NAIL CARE COMPOSITION

FIELD OF THE INVENTION

The present invention provides a nail care composition. More particularly, the invention provides aqueous alcohol-free compositions comprising succinic acid or salts thereof, which compositions are useful for improving nail health and appearance.

BACKGROUND OF THE INVENTION

Nails are often subjected to a wide variety of conditions that can cause damage. These include exposure of nails to chemicals such as nail polish removers (e.g. acetone), detergents, and alkaline conditions; the use of glues and adhesives for the attachment of plastic artificial nails over the true natural nail; traumas; and stresses. Moreover, nail health can be affected with aging. Thus, there is the great need in accelerating nail growth and regeneration, and improving nail health and appearance.

Frequently, nail care compositions contain alcohols. Alcohols having about 2-8 carbon atoms (e.g. ethanol, butanol, or isopropanol) are typically used to solubilize components of compositions and enhance absorption of active components of compositions through a skin barrier. However, the disadvantage in the use of alcohols as solvents is that they are irritants for skin and nails. As reported, alcohol is toxic for skin cells and consequently may be harmful to the skin and nails after repeated use. L. Li et al. PNAS 88: 1908-1912 (1991). Therefore, there is a need for a nail care composition, free of alcohols.

U.S.S.R. Pat. No. 957905 (in Bulletin of Inventions, Discoveries, Industrial Prototypes, and Trade Marks [in Russian], No. 34, 1982) teaches an alcohol containing herbal lotion for nail care, the lotion contains 5 to 10% w/w extract of hops, 5 to 10% w/w extract of coltsfoot, 30-40% w/w polyethyleneglycol-40, 0.1 to 0.2% w/w fragrances, 0.1 to 0.2% w/w succinic acid, and ethyl alcohol/water up to 100% w/w. U.S.S.R. Pat. No. 957905 teaches that the goal to use of this composition is to prevent a nail splitting and fragility arising from the use of a previously known lotion for nails comprising alcohol, water, and fragrance. The herbal extracts of the lotion are multicomponent compositions of biologically active organic substances. Extract of coltsfoot (Tussilago farfara) contains substances: mucilage, inulin, tannins, flavonoids, triterpenes, pyrrolizidine alkaloids, bitter glycosides, choline, phytosterols, and tussilagone (sesquiterpene). Extract of hops (Humulus lupulus) contains substances: more of 150 aroma substances; tannins; flavonoids including kaempferol and quercetin mono- and diglycosides; xanthohumol and other chalcones; phenol-carboxylic acids (ferulic and chlorogenic acids); phytoestrogen flavonoids including 8-prenylnaringenin, and structurally related hop flavonoids, 6-prenylnaringenin, 6,8-diprenylnaringenin and 8-geranylnaringenin. Accordingly U.S.S.R. Pat. No. 957905, the effect of the lotion is achieved as a total effect of all active substances which are included in the lotion, whereas the effect of each substance is unknown.

Surprisingly, I found that the desired effect of improving nail health and appearance can be achieved with the use of succinic acid alone without of the active herbal extracts indicated in the U.S.S.R. Pat. No. 957905. Moreover, the effect of succinic acid is achieved in alcohol-free medium that is a significant advantage for consumers, since alcohol-free nail care compositions are safe and

non-toxic as compared to alcohol containing compositions. It is another surprise that the composition containing succinic acid or salts thereof is effective in aqueous alcohol-free medium under topical use, because of low absorption hydrophilic molecules such as succinic acid or salts thereof by skin and nails. It is generally believed that aqueous compositions are not effective for topical use in the absence of promoters of absorption (e.g. alcohols) because of barrier function of skin and nail. Thus, it is unexpectedly that alcohol-free aqueous composition of succinic acid is effective for improvement of nail health and appearance. Accordingly, it is an object of the invention to provide an aqueous alcohol-free nail care composition comprising an effective amount of succinic acid or salt thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an aqueous alcohol-free nail care composition comprising an effective amount of succinic acid or salt thereof.

As used herein, the term "nail" means fingernail or toenail.

As used herein, the term "aqueous" means that water is used as a major carrier or diluent in compositions of the invention. Nonexclusive examples of water suitable for the use in the compositions of the invention are distilled water, deionized water, pharmaceutical water, water with content of heavy water isotopes distinct of the natural such as deuterium depleted water, oxygen- 17 depleted water, and oxygen- 18 depleted water.

As used herein, the term "alcohol-free" means that compositions of the inventions do not contains alcohols having about 2-8 carbon atoms, e.g. ethanol, butanol, or isopropanol.

As used herein, the term "nail care composition" refers to any composition which comprises one or more agents which, when transferred from an article to a nail or skin surrounding the nail, provide a nail benefit. Representative materials are discussed in detail below.

The salts of succinic acid suitable for use herein are those salts prepared by the reaction of succinic acid with safe and non-toxic organic or inorganic base. Examples of such bases include, but are not limited to, sodium hydroxide, potassium hydroxide, ammonium hydroxide, monoethanolamine, diethanolamine and triethanolamine.

In a preferred embodiment, the effective amount of succinic acid or salts thereof is from about 0.21 to about 10 % by weight. In a preferred embodiment, the composition has a pH from about 3.8 to about 7.5.

In a preferred embodiment, the composition of the present invention is a solution.

In a preferred embodiment, the composition of the present invention is a spray.

In another preferred embodiment, the composition of the present invention is an emulsion.

In still another preferred embodiment, the composition of the present invention is a gel.

In a preferred embodiment, the composition of the present invention additionally comprising from about 0.01 to 10% by weight a gelling agent, preferably from about 0.2% to about 5.0% by weight.

Nonexclusive examples of suitable gelling agents include crosslinked carboxylic acid polymers; unneutralized crosslinked carboxylic acid polymers; unneutralized modified crosslinked carboxylic acid polymers; unneutralized crosslinked allyl ether/acrylate copolymers (e.g., Salcare SC90 commercially available from Allied Colloids); crosslinked ethylene/maleic anhydride copolymers; unneutralized crosslinked ethylene/maleic anhydride copolymers (e.g., EMA 81 commercially available from Monsanto); unneutralized crosslinked copolymers of sodium polyacrylate, mineral oil, and PEG-I trideceth-6 (e.g., Salcare SC91 commercially available from Allied Colloids); unneutralized crosslinked copolymers of methyl vinyl ether and maleic anhydride (e.g., Stabileze QM-PVM/MA copolymer commercially available from International Specialty Products); hydrophobically modified nonionic cellulose polymers; hydrophobically modified ethoxylate urethane polymers (e.g., Ucare Polyphobe Series of alkali swellable polymers commercially available from Union Carbide); and combinations thereof. In this context, the term "unneutralized" means that the optional polymer and copolymer gelling agent materials contain unneutralized acid monomers.

Preferred gelling agents include water-soluble unneutralized crosslinked ethylene/maleic anhydride copolymers, water-soluble unneutralized crosslinked carboxylic acid polymers, and water-soluble hydrophobically modified nonionic cellulose polymers. The crosslinked carboxylic acid polymers and hydrophobically modified nonionic cellulose polymers are described in detail hereinbelow.

The carboxylic acid polymers suitable for use herein are those crosslinked compounds containing one or more monomers derived from acrylic acid, substituted acrylic acids, esters of acrylic acid, esters of substituted acrylic acids, corresponding salts thereof, and combinations thereof, wherein the crosslinking agent contains two or more carbon-carbon double bonds and is derived from a polyhydric alcohol. Specific examples of these carboxylic acid polymers include crosslinked carboxylic acid homopolymers and crosslinked carboxylic acid copolymers. Combinations of these two types of polymers are also useful herein. Examples of carboxylic acid polymers include, but are not limited to, acrylic acid/ethyl aery late copolymers and the carboxy vinyl polymers sold by the B. F. Goodrich Company under the trade mark of Carbopol resins such as Carbopol 934, Carbopol 940, Carbopol 950, Carbopol 954, Carbopol 980, Carbopol 951 and Carbopol 981. Neutralizing agents suitable for use in neutralizing acidic group containing hydrophilic gelling agents herein include sodium hydroxide, potassium hydroxide, ammonium hydroxide, monoethanolamine, diethanolamine and triethanolamine.

The hydrophobically modified nonionic cellulose polymers suitable for use herein are those compounds which have been modified to comprise substituted hydrophobic groups to make the polymer less soluble in water. Hence, the nonionic cellulose polymers comprise a water-soluble cellulosic chain (or hydrophilic cellulosic chain) which forms the backbone, wherein the backbone comprise substituted hydrophobic groups. Suitable cellulose ether substrates include any known or otherwise effective water-soluble nonionic cellulose ether. Nonlimiting examples of suitable water-soluble nonionic cellulose ethers include, but are not limited to, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose,

ethyl hydroxyethyl cellulose, and methyl hydroxyethyl cellulose. The amount of the nonionic substituent (e.g., methyl, hydroxyethyl, or hydroxypropyl substituent) is not critical provided that the amount is sufficient to assure that the ether is water-soluble. Optional materials suitable for use in the aqueous alcohol-free nail care composition of the present invention include, but are not limited to, preservatives, surfactants, conditioning polymers, electrolytes, pH adjusting agents, perfume oils, perfume solubilizing agents, protein derivatives, and colouring agents. The concentration of such optional ingredients generally ranges from zero to about 25%, more typically from about 0.05% to about 25%, even more typically from about 0.1% to about 15%, by weight of the composition.

The compositions of the invention are prepared by methods well-known from the art. Such methods include, but are not limited to, mixing the ingredients of the composition and packaging resulted mixtures to suitable packages, e.g. tubes.

Further, the present invention provides a method for nail care, which method comprises a step of applying an effective amount of the composition of the invention to the nail and skin surrounding the nail. For example, 0.5 g of the composition of the invention is applied onto nail plate (e.g. fingernail or toenail) and skin surrounding the nail plate for one time per day or several times per day. The composition may be applied for one day or longer, preferably for 30 days. As used herein, the term "effective amount" means an amount sufficient to provide the desired effect on nail health and appearance. Because of the compositions and methods of the present invention, it is possible to improve nail health and appearance, accelerate nail growth and

regeneration, to make nails more strength and flexible, and eliminate nail problems such as changes in the shape and texture of nails, thickened nails, nail fragility, and brittle nails.

The following examples are presented to demonstrate the invention. The examples are illustrative only and are not intended to limit the scope of the invention in any way.

Example 1

This example shows a representative gel for nail care.

The method for preparing the gel was as follows: the succinic acid, water, carboxyethylcellulose and other components were mixed.

Example 2

This example shows a representative solution for nail care.

Content, % w/w

Succinic acid 1

Sodium hydroxide 0.5

Benzalconium chloride 0.2

EDTA 0.1

Distilled water up to 100

The method for preparing the solution was as follows: the succinic acid, water, and other components were mixed.

Example 3

This example shows a representative emulsion for nail care.

The method for preparing the emulsion was as follows: the succinic acid, almond oil, water, and other components were mixed.

Example 4

This example shows a representative spray for nail care.

The method for preparing the spray was as follows: the succinic acid, water, carboxyethylcellulose and other components were mixed.

Example 5

This example demonstrates the method for nail care. Gel of the example 1 of the invention was used. The 0.5 g of the gel is applied onto fingernail nail plate and skin surrounding the nail plate one time per day for 4 weeks.

Women 38 years old, improved appearance of fingernails and eliminate problems such as splitting nails. Average rate of nail growth increased from 2.2 mm/month to 3.0 mm/month.

Women 43 years old, improved appearance of fingernails and eliminate problems such as splitting nails and nail fragility. Average rate of nail growth increased from 2.1 mm/month to 3.2 mm/month.

Women 23 years old, improved appearance of fingernails and eliminate problems such as splitting nails. Average rate of nail growth increased from 2.6 mm/month to 3.6 mm/month.

Thus, the use of the gel of the invention improved nail health and appearance.