Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-01-11
2001-10-30
Kishore, Gollamudi S. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S064000, C514S844000, C514S845000, C514S846000, C514S847000, C514S848000, C514S169000, C514S058000
Reexamination Certificate
active
06309653
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cholesterol ester clathrate and hydrous composition comprising thereof and more particular, relates to the improvement of the stability in hydrating and emulsifying said hydrous composition.
BACKGROUND OF THE INVENTION
Water-holding in skin is an essential factor for keeping the skin in good condition. So, a lot of cosmetics and pharmaceutical preparations which intend the moisturizing are sold in the market, and a lot of humectants are developed. Among of these, a hydrous oily component, e.g., cholesterol ester which is excellent in hydration property and moisturizing property, are used in particularly cosmetics.
However, in case of compounding such a hydrous oily component which was included a lot of water to the cosmetics, it had some problems in stability, since water was separated at a high temperature or temperature change with the passage of time.
Therefore, for keeping the stability of the cosmetics which comprising oil and water, various surfactants has been used in separately or by combining two or more as an emulsifier.
However, ionic surfactants such as alkyl sulfate and higher fatty acid salt has an apprehension of skin irritation, in the case where they are used at high concentration. And in case of using nonionic surfactants such as polyoxyethylene type, it has a problem in solubility such that nonionic surfactants inactivate an antiseptic such as paraben.
In order to solve these problems, it has been developed techniques which uses cyclodextrin or its derivatives as an emulsifier. Namely, Japanese Unexamined Patent Publication No. Sho 58-58139 discloses the technique of emulsification by the specific process that cyclodextrin is used by combination with oil soluble surfactant. Also, Japanese Unexamined Patent Publication No. Sho 63-194726 discloses the technique which is used methylated &bgr;-cyclodextrin as an assistant emulsifier.
However, the problems such as skin irritation has not solved completely, since conventional surfactants are used by combining in these techniques.
In order to solve these problems, as for the example which is obtained the emulsion cosmetics without using any surfactant, the content in Japanese Unexamined Patent Publication No. Hei 3-284611 and U.S. Pat. No. 5,447,920 are listed. Japanese Unexamined Patent Publication No. Hei 3-284611 discloses a cosmetic comprising a hydroxyalkylated cyclodextrin, oil and water. U.S. Pat. No. 5,447,920 discloses a liquid or powdery cosmetic composition which comprises an inclusion product with a hydroxyalkylated cyclodextrin formulated therein. The cosmetic containing the hydroxyalkylated cyclodextrin is described as having improved product characteristics such as useability and stability, and effectively preventing skin roughening.
However, although hydroxyalkylated cyclodextrin demonstrates excellent solubility in hydrophilic solvents such as water, it does not do well in emulsion cosmetics primarily due to hydroxyalkylated cyclodextrin's lack of solubility in nonpolar group such as oils. In other words, a cosmetic containing hydroxyalkylated cyclodextrin displays insufficient water-holding capacity for keeping the moisture if the cosmetics contain substantial amount of oils (e.g., a water-in-oil type of cosmetics).
Thereupon, it has been developed the techniques used a hydroxyalkylated cyclodextrin which is effectively functioned to the composition as a hydrous stabilizer at the same time as an emulsifier.
However, in the water-holding of lipstick, and the like by using these techniques, the water-holding under the severe conditions such that is left for a long period of time and at 90° C. in the preparation time, is still insufficient. It sometimes occurs the aggregation of coloring agent and separate into a water phase and an oil phase or an emulsion phase, it is desired the further improvement.
SUMMARY OF THE INVENTION
In view of the above-mentioned problems of the prior art, the object of the present invention is to provide a cholesterol clathrate which has an excellent stability, safety and high water-holding capacity for keeping the moisture, and has an emulsifying effect in itself, and is to provide a hydrous composition which has an excellent stability, safety and high hydrous capacity for keeping the moisture, and has extremely excellent effect which is not separated even under the severe condition such as high temperature.
As the result of diligent studies of the inventors for attaining the above-mentioned object, it has been found that cholesterol ester clathrate comprising a cholesterol ester included in a hydroxyalkylated cyclodextrin can be functioned as an excellent emulsifier by hydrophilic nature of cyclodextrin and lipophilic nature of cholesterol ester. And, in case of compounding the composition which comprising said cholesterol clathrate and water into the cosmetics and the like, it also has been found that the cosmetics which is excellent in stability and safety, and has the specific property which is rich in water-holding capacity for keeping the moisture can be obtained. Further, it also has been found that the compositions which comprising a hydroxyalkylated cyclodextrin, water, and a hydrous stabilizer has extremely high hydration properties, and the compositions which comprising a hydroxyalkylated cyclodextrin, a cholesterol ester, water, and a clay mineral can be improved the separation stability at high temperature. Accordingly, the present invention has been accomplished.
Namely, in a first aspect of the present invention, there is provided a cholesterol ester clathrate comprising a cholesterol ester which is partly included in a hydroxyalkylated cyclodextrin primarily due to the combined hydrophilic characteristic of hydroxyalkylated cyclodextrin and lipophilic characteristic of cholesterol ester. Said cholesterol ester clathrate forms small, fine emulsion particles which can be uniformly distributed in emulsion cosmetics.
In a second aspect of the present invention, there is provided a hydrous composition comprising a hydroxyalkylated cyclodextrin, a cholesterol ester and water.
In said hydrous composition, preferably, the hydrous composition is composed of water and the cholesterol ester clathrate which is formed by the hydroxyalkylated cyclodextrin and the cholesterol ester, wherein said cholesterol ester is partly included in the hydroxyalkylated cyclodextrin primarily due to the combined hydrophilic characteristic of hydroxyalkylated cyclodextrin and lipophilic characteristic of cholesterol ester. Said cholesterol ester clathrate-containing hydrous composition forms small, fine emulsion particles which can be uniformly distributed in the emulsion cosmetics.
Also, in said hydrous composition, preferably, said composition comprises 5 to 30% by weight of the hydroxyalkylated cyclodextrin, 5 to 80% by weight of the cholesterol ester, and 5 to 60% by weight of water.
Further, in said hydrous composition, preferably, the ratio of the compounding amount of the hydroxyalkylated cyclodextrin and the cholesterol ester is existed within the range represented by the slant line of the triangular diagram shown in FIG.
1
.
In a third aspect of the present invention, there is provided a hydrous composition comprising a hydroxyalkylated cyclodextrin, water, and one or more of a hydrous stabilizer which is/are selected from the group such as alkylated polysiloxane polyethyleneglycol copolymer, alkyl silicated anhydrous silicate, alkyl-modified silicone resin coated powder, glyceryl-modified silicone resin coated powder, dextrin fatty acid ester.
In said hydrous composition, preferably, said hydrous composition further comprising a hydrous oily component.
Also, in said hydrous composition, preferably, said composition comprises 5 to 30% by weight of the hydroxyalkylated cyclodextrin, 5 to 60% by weight of water and 5 to 80% by weight of the hydrous oily component with respect to the whole amount of the hydrous composition.
Further, in said hydrous composition, preferably, the ratio of the compounding amount of the hyd
Hamano Yohei
Ito Kenzo
Matsuda Hajime
Matsumoto Takashi
Minami Takashi
Kishore Gollamudi S.
Shiseido Co. Ltd.
Snider Ronald R.
Snider & Associates
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