WO2007060381A1 - Strontium-containing compositions and their use in methods of cosmetic treatment - Google Patents

Abstract

The present invention provides cosmetic formulations comprising strontium in an amount of up to 2.5% by weight, preferably up to 2.1% by weight, together with a physiologically acceptable carrier or excipient, wherein the strontium is present in the form of strontium chloride, strontium acetate or a hydrate thereof. Such formulations may be used to enhance the cosmetic appearance and/or the personal well-being of a subject, preferably a human subject, when topically applied to the body.

Description

STRONTIUM-CONTAINING COMPOSITIONS AND THEIR USE IN METHODS OF COSMETIC TREATMENT

The present invention relates to novel strontium-containing compositions and their use in methods of cosmetic treatment.

Strontium compounds are known for topical use in the reduction of skin irritation. For example, both WO 97/48371 and WO 96/19184 (Cosmederm) describe topical formulations containing strontium for preventing, reducing or eliminating the potential irritation caused by topical application of products containing irritating agents, especially cosmetic products containing hydroxy acids or other exfoliating agents. In the formulations described, the divalent strontium cation is provided at a concentration which is effective to reduce irritation to the skin. The concentrations of strontium salts that provide an optimum consumer benefit in terms of anti-irritant properties are approx. 4 to 6% by weight (approx. 190 to 28OmM). Strontium nitrate is the preferred choice of anti-irritant agent and is generally used at a concentration of 250 niM (5.7% by weight).

US-A-5,866,168 (L'Oreal) describes dermatological/pharmaceutical compositions comprising at least one lanthanide, manganese, tin, zinc, yttrium, cobalt, barium or strontium salt as a substance P antagonist. Such compositions are intended for use in the medical treatment and/or alleviation of pain associated with certain skin disorders, including skin ulcers, hypertrophic cicatrization and acne rosacea.

More recently, strontium compounds have been proposed for use in other methods of medical treatment. The use of strontium compounds to treat sub-dermal soft tissue pain is described in WO 03/028742 (Santosolve). WO 04/849920 (Santosolve) relates to strontium compounds for inflammatory treatment.

We have now surprisingly found that compositions containing certain strontium compounds in low concentrations are effective to enhance the cosmetic appearance and/or the personal well-being of a subject, preferably a human subject, when topically applied to the body.

Thus, viewed from one aspect the invention provides a cosmetic formulation comprising strontium in an amount of up to 2.5% by weight, together with a physiologically acceptable carrier or excipient, wherein the strontium is present in the form of strontium chloride, strontium acetate or a hydrate thereof.

Viewed from a further aspect the invention provides a method of cosmetic treatment of a human or non-human subject, preferably a human subject, said method comprising topically applying to said subject a composition comprising strontium in an amount of up to 2.5% by weight, wherein the strontium is present in the form of strontium chloride, strontium acetate or a hydrate thereof.

Viewed from a still further aspect the invention provides the use as a cosmetic preparation of a composition comprising strontium in an amount of up to 2.5% by weight, wherein the strontium is present in the form of strontium chloride, strontium acetate or a hydrate thereof.

The term "cosmetic" as used herein in relation to any product or method of treatment is intended to define a product or treatment which is used or intended for use solely for cosmetic purposes, i.e. to enhance or maintain the cosmetic appearance and/or the personal welfare of a human or non-human subject. Cosmetic treatment includes any method which serves (i) to maintain or alter (e.g. enhance) a subject's appearance; (ii) to protect a subject from environmental conditions such as sunlight, wind, extremes in temperature and/or humidity, etc.; or (iii) to produce a biological change in the subject's skin for cosmetic purposes. Cosmetic treatment specifically excludes any method of medical treatment of a subject, in particular any method for treating or alleviating the symptoms of a disease.

In a preferred aspect of the invention, the compositions herein described may be employed to impart a pleasant or comfortable feeling (e.g. a soothing and/or calming effect) to the skin following topical application, e.g. on application to the skin's surface. For example, these may provide effective relief to hypersensitive or sensitized skins. Such skins may be generally described as "uncomfortable" or, more specifically, may be associated with one or more of the following symptoms: discomfort, stinging, burning, itching and tightness. The compositions according to the invention may also be used to provide effective relief to skin either prior to, during or following exposure to harsh weather conditions, such as wind, cold, sun, humidity, etc. Methods of cosmetic treatment of sensitive, hypersensitive or sensitized skins form a preferred aspect of the invention. To the extent that such methods are "cosmetic", these are not considered to encompass the treatment of conditions related to an identifiable skin disease or disorder. The compositions according to the invention comprise strontium in the form of strontium chloride, strontium acetate or a hydrate thereof. Mixtures of any of these compounds may also be employed. A preferred form of strontium is strontium chloride. Particularly preferably, this may be used in the form of strontium chloride hexahydrate. The concentration of strontium in the compositions according to the invention will typically be up to about 2.1% by weight (w/w calculated as strontium), preferably in the range 0.5 to 2.1% by weight, more preferably 0.7 to 2.0% by weight, e.g. 1.0 to 2.0% by weight.

The strontium compounds herein described may be dissolved or dispersed in any appropriate vehicle, e.g. a physiologically acceptable carrier or excipient such as those described herein. Preferred carriers and excipients are those which are non- irritating to the skin. Although the strontium compounds herein described may be employed as the sole active component of a cosmetic formulation, preferably these will be used in a conventional cosmetic formulation in order to further enhance the cosmetic properties of the product. Examples of such products which contain safe (i.e. non-irritating) cosmetics to which the strontium compounds may be added include the following:

Vaseline^® Intensive Care Extra Strength Body Lotion (Lilleborg AS, Oslo, Norway) contains: water, glycerin, petrolatum, paraffinum liquidum, stearic acid, glycol stearate, stearamide AMP, cetyl acetate, acetylated lanolin alcohol, glyceryl stearate, triethanolamine, dimethicone, magnesium aluminum silicate, PEG-40 stearate, cetyl alcohol, perfume, methylparaben, propylparaben, carbomer, disodium EDTA, DMDM and hydantoin.

Natusan Baby Lotion (Johnson & Johnson, Dusseldorf, SCA Hygiene Products AS, Tønsberg, Norway) contains: water, paraffinum liquidum, petrolatum, Elaeis Guineensis oil, lanolin, glycerin, glycine soya oil, helianthus annusus seed oil, dimethicone, cetyl alcohol, stearyl alcohol, acrylates/C_lo-3o alkyl acrylate crosspolymer, carbomer, sodium hydroxide, phenoxyethanol, methylparaben, propylparaben and perfume.

Wella Balsam Shampoo (Wella AS, Darmstadt, Germany) contains: water, cetearyl alcohol, cetrimonium chloride, dimethicone, phenoxyethanol, perfume, isopropyl alcohol, methylparaben, CL 77891, buxus chinensis, citrus dulcis and pyrus malus.

Natusan^® pH 5.5 Shampoo (Johnson & Johnson, Maidenhead, UK, SCA Hygiene Products AS, Tønsberg, Norway) contains: water, ammonium lauryl sulphate, ammonium laureth sulphate, cocamidopropyl betaine, glycol distearate, lauramide MEA, methylparaben, tetrasodium EDTA, sodium benzoate, guar hydroxypropyltrimonium chloride, BHT, silicone, guanternium-13, acrylamidopropyltrimonium chloride/acrylamide copolymer, panthenol, PEG-14M, PEG-4, wheat amino acids, phytantriol, citric acid, iodopropynyl butylcarbamate, propylene glycol, quaternium-80, sodium chloride, polysorbate 20, PEG-4 laurate, PEG-4 dilaurate and perfume.

Vaseline^® Intensive Care Mild Shower Gel (Chesbrough Pond Inc., USA, Lilleborg AS, Oslo, Norway) contains: water, sodium laureth sulfate, glycerin, cocamidopropyl betaine, glycol distearate, perfume, lanolin alcohol, stearic acid, PPG-9, acrylates/Qo-so alkyl acrylate crosspolymer, guar hydroxypropyltrimonium chloride, PEG-40 hydrogenated castor oil, laureth-4, aloe barbadensis, potassium sorbate, sodium benzoate, tocopheryl acetate, citric acid, sodium hydroxide and sodium chloride.

Some of the cosmetic products mentioned above contain certain components that might be regarded as skin irritants when used at high concentrations. However, in the products listed, these are not present in an amount sufficient to irritate the skin. The strontium compounds herein described are not intended for use in preventing or reducing the irritation which may be associated with any conventional cosmetic products. Where any potentially skin irritating components are present in the formulations according to the invention, these will generally be present in sufficiently low concentrations that these do not irritate the skin. Such concentrations will depend on the nature of the skin irritant but typically will be of the order of less than 5% by weight, preferably less than 3% by weight, e.g. less than 2% by weight. Most preferably, the compositions of the invention will be substantially free from any skin irritating components. For example, any such components will be present in an amount of less than 1% by weight, e.g. less than 0.5% by weight.

As used herein, the terms "skin irritating component" and "skin irritant" are used interchangeably to define any compound which when topically applied to a human or non-human subject (e.g. when applied to the surface of the skin) at a given concentration will irritate the skin. Symptoms of skin irritation may include itching (pruritus), inflammation, stinging, burning, tightness of the skin, erythema or oedema. Skin irritants may include not only components of cosmetic products which may be considered inert, e.g. fragrances, preservatives, solvents, etc., but also active components of the products such as exfoliants and skin cell renewal agents, anti-perspirant compounds, skin protective agents, chemical sunscreen agents, etc. Known skin irritants include, for example, those compounds conventionally used as exfoliants and/or cell renewal agents to reduce the occurrence or severity of skin wrinkles, and anti-acne agents. Such compounds include carboxylic acids such as alpha-hydroxy acids (e.g. lactic acid, glycolic acid), beta-hydroxy acids (e.g. salicylic acid); retinoids (e.g. tretinoin, retinol); peroxides (e.g. benzoyl peroxide); and organic alcohols.

In a preferred embodiment of the invention the strontium compounds herein described are not provided in any conventional anti-aging or anti-wrinkle product, e.g. one containing alpha-hydroxy acids, beta-hydroxy acids or a retinoid. Preferably, the compositions in accordance with the invention will thus be substantially free from any anti-aging or anti-wrinkle agents. For example, these will contain less than 1% by weight, preferably less than 0.1% by weight, more preferably less than 0.01% by weight, of any anti-aging or anti-wrinkle agent such as an alpha-hydroxy acid, beta-hydroxy acid or retinoid. Other known skin irritants include the following: acetyl choline and its salts - spironolactone methotrexate aminocapric acid chinophen and its salts or derivatives trichloro-acetic acid - epinephrine rauwolfϊa serpentia (in any form) alkyne alcohols allyl isothicyanate nalorphine - aniline procainamide benzidine

4-aminosalicylic acid toluidines - xylidines anthracene oil antibiotics antimony compoumds apomorphine - arsenic atropa belladonna L. atropine benzene beryllium - brompheniramine tetracaine tolbutamine tetracaine tolbutamide cadmium carbon disulphide - catalase

2,2,2-trichloroethane- 1 , 1 -diol chlorine chloroethane curare - hydrogen cyanide dichloroethane dichloroethylene dimethylamine disulfϊram - ephedrine ethylene oxide fluorouracil progestogens hexachloroethane - hyoscyamus niger L. iodine ipecacuanha barbiturates mercury - metaldehyde nicotine amyl nitites nitrobenzene noradrenaline - oestrogens picric acid radioactive substances gold salts glucocorticosteroids strychnine neodymium compounds - tellurium compounds tetrachloroethylene carbon tetrachloride thallium compounds yohimbine - dimethylsulfoxide

4-tert-butylphenol dioxane chloroform coal tar Included in this listing of compounds are salts, esters and other derivatives which form any of the above-mentioned compounds in vivo.

Preferably, the compositions according to the invention will be substantially free from any of the above-mentioned compounds, for example these will be present in an amount of less than 1% by weight, more preferably less than 0.1% by weight, e.g. less than 0.01 % by weight.

The formulations herein described will generally be prepared by simple mixing of an appropriate amount of the chosen strontium compound into the chosen formulation vehicle, optionally together with any cosmetic components as are desired. Suitable topical vehicles and vehicle components for use with the formulations according to the invention are well known in the field of cosmetics and include such vehicles as solvents (e.g. water, organic solvents such as alcohols, glycols); lipid-based materials such as fatty acids, acylglycerols, phosphoglycerides; protein-based materials such as collagen and gelatin; silicone-based materials such as cyclomethicone, dimethicone; hydrocarbon-based materials such as petrolatum and squalene; anionic, cationic and amphoteric surfactants and soaps; sustained release vehicles such as microsponges and polymer matrices; stabilizing and suspending agents; and emulsifying agents. Other components may be provided to improve the stability or effectiveness of the formulations such as preservatives, redox agents (e.g. antioxidants), skin penetration enhancers, sustained release materials, viscosity modifiers, pH modifiers, etc. Other components which may be present include perfumes, sunscreens, odour absorbers and colourants. The amounts of these various adjuvants and additives are those conventionally used in the cosmetic field and may range, for example, from 0.01 to 20% of the total weight of the formulation.

The compositions according to the invention may be used as cosmetic preparations, in particular as skin and hair products. In use, these will be topically applied to the body of a human or non-human animal, preferably to a human. For example, these may be administered directly onto the skin's surface (on any area of the skin), onto the hair (wet or dry hair) and/or onto the nails.

The compositions may be provided in a variety of forms, including solids (e.g. soaps or cleansing bars), liquids, emulsions, semi-solids (e.g. creams, gels, lotions or pastes), powders or aerosols. Preferably, these may be provided in the form of a high viscosity fluid, e.g. a gel.

Examples of topical products used as cosmetics and to which the strontium compounds herein described may be added include skin care products such as moisturising creams and lotions, skin cleansers and toners, exfoliants and skin cell renewal agents, anti-wrinkle products; fragrances such as perfumes, deodorants and anti-perspirants; shaving products such as shaving creams and after-shaves; depilatories and other hair removal products; sunbathing products such as tanning lotions, sunscreens, sunblocks and after-sun products; artificial tanning products; skin-whitening products; cleansing products such as toilet soaps and gels; bath products such as bath and shower compositions, after-bath compositions; eye care products such as eye lotions and make-up removers; make-up products such as foundations, blushers, eye shadows and eye liners, lipsticks, mascaras, powders; products for application to the lips such as lip balms and sticks; hair care and treatment products such as shampoos, conditioners, colourants, dyes, bleaches, permanent- waving or straightening compositions; baby products such as wet wipes, lotions, oils, shampoos, powders; products for intimate hygiene such as deodorants and douches; skin or facial peels and masks; and products for nail care such as nail hardeners and nail varnishes.

When used in any of the skin care products herein described, the strontium compounds are effective to impart a pleasant (e.g. soothing and/or calming) effect on the skin, hair or nails, especially on the skin.

In a preferred aspect of the invention, the strontium compounds herein described may be used in an after-sun product where these are effective in soothing or calming the skin following exposure to the sun.

The present invention is further illustrated by the following non-limiting Example:

Example 1 : Preparation of strontium chloride (2% strontium) containing product

Strontium chloride hexahydrate (6.05 g) was mixed into Vaseline Intensive Care Extra Strength Body Lotion (Lilleborg AS, Oslo, Norway) (94g) using a mortar and pestle. The lotion was filled into a plastic vial.

The lotion contained 2% (w/w) strontium.

Claims

Claims:

1. A cosmetic formulation comprising strontium in an amount of up to 2.5% by weight, together with a physiologically acceptable carrier or excipient, wherein the strontium is present in the form of strontium chloride, strontium acetate or a hydrate thereof.

2. A cosmetic formulation as claimed in claim 1 which comprises strontium in an amount of up to about 2.1% by weight.

3. A cosmetic formulation as claimed in claim 1 or claim 2, wherein the strontium is present in the form of strontium chloride hexahydrate.

4. A cosmetic formulation as claimed in any one of claims 1 to 3 which is substantially free from any skin irritating components.

5. A cosmetic formulation as claimed in any one of claims 1 to 4 which is provided in the form of a gel.

6. A method of cosmetic treatment of a human or non-human subject, said method comprising topically applying to said subject a composition comprising strontium in an amount of up to 2.5% by weight, wherein the strontium is present in the form of strontium chloride, strontium acetate or a hydrate thereof.

7. A method as claimed in claim 6, wherein said subject is a human subject.

8. A method as claimed in claim 6 or claim 7, wherein said composition comprises strontium in an amount of up to about 2.1% by weight.

9. A method as claimed in any one of claims 6 to 8, wherein said composition comprises strontium in the form of strontium chloride hexahydrate.

10. A method as claimed in any one of claims 6 to 9, wherein said composition is substantially free from any skin irritating components.

11. A method as claimed in any one of claims 6 to 10, wherein said composition is provided in the form of a gel.

12. The use as a cosmetic preparation of a composition as defined in any one of claims 6 to 11.