Amphipatic lipid dispersion

Details Amphipatic lipid dispersion Amphipatic lipid dispersion

1999-12-21

2004-12-14

Padmanabhan, Sreeni (Department: 1619)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C424S070100, C424S070210, C424S070310, C424S078030, C514S613000, C514S666000, C514S667000, C514S669000, C514S671000, C514S880000

Reexamination Certificate

active

06830754

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dispersion containing an amphipatic lipid as a dispersoid, a washing-away type cosmetic composition which comprises the amphipatic lipid, has an emulsion-like or pearl-lustrous appearance and has low skin irritation, and another washing-away type cosmetic composition which comprises an amphipatic lipid having a definite average particle size, has an emulsion-like or pearl-lustrous appearance and has low skin irritation.
2. Description of the Related Art
With a view to imparting good appearance to a washing-away type cosmetic composition such as body shampoo, hair shampoo, rinse or the like which is washed away after application to the skin or hair, a dispersion of an emulsifying agent or a pearling agent is conventionally employed for such a composition to impart it an emulsion-like or pearl-lustrous appearance.
Such a washing-away type cosmetic composition contains a surfactant, which sometimes causes dry skin or inflammation. Surfactants not so irritating to the skin are therefore being developed, but development of a novel low-irritating surfactant needs tremendous time and cost.
There are several attempts made to incorporate an amphipatic lipid such as ceramide in a washing-away type cosmetic composition, thereby protecting the skin or hair. Described specifically, reported are a hair cosmetic composition comprising an amide derivative, which is a substance analogous to ceramide (Japanese Patent Application Laid-Open No. 9913/1989); a hair cosmetic composition comprising a glycoceramide and a cationic surfactant (Japanese Patent Application 502660/1994); and a cleansing or treatment composition for hair or skin which comprises an anionic surfactant, amphoteric surfactant, cationic polymer and ceramide or glycoceramide (Japanese Patent Application Laid-Open No. 59443/1996). In the above-described cosmetic compositions, however, only a small amount (about 2 wt. % at the maximum) of a ceramide can be incorporated stably because it is solid at room temperature. On the other hand, if the ceramide is incorporated in the cosmetic composition after it is dissolved in another medium and then emulsified, it does not exhibit sufficient effects.
An object of the present invention is therefore to provide a washing-away type cosmetic composition which can sufficiently exhibit properties of an amphipatic lipid which is in the solid form at room temperature and a dispersion employed for it.
SUMMARY OF THE INVENTION
In one aspect of the present invention, there are thus provided a dispersion comprising, in an aqueous medium, the following components (a) and (b):
(a) 5 to 40 wt. % of, as a dispersoid, an amphipatic lipid having, in the molecule thereof, at least one hydroxy and amide group; and
(b) 2 to 55 wt. % of a surfactant; and a washing-away type cosmetic composition comprising the dispersion.
In another aspect of the present invention, there is also provided a washing-away type cosmetic composition comprising the following components (A) and (B):
(A) 0.01 to 10 wt. % of an amphipatic lipid having an average particle size of 0.5 to 150 &mgr;m and having, in the molecule of the amphipatic lipid, at least one hydroxy and amide group; and
(B) 5 to 95 wt. % of a surfactant.
The dispersion according to the present invention has, as a dispersoid, a solid-particulate amphipatic lipid dispersed in an aqueous medium. It is useful as a component for a washing-away type cosmetic composition having both good emulsion-like or pearl-lustrous appearance and having low skin irritation. The washing-away type cosmetic composition according to the present invention has, as described above, a good emulsion-like or pearl-lustrous appearance and in addition, has low skin irritation because the amount of the surfactant, which is contained in the composition, adsorbed to the skin is small.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The term “an amphipatic lipid which has, in the molecule of thereof, at least one hydroxy and amide group” means a natural ceramide or a synthetic ceramide, or a substance analogous thereto (pseudo-ceramide) available by the synthesis or the like of the natural or synthetic ceramide, which is in the solid form at room temperature (25° C.). Examples of the amphipatic lipid include “Ceramide H03” (trade name, product of Sederma S. A.), Ceramide II (trade name, product of Sederma S. A.), “Questamide H” (trade name, product of Quest International), “Ceramide TIC-001” (trade name, product of Takasago International Corp.), and “Sofcare Ceramide SL-E” (trade name; product of Kao Corp.). The amphipatic lipid is preferred to have a melting point not less than 30° C., more preferably not less than 40° C. in consideration of the stability of the dispersion or the like formed using it. Particularly preferred examples of the ceramide analogous substance available by synthesis include amide derivatives represented by the below-described formula (1) including the above-exemplified Sofcare Ceramide SL-E.
wherein R
1
and R
2
are the same or different and each independently represents a linear or branched, saturated or unsaturated C
7-39
hydrocarbon group which may be substituted by at least one hydroxyl group, and R
3
and R
4
are the same or different and each independently represents a hydrogen atom, a phosphate salt residue, a sulfate salt residue or a saccharide residue, with the proviso that at least one hydroxyl group is contained in the molecule.
In the formula (1), preferred as R
1
are linear or branched, saturated or unsaturated C
9-25
hydrocarbon groups, preferred as R
2
are linear or branched, saturated or unsaturated, C
10-26
hydrocarbon groups and preferred as R
3
or R
4
is a hydrogen atom.
The preparation process of the above-described amide derivative (1) is described specifically in Japanese Patent Application Laid-Open No. 228048/1987, Japanese Patent Application Laid-Open No. 216852/1988 and the like.
As the amphipatic lipid serving as the component (a), those exemplified above can be used either singly or in combination. In the dispersion of the present invention, it is incorporated in an amount of 5 to 40 wt. %, preferably 10 to 30 wt. %.
As the surfactant serving as the component (b) of the dispersion of the present invention, at least one surfactant selected from nonionic surfactants, anionic surfactants, amphoteric surfactants and the like ordinarily employed for cosmetics can be used. Among them, examples of the nonionic surfactant include alkyl polyglycosides, polyoxyalkylene alkyl or alkenyl ethers, polyoxyalkylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyoxyalkylene sorbitol fatty acid esters, polyoxyalkylene glycerin fatty acid esters, polyglycerin fatty acid esters, fatty acid monoglycerides, polyethylene glycol fatty acid esters and fatty acid alkanol amides. Examples of the anionic surfactant include polyoxyalkylene alkyl ether acetic acids or salts thereof, N-acylamino acid salts, polyoxyalkylene alkyl ether sulfate salts, polyoxyalkylene alkyl ether phosphate salts, alkyl phosphate salts, N-acylmethyl taurine salts, alkyl sulfosuccinate salts, polyoxyalkylene alkylsulfosuccinate salts and fatty acid salts. Examples of amphoteric surfactant include alkylaminoacetate betaines, alkylamine oxides, alkylamidopropyl betaines, alkylhydroxysulfobetaines and amidoamino acids (imidazoline-type betaines).
Among them, preferred are nonionic surfactants and polyoxyethylene alkyl ether acetic acids or salts thereof. As the nonionic surfactant, that selected from alkyl polyglycosides, polyoxyalkylene alkyl or alkenyl ethers, polyoxyalkylene sorbitan fatty acid esters and sorbitan fatty acid esters is preferred.
Particularly preferred examples of the nonionic surfactant include alkyl polyglycosides, for example, those in which the alkyl group has 8 to 14 carbon atoms and the condensation degree of glucose is 1 to 2; polyoxyalkylene alkyl or alkenyl ethers, for example, those in which the alkyl or alkenyl group has 8 to 18 carbon atoms and the number of mol

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