Patent Application
20050048011
The present invention relates to a skin preparation for external application and a cosmetic material, characterized in that a tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a salt thereof is blended.
Tocopherols (e.g., α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol) known as vitamin E and derivatives thereof such as tocopherol acetate and tocopherol nicotinate are known to provide efficacy and effect such as activities of antioxidation, vital membrane stabilization, immunoactivation and acceleration of blood circulation and have been long blended in medical preparations, cosmetics, samples and the like.
However, these compounds are oil-soluble and cannot be uniformly dispersed in an aqueous solution or an emulsion. In the case of preparing a medical or cosmetic product in the solubilized or emulsion state, a nonionic surfactant is generally used to enable uniform dispersion, however, some nonionic surfactants are highly irritating or give rise to environmental pollution and therefore, in view of safety, use of the nonionic surfactant is considered undesirable and improvement is demanded in this point.
Furthermore, tocopherols in the simple form are readily oxidized and unstable and therefore, are used as an organic acid ester derivative such as acetate ester, nicotinate ester or succinate ester in many cases. In order to allow the organic acid ester derivative to exert in vivo the physiological activity as tocopherol, the ester bond moiety must be hydrolyzed by an enzyme such as esterase, however, the conversion rate of those derivatives is not sufficiently high and the effect of increasing the concentration in the tissue is low.
It is an object of the present invention to improve the solubility and emulsifiability of tocopherol in skin preparations for external application and provide a composition which undergoes efficient conversion to active tocopherol in the skin tissue.
As a result of extensive investigations to overcome the above-described problems, the present inventors have found that a tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a salt thereof have useful solubility and emulsifiability, and have accomplished the present invention. As used herein, “having a substituent on the N atom” means to have a substituent other than an alkylcarboxylate group on an amino group of the aminoalkylcarboxylate.
The present inventors have also found that the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a salt thereof are efficiently converted to active tocopherol in skin tissue, and have accomplished the present invention.
More specifically, the present invention relates to the following matters.
[1] A skin preparation for external application, comprising a tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a salt thereof.
[2] The skin preparation for external application as described in [1] above, wherein the tocopherol aminoalkylcarboxylate ester is one or more compound selected from α-tocopherol derivatives, β-tocopherol derivatives, γ-tocopherol derivatives and δ-tocopherol derivatives.
[3] The skin preparation for external application as described in [2] above, wherein the tocopherol amino-alkylcarboxylate ester is an α-tocopherol aminoalkylcarboxylate ester or a γ-tocopherol aminoalkylcarboxylate ester.
[4] The skin preparation for external application as described in any one of [1] to [3] above, wherein the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom comprises a compound represented by formula (I):
(wherein R1 and R2 may be the same or different and each represents a lower alkyl group or a hydrogen atom, R3and R4 each represents a hydrogen atom or a methyl group and R represents a branched or linear alkylene group which may have a substituent, provided that R1 and R2 are not a hydrogen atom at the same time).
[5] The skin preparation for external application as described in any one of [1] to [4] above, wherein the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom comprises a compound represented by formula (II):
(wherein R1 and R2 may be the same or different and each represents a lower alkyl group or a hydrogen tom, R3 and R4 each represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 7, provided that R1 and R2 are not a hydrogen atom at the same time).
[6] The skin preparation for external application as described in any one of [1] to [5] above, wherein the aminoalkylcarboxylic acid of the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom is a compound selected from the group consisting of glycine, alanine, β-alanine, valine, leucine, isoleucine, phenylalanine, methionine, cysteine, serine, threonine, tyrosine, thyroxine, histidine, proline, 4-hydroxyproline, aspartic acid, glutamic acid and their N-alkyl derivatives and N,N-dialkyl derivatives.
[7] The skin preparation for external application as described in any one of [1] to [6] above, wherein the aminoalkylcarboxylic acid of the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom has a monoamino group and the monoamino groiup is a monoalkylamino group.
[8] The skin preparation for external application as described in any one of [1] to [7] above, wherein the aminoalkylcarboxylic acid of the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom has a monoamino group and the monoamino group is a dialkylamino group.
[9] The skin preparation for external application as described in [7] above, wherein the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom is an N,N-dimethylglycine ester of tocopherol.
[10] The skin preparation for external application as described in [8] above, wherein the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom is a tocopherol sarcosine ester.
[11] The skin preparation for external application as described in any one of [1] to [10] above, wherein the salt is a hydrohalogenic acid salt.
[12] The skin preparation for external application as described in [11] above, wherein the hydrohalogenic acid is hydrochloric acid.
[13] The skin preparation for external application as described in any one of [1] to [12] above, wherein the content of the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a salt thereof is from 0.01 to 10 mass %.
[14] A cosmetic material comprising the skin preparation for external application described in any one of [1] to [13] above.
The tocopherol aminoalkylcarboxylate ester derivative having a substituent on the N atom and/or a salt thereof for use in the skin preparation for external application of the present invention are described below.
In the present invention, the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom is, for example, a compound represented by the following formula (I) and/or a salt thereof:
(wherein R1 and R2 may be the same or different and each represents a lower alkyl group or a hydrogen atom, R3 and R4 each represents a hydrogen atom or a methyl group and R represents a branched or linear alkylene group which may have a substituent, provided that R1 and R2 are not a hydrogen atom at the same time).
As seen from the formula above, the tocopherol which can be used in the present invention includes α-, β-, γ- and δ-tocopherol derivatives. Among these, preferred are α-tocopherol where R3 and R4 are methyl, and γ-tocopherol where R3 is methyl and R4 is a hydrogen atom.
These tocopherol derivatives have an asymmetric carbon atom at the 2-position of the chromanol ring and therefore, steric isomers such as d form and dl form are present. Needless to say, the present invention includes all of these isomers.
The lower alkyl group in the definition of R1 and R2 of formula (I) is a linear or branched alkyl group having from 1 to 6 carbon atoms and examples thereof include methyl, ethyl, n-propyl, n-butyl, isopropyl, isobutyl, 1-methylpropyl, tert-butyl, n-pentyl, 1-ethylpropyl, isoamyl and n-hexyl. Among these, most preferred are a methyl group and an ethyl group.
Examples of the aminoalkylcarboxylic acids constituting the tocopherol aminoalkylcarboxylate ester for use in the present invention include glycine, alanine, βalanine, valine, leucine, isoleucine, phenylalanine, methionine, cysteine, serine, threonine, tyrosine, thyroxine, histidine, proline, 4-hydroxyproline, aspartic acid, glutamic acid and their N-alkyl derivatives and N,N-dialkyl derivatives.
Among these aminoalkylcarboxylic acids, preferred are dimethylglycine and sarcosine.
These aminoalkylcarboxylic acids may be any of D form, L form and DL form but in view of bioactivity and the like, L form or DL form is preferred.
In the present invention, a salt is preferred and the salt is preferably a hydrohalogenic acid salt, more preferably an HCl salt or an HBr salt. In particular, the HCl salt is advantageous in that the solubility in water increases and due to its powder form, handling is facilitated.
The tocopherol aminoalkylcarboxylate ester derivative having a substituent on the N atom for use in the present invention may be produced by various methods, but a representative method is described below.
The production method is described by referring to the case of R═(CH2)n (wherein n represents an integer of 1 to 7) which is a preferred example.
This compound can be easily obtained by performing an esterification reaction of a tocopherol represented by the following formula (III):
(wherein R3 and R4 each represents a hydrogen atom or a methyl group) and any one of an aminoalkylcarboxylic acid represented by the following formula (IV):
(wherein R1 and R2 may be the same or different and each represents a lower alkyl group or a hydrogen atom, and R represents a branched or linear alkylene group which may have a substituent, provided that R1 and R2 are not a hydrogen atom at the same time), its reactive acid derivative and a salt thereof such as hydrohalogenic acid salt, in a usual manner.
In the case of directly performing the esterification using a free aminoalkylcarboxylic acid, usually, the reaction is preferably performed in the presence of an active esterification reagent (dehydrating agent) such as dicyclohexylcarbodiimide and N,N-disuccinimide oxalate. At this time, the solvent is most preferably pyridine.
If desired, the aminoalkylcarboxylic acid having a substituent on the N atom after the completion of reaction is preferably subjected to a treatment for removing the protective group using an aminoalkylcarboxylic acid in which the amino group is protected, for example, by an N-tert-butoxycarbonyl (BOC) group, a benzyloxycarbonyl group or a 2-nitrobenzenesulfonyl group.
In the method of using a reactive acid derivative, an acid halide, particularly acid chloride is preferably used.
In the case of producing a hydrohalogenic acid salt of a tocopherol aminoalkylcarboxylate ester, the hydrohalogenic acid salt may be produced by once producing an ester form and reacting it with a hydrohalogenic acid (gas phase or solution) in a usual manner, or a hydrohalogenic acid salt of an aminoalkylcarboxylic acid represented by formula (IV) may be previously used as a starting material.
The thus-obtained tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a hydrohalogenic acid salt thereof are excellent in the solubility and emulsifiability as compared with tocopherols in a simple form. Furthermore, when applied as a skin preparation for external application, these are readily hydrolyzed by an esterase or carboxyl esterase in the skin tissue to produce an active free tocopherol.
Therefore, the tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a hydrohalogenic acid salt thereof of the present invention can be used as an active ingredient of skin preparations for external application which are expected to have efficacy and effect such as activities of antioxidation, vital membrane stabilization, immunoactivation and acceleration of blood circulation.
The present invention relates to a skin preparation for external application where a tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a hydrohalogenic acid salt thereof is blended, and the skin preparation for external application of the present invention can be used as a cosmetic material.
The cosmetic material of the present invention includes, in a wide sense, cosmetic materials which come into contact with skin on use, for example, skin milk, skin cream, foundation cream, massage cream, cleansing cream, shaving cream, cleansing foam, skin lotion, lotion, pack, shampoo, rinse, hair restorer, hair nourishment, hair dye, hair conditioner, toothpaste, gargle, permanent waving agent, ointment, bath preparation and body soap. The user may be any user irrespective of sex or age.
In the skin preparation for external application and the cosmetic material of the present invention, ingredients commonly used in skin preparations for external application can be blended within the range of not impairing the effect of the present invention. Examples thereof include chemicals described in Japanese Standards of Cosmetic Ingredients (JSCI), 2nd Edition, Annotation, compiled by Nippon Koteisho Kyokai, issued by Yakuji Nippo, Ltd. (1984), Specifications of Ingredient Other Than Those Listed in JSCI, supervised by Examination Division, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, issued by Yakuji Nippo, Ltd. (1993), Specifications of Ingredient Other Than Those Listed in JSCI, Supplement, supervised by Examination Division, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, issued by Yakuji Nippo, Ltd. (1993), The Comprehensive Licensing Standards of Cosmetics by Category, supervised by Examination Division, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, issued by Yakuji Nippo, Ltd. (1993), and Kesho-hin Genryo Jiten (Handbook of Cosmetic Ingredients), Nikko Chemicals (1991).
The present invention is described in greater detail below by referring to Examples, however, the present invention is not limited to these Examples. In Examples, the amount blended is in the unit of mass %.
Ingredients 1) and 2) to 4) were uniformly dispersed and dissolved and the resulting solution was added to 5) with stirring to obtain the objective lotion.
Ingredients 1) and 2) to 4) were uniformly dispersed and dissolved and the resulting solution was added to 5) with stirring to obtain the objective lotion.
Ingredients 1) to 4) were uniformly dispersed and dissolved and the resulting solution was added to 5) with stirring to obtain the objective lotion.
(Results)
Lotion 1 obtained in Examples 1 and 2 was uniformly dissolved and exhibited good aging stability. On the other hand, in Comparative Example 1, uniform dissolution or dispersion could not be attained and a lotion having excellent solubility could not be obtained.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added to 4) with stirring to obtain the objective lotion.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added to 4) with stirring to obtain the objective lotion.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added to 4) with stirring to obtain the objective lotion.
(Results)
Lotions 4 and 5 obtained in Examples 3 and 4 were uniformly dissolved and exhibited good aging stability. On the other hand, in Comparative Example 2, uniform dissolution or dispersion could not be attained, floating of oil droplets was confirmed and a lotion 6 having excellent solubility could not be obtained.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion.
(Results)
Lotions 7 and 8 obtained in Examples 5 and 6 were uniformly dissolved and exhibited good aging stability. On the other hand, in Comparative Example 3, uniform dissolution or dispersion could not be attained, floating of oil droplets was confirmed and a lotion having excellent solubility could not be obtained.
Ingredient 1) was uniformly dispersed in 2) and the resulting dispersion was added to 3) with stirring to obtain the objective gel preparation 1 for external application.
Ingredient 1) was uniformly dispersed in 2) and the resulting dispersion was added to 3) with stirring to obtain the objective gel preparation 2 for external application.
Ingredient 1) was uniformly dispersed in 2) and the resulting dispersion was added to 3) with stirring to obtain the objective gel preparation 3 for external application.
(Results)
Gel preparations 1 and 2 for external application obtained in Examples 7 and 8 had a translucent gel appearance and exhibited good aging stability. On the other hand, in Comparative Example 4, gel was not formed.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 5) with stirring to obtain the objective milky lotion 1.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 5) with stirring to obtain the objective milky lotion 2.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 5) with stirring to obtain the objective milky lotion 3.
(Results)
Milky lotions 1 and 2 obtained in Examples 9 and 10 gave good feeling on use and exhibited good aging stability. On the other hand, in Comparative Example 5, emulsion was not formed and a milky lotion could not be obtained.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 4.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 5.
Any one of 1) to 3) was uniformly dispersed and dissolved in 5) to 6) and thereto, 9) in which 8) was previously dissolved was added with stirring to obtain the objective milky lotion 6.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 7.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the objective milky lotion 8.
(Results)
Milky lotions 4 to 7 obtained in Examples 11 to 14 gave good feeling on use and exhibited good aging stability. On the other hand, in Comparative Example 6, emulsion was not formed and a milky lotion could not be obtained.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 9.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 10.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 6) in which 5) was previously dissolved with stirring to obtain the objective milky lotion 11.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 12.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the objective milky lotion 13.
(Results)
Milky lotions 9 to 12 obtained in Examples 15 to 18 gave good feeling on use and exhibited good aging stability. On the other hand, in the milky lotion 13 obtained in Comparative Example 7, phase separation was observed after a few days and good aging stability could not be obtained.
Evaluation of Skin Penetrability
(Method)
In each of φ+35 mm plastic Petri dishes, 1 ml of a Dulbecco's MEM medium containing 1), 2), 3) or 4) was placed and a nylon mesh and a lens paper were sequentially laid thereon. On the lens paper, a skin removed from the back of a hairless mouse was placed such that the epidermis came into contact with the lens paper. At this time, the dermis side was covered with a parafilm and thereby prevented from drying.
After the passage of 4 hours at 37° C., the skin was washed with a phosphoric acid buffer solution and homogenized. Then, the amount of α-tocopherol in the skin was measured. The determination of α-tocopherol was performed by high performance liquid chromatography.
The conditions for measurement by high performance liquid chromatography were as follows.
The skin treated with α-tocopherol dimethylglycine ester hydrochloride or α-tocopherol sarcosine ester hydrochloride had significant increase of the α-tocopherol amount.
Conversion to α-Tocopherol in Keratinocyte of Human Epidermis
(Method)
Commercially available keratinocytes of normal human epidermis were cultured in the medium attached. The cells were harvested and spalled by freeze-thawing method. To this cell spall solution, 1), 2), 3) or 4) was added to have a final concentration of 1 mM. The resulting solution was kept at 37° C. for 2 hours and then the amount of α-tocopherol liberated in the reaction solution was measured. The determination of α-tocopherol was performed by high performance liquid chromatography.
The conditions for measurement by high performance liquid chromatography were as follows.
The cell spall solution in which α-tocopherol dimethylglycine ester hydrochloride or α-tocopherol sarcosine ester hydrochloride was added, had significant increase of the α-tocopherol amount.
Ingredients 1) and 2) to 4) were uniformly dispersed and dissolved and the resulting solution was added to 5) with stirring to obtain the objective lotion 10.
Ingredients 1) and 2) to 4) were uniformly dispersed and dissolved and the resulting solution was added to 5) with stirring to obtain the objective lotion 11.
Ingredients 1) and 2) to 4) were uniformly dispersed and dissolved and the resulting solution was added to 5) with stirring to obtain the objective lotion 12.
(Results)
Lotions 10 and 11 obtained in Examples 21 and 22 was uniformly dissolved and exhibited good aging stability. On the other hand, in Comparative Example 10, uniform dissolution or dispersion could not be attained and a lotion having excellent solubility could not be obtained.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added to 4) with stirring to obtain the objective lotion 13.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added to 4) with stirring to obtain the objective lotion 14.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added to 4) with stirring to obtain the objective lotion 15.
(Results)
Lotions 13 and 14 obtained in Examples 23 and 24 were uniformly dissolved and exhibited good aging stability. On the other hand, in Comparative Example 11, uniform dissolution or dispersion could not be attained, floating of oil droplets was confirmed and a lotion having excellent solubility could not be obtained.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion 16.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion 17.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion 18.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion 19.
Ingredients 1), 2) and 3) were uniformly dispersed and dissolved and the resulting solution was added with stirring to 5) in which 4) was previously dissolved, to obtain the objective lotion 20.
(Results)
Lotions 16 to 19 obtained in Examples 25 to 28 were uniformly dissolved and exhibited good aging stability. On the other hand, in Comparative Example 12, uniform dissolution or dispersion could not be attained, floating of oil droplets was confirmed and a lotion having excellent solubility could not be obtained.
Ingredient 1) was uniformly dispersed in 2) and the resulting dispersion was added to 3) with stirring to obtain the objective gel preparation 4 for external application.
Ingredient 1) was uniformly dispersed in 2) and the resulting dispersion was added to 3) with stirring to obtain the objective gel preparation 5 for external application.
Ingredient 1) was uniformly dispersed in 2) and the resulting dispersion was added to 3) with stirring to obtain the objective gel preparation for external application.
(Results)
Gel preparations 4 and 5 for external application obtained in Examples 29 and 30 had a translucent gel appearance and exhibited good aging stability. On the other hand, in Comparative Example 13, gel was not formed.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 5) with stirring to obtain the objective milky lotion 14.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 5) was added with stirring to obtain the objective milky lotion 15.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added to 5) was added with stirring to obtain the objective milky lotion 16.
(Results)
Milky lotions 14 and 15 obtained in Examples 31 and 32 gave good feeling on use and exhibited good aging stability. On the other hand, in Comparative Example 14, emulsion was not formed and a milky lotion could not be obtained.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 17.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 18.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 19.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 20.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and this was added, with stirring, to 6) in which 5) was previously dissolved to obtain the objective milky lotion 21.
(Results)
Milky lotions 17 to 20 obtained in Examples 33 to 36 gave good feeling on use and exhibited good aging stability. On the other hand, in Comparative Example 15, emulsion was not formed and a milky lotion could not be obtained.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the objective milky lotion 22.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the objective milky lotion 23.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the objective milky lotion 24.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the objective milky lotion 25.
Ingredient 1) was uniformly dispersed and dissolved in 2) to 4) and the resulting solution was added with stirring to 6) in which 5) was previously dissolved, to obtain the milky lotion 26.
(Results)
Milky lotions 22 to 25 obtained in Examples 37 to 40 gave good feeling on use and exhibited good aging stability. On the other hand, in the milky lotion obtained in Comparative Example 16, phase separation was observed after a few days and good aging stability could not be obtained.
Evaluation of Skin Penetrability
(Method)
In each of φ35 mm plastic Petri dishes, 1 ml of a Dulbecco's MEM medium containing 1), 2) or 3) was placed and a nylon mesh and a lens paper were sequentially laid thereon. On the lens paper, a skin removed from the back of a hairless mouse was placed such that the epidermis came into contact with the lens paper. At this time, the dermis side was covered with a parafilm and thereby prevented from drying.
After the passage of 4 hours at 37° C., the skin was washed with a phosphoric acid buffer solution and homogenized. Then, the amount of γ-tocopherol in the skin was measured. The determination of γ-tocopherol was performed by high performance liquid chromatography.
The conditions for measurement by high performance liquid chromatography were as follows.
The skin treated with γ-tocopherol dimethylglycine ester hydrochloride or γ-tocopherol sarcosine ester hydrochloride had significant increase of the γ-tocopherol amount.
Conversion to γ-Tocopherol in Keratinocyte of Human Epidermis
(Method)
Commercially available keratinocytes of normal human epidermis were cultured in the medium attached. The cells were harvested and spalled by freeze-thawing method. To this cell spall solution, 1), 2) or 3) was added to have a final concentration of 1 mM. The resulting solution was kept at 37° C. for 2 hours and then the amount of γ-tocopherol liberated in the reaction solution was measured. The determination of γ-tocopherol was performed by high performance liquid chromatography.
The conditions for measurement by high performance liquid chromatography were as follows.
The cell spall solution in which γ-tocopherol dimethylglycine ester hydrochloride or γ-tocopherol sarcosine ester hydrochloride was added, had significant increase of the γ-tocopherol amount.
Permeability of Three Dimensional Model of Human Skin Tissue and Tocopherol Conversion
40 μL of a 1% solution of the below test substances 1) to 7) dissolved or dispersed in Dulbecco's PBS (−) were applied onto the tissue surface of a three dimensional model of human skin tissue (TESTSKIN™ LSD-d, Toyobo K. K.) and were cultured at 37° C. under 5% CO2 for 6 hours. After this, the solutions of the test substances were removed by aspiration and sampling was carried out.
The sample model skin was washed with Dulbecco's PBS (−) and the tissue surfaces onto which the test substances were applied were punched out with a φ 6 mm punch, and were homogenated in a HEPES buffer solution (pH 7.2), and quantitative analysis of the α-tocopherol and γ-tocopherol were carried out by high speed liquid chromatography. Quantitative analysis of the amount of protein in the model skin was carried out according to the Lowry method.
The high speed liquid chromatography measurement conditions were as described below.
The amounts of α-tocopherol and γ-tocopherol for the samples processed with each test substance were as follows.
For the processes carried out using α-tocopherol dimethylglycine ester hydrochloride, α-tocopherol sarcosine ester hydrochloride, γ-tocopherol dimethylglycine ester hydrochloride, and γ-tocopherol sarcosine ester hydrochloride, the level of tocopherol was significantly increased.
The skin preparation for external application of the present invention comprising a tocopherol aminoalkylcarboxylate ester having a substituent on the N atom and/or a salt thereof is favored with improved solubility and emulsifiability of tocopherol and efficient conversion to active tocopherol in skin tissue and therefore, can be applied over a wide range such as skin preparations for external application and cosmetic materials.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2001-331581 | Oct 2001 | JP | national |
| 60359334 | Feb 2002 | US | national |
| 2002-110107 | Apr 2002 | JP | national |
| 60373579 | Apr 2002 | US | national |
This application is an application filed under 35 U.S.C. 111(a) claiming pursuant to 35 U.S.C. 119 (e) of the filing date of Provisional Application 60/359,334 on Feb. 26, 2002, Provisional Application 60/373,579 on Apr. 19, 2002, pursuant to 35 U.S.C. 111(b).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP02/11152 | 10/28/2002 | WO |
