STABLE UREA COMPOSITIONS

FIELD

[0001] The present disclosure relates to aqueous stable urea compositions and methods for their preparation. The urea compositions may find use in cosmetic and pharmaceutical compositions.

BACKGROUND

[0002] Urea is known to exhibit various physiological functions and is often used in cosmetic or pharmaceutical compositions particularly compositions for topical application. Urea is added to cosmetic compositions and pharmaceutical compositions with the object of preventing skin chapping and retaining moisture.

[0003] However, the urea in the compositions may be prone to decomposing into ammonia and carbon dioxide during storage, increasing the pH and generating an unacceptable ammonia odor.

[0004] Typically, aqueous urea compositions are prepared as acidic compositions. See, for example, US 6,355,259 and US 2005/0042182.

[0005] It would therefore be desirable to provide alternative, substantially stable, compositions of urea, particularly compositions which address one or more of the above highlighted problems and deficiencies.

[0006] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

SUMMARY

[0007] In a first aspect, there is provided a substantially stable, aqueous alkaline composition of urea, a substituted derivative of urea, or mixtures thereof.

[0008] In a second aspect, there is provided a substantially stable, aqueous alkaline composition of urea, a substituted derivative of urea, or mixtures thereof comprising;

up to about 30% by weight of urea, a substituted derivative of urea, or mixtures thereof, based on the total weight of the composition; and

the balance as water;

wherein the composition has a pH greater than 7.0. [0009] In a third aspect, there is provided a substantially stable, aqueous alkaline composition of urea, a substituted derivative of urea, or mixtures thereof comprising;

up to about 30% by weight of urea, a substituted derivative of urea, or mixtures thereof, based on the total weight of the composition;

one or more bases; and

the balance as water;

wherein the composition has a pH greater than 7.0.

[00010] By 'substantially stable' it is meant that the amount of urea, substituted derivative of urea, or mixtures thereof in the composition decreases by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 5% by weight, when the composition is stored at 40°C for one month.

[00011] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 8% by weight, when the composition is stored at 40°C for two months.

[00012] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, when the composition is stored at 40°C for three months.

[00013] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, when the composition is stored at 40°C for six months or for 12 months.

[00014] The amount of urea in the composition may be substantially unchanged when the composition is stored at 5°C for six months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 5°C for six months.

[00015] The amount of urea in the composition may be substantially unchanged when the composition is stored at 23°C for twelve months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 23°C for twelve months.

[00016] The stability of the alkaline aqueous urea compositions is surprising as urea is generally regarded as being more stable in an acidic environment.

[00017] In any one of the herein disclosed aspects or embodiments the pH of the composition may change by less than 1 pH unit, or less than 0.5 pH units, or less than 0.3 pH units, or less than 0.2 pH units when the composition is stored for 12 months at 23°C. [00018] In any one of the first to third aspects the urea, or substituted derivative of may be represented by the formula:

wherein Ri, R ₂ , R ₃ and R ₄ are independently selected from hydrogen, a Ci-C ₄ alkyl group, a Ci-C ₄ alkyl group substituted with one or more of amine, ester, carboxyl, alkoxy or halide, and a C ₂ -C ₆ hydroxyalkyl group containing from 1 to 5 hydroxyl groups.

[00019] In any one of the first to third aspects the substantially stable urea composition may have a pH greater than or equal to about 7.5, or greater than or equal to about 8.0, or greater than or equal to about 8.5, or greater than or equal to about 9, or greater than or equal to about

9.5.

[00020] In any one of the first to third aspects the substantially stable urea composition may have a pH in the range from about 7.0 to about 12.0, or from about 7.0 to about 11.0, or from about 7.0 to about 10.0, or from about 8.0 to about 12.0, or from about 8.0 to about 11.0, or from about 8.0 to about 10.0, or from about 8.5 to about 9.5, or from about 9.0 to about 9.5.

[00021] In any one of the first to third aspects the substantially stable urea composition may comprise about 0.1% to about 30% by weight of urea, a substituted derivative of urea, or mixtures thereof, based on the total weight of the composition. The substantially stable urea composition may comprise about 5% to about 15% by weight of urea, a substituted derivative of urea, or mixtures thereof, based on the total weight of the composition. The composition may comprise about 7% to about 13% by weight of urea, a substituted derivative of urea, or mixtures thereof, based on the total weight of the composition. In other embodiments the composition may comprise about 1% to about 10% by weight of urea, a substituted derivative of urea, or mixtures thereof, or about 2% to about 7%, based on the total weight of the composition.

[00022] As used herein the term "base" may refer to a compound that can accept a proton when dissolved in a protic solvent. When present, the substantially stable urea composition may comprise one or more weak bases.

[00023] When present, the one or more bases may be any pH adjuster that shifts pH above 7.0, that is, an alkaline pH adjuster. When present the one or more bases may be selected from metal salts, such as hydroxides, carbonates, bicarbonates or selected from phosphates, ammonia, amino acids or amines.

[00024] When present, the one or more bases may be selected from one or more alkali metal and alkaline earth salts. The alkali metal and alkaline earth salts may be selected from one or more carbonate and bicarbonate salts. Preferred bases include alkali metal hydroxides, carbonates and bicarbonates. Exemplary bases include sodium hydroxide, sodium carbonate and sodium bicarbonate. Other exemplary bases include potassium hydroxide, triethanolamine, 2-amino-2-hydroxymethyl-l,3-propanediol, disodium phosphate, ammonium hydroxide, trisodium citrate or tetrasodium EDTA, or amino acids, such as, for example, arginine, lysine or histidine.

[00025] When present, the substantially stable urea composition may comprise up to about 30% by weight of one or more bases, or up to about 20% by weight, or up to about 15% by weight or up to about 10% by weight, based on the total weight of the composition. The composition may comprise about 1 to about 10% by weight of one or more bases, or about 2 to 7% by weight of one or more bases, or about 1% to about 5%.

[00026] In any one of the first to third aspects the substantially stable urea composition may further comprise one or more skin penetration enhancers. The skin penetration enhancer may be selected from one or more alcohols, glycols, polyols, fatty acids, surfactants, ether alcohols, cyclic ether alcohols, alkoxy substituted cyclic ethers and fatty alcohol esters.

[00027] In any one of the first to third aspects the substantially stable urea composition may comprise up to 30% by weight of one or more skin penetration enhancers, based on the total weight of the composition. The skin penetration enhancer may be present in an amount of about 1 to about 20% by weight, or about 2 to about 15%, or about 3 to about 10%, based on the total weight of the composition.

[00028] In any one of the first to third aspects the substantially stable urea composition may further comprise one or more surfactants. The surfactant may be an anionic surfactant, a cationic surfactant, a non-ionic surfactant, an amphoteric surfactant, or mixtures thereof.

[00029] The composition may comprise up to 50% by weight of one or more surfactants based on the total weight of the composition, or up to 20% by weight, or up to 10% by weight. The composition may comprise about 2% to about 20% by weight surfactant, or about 5 to about 20% by weight surfactant, or about 5 to about 20% by weight, or about 5 to about 15% by weight, based on the total weight of the composition.

[00030] In any one of the first to third aspects the substantially stable urea composition may comprise one or more acceptable carriers and excipients, including preservatives, anti-oxidants, anti-inflammatories, emollients, moisturisers, sun screen agents, buffers, humectants, solubilisers, fragrances, exfoliants, colourants, metal ions, viscosity modifying agents and essential oils, selected so as to facilitate and/or enhance application, removal, user experience and/or efficacy. Other agents may be contemplated. The further components are preferably miscible and compatible and do not detract from the function of urea as herein described or detract from the stability and function of the composition.

[00031] The metal ions may comprise one or more transition metal or non-transition metal ions. The metal ions may be capable of complexing with melanoidins. The metal ions may aid in the removal of melanoidins, for example, by precipitating them as complex salts. The metal ions may be in the form of one or more metal complexes.

[00032] Up to about 10% by weight of metal ions may be present in the composition, preferably up to about 5% by weight, based on the total weight of the compositions.

[00033] In an embodiment, the substantially stable aqueous alkaline composition of urea comprises:

up to about 30% by weight of urea;

up to about 20% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 7.0.

[00034] In an embodiment, the substantially stable aqueous alkaline composition of urea comprises:

up to about 30% by weight of urea;

up to about 20% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 8.0.

[00035] In an embodiment, the substantially stable aqueous alkaline composition of urea comprises:

up to about 30% by weight of urea;

up to about 20% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 9.0.

[00036] In an embodiment, the substantially stable aqueous alkaline composition of urea comprises:

up to about 30% by weight of urea; up to about 20% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 7.0; and

wherein the amount of urea decreases by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 5% by weight, when the composition is stored at 40°C for one month.

[00037] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 8% by weight, when the composition is stored at 40°C for two months.

[00038] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, when the composition is stored at 40°C for three months.

[00039] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, when the composition is stored at 40°C for six months.

[00040] The amount of urea in the composition may be substantially unchanged when the composition is stored at 5°C for six months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 5°C for six months.

[00041] The amount of urea in the composition may be substantially unchanged when the composition is stored at 23°C for twelve months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 23°C for twelve months.

[00042] In any one of the foregoing aspects and embodiments, the compositions may find use in cosmetic, dermatological, skin care, sunscreen or other applications in the beauty, well- being and healthcare segments.

Advantages of the present urea compositions

[00043] The urea compositions of the present disclosure may possess one or more of the following advantages compared to prior art urea compositions.

• the urea composition is non-irritating to the skin.

• the urea composition possesses excellent long term stability

• the urea composition is cosmetically and aesthetically appealing. DESCRIPTION OF PREFERRED EMBODIMENTS

[00044] Before the present compositions, components and/or methods are disclosed and described, it is to be understood that unless otherwise indicated this invention is not limited to specific compositions, components, methods, or the like, as such may vary, unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[00045] It must also be noted that, as used in the specification and the appended claims, the singular forms 'a', 'an' and 'the' include plural referents unless otherwise specified. Thus, for example, reference to 'a skin penetration enhancer' may include more than one skin penetration enhancer, and the like.

[00046] Throughout this specification, use of the terms "comprises" or "comprising" or grammatical variations thereon shall be taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof not specifically mentioned.

[00047] Disclosed herein are advantageous urea compositions and methods for their preparation. The compositions and methods are based on an aqueous alkaline urea or substituted urea composition.

Urea or urea derivative

[00048] The urea, or substituted derivative of urea, may be represented by the formula:

o wherein Ri, R ₂ , R ₃ and R ₄ are independently selected from hydrogen, a Ci-C ₄ alkyl group, a Ci-C ₄ alkyl group substituted with one or more of amine, ester, carboxyl, alkoxy or halide or a C ₂ -C ₆ hydroxyalkyl group containing from 1 to 5 hydroxyl groups.

Base

[00049] The compositions of the present disclosure may further comprise one or more bases. Preferably, the compositions may comprise one or more weak bases. The one or more bases may be used to modify the pH of the composition. [00050] The one or more bases may be any pH adjuster that shifts pH above 7.0, that is, an alkaline pH adjuster. The one or more bases may be selected from metal salts, such as hydroxides, carbonates, bicarbonates or selected from phosphates, ammonia, amino acids or amines.

[00051] The one or more bases may be selected from one or more alkali metal and alkaline earth salts. The alkali metal and alkaline earth salts may be selected from one or more carbonate and bicarbonate salts. Preferred bases include alkali metal hydroxides, carbonates and bicarbonates. Exemplary bases include sodium hydroxide, sodium carbonate and sodium bicarbonate. Other exemplary bases include potassium hydroxide, sodium hydroxide, triethanolamine, 2-amino-2-hydroxymethyl-l,3-propanediol, disodium phosphate, ammonium hydroxide, trisodium citrate or tetrasodium EDTA. Amino acids may be selected from one or more amino acids, including but not limited to, arginine, lysine and histidine.

[00052] The composition may comprise up to about 30% by weight of one or more bases, or up to about 20% by weight, or up to about 15% by weight or up to about 10% by weight, based on the total weight of the composition. The composition may comprise about 1 to about 10% by weight of one or more bases, or about 2 to 7% by weight of one or more bases.

Penetration enhancers

[00053] The composition of the present disclosure may comprise one or more skin penetration enhancers included to enhance the artificial tan removal performance of the composition. Any skin penetration enhancer known in the art for use in personal care compositions may be used herein.

[00054] The penetration enhancers may be selected from one or more, alcohols, glycols, polyols, fatty acids, surfactants, oils, ether alcohols, cyclic ether alcohols, alkoxy substituted cyclic ethers or fatty alcohol esters. Preferred alcohols include ethanol and isopropanol. Preferred glycols include propylene glycol. Preferred oils include isopropyl myristate. Preferred ether alcohols include, but are not limited to, butoxydiglycol, ethoxyethanol, methoxyethanol, phenoxydiglycol, phenoxyethanol, phenoxyisopropanol, methoxypropanol and methoxydiglycol, the most preferred being ethoxydiglycol. A preferred alkoxy substituted cyclic ether includes dimethyl isosorbide. Preferred fatty alcohol esters range between approximately C9 to C15 with the most preferred fatty alcohols ester being C12 to C15 alcohol benzoates, C12 to C15 alcohol lactates and C12 to C15 alcohol octanoates.

[00055] The composition may comprise up to 30% by weight of one or more skin penetration enhancers, based on the total weight of the composition, or up to about 20% by weight, or up to about 15% by weight. The skin penetration enhancer may be present in an amount of about 1 to about 20% by weight, or about 2 to about 15%, or about 3 to about 10%, based on the total weight of the composition.

Surfactants

[00056] The composition of the present disclosure may comprise a surfactant or a mixture of surfactants. Any surfactant known in the art for use in personal care compositions may be used herein.

[00057] The surfactant may be an anionic surfactant, a cationic surfactant, a non-ionic surfactant, an amphoteric surfactant, or mixtures thereof. Preferably, the surfactant is an amphoteric surfactant.

[00058] Suitable anionic surfactants include alkyl sulphates, alkyl ether sulphates, alkaryl sulphonates, alkyl succinates, alkyl sulphosuccinates, acyl taurates, acyl glutamates, N-alkoyl sarcosinates, alkyl phosphates, alkyl ether phosphates, alkyl ether carboxylates, and alpha- olefin sulphonates, especially their sodium, potassium, magnesium, ammonium and mono-, di- and triethanolamine salts. The alkyl and acyl groups generally contain from 8 to 18 carbon atoms and may be unsaturated. The alkyl ether sulphates, alkyl ether phosphates and alkyl ether carboxylates may contain from 1 to 10 ethylene oxide or propylene oxide units per molecule, and preferably contain from 1 to 5 ethylene oxide units per molecule, more preferably contain 2 to 3 ethylene oxide units per molecule.

[00059] Examples of suitable anionic surfactants include sodium lauryl ether sulphate, sodium oleyl succinate, ammonium lauryl sulphosuccinate, ammonium lauryl sulphate, sodium dodecylbenzene sulphonate, triethanolamine and sodium salts of dodecylbenzene sulphonate and sodium N-lauryl sarcosinate.

[00060] The most preferred anionic surfactants are sodium lauryl ether sulphate 1 ethylene oxide (EO), 2EO, and 3EO, ammonium lauryl sulphate, ammonium lauryl ether sulphate 1EO, 2EO and 3EO, and triethanolamine and sodium salts of dodecylbenzene sulphonate.

[00061] Suitable cationic surfactants include quaternary ammonium salts. Cetyl- trimethylammonium chloride is a specific example of a suitable cationic surfactant. Other suitable cationic surfactants may include tetramethylammonium hydroxide or chloride, octyltrimethylammonium hydroxide or chloride, dodecyltrimethylammonium hydroxide or chloride, hexadecyltrimethyl- ammonium hydroxide or chloride, octyldimethylbenzylammonium hydroxide or chloride, decyldimethylbenxylammonium hydroxide or chloride, didodecyldimethylammonium hydroxide or chloride, dioctadecyldimethylammonium hydroxide or chloride, tallow trimethylammonium hydroxide or chloride, cocotrimethylammonium hydroxide or chloride. [00062] Suitable non-ionic surfactants may include condensation products of aliphatic (C9- C18) primary or secondary linear or branched chain alcohols or phenols with alkylene oxides, usually ethylene oxide and generally having from 2 to 30 EO groups, more preferably at least 3 EO, still more preferably at least 5 EO, but usually not more than 25 EO, more preferably not more than 20 EO or even not more than 15 EO.

[00063] Other suitable non-ionic surfactants include alkylpolyglycosides and mono- or di- alkyl alkanolamides. Examples of the latter non-ionics include coco mono- or di-ethanolamide and coco mono-isopropanolamide.

[00064] Suitable amphoteric and zwitterionic surfactants may include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulphobetaines (sultaines) , alkyl glycinates, alkyl carboxyglycinates, alkyl amphopropionates, alkylamphoglycinates, alkyl amidopropyl and hydroxy sultaines, wherein the alkyl and acyl groups have 8 to 19 carbon atoms. Examples include lauryl amine oxide, cocodimethyl sulphopropyl betaine and preferably lauryl betaine, cocamidopropyl betaine and sodium cocamphopropionate.

[00065] The surfactant may present in the composition in an amount of 1- 50%, preferably at least 2%, more preferably at least 3%, still more preferably at least 5%, even more preferably at least 7%, but typically not more than 30%, preferably not more than 20%, by weight of the composition.

Preservatives

[00066] Although the present compositions have an excellent anti-microbial profile, a preservative may also be employed to further increase the shelf-life of the composition. A number of well-known and pharmaceutically acceptable preservatives may be used in the present composition, including, for example, parabens, sodium benzoate, potassium sorbate, thimerosal, chlorobutanol, benzalkonium chloride, phenoxyethanol or benzyl alcohol and combinations thereof. Benzyl alcohol and phenoxyethanol are preferred preservatives. The composition may also comprise one or more salts of EDTA, for example sodium salts of EDTA, such as Na^EDTA. These may serve to enhance preservation.

[00067] A suitable amount of preservative will depend on a number of factors,

including, for example, the particular preservative selected, the intended shelf-life of the composition, and the results of preservative effectiveness and minimum preservative studies. When used, the amount of the preservative in the composition will typically be from about 0.001% to about 5% by weight, preferably from about 0.01% to about 2% by weight and more preferably from about 0.01% to about 1.0% by weight of the composition.

[00068] Other ingredients which extend shelf life can be added such as, for example, antioxidants. Examples of antioxidants include butyl hydroxytoluene, ascorbyl palmitate, tocopheryl, propyl gallate, sodium metabisulfite, potassium metabisulfite and other pharmaceutically acceptable antioxidants. Typically, the antioxidant will be present in the composition or composition in an amount of from about 0.01% to about 5% by weight of the composition.

Further components

[00069] The compositions of the present disclosure may contain one or more further components for ease of application and/or user feel. For example, fragrances, colourants, moisturisers, ant-inflammatory agents, essential oils, exfoliants and skin firming agents.

[00070] Non-limiting examples of essential oils include bergamot, chamomile german, chamomile maroc, chamomile roman, cinnamon zeylanicum, clove buds, eucalyptus globulus, frankincense, fennel, hyssop, juniper, lemon grass, mountain savoury, niaouli, red thyme, rosemary, rose geranium, tagestes and ylang ylang.

[00071] Illustrative but non-limiting examples of fragrances include myrcene, dihydromyrenol, citral, tagetone, cis-geranic acid, citronellic acid and mixtures thereof. Preferably, the amount of fragrance employed in the composition is in the range from 0.0001 to 10%, more preferably 0.002 to 5%, most preferably 0.005 to 2% by weight of the composition.

[00072] The compositions of the present disclosure may also contain one or more of emollients, moisturisers, viscosity modifying agents, buffers, humectants and solubilisers. The further components are preferably miscible and compatible and do not detract from the function of urea as herein described or detract from the stability and function of the composition.

[00073] The solubiliser may comprise one or more of the following: Gelucire 44/14, Gelucire 50/13, Peceol, Labrafil M2125 CS, Labrafil M1944 CS, Labrasol, Tween 80, Crodasol, Brij 30, Glycerox 767, NOVOL (Oleyl Alcohol), ETOCAS (PEG-35 Castor Oil), Arlasolve (Dimethyl lsosorbide), PEG300, Maisine 35-1, Transcutol HP, Glycerin, Span 80, Span 85, Compritol 888, Propylene Glycol, Dibutyl Sebacate, Triacetin, Miglyol 810, Miglyol 812, Myvacet, Softigen 701, Softigen 767, Kolliphor HS 15, Kolliphor RH40, Kolliphor RH60, Kolliphor ELP, Cetyl Palmitate, Lauroglycol 90, Lauroglycol FCC, Labrafac PG, Labrafac Lipophile WL 1349, Miranol, Soybean Oil, Corn Oil, Olive Oil, Castor Oil, Sesame Oil, Light Mineral Oil, Heavy Mineral Oil, Coconut Oil, Canola Oil, Dimethyl Sulfoxide (DMSO), N- Methylpyrrolidone (NMP), Benzyl Benzoate, Capryol 90, Capryol PGMC, Glyceryl Monostearate, Vitamin E TPGS and Benzyl Alcohol. This list is exemplary, and other appropriate solubilisers, known to those skilled in the art to enhance aqueous solubility may be used.

[00074] The composition may contain one or more moisturisers or anti-irritants, such as, for example, glycerine, Aloe Barbadensis leaf juice extract of sodium pyrrolidone carboxylate. The amount of moisturizer or anti-irritant may be between 0.01 and 5% by weight.

[00075] The compositions may contain one or more solvents in addition to water. The solvents are preferably soluble in water. Exemplary solvents include alcohols and polyols. Non-limiting examples of solvents include ethylene glycol and propylene glycol.

[00076] The composition may also contain one or metal ions. The metal ions may be ions of copper, iron, zinc, calcium and magnesium. The metal ions are preferably in the form of water soluble salts. The metal ions may be in the form of one or more metal complexes.

[00077] Up to about 10% by weight of metal ions may be present in the composition, preferably up to about 5% by weight, based on the total weight of the composition.

Vehicle

[00078] The vehicle of the presently disclosed composition is preferably suitable for use in applications that require direct contact with human skin.

[00079] The composition may be in a form of a cream, foam, gel, lotion, solution, emulsion, pomade, mousse, balm, pump spray, aerosol spray, a wipe or any combinations thereof.

[00080] Further preferred embodiments of the present disclosure include:

[00081] A substantially stable aqueous alkaline urea composition comprising:

about 4-20% by weight of urea;

about 2-15% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 7.0.

[00082] A substantially stable aqueous alkaline urea composition comprising:

about 4-20% by weight of urea;

about 2-15% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 8.0.

[00083] A substantially stable aqueous alkaline urea composition comprising:

about 4-20% by weight of urea;

about 2-15% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 9.0. [00084] A substantially stable aqueous alkaline urea composition comprising: about 4-20% by weight of urea;

about 2-15% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 8.0; and

wherein the amount of urea decreases by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 5% by weight, when the composition is stored at 40°C for one month.

[00085] In any one of the further preferred embodiments the amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 8% by weight, when the composition is stored at 40°C for two months.

[00086] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, when the composition is stored at 40°C for three months.

[00087] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, when the composition is stored at 40°C for six months.

[00088] The amount of urea in the composition may be substantially unchanged when the composition is stored at 5°C for six months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 5°C for six months.

[00089] The amount of urea in the composition may be substantially unchanged when the composition is stored at 23°C for twelve months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 23°C for twelve months.

[00090] Further preferred embodiments of the present disclosure include:

[00091] A substantially stable aqueous alkaline urea composition comprising:

about 8-12% by weight of urea;

about 3-7% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 7.0.

[00092] A substantially stable aqueous alkaline urea composition comprising:

about 8-12% by weight of urea;

about 3-7% by weight of a bicarbonate or carbonate salt; and the balance as water;

wherein the composition has a pH greater than 8.0.

[00093] A substantially stable aqueous alkaline urea composition comprising:

about 8-12% by weight of urea;

about 3-7% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 9.0.

[00094] A substantially stable aqueous alkaline urea composition comprising:

about 8-12% by weight of urea;

about 3-7% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 8.0; and

wherein the amount of urea decreases by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 5% by weight, when the composition is stored at 40°C for one month.

[00095] In any one of the further preferred embodiments the amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 8% by weight, when the composition is stored at 40°C for two months.

[00096] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, when the composition is stored at 40°C for three months.

[00097] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, when the composition is stored at 40°C for six months.

[00098] The amount of urea in the composition may be substantially unchanged when the composition is stored at 5°C for six months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 5°C for six months.

[00099] The amount of urea in the composition may be substantially unchanged when the composition is stored at 23°C for twelve months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 23°C for twelve months.

[000100] Further preferred embodiments of the present disclosure include:

[000101] A substantially stable aqueous alkaline urea composition comprising: about 2-7% by weight of urea;

about 1-5% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 7.0.

[000102] A substantially stable aqueous alkaline urea composition comprising:

about 2-7% by weight of urea;

about 1-5% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 8.0.

[000103] A substantially stable aqueous alkaline urea composition comprising:

about 2-7% by weight of urea;

about 1-5% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 9.0.

[000104] A substantially stable aqueous alkaline urea composition comprising:

about 2-7% by weight of urea;

about 1-5% by weight of a bicarbonate or carbonate salt; and

the balance as water;

wherein the composition has a pH greater than 8.0; and

wherein the amount of urea decreases by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 5% by weight, when the composition is stored at 40°C for one month.

[000105] In any one of the further preferred embodiments the amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 8% by weight, when the composition is stored at 40°C for two months.

[000106] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, or less than 10% by weight, when the composition is stored at 40°C for three months.

[000107] The amount of urea in the composition may decrease by less than 20% by weight, or less than 15% by weight, when the composition is stored at 40°C for six months.

[000108] The amount of urea in the composition may be substantially unchanged when the composition is stored at 5°C for six months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 5°C for six months.

[000109] The amount of urea in the composition may be substantially unchanged when the composition is stored at 23°C for twelve months. For example, the amount of urea may decrease by less than 5% by weight, or less than 4% by weight, or less than 3% by weight when the composition is stored at 23°C for twelve months.

[000110] The compositions of any one of the preferred embodiments may contain one or more of the further components as disclosed herein.

[000111] Further preferred embodiments of the composition of the present disclosure comprise the components as outlined in Tables 1, 2, and 3.

TABLE 3

Composition 63/14/3

Component

% by weight TABLE 3

Water 64.7

Urea 10.0

Cocoamidopropyl betaine 10.0

Sodium bicarbonate 5.0

Ethoxydiglycol 6.0

PEG-40 hydrogenated castor oil 1.8

Glycerine 1.5

Tetrasodium EDTA 0.6

Fragrance 0.3

Aloe Barbadensis leaf juice 0.1

Total 100.0

[000112] The compositions of Tables 1, 2 and 3 may contain one or more of the further components as disclosed herein.

EXAMPLES

[000113] The following Examples describe the compositions according to the present disclosure and are intended to illustrate the disclosure. The Examples are not to be construed as limiting in any way the scope of the present disclosure.

[000114] The method by which the compositions of the present disclosure are prepared is not critical. A preferred method comprises mixing the components at ambient temperature with stirring to provide a single-phase solution.

Comparison between acidic and basic compositions

[000115] The acidic and basic (alkaline) compositions as detailed in Table 4 were prepared. Two comparative compositions containing an alphahydroxy acid blend and having a pH of about 4 were compared to a composition according to the present disclosure comprising urea and sodium bicarbonate of pH about 9.

TABLE 4

Composition # F32/17/20 F32/16/3 F32/17/21

% by weight % by % by

weight weight

Water 78.8 64.0 75.7 TABLE 4

Multifruit BSC ®

10.0 10.0 0

(alphahydroxy acid blend)

Sodium bicarbonate 0 0 6.0

Urea 5 0 10.8

Propylene glycol and Aloe Barbadensis

2.0 0 2.2 extract

Glycerine 1.5 0 0

Ethoxydiglycol 0 25.0 0

Laureth-4 0 0 4.0

Benzyl alcohol 1.0 0 1.1

Xanthan Gum 0 1.0 0

Magnesium Aluminum Silicate 1.5 0 0

Allantoin 0.2 0 0.2

Total 100.0 100.0 100.0 pH 4.08 4.44 8.89

Comparison between alkali metal salt and urea compositions

[000116] Compositions according to the present disclosure containing urea, sodium bicarbonate, and a mixture of both, were compared to a composition (63/12/2) absent urea and sodium bicarbonate and in which alkalinity was effected by the addition of sodium hydroxide. The compositions and results are summarized in Table 5.

TABLE 5

Composition # 63/18/3 63/20/9 63/14/3 63/12/2

% by % by % by % by weight weight weight weight

Water 74.8 71.9 64.7 87.9

Sodium bicarbonate 5.0 0 5.0 0

Urea 0 10.0 10.0 0

Glycerine 1.5 1.5 1.5 1.0

Ethoxydiglycol 6.0 6.0 6.0 6.5 TABLE 5

Cocoamidopropyl betaine 0

10.0 10.0 10.0

(30% solution)

Tetrasodium EDTA 0.6 0.6 0.6 0

Aloe Barbadensis leaf juice 0 0 0.1 0

Fragrance 0.3 0 0.3 0.4

PEG-40 hydrogenated castor oil 1.8 0 1.8 2.3

Total 100.0 100.0 100.0 100.0 pH 9.0 9.6 9.6 9.2

[000117] Sodium bicarbonate alone may leave a white powdery residue on the skin which is cosmetically undesirable. The addition of urea counteracts this and no white powdery residue is observed.

[000118] Table 6 details examples of compositions prepared according to the

present disclosure.

TABLE 6

Composition 63/1/1 Composition 63/1/2

Component

(% by weight) (% by weight)

Water 64.4 64.4

Sodium carbonate 5.0 0

Sodium bicarbonate 0 5.0

Urea 10.0 10.0

Propylene glycol and Aloe 2.0 2.0

Barbadensis

Glycerine 1.5 1.5

Ethoxydiglycol 6.0 6.0

Benzyl alcohol 1.0 1.0

Cocamidopropyl Betaine 10.0 10.0

Tetrasodium EDTA 0.1 0.1

Total 100.0 100.0

pH 11.12 8.78 [000119] Table 7 summarises the results of a long-term shelf-life study of the compositions of Table 6.

[000120] It is evident that the compositions possess excellent stability in an accelerated storage test conducted in accordance with standard practice. The amount of urea decreased by less than or equal to 10% by weight when the compositions were stored for 3 months at 40°C. This is unexpected and highly advantageous in terms of maintaining composition efficacy.

[000121] When stored at 5°C for six months the compositions of the present disclosure showed no appreciable change in the amount of urea.

[000122] In a further example, a composition comprising components as formulation 63/14/3 in Table 5, except that the amount of urea was about 5% by weight and the amount of sodium carbonate was about 2.5% by weight, was stored for 12 months at 23°C. The initial pH of the composition was 9.00. After 12 months the pH was 9.08. The amount of urea in the composition after storage for 12 months was not measurably different to that present in the starting composition. The result indicates that aqueous urea compositions having high long term stability to urea decomposition and minimal, if any, pH drift may be produced.

[000123] It is to be understood that while the present disclosure has been described in conjunction with the specific embodiments thereof, the foregoing description is intended to illustrate and not limit the scope of the disclosure. Other aspects, advantages and modifications will be apparent to those skilled in the art to which the disclosure pertains. Therefore, the above examples are put forth to provide those skilled in the art with a complete disclosure and description of how to make and use the disclosed compositions, and are not intended to limit the scope of the disclosure.

[000124] For the sake of brevity, only certain ranges are explicitly disclosed herein.

However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited.

[000125] All documents cited are herein fully incorporated by reference for all

jurisdictions in which such incorporation is permitted and to the extent such disclosure is consistent with the description of the present disclosure.