, albumin, collagen, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, methylhydroxypropyl cellulose, soluble starch, carboxymethyl starch, methyl starch, propyleneglycol alginate, salts of alginic acid, polyvinylalcohol, polyvinylpyrrolidone, polyvinylmethylether, carboxyvinyl polymers, sodium polyacrylate, polyethyleneglycol, ethylene oxide/propylene oxide copolymers, cationated cellulose, sodium chondroitin sulfate and sodium hyaluronate.

9. The emulsion-type cosmetic composition as claimed in claim 6, wherein a content of said trehalose-6-fatty acid ester is 0.01-20 wt. %, preferably 0.1-10 wt. % and a content of said water-soluble polymer is 0.001-40 wt. %, preferably 0.01-20 wt. %.

10. The emulsion-type cosmetic composition as claimed in claim 6, wherein said emulsion-type cosmetic composition is a massage cream, a cleansing cream, a skin cream, a foundation cream, a makeup base, a hair cream, a massage jelly or a medicinal jelly.

11. A liposome comprising a membrane wall composed of a trehalose fatty acid ester.

12. The liposome as claimed in claim 11, wherein said trehalose fatty acid ester is trehalose difatty acid ester.

13. The liposome as claimed in claim 11, wherein fatty acid of which said trehalose fatty acid ester is constituted is a saturated or unsaturated fatty acid which has 8-22 carbon atoms, preferably 10-18 carbon atoms, and may have a hydroxyl group or other substituents.

14. A liposome comprising a membrane wall mainly composed of at least one trehalose fatty acid ester selected from the group consisting of trehalose dilaurate, trehalose dipalmitate, trehalose diundecylenate, trehalose dimyristate and trehalose distearate.