Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2002-02-19
2003-05-20
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S060000, C424S400000, C424S401000
Reexamination Certificate
active
06565834
ABSTRACT:
The invention relates to a composition capable of reducing oil and grease secretion from skin. It is particularly found useful to have the formulation in a vanishing cream base.
Sebum is produced by the disruption of the cells in which it is formed (in the basal layer of the gland). This function may be termed holocrine secretion. Being liquid inside the duct and hair follicle, sebum diffuses up and down the follicular canal. Upon reaching the skin surface it combines with epithelial lipids (from the keratinizing cells) and emulsifies as an oily liquid with water from the sweat glands. In this way a semi-solid, slightly acidic, hydrophilic film is formed on the skin and in the hair follicles.
The quantity of sebum produced is directly proportional to the size of the gland. The rate of sebum production varies in different individuals, some having oilier skins than others. Male sex hormones increase sebum production. Increased temperature also increases production.
The literature is replete with methods and compositions for eliminating, treating or at least reducing the levels of skin oils and greasiness. None have proved totally satisfactory.
WO9823257 (Unilever) discloses a cosmetic method for reducing or inhibiting oil and grease generation from human skin by applying a C11-C30 alkyl or alkenyl ester of salicylic acid. WO9717060 (Procter and Gamble) discloses a topical composition comprising niacinamide and other actives for regulating the shiny or oily appearance of the skin.
The cosmetically acceptable carriers are one or more compatible solid or liquid fillers or diluents, and these are chosen based on the product type. Cosmetic compositions to deliver different benefit agents are prepared using different emulsifying systems and vehicles. Vanishing cream base, which generally comprises fatty acids and alkali metal soaps, is one of the preferred forms of such a cosmetically acceptable vehicle as this gives a desirable matt feel to the skin.
It is an advantage of the present invention to be able to provide an improved method for controlling, reducing or inhibiting oiliness and greasiness in human skin. It has been found that when a combination of niacinamide and C
11
-C
30
alkyl or alkenyl ester of salicylic acid are formulated in a specific carrier such as a vanishing cream base there is a synergistic benefit on oil control of the skin.
According to a first aspect of the invention, there is provided a cosmetic composition for reducing or inhibiting oiliness and greasiness in human skin which involves topical application to the skin of a safe and effective amount of salicylate ester and niacinamide in a vanishing cream base as the carrier, wherein the salicylate ester has the formula C
6
H
4
COOR0H wherein R is a C
11
-C
30
alkyl or alkenyl radical.
Thus according to an aspect the invention of the cosmetic composition comprises:
a.
5 to 25% by weight C
12
-C
20
fatty acids;
b.
0.1 to 10% by weight surfactant;
c.
0.01 to 10% niacinamide;
d.
0.01 to 10% C
11
-C
30
alkyl or alkenyl ester of salicylic acid;
e.
optionally other skin lightening agent(s).
According to a preferred aspect of the invention the cosmetic composition comprises:
a.
5-25% by weight C
12
-C
20
fatty acids;
b.
0.1-10% by weight fatty acid soap;
c.
0.01 to 10% niacinamide;
d.
0.01-10% tridecyl (C
13
) salicylic acid;
e.
optionally other skin lightening agent(s).
Now it has been found that oil and grease production by skin may be controlled, reduced and/or inhibited through application of a cosmetic composition including as active a derivative of salicylic acid having formula C
6
H
4
COOROH wherein R is a C
11
-C
30
alkyl or alkenyl radical in combination with niacinamide in a vanishing cream base. The composition essentially contains fatty acid as the main oil phase which is emulsified by surfactants. The surfactant may be anionic, nonionic, cationic or amphoteric and is preferably fatty acid soap.
By the term “skin” is meant to include all areas containing sebaceous glands, such as face, back, chest and scalp.
The salicylate esters will generally be amounts in the range from 0.01 to 10%, preferably from 0.1 to 5%, optimally from 0.1 to 3% by weight of the composition. Niacinamide will generally be in the range 0.01 to 10% and more preferably 0.1-3%. The two are preferably formulated in a vanishing cream base comprising 5-25% by weight C
12
-C
20
fatty acids and 0.1-10% by weight of a surfactant, which is preferably fatty acid soap.
The surfactant may be selected from anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a C
10
-C
20
fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C
2
-C
10
alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di- fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di- C
8
-C
20
fatty acids; block copolymers (ethylene oxide/propylene oxide); and polyoxyethylene sorbitan, as well as combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g. methyl gluconamides) are also suitable nonionic surfactants.
Preferred anionic surfactants are soap, and others such as alkyl ether sulfate and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, C
8
-C
20
acyl isethionates, acyl glutamates, C
8
-C
20
alkyl ether phosphates and combinations thereof.
Further examples of suitable surfactant compounds may be chosen from the commonly used actives described in “Surfactants in Cosmetics”, II Edition, 1997, Eds. M. M. Rieger and L. D. Rhein, Marcel Dekker Inc. New York.
Emollient materials may also serve as pharmaceutically physiologically and/or cosmetically acceptable carriers. These may be in the form of silicone oils and synthetic esters. Amounts of the emollients may range anywhere from 0.1 to 50%, preferably between 1 and 20% by weight.
Silicone oils may be divided into the volatile and non-volatile variety. The term “volatile” as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethyl- siloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms. Linear volatile silicone materials generally have viscosities less than 5 centistokes at 25° C. while cyclic materials typically have viscosities of less than 10 centistokes.
Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from 5 to 100,000 centistokes at 25° C. Among the preferred non-volatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from 10 to 400 centistokes at 25° C.
Among the suitable ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters.
(4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and arachidyl behenate.
(5) S
Kini Mridula
Rajwade Lalitagauri
Sona Pushker
Surianarayanan Ramesh
Dodson Shelley A.
Plotkin Ellen
Unilever Home & Personal Care USA , division of Conopco, Inc.
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