Field of the invention

The present invention relates to an improved cosmetic composition suitable for skin care application and a process for the preparation of the said composition. The present invention particularly relates to low pH cosmetic composition which is skin friendly and preferably having pH below 6.0. The composition of the present invention comprises emulsifier(s) derived from N-Acyl acidic amino acid, sugar based emulsifier(s) and high molecular weight fatty acid which is compatible to incorporate skin benefiting agents including acidic skin care agents in association with cosmetically acceptable vehicle in skin care formulation and is also stable.

The composition of the present invention is suitable for topical application to skin and which can deliver skin benefit properties such as, but not limited to, anti-aging, wrinkle-reducing, skin whitening, anti-acne, wound healing, sebum reduction, skin nutritional, photo protection, moisturisation and the like

As used herein, the term "cosmetic composition" is intended to describe compositions for topical application to skin. As used herein, "topical" means applied to the surface of the skin. The compositions of the subject invention are administered topically to a biological subject, i.e., by the direct laying on or spreading of the composition on the skin of the subject.

Background of the invention

There is an increasing demand nowadays for skin compatible cosmetic preparations with lower irritancy and sensorial properties equivalent to vanishing cream. The traditionally used vanishing cream contains high levels of fatty acids and alkaline metal soap as an emulsifier which is important to physical stability of the product. However the presence of soap increases the pH value of the product and the cosmetic composition becomes alkaline. Such a product is stable only under alkaline condition.

The surfaces of human skin are normally having pH of 4.0- 6.0. Upon contact with an alkaline substance, the skin secretes acidic substances to restore the normal pH value. This process results in disturbance to the skin physiology and causes secretions such as sebum, sweat etc resulting in discomfort. Accordingly , it is desired that cosmetics such as creams, lotions etc. when applied to the skins are conditioned to weakly acidic or neutral pH while maintaining the characteristics of the traditional vanishing cream. On incorporation of acidic skin benefit agent, the anionic fatty soap emulsifier gets split to fatty acid and alkaline metal salt of acidic skin benefit agents and resulting in drop in pH and thereby causes physical instability. The lack of physical stability of the fatty acid soap emulsified vanishing creams at low pH is a disadvantage that restricts the use of valuable acidic skin benefit actives, such as alpha and / or beta hydroxy carboxylic acids.
A wide verity of acidic skin benefit compounds such as hydroxy acids are formulated into vanishing cream, stabilized with anionic and non ionic emulsifier (s).

Prior art

US Patent. No. 6979452 B2 (Yan Zhou, et al) discloses low pH, high skin friction cosmetic cream containing solid asymmetric particles which includes fatty acid crystals, mica, talc and clay , an anionic emulsifier and a cosmetically acceptable vehicle . It describes extensively the use of ethoxylated non-ionic surfactants such as ethoxylated alkyl ether, ethoxylated sorbitan esters, ethoxylated fatty alcohols and ethoxylated fatty acid esters. The anionic emulsifiers are selected from sulphates, sulphonates, succinates, isothionates, sarcosinates, and taurates. Sodium cetostearyl sulphate has been used as an exemplary anionic emulsifier as evidenced by its use in all experiments covered in the patent. The acidic skin benefit agents are selected from alpha & beta hydroxyl acids some namely glycolic, lactic and salicylic.

Although these compositions are said to be stable at low pH and giving desired sensory properties, the irritancy level of emulsifiers has not been realized.

It is very common that sulphate & sulphonate based anionic emulsifiers exhibit an irritancy potential as mentioned in US pat no 4,536,519 by Suzuki et al. An emulsified system prepared with a higher alcohol sulfate has a defect of giving excessively keen irritations to the skins as well as being unstable due to gradual hydrolysis of the alcohol sulfate with time. Use of ethoxylated (PEG) derived non ionic emulsifiers also increase the risk of skin irritation. The cumulative irritancy of these emulsifiers and skin benefit agents are often discouraged from using these composition and more particularly those having sensitive skin. Therefore, it is a challenge in making composition that is not only stable at low pH with desired sensory characteristics but also reduces the risk of skin irritations due to the used emulsifiers.

U.S. Pat. No. 6,153,177 (Bartolone et al.) discloses vanishing creams containing acid soap, which includes alkali or alkaline earth metal salts of alpha-hydroxy acid (AHA) to achieve skin lightening benefit. Care was taken not to include the acid form of AHA into the formulation in order to avoid destabilization of the emulsion by the acid for the reasons stated above. Use of completely neutralized acidic carboxylic group by inorganic bases render these compounds inactive and result of these composition not giving benefit of hydroxy acids. Therefore, it was clear that further work was necessary in order to enhance the performance of vanishing creams in delivery of acidic skin benefit agent.

WO 01/70188(Dwiwahyu et al) discloses low pH (1-6.5) non-acid soap vanishing cream with enhanced stability and skin benefit properties. A C8-C22 fatty acid substituted saccharide is used to stabilize the low pH stearic acid based vanishing cream. These compositions lack the sensory characteristics due to the lack of proper emulsifier systems

U.S. Pat. No. 4,536,519 (Suzuki, et al) discloses emulsified cosmetic compositions, including vanishing cream, using a neutralized phosphoric acid ester as an emulsifier, a nonionic surfactant with HLB<6 and fatty components including natural oil, wax, fat, and fatty acid or alcohol at pH of neutral to weakly acidic. These compositions lack the sensory characteristics of traditional vanishing creams due to the lack of a proper emulsifier system and also have not realized the direct expose of hydroxy acids tend to irritant to skin

Struewing in US patent 5654341 discloses a low pH skin treatment composition containing cationic surfactant, fatty acid and oleaginous hydrocarbon component in oil-in-water emulsion. It further describes addition of fatty acid to the cationic surfactant to form a complex which prevents the cationic surfactant from irritating the skin, and at the same time reduces the pH of the composition but does not provide any vanishing cream like sensory characteristics due to the complete reaction of fatty acid with cationic surfactant.

The world wide trend of cosmetic development strongly suggests that consumers not only want cosmetic products with general functions like protection skin from UV light and beauty culture, but also one which is safe to their skin. Therefore there is a need in the present day environment for a cosmetic composition for a composition such as vanishing cream having skin balance pH, low skin irritation and desired sensory properties.

Objectives of the present invention

Therefore the main objective of the present invention is to provide an improved cosmetic composition suitable for skin care application

Another objective of the present invention is to provide an improved cosmetic composition suitable for skin care application which is pH compatible and having sensory properties like those of vanishing cream.

Yet another objective of the present invention is to provide an improved cosmetic composition suitable for skin care application containing high molecular weight fatty acid selected from C 12- C 22 fatty acids to attain the desired sensory feel like that of vanishing creams

Still another objective of the present invention is to provide an improved cosmetic composition suitable for skin care application containing emulsifiers which are stable at low pH chosen from the group of N-acyl acidic amino acids and those derived there from and sugar-based emulsifiers preferably sucrose esters and alkylpoly glucosides

Yet another object of the present invention is to provide an improved cosmetic composition suitable for skin care application having a low pH, preferably <6.0.

Yet another object of the present invention is to provide an improved cosmetic composition that further aid in incorporating skin benefiting agents including acidic skin care agents and yet be stable at low pH

Still another objective of the present invention is to provide a process for the preparation of the improved cosmetic composition suitable for skin care application

The above mentioned objectives have been achieved by our undertaking sustained R & D by developing a cosmetic composition containing a proper emulsifier system consisting of a combination of emulsifiers derived from both N-Acyl acidic amino acid and sugar based emulsifiers, high molecular weight fatty acid(s) selected from , CI2 -C22 fatty acid or their combinations. This composition is having properties similar to vanishing cream and is comfortable to human skin and aid in incorporating skin benefiting ingredients including acidic skin care agents, the composition being also stable.

Summary of the invention

Accordingly, the present invention provides an improved cosmetic composition suitable for skin application which comprises:

a) at least about 4% weight of the composition of high molecular weight fatty acid selected from , C12 -C22 fatty acid or their combinations

b) at least one emulsifier derived from N- Acyl acidic amino acid (s)

c) at least one sugar based emulsifier and

d) a cosmetically acceptable vehicle comprising deionized water, chelating agents, and emollients.

In a preferred embodiment of the invention the C12 - C22 fatty acid used in the composition may be selected from C14 to C 18 fatty acids , more preferably, stearic and / or palmitic acid or their combination

In another embodiment of the invention the emulsifier derived from N- Acyl acidic amino acid (s) used in the composition may be preferably alkali or alkaline earth metal salts of N-acyl acidic amino acids or more preferably alkali metal salts of acylglutamic acid and/ or acylaspartic acid and the like

In yet another embodiment of the invention the sugar based emulsifier used in the composition may be preferably glucosides. Preferably selected from sucrose esters and/or alkylpoly glucosides

In yet another preferred embodiment of the invention the pH of the composition may be less than 6.0.

In another embodiment of the invention the composition may contain skin benefiting agents including acidic skin care agents which includes but not limited to alpha and / or beta hydroxy acids, sunscreen agents, anti-ageing agents.

In yet another embodiment of the invention the composition may contain preservatives, essential oils , perfume, rheology modifiers, and anti oxidants.

According to another embodiment of the present invention there is provided a process for the preparation of an improved cosmetic composition suitable for skin application which comprises:

(i) Mixing sugar based emulsifier along with at least 4 % by weight of the composition , a high molecular weight fatty acid selected from C12 - C 22 fatty acids, emollients and heating the mixture to a temperature in the range of 70°C to 80°C .

(ii) Mixing at least one emulsifier selected from the group N- Acyl acidic amino acid (s), in deionized water along with chelating agents, and heating the mixture to a temperature in the range of 70°C to 80°C

(iii) Adding the mixture obtained in step (i) to the mixture obtained in Step (ii ) with high speed mixing followed by homogenization and

(iv) cooling the resulting product to room temperature.

In a preferred embodiment the temperature used in step (i) may preferably be 78°C.

In another embodiment the temperature used in step (ii) may preferably 75°C.

In another preferred embodiment of the invention rheology modifiers may be added in step (ii).

In another preferred embodiment the chelating agents and rheology modifiers may be added, individually or combined together.

Similarly in another preferred embodiment of the invention the perfume and anti oxidant may be added in step (iv) individually or combined together, after cooling the resulting product to room temperature

In another preferred embodiment of the invention appropriate skin benefit agents may be added in step (iv) after cooling the resulting product to room temperature and the mixing is continued till the resulting composition is homogeneous.

The pH of the composition of this invention is less than 6.0, preferably between 3 to 6 and most preferably from about 4 to 5.7.

Detailed description of the invention

High Molecular weight fatty acid:

Acidic ingredients are more specifically high molecular weight fatty acids. Fatty acids are obtained by hydrolysis of vegetable oils and animal fats. In their pure state they are solid, crystalline, opaque white material. Stearic acid provides an oil phase of the emulsion which melts above body temperature and crystallizes in a suitable form so as to be invisible in use and give a dry, draggy, non-greasy; non-shiny film and also matte finish feel to skin; spread easily on the skin; absorb or "vanish" rapidly into the skin.
The preferred high molecular weight fatty acid (s) used in the composition is selected from C12 -C22 fatty acid preferably C14 to C 18. The preferred fatty acids used are stearic acid, palmitic acid or their combinations. This high molecular weight fatty acid used is preferably stearic - palmitic mixture. More preferably the ratio being roughly 55: 45 Palmitic to stearic on a weight basis since they are commercially available and most inexpensive and aesthetically acceptable carrier.
The composition of the present invention contain at least 4% of the acidic ingredients, preferably 8% to 22%, more preferably 10% to 20%, by weight of the composition to attain vanishing cream like sensory properties.
N-Acyl acidic amino acid derived emulsifier (s):
Emulsifiers are advantageously chosen from the group of N-acyl acidic amino acids and alkali or alkaline earth metal salts of N-acyl acidic amino acids such as, but not limited to, mono/disodium acyl glutmates, mono/disodium caprylic acid/capric acid glutamate, di-TEA palmitoyl aspartate and the like.
For the purpose of the present invention, it is particularly advantageous to use salts of N- acyl acidic amino acids, due to its stability at low pH. Mono/ dibasic salts, of acylglutamic acid in particular sodium acyl glutamates, which are characterized by the following structures:

R is an alkyl and/or alkenyl, aralkyl, containing 6 to 30 carbon atoms,
M is an alkali metal and/or alkaline earth metal, ammonium, alkylammonium, alkanolammonium or glucammonium.
Preferred anionic emulsifiers include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts)
Of the mono/disodium acyl glutamates in turn, mono/disodium cocoyl glutamate, mono/disodium lauroyl glutamate, mono/disodium myristoyl glutamate, mono/disodium stearoyl glutamate,mono/disodium tallowyl glutamate and mono/didisodium capryloyl glutamate have proven particularly advantageous.
Amounts of anionic emulsifier in the composition are in the range of about 0.1 to about 10% by weight, preferably about 0.25% to about 3%, more preferably about 0.5% to about 1.5%.
Sugar Based Emulsifier(s):
Selected sugar base emulsifiers preferably, solid and more preferably have a mixture of mono fatty alkyl group containing 8 to 22 carbon atoms with sugar moiety, ither alone or in combination: In the present invention the sugar-based emulsifiers used is preferably sucrose esters and/or alkylpoly glucosides .
The head moiety of sugar-based emulsifiers contains a number of free hydroxyl groups, which bind water and could provide additional skin moisturisation, having an impact on the stratum corneum pliability and on the penetration potential actives leading to a significantly better skin hydration and barrier improving potential of creams based on an alkylpolyglucoside emulsifier (Cetearyl glucoside&Cetearyl alcohol) compared to commonly used PEG emulsifiers [Savic, S., Tamburic, S., Savic, M., Cekic, N., Milic, J., Vuleta, G., Vehicle-controlled effects of urea on normal and SLS-irritated skin, Int. J. Pharm. 271 (2004) 269-280.]
These emulsifiers are also known as promoters of liquid crystal mesophases, which could provide additional stabilisation of the system and the formation of specific colloidal structure with high percentage of interlamelarlly fixed or "depot" water [ Savic, S., Vuleta, G., Daniels, R., Mtiller-Goymann, CC., Colloidal microstructure of binary systems and model creams stabilized with an alkylpolyglucoside non-ionic emulsifier, Colloid Polymer Sci. 283 (2005) 439-451].
Sugar emulsifiers used in this invention may be chosen from those commercially from SEPPIC Inc. under the trade name MONTANOV L(C 14-22 Alcohol/C 12-20 Alkyl glucoside),MONTANOV S(Cocoglucoside/Coconut alcohol), MONTANOV WO 18 (Isostearyl alcohol/Isostearyl glucoside), MONTANOV 14(Myristyl alcohol/Myristyl glucoside), MONTANOV 68(Cetearyl alcohol/Cetearyl glucoside), MONTANOV 82 (Cetearyl alcohol/Cocoglucoside), MONTANOV 202 (Arachidyl alcohol/Behenyl alcohol/Arachidyl glucoside). Tagocare CG 90 (Cetearyl glucoside). Sugar emulsifiers available commercially from Croda under the trade name Crodesta F-10(Sucrose distearate), Crodaderm B(Sucrose Polybehenate), Crodaderm S(Sucrose Polysoyate), Crodesta F-160(Sucrose stearate), Crodesta
F-110 (Sucrose stearate (and)Sucrose distearate. Sugar emulsifiers available commercially from Cognis are under the trade name Emulgade Sucro (Sucrose polystearate). Other sugar emulsifiers are Sucrose dilaurate, Sucrose Hexaerucate, Sucrose hexaoleate/hexapalmitate/Hexastearate, Sucrose Hexa palmitate, Sucroselaurate, Sucrose Myristate, Sucrose Octaacetate, Sucrose Oleate, Sucrose palmitate, Sucrose Pentaerucate, Sucrose Polylaurate, Sucrose polylinoleate, Sucrosepolypalmitate, Sucrose Ricinoleate, Sucrose Tetraisostearate, Sucrose Tetrastearate Triacetate,Sucrose TriBehenate.Sucrose Tristearate and the like.
Amounts of sugar based emulsifier used in the composition are in the range of about 0.1 to about 10% by weight, preferably about 0.5% to about 5%, more preferably about 1.0 % to about 3.0 %.
Acidic Skin care Agents:
The composition of the present invention may contain acidic skin care agents. Acidic skin care agents are considered as known active ingredients for improving the skin structure, increase smoothness, firmness, moisture content and skin lightening which act by suppressing melanogenesis by inhibiting formation of tyrosinase.
The preferred acidic skin benefit agents are hydroxy acids, most preferably alpha and beta hydroxy acids
Illustrative of alpha hydroxy acid group of materials are: 2-hydroxyethanoic acid (glycolic acid); 2-hydroxypropanoic acid (lactic acid); 2-methyl 2- hydroxypropanoic acid (methyllactic acid); 2- hydroxybutanoic acid; 2-hydroxypentanoic acid; 2-hydroxyhexanoic acid; 2-hydroxyheptanoic acid; 2-hydroxyoctanoic acid; 2- hydroxynonanoic acid; 2-hydroxydecanoic acid; 2- hydroxyundecanoic acid; 2-hydroxydodecanoic acid (alpha- hydroxylauric acid); 2- hydroxytetradecanoic acid (alpha- hydroxymyristic acid); 2-hydroxyhexadecanoic acid (alpha- hydroxypalmitic acid); 2-hydroxyoctadecanoic acid (alpha- hydroxystearic acid); 2- hydroxyeicosanoic acid (alpha- hydroxyarachidonic acid); 2-phenyl 2-hydroxyethanoic acid (mandelic acid); 2,2-diphenyl 2-hydroxyethanoic acid (benzilic acid); 3-phenyl 2- hydroxypropanoic acid (phenyl lactic acid); 2-phenyl, 2-methyl, 2-hydroxyethanoic acid (atrolactic acid); 2- (4'-hydroxyphenyl) 2-hydroxyethanoic acid; 2- (4'-chlorophenyl 2- hydroxyethanoic acid; 2- (3- hydroxy-4'-methoxyphenyl) 2-hydroxyethanoic acid; 2- (4'- hydroxy-3'-methoxyphenyl) 2-hydroxyethanoic acid; 3'- (2- hydroxyphenyl) 2-hydroxypropanoic acid; 3- (4'-hydroxyphenyl) 2-hydroxypropanoic acid; and 2- (3', 4'-dihydroxyphenyl) 2- hydroxyethanoic acid.
Most preferred of this group of materials is glycolic acid, lactic acid, 2-hydroxyoctanoic acid or combinations thereof
Illustrative of the beta-hydroxy carboxylic acids is salicylic acid. The present composition comprises a mixture of both a beta-hydroxy carboxylic acid and an alpha-hydroxy carboxylic acid in free form or as encapsulated form, the optimum combination is a mixture of salicylic acid and lactic acid.
Amounts of acidic skin benefit agents like alpha & beta hydroxyacids in the composition are in the range of about 0.1 to about 20% by weight, preferably about 0.50% to about 15 %.
Other Optional Skin Benefit agents and Cosmetic Adjuncts
Suitable other skin benefit agents which may present in the composition include anti-aging, wrinkle-reducing, skin whitening, anti-acne, wound healing, moisturizing, sebum reduction agents, vitamins, Proteins and minerals, UV diffusing/protection agents. Examples of these include kojic acid and esters, ferulic acid and ferulate derivatives, vanillic acid and esters, dioic acids (such as sebacic and azelaic acids) and esters, retinol, retinal, retinyl esters, hydroquinone, t-butyl hydroquinone, calcium alginate, hyaluronic acid, vitamin E acetate, K, Ca,ascorbic acid,vitamin C, mulberry extract, licorice extract, Hydrolysed Soy protein, Hydrolysed milk protein ,Allantoin and phenolic acid glycosidic polyhydroxybenzylate derivatives
The composition of the present invention preferably includes an effective amount of a sunscreen and/or sun-block agent to enhance synergistically the benefit of the composition in providing for skin lightening. Organic and inorganic sunscreens/sun-blocks or combinations thereof may be suitably employed in the composition.
Ultraviolet light is a predominant cause of skin darkening. Thus, compositions comprising UVA and/or UVB sunscreen are desirable.
A wide variety of conventional sunscreen agents are suitable for use in combination with the skin lightening composition of the present invention. Suitable sunscreen agents include, p- aminobenzoic acid, its salts and its derivatives (ethyl, isobutyl, glyceryl esters; p- dimethylaminobenzoic acid); anthranilates (i.e.,o-aminobenzoates; methyl, menthyl, phenyl, benzyl, phenylethyl, linalyl, terpinyl, and cyclohexenyl esters); salicylates (amyl, phenyl, benzyl, menthyl, glyceryl, and dipropyleneglycol esters); cinnamic acid derivatives (menthyl and benzyl esters, a-phenyl cinnamonitrile; butyl cinnamoyl pyruvate); dihydroxycinnamic acid derivatives (umbelliferone, methylumbelliferone, methylaceto-umbelliferone); trihydroxycinnamic acid derivatives (esculetin, methylesculetin, daphnetin, and the glucosides, esculin and daphnin); hydrocarbons (diphenylbutadiene, stilbene); dibenzalacetone and benzalacetophenone; naphthol- sulfonates (sodium salts of 2- naphthol-3,6-disulfonic and of 2-naphthol-6,8-disulfonic acids); di- hydroxy-naphthoic acid and its salts; o-and p- hydroxybiphenyldisulfonates; coumarin derivatives (7-hydroxy, 7-methyl, 3-phenyl); diazoles (2-acetyl-3- bromoindazole, phenyl benzoxazole, methyl naphthoxazole, various aryl benzothiazoles); quinine salts (bisulfate, sulfate, chloride, oleate, and tannate); quinoline derivatives (8-hydroxyquinoline salts, 2- phenylquinoline); hydroxy-or methoxy-substituted benzophenones; uric and vilouric acids; tannic acid and its derivatives (e. g., hexaethylether); (butyl carbotol) (6-propyl piperonyl) ether; hydroquinone; benzophenones (oxy-benzene, sulisobenzone, dioxybenzone, benzoresorcinol, 2, 2', 4, 4'-tetrahydroxybenzophenone, 2, 2'-dihydroxy-4, 4'- dimethylbenzophenone, octabenzone);
4- isopropyldibenzoylmethane; butyl-methoxydibenzoylmethane; etocrylene; and 4-isopropyl-di- benzoylmethane.
Of these, 2-ethylhexyl-p-methoxycinnamate, 4, 4'-t- butylmethoxydibenzoyl-methane, 2- hydroxy-4- methoxybenzophenone, octyldimethyl-p-aminobenzoic acid, digalloyltrioleate, 2, 2- dihydroxy-4- methoxybenzophenone, ethyl-4- (bis (hydroxypropyl) ) aminobenzoate, 2- ethylhexyl-2- cyano-3,3-diphenylacrylate, 2-ethylhexylsalicylate, glyceryl-p-aminobenzoate, 3,3,
5- trimethylcyclohexylsalicylate, methylanthranilate, p- dimethyl-aminobenzoic acid or aminobenzoate, 2-ethylhexyl-p- dimethyl-amino-benzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2- (p-dimethylaminophenyl)-5-sulfonicbenzoxazoic acid and mixtures of these compounds, are preferred.
More preferred sunscreens useful in the compositions useful in the subject invention are 2- ethylhexyl- p-methoxycinnamate, butylmethoxydibenzoylmethane, 2-hydroxy- 4- methoxybenzophenone, octyldimethyl-p-aminobenzoic acid and mixtures thereof.
A safe and effective amount of sunscreen may be used in the compositions useful in the subject invention. The composition preferably comprises from about 0.1% to about 20%, more preferably from about 0.5% to about 10%, of one or more sunscreen agent (s).
Useful inorganic sunscreens or sun-blocks include, but are not limited to, zinc oxide iron oxide, silica, such as fumed silica, and titanium dioxide.
Ultrafine titanium dioxide in either of its two forms, namely water-dispersible titanium dioxide and oil- dispersible titanium dioxide is especially suitable for the invention.
Water-dispersible titanium dioxide is ultra-fine titanium dioxide, the particles of which are non- coated or which are coated with a material to impart a hydrophilic surface property to the particles. Examples of such materials include aluminium oxide and aluminium silicate.
Oil-dispersible titanium dioxide is ultrafine titanium dioxide, the particles of which exhibit a hydrophobic surface property, and which, for this purpose, can be coated with metal soaps such as aluminium stearate, aluminium laurate or zinc stearate, or with organosilicone compounds.
By topical application to the skin of a mixture of inorganic sunscreens or sun block agents and/or organic sunscreens, synergistically enhanced protection of the skin against the harmful effects of both UVA and UVB rays is achievable.
The total amount of inorganic sunscreen or sun block that is preferably incorporated in the composition according to the invention is from 0.1 to 5% by weight of the composition
Suitable anti-irritancy agents include gluconolactone, borage seed oil, wild borage, dextran, alpha-bisabolol (extracted from chamomille), azulene (extracted from yarrow), resveratrol, petroselenic acid and combinations thereof. Each of these can be present at levels ranging from about 0.0001 to about 5%, preferably from about 0.001 to about 1%, optimally from about 0.01 to about 0.5% by weight of the composition.
Herbal extracts may also be included as components of the composition and are particularly effective for controlling the level of sebum/oil. Suitable extracts include horseradish, oats, neem, beet, broccoli, tea, pumpkin, soybean, barley, walnut, flax, ginseng, poppy, avocado, pea, sesame, dandelion, wheat, nettle, cashew, pineapple, apple, asparagus, Brazil nut, chickpea, grapefruit, orange, cucumber, buckwheat, strawberry, ginko, tomato, blueberry, cowpea and grape extracts.
The composition of the invention may contain other skin whiteners, For example, it may contain one or more of ascorbic acid and its salts and esters, placenta extract, kojic acid and its salts and esters, glucosamine and its salts and esters, azelaic acid and its salts and esters, retinol and its salts and esters, pyridoxine and its salts and esters, tranexamic acid and its salts and esters, arbutin, photosensitive substances, sulfur, 4-hydroxycinnamic acid, ginseng extract, licorice root extract, etc. The amount of the additional skin whitener to be in the composition may be from 0.1 to 10.0% by weight.
pH adjusting agents may be used to maintain the desired pH, if necessary, especially in the presence of certain acidic actives which may significantly lower the pH of the compositions. Preferred pH adjusting agents include inorganic or organic bases such as ammonium hydroxide, potassium hydroxide, sodium hydroxide and triethanolamine. Preferred pH adjusting agents also include inorganic acids such as hydrochloride acid.
Cosmetically acceptable vehicle
Inorganic rheology modifying agent may be optionally present in the inventive compositions as a Co-structurant, most preferred is magnesium aluminum silicate, commercially available as Veegum. RTM. K available from the R. T. Vanderbilt Company. Amounts of the inorganic thickening agent may range from about 0.01 to about 10%, preferably from about 0.5 to about 3%, optimally from about 0..1 to about 1% by weight.
Fatty alcohols are generally selected from those with a carbon chain length C12-C22. It is preferred that the fatty alcohol is a saturated fatty alcohol. It is also particularly preferred that at least 50% of the total fatty alcohols, by weight of fatty alcohol, are solid at a temperature of at
least 35°C. The total concentration of the fatty alcohol is in the range from 0.5 to 5% by weight of the cosmetic composition and more preferably from 4 to 7%.
Emollient materials in the form of mineral oils, silicone oils and synthetic esters may be incorporated into compositions of the present invention. Amounts of the emollients may range anywhere from about 0.1 to about 30%, preferably between about 0.5 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 polydimethylsiloxanes containing from about 3 to about 9, preferably from about 4 to about 5, silicon atoms.
Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25° C. while cyclic materials typically have viscosities of less than about 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 about 5 to about 100,000 centistokes at 25° C.
Suitable ester emollients include: (1) alkenyl esters of fatty acids having 10 to 20 carbon atoms, such as methyl myristate, methyl stearate, oleyl myristate, oleyl stearate, or butyl oleate; (2) ether-esters such as fatty acid esters of ethoxylated fatty alcohols; (3) polyhydric alcohol esters, such as 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; (4) wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate; (5) sterols esters, such as cholesterol fatty acid esters.
The preferred ester emollients are isopropyl myristate,isopropyl palmitate,isostearyl palmitate, tridecyl salicylate,CI2-15 octanoate and isopropyl stearate or any mixtures thereof.
The compositions of the present invention most preferably further include an ingredient selected from the group consisting of antioxidants, chelating agents, and mixtures thereof to improve the stability of the cosmetic cream. These ingredients provide an additional level of protection against oxidation of skin benefit agents in the cosmetic cream. Common examples of antioxidants, reducing agents and chelating agent for the present formulations can be found in the CTFA International Cosmetic Ingredient Dictionary 4th Edition, The Cosmetic, Toiletry, and Fragrance Association, Inc., Washington, D.C., 1991.
Preferable antioxidants are rac-6-hydroxy-2,5,7,8-tetra-methylchromane-2-carboxylic acid (trolox), propyl gallate, n-propyl trihydroxybenzoate, t-butyl hydroquinone and butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tocopheryl acetate, ascorbyl palmitate, hydroquinone, dibutyl hydroquinone, grape seed oil, pomegranate seed oil, apple seed oil and the like.
Suitable examples of chelating agents include, EDTA, citric acid, tartaric acid, organo- aminophosphonic acids and organo phosphonic acid components including certain of the commercially available DequestTM compounds, marketed by Monsanto. Preferred is EDTA- disodium.
Antioxidants are included in the inventive compositions in an amount of from 0.01 to 10%, preferably from 0.1 to 0. 5%, Chelating agents are included in the inventive compositions in an amount of from 0.01 to 1%, preferably from 0.05 to 0.5%, most preferably from 0.05 to 0.3%.
Organic thickners/ viscosifiers in amounts of up to about 2% by weight of the composition may also be included. The exact amount thickeners vary depends desired consistency and thickness of the final composition. Suitable thickeners include xanthan gum, sodium carboxymethyl cellulose, hydroxyalkyl and alkyl celluloses (particularly hydroxypropyl cellulose) and polyacrylamide dispersions in isoparaffin such as those sold by Seppic Inc. under the Sepigel 305 trademark
Anti-microbial agents may also be useful in compositions of the present invention. Typically the anti-microbial agents are selected from triclosan, tricarbanilide, tea tree oil, farnesol, farnesol acetate, hexachlorophene, C4-C20 quaternary ammonium salts such as benzalconium chloride and a variety of zinc or aluminum salts. Typically the zinc or aluminum salts are compounds such as zinc pyridinethione, zinc sulphate, zinc chloride, zinc phenolsulphonate, aluminum chloride, aluminum sulphate and aluminum chlorhydrate. Amounts of the anti-microbial ageht may range from about 0.1 to about 5%, preferably from about 0.2 to about 1%, optimally about 0.3% by weight of the composition.
Preservatives may also desirably be incorporated into the cosmetic compositions of this invention to protect against the growth of potentially harmful microorganisms. Suitable traditional preservatives include alkyl esters of para- hydroxybenzoic acid. Other preservatives which have more recently come into use include hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Cosmetic chemists are familiar with appropriate preservatives and routinely choose them to satisfy the preservative challenge test and to provide product stability. Particularly preferred preservatives are disodium EDTA, phenoxyethanol, methyl paraben, butyl paraben, propyl paraben, imidazolidinyl urea (commercially available as Germall 1157), sodium dehydroacetate and benzyl alcohol.
The preservatives should be selected having regard for the use of the composition and possible incompatibilities between the preservatives and other ingredients in the emulsion. Preservatives are preferably employed in amounts ranging from about 0.01% to about 2% by weight of the composition.
Humectants of the polyhydric alcohol-type like glycerin, propylene glycol, butylenes glycol, pentalene glycol, capryllyl glycol may also be employed as cosmetically acceptable carriers in compositions of this invention. The amount of humectants may range anywhere from 0.5 to 30%, preferably between 1 and 15% by weight of the composition.
The essential oil which may present in the formulation but not limited to grape fruit seed oil, lemon grass oil, eucalyptus oil, orange oil, ylang ylang oil, peppermint oil, cinnamon oil, clove
oil, rosemary oil, lavender oil, spearmint oil, cederwood oil, lemon oil, de lemonin, sandal wood oil, ginger oil
The details of the invention are given in the Examples given below which are provided solely to illustrate the invention and therefore should not be construed to limit the scope of the invention
Example 1
Preparation of a Vanishing Cream Composition useful as a Fairness cream
The composition is made in the following way. In an oil melting vessel 2.0g of Emulgade PL 68/50(Cetearyl Glucoside/Cetearyl alcohol), 19.0g of Stearic acid, 0.25g of Cetyl alcohol, 1.50g of Parsol MCX(Octyl methoxycinnamate), 0.50 g of Parsol 1789(Butyl methoxydibenzoyl methane), l.Og of Dimethicone, 1.50g of Isopropyl myristate, 0.1 Og of Propylparaben, 0.25g of Methylparaben were heated to 78°C to get uniform mixture.
In amain vessel, 59.8 g ofdeionised water was taken and to this added 0.05gofEDTA- DS, l.Og of Emulgin SG (Sodium Stearoyl Glutamate), 1.50g of Sepigel 305 (Polyacrylamide/ C13-14 isoparaffin/laurath -7) and stirred well and heated to 75° C.
The mixture in the oil melting vessel was transferred to the main vessel with high speed mixing and homogenized. The resulting composition was cooled to 45°C.
In a separate vessel 0.25g salicylic acid was dissolved in 2.0 g of glycerin and added to it 5.0g of lactic acid. pH of this mixture was adjusted to ~ pH 5 using 1.7 g KOH. This mixture was added to the main vessel and thoroughly mixed. The resulting composition was cooled to room temperature. 2.0 g of licorice extract was added to the above mixture in the main vessel. 0.1 Og of Butylated Hydroxy Tolune (BHT) dissolved in 0.5g of perfume (Vanity Ind) in another vessel and the mixture was added to the main vessel and mixed till composition was uniform.
A series of tests were conducted and established the stability of the preferred above said composition containing N- Acyl acidic amino acid derived emulsifier(s) and sugar based emulsifier(s) as stabilizing agent for low pH vanishing cream wherein the pH of the product found to be 5.5.
Example 2:
Composition for a moisturizing lotion
The composition was made in the following way. In an oil melting vessel 1.5 g of Emulgade Sucro ( Sucrose Polystearate), 6.0g of Stearic acid, 0.5g of Cetyl alcohol, 1.5g of Parsol MCX (Octyl methoxycinnamate), 0.5g of Parsol 1789(Butyl methoxydibenzoyl methane), l.Og of Dimethicone, 5.0g of Isopropyl myristate, 0.1 Og of Propylparaben, 0.25g of Methylparaben were taken and heated to 78°C and melt to uniform mixture.
In a main vessel, 69.2 g of deionised water was taken and to this added 0.05 g of EDTA-DS, l.Og of Emulgin SG (Sodium Stearoyl Glutamate ), 5.0 g of glycerin, 1.1 Og of Sepigel 305(Polyacrylamide/C13-14 isoparaffin/laurath -7) and the mixture was heated to 75°C. The mixture in the oil melting vessel was transferred to the main vessel with high speed mixing and homogenized. The resulting composition was cooled to 45°C.
In a separate vessel 5.0g of lactic acid was taken and pH was adjusted to ~ pH 5 using 1.70g KOH. This mixture was added to the main vessel under mixing. The resulting composition was cooled to room temperature. 0.10g of Butylated Hydroxy Tolune (BHT) dissolved in 0.5g of perfume (Vanity Ind) in another vessel and the mixture was added to the main vessel and mixed till composition was uniform.
A series of tests were conducted and established the stability of the preferred above said composition containing N- Acyl acidic amino acid derived emulsifier(s) and sugar based emulsifier(s) as stabilizing agent for low pH vanishing cream wherein the pH of the product found to be 5.7
Example -3:
Preparation of a Vanishing Cream useful as anti acne cream
The composition is made in the following way. In an oil melting vessel 2.2g of Tego care CG 90 (Cetearyl Glucoside), 20.0g of Stearic acid, O.lg of Cetyl alcohol, l.Og of Parsol MCX (Octyl
methoxycinnamate), l.Og of Dimethicone, l.Og of Isopropyl myristate, were heated to 78° C to get a melt having uniform mixture.
In a main vessel, 60.6 g of deionised water was taken and to this added 0.2 g of EDTA- DS, l.Og of Emulgin SG (Sodium Stearoyl Glutamate ), l.Og Caprylyl glycol, 1.50g of Sepigel 305 (Polyacrylamide/C13-14 isoparaffin/laurath -7) and stirred well and heated to 75° C.
The mixture in the oil melting vessel was transferred to the main vessel with high speed mixing and homogenized. The resulting composition was cooled to 45°C.
In a separate vessel l.Og salicylic acid was dissolved in 2.0 g of glycerin and added to it 5.0g of lactic acid. pH of this mixture was adjusted to ~ pH 4.5 using 1.3 g KOH. This mixture was added to the main vessel and thoroughly mixed. The resulting composition was cooled to room temperature. 0.1 Og of Butylated Hydroxy Tolune (BHT) was dissolved in a mixture of 0.25g of Eucalyptus oil, 0.25 g of Cinnamon oil, 0.25 g of clove oil and 0.25 g of lemon grass oil in another vessel and the mixture was added to the main vessel and mixed till composition was uniform.
A series of tests were conducted and established the stability of the preferred above said composition containing N- Acyl acidic amino acid derived emulsifier(s) and sugar based emulsifier(s) as stabilizing agent for low pH vanishing cream wherein the pH of the product found to be 4.2.
Example -4
Preparation of Vanishing Cream composition useful as UV protection cream
The composition is made in the following way. In an oil melting vessel 2.0g of Emulgade PL 68/50(Cetearyl Glucoside/ Cetearyl alcohol), 20.0g of Stearic acid, 0.5g of cetyl alcohol, 5.0g of Parsol MCX (Octyl methoxycinnamate), 1.0 g of Parsol 1789(Butyl methoxydibenzoyl methane), 3 .0g Benzophenone -3, l.Og of Dimethicone, 1.50g of Isopropyl myristate, 0.1 Og of Propylparaben, 0.25g of Methylparaben were heated to 78°C to get a melt having uniform mixture.
In amain vessel, 61.7 g of deionised water was taken and to this added 0.05gofEDTA- DS, 0.5g of Eumulgin SG (Sodium Stearoyl Glutamate ), lg of glycerin, 1.80g of Sepigel 305(Polyacrylamide/C13-14 isoparaffin/ laurath -7) and stirred well and heated to 75° C.
The mixture in the oil melting vessel was transferred to the main vessel with high speed mixing and homogenized. The resulting composition was cooled to room temperature.
0.1 Og of Butylated Hydroxy Tolune (BHT) dissolved in 0.5g of perfume (Vanity Ind) in another vessel and the mixture was added to the main vessel and mixed till composition was uniform.
A series of tests were conducted and established the stability of the preferred above said composition containing N- Acyl acidic amino acid derived emulsifier(s) and sugar based emulsifier(s) as stabilizing agent for low pH vanishing cream wherein the pH of the product found to be 5.7.
Example -5
Preparation of an Anti Acne Composition with Encapsulated Salicylic acid
The composition is made in the following way. In an oil melting vessel 2.0g of Emulgade PL 68/50(Cetearyl Glucoside/ Cetearyl alcohol), 12.0g of Stearic acid, 2.0g of Cetyl alcohol, l.Og of Parsol MCX(Octyl methoxycinnamate), l.Og of Dimethicone, 0.50g of Isopropyl myristate, 0.1 Og of Propylparaben, 0.25g of Methylparaben were heated to 78°C to get a melt having uniform mixture.
In amain vessel, 67.9 g of deionised water was taken and to this added 0.05gofEDTA- DS, 0.5g of Emulgin SG (Sodium Stearoyl Glutamate ), l.Og caprylyl glycol, 1.40g of Sepigel 305(Polyacrylamide/C13-14 isoparaffin/laurath -7) and stirred well and heated to 75° C.
The mixture in the oil melting vessel was transferred to the main vessel with high speed mixing and homogenized. The resulting composition was cooled to 45°C.
5.0g of lactic acid was taken in a separate container and pH was adjusted to ~ pH 5 using 1.7 g KOH. This mixture was added to the main vessel and thoroughly mixed. The resulting composition was cooled to room temperature. 0.1 Og of Butylated Hydroxy Tolune (BHT) dissolved in 0.5g of perfume (Vanity Ind) in another vessel and the mixture was added to the main vessel. 3.0 g of encapsulated salicylic acid (Chronosphere SAL) was added to the main vessel and mixed slowly until composition was uniform.
A series of tests were conducted and established the stability of the preferred above said composition containing N- Acyl acidic amino acid derived emulsifier(s) and sugar based emulsifier(s) as stabilizing agent for low pH vanishing cream wherein the pH of the product found to be 5.5.
Advantages of the invention
1 The composition is suitable for skin care application
2. The composition has skin friendly pH and sensory properties like those of vanishing cream and are also stable.
3. The composition is capable of incorporating acidic skin benefiting agents.

WE CLAIM:

1. An improved cosmetic composition suitable for skin application which comprises:

a) at least about 4% weight of the composition of high molecular weight fatty acid selected from , C12 -C22 fatty acid or their combinations

b) at least one emulsifier derived from N- Acyl acidic amino acid (s)

c) at least one sugar based emulsifier and

d) a cosmetically acceptable vehicle comprising deionized water, chelating agents and emollients.

2. An improved cosmetic composition as claimed in claim1 wherein the composition contains preservatives, anti oxidants, rheology modifiers, essential oils and perfume.

3. An improved cosmetic composition as claimed in claim 1 wherein the C12 - C22 fatty acid used in the composition is selected from C14 to C18 fatty acids, more preferably stearic and / or palmitic acid or their combination, the preferable ratio being about 55: 45 Palmitic to stearic on a weight basis, and the amount of fatty acids in the composition is preferably 8% to 22% , more preferably 10% to 20%, by weight of the composition

4. An improved cosmetic composition as claimed in claims 1 to 3 wherein the emulsifier derived from N- Acyl acidic amino acid (s) used is preferably alkali or alkaline earth metal salts of N- acyl acidic amino acids or more preferably alkali metal salts of acylglutamic acid and / or acyl aspartic acid and the like, and the amount of emulsifier used in the composition are in the range of about 0.1 to about 10% by weight, preferably about 0.25% to about 3%, more preferably about 0.5% to about 1.5%.

5. An improved cosmetic composition as claimed in claims 1 to 4 wherein the sugar based emulsifier used in the composition is preferably selected from sucrose esters and/or alkylpoly glucosides and the amounts of sugar based emulsifier in the composition are in the range of about 0.1 to about 10% by weight, preferably about 0.5% to about 5%, more preferably about 1.0% to about 3.0 %.

6. An improved cosmetic composition as claimed in claims 1 to 5 wherein the pH of the composition is less than 6.0

7. An improved cosmetic composition as claimed in claims 1 to 6 wherein the composition contains skin benefiting agents selected from alpha and / or beta hydroxy acids, UV light absorbing agents, anti-ageing agents.

8. An improved cosmetic composition as claimed in claim 7 wherein, the alpha and / or beta hydroxy acids used in the composition is either single or a mixture of both beta-hydroxy acid and an alpha-hydroxy acid such as a mixture of salicylic acid and lactic acid and the amount of acidic skin benefit agents used in the composition being in the range of about 0.1 to about 20% by weight, preferably about 0.50% to about 15 %.

9. An improved cosmetic composition as claimed in claims 7 wherein the amount of UV light absorbing agent used in the compositions ranges from about 0.1% to about 20%, more preferably from about 0.5% to about 10%,.

10. An improved cosmetic composition as claimed in claims 1 to 9 wherein the composition contains chelating agents in an amount of from 0.01 to 1%, preferably from 0.05 to 0.5%, most preferably from 0.05 to 0.3%.

11. An improved cosmetic composition as claimed in claims 1 to 10 wherein amounts of the emollients may range anywhere from about 0.1 to about 30%, preferably between about 0.5 and 20% by weight of the composition.

12. A process for the preparation of an improved cosmetic composition suitable for skin application which comprises:

(i) : Mixing sugar based emulsifier along with at least 4 % by weight of the composition , a high molecular weight fatty acid selected from C12 - C22 fatty acids and emollients, and heating the mixture to a temperature in the range of 70°C to 80°C

(ii) : Mixing at least one emulsifier selected from the group N- Acyl acidic amino acid (s), in deionized water along with chelating agents, and heating the mixture to a temperature in the range of 70°C to 80°C

(iii) : adding the mixture obtained in step (i) to the mixture obtained in Step (ii ) with high speed mixing followed by homogenization and .

(iv) : Cooling the resulting product to room temperature.

13. A process as claimed in claims 12 wherein preservatives and rheology modifiers are added in step (ii) and essential oils, perfume, anti oxidants and acidic skin benefiting agents are added in Step (iii) after cooling the mixture to room temperature.

14. An improved cosmetic composition suitable for skin application substantially as herein described with reference to the Examples

15. A process for the preparation of an improved cosmetic composition suitable for skin application substantially as herein described with reference to the Examples