A soap bar composition

Abstract

The present invention relates to a soap bar composition. It more particularly relates to delivering anti-inflammatory benefit to skin which has been washed with the soap bar, thereby reducing damage due to exposure to UV rays by enhanced free radical scavenging. This has been achieved by incorporating vitamin C and vitamin E in a soap bar composition comprising high amount of starch.

Description

[0001] A SOAP BAR COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to a soap bar composition. It more particularly relates to delivering anti-inflammatory benefit to skin which has been washed with the soap bar, thereby reducing damage due to exposure to UV rays by enhanced free radical scavenging.

[0004] Background of the Invention

[0005] Inflammation, a complicated biological host response to harmful stimuli, is a mechanism by which the host removes the stimuli and initiates the healing process for self-protection. The innate immune system for a host is the first line of defence against invading organisms in a non-specific manner. Dysregulated inflammation may cause various personal care problems including gingivitis / periodontitis (in the oral cavity), dandruff (on scalp / hair) and eczema / acnes (on skin). To assist the host organism (e.g. the human or animal) several anti-inflammatory agents either through topical application or through oral consumption have been developed and used to mitigate the above problems.

[0006] The skin is one of the largest organs of the body which is the protective layer against possible external damaging factors like UV radiation, heat, harmful microorganisms, and pollution. These damaging factors can lead to problems like eczema, acne, skin hyperpigmentation, enhanced skin aging leading to wrinkles etc. These problems can also lead to skin being left with a displeasing cosmetic appearance.

[0007] Thus, inflammation is a process that is manifest on the topical surface of the human or animal body in one or all of the above described conditions. The present inventors have attempted to alleviate the symptoms of the above conditions by developing new actives, especially those which could be derivatized from compounds found in extracts of natural materials. Natural materials from which many actives have been extracted include ginger, turmeric, tea, grape, tomato and a host of others. One such active is curcumin which has been known for a long time to alleviate very many health and cosmetic problems. Vitamins whether extracted from natural sources or prepared synthetically have also been used for such purposes. An effective way of ensuring the efficacy of any active is to incorporate it in a leave-on composition like a cream, ointment, gel, lotion or liquid composition that can be applied on skin and left thereon to ensure effectiveness over extended period of time till the skin in washed again during a shower, bath or similar washing procedure.

[0008] A more difficult problem to solve is to ensure the effectiveness of such actives when incorporated in a wash off composition like a body-wash, handwash, bathing soap, face wash, shampoo or similar composition that are primarily meant for cleansing the topical surface of the body like skin, scalp and hair. The present inventors in seeking to solve such a problem of depositing actives on to skin in effective amounts through a wash off composition, found that a combination of two vitamins (vitamin C and vitamin E) when incorporated in a soap bar composition containing high amount of starch interacted synergistically to deliver enhanced anti-inflammatory benefits.

[0009] Therefore, one of the advantages of the present invention is that by way of free radical scavenging, cosmetic benefits like skin brightening, reducing hyperpigmentation and dark spots may be obtained.

[0010] It is thus an object of the present invention to provide for enhanced anti-inflammatory benefits that can effectively be delivered from a skin cleansing composition like a soap bar.

[0011] Summary of the Invention

[0012] The first aspect of the present invention relates to a soap bar composition comprising

[0013] (i) 0.00001 to 0.1 wt% vitamin C or its derivative;

[0014] (ii) 0.00001 to 0.5 wt% vitamin E or its derivative;

[0015] (iii) 5 to 25 wt% starch;

[0016] (iv) 40 to 80 wt% soap;

[0017] (v) 5 to 30 wt% water;and wherein the vitamin C or its derivative is selected from one or more of ascorbic acid, sodium ascorbyl phosphate, 3-O-ethyl ascorbic acid, ascorbyl methylsilanol pectinate, magnesium ascorbyl phosphate, ascorbyl glucoside, and tetrahexyldecyl ascorbate; preferably ascorbic acid or sodium ascorbyl phosphate; and wherein Vitamin E or its derivative is selected from one or more of alpha tocopherol acetate, d- alpha-tocopherol acetate and d-alpha-tocopherol succinate; preferably alpha tocopherol acetate.

[0018] Another aspect of the present invention relates to a method of providing enhanced antiinflammatory benefit to skin comprising the steps of (i) applying a composition of the first aspect on to the skin preferably diluted with water, followed by (ii) rinsing said skin with water.

[0019] Detailed Description of the Invention

[0020] Any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of’ or “composed of.” In other words, the listed steps or options need not be exhaustive. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word “about”. Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and may be abbreviated as “wt%”. The use of any and all examples or exemplary language e.g. “such as” provided herein is intended merely to better illuminate the invention and does not in any way limit the scope of the invention otherwise claimed.

[0021] Preferably, the composition is applied to an animate substrate e.g. human skin. ‘Skin’ as used herein, preferably means to include skin on any part of the body e.g. face, neck, chest, back, arms, underarms, hands, legs, buttocks and scalp. The invention relates to a cleansing composition which is primarily meant for cleaning the topical surface of the human body. The cleansing is generally carried out by applying the composition of the invention on to the desired surface preferably diluted with water followed by the step of rinsing the skin with water or wiping the skin with a wipe to be substantially free of the composition.

[0022] By way of the present invention the cleansing composition also ensures deposition of sufficient amounts of the two vitamins on to the skin in desired quantities as to synergistically interact to deliver enhanced anti inflammatory benefit.

[0023] The composition comprises vitamin C or a derivative thereof. Vitamin C (ascorbic acid, ascorbate) is a simple low-molecular-weight carbohydrate that is essential for the body as a water-soluble vitamin. Vitamin C has both oxidized and reduced forms: L-dehydroascorbic and L-ascorbic acid.

[0024] Vitamin C is involved in the formation of the skin barrier and collagen in the dermis and plays a physiological role in the skin against skin oxidation, in antiaging of wrinkles, and in cell signal pathways of cell growth and differentiation, which are related to the occurrence and development of various skin diseases.

[0025] For use in the present invention, vitamin C or its derivative is selected from one or more of ascorbic acid, sodium ascorbyl phosphate, 3-O-ethyl ascorbic acid, ascorbyl methylsilanol pectinate, magnesium ascorbyl phosphate, ascorbyl glucoside, and tetrahexyldecyl ascorbate; preferably ascorbic acid or sodium ascorbyl phosphate.

[0026] Vitamin C or its derivatives which may be used in the present invention may be one or more of the following:

[0027] Sodium ascorbyl phosphate: Sodium ascorbyl phosphate is an active stable vitamin C derivative ingredient for the cosmetics industry. It liberates vitamin C in the skin and protects the cells of the skin, promotes collagen formation, controls the formation of senile keratosis, and lightens dark skin.

[0028] 3-O-Ethyl ascorbic acid:

[0029] 3-O-ethyl ascorbic acid promotes the production of collagen, which significantly improves the structure of the skin cells and the overall condition of skin.

[0030] Ascorbyl methylsilanol pectinate:

[0031] It is known to improve skin texture, as well as helping with reducing aging and dark spots.

[0032] Magnesium ascorbyl phosphate (MAP):

[0033] Magnesium ascorbyl phosphate (MAP) has all the functions of vitamin C and is very stable. It has can effectively resist UV radiation and promotes collagen production. This product is recommended for skin whitening / lightening applications, as well as anti-aging and anti-wrinkle products.

[0034] Ascorbic acid:

[0035] Vitamin C (L-ascorbic acid), USP is an active form of vitamin C as it occurs naturally. It can improve appearance of aged and fragile skin. It is widely used as an add-on ingredient in skinlightening products to correct hyperpigmentation and age spots.

[0036] Ascorbic acid

[0037] Ascorbyl glucoside: Ascorbyl glucoside is a water-soluble Vitamin C derivative with superior stability. It resists degradation, and has the same lightening, sun protective and anti-aging properties as ascorbic acid.

[0038] Tetrahexyldecyl ascorbate:

[0039] Tetrahexyldecyl ascorbate is a very stable, oil-soluble Vitamin C ester.

[0040] It has excellent skin penetration and as a result offers increased cell protection against IIV-B radiation. It can improve appearance of aged and fragile skin. It is widely used as an add-on ingredient in skin-lightening products to correct hyperpigmentation and age spots.

[0041] Aminopropyl ascorbyl phosphate:

[0042] It is a stabilized vitamin C derivative. It is ideal for whitening and anti-wrinkle applications.

[0043] Vitamin C or its derivative is preferably included in 0.0001 to 0.02%, more preferably 0.0001 to 0.0015% by weight of the composition.

[0044] The above are non-limiting examples of Vitamin C or its derivative. It is also within the scope of the present invention to include other derivatives, esters and isomers of vitamin C.

[0045] Vitamin E or its derivative for use in the present invention is selected from one or more of alpha tocopherol acetate, d-alpha-tocopherol acetate and d-alpha-tocopherol succinate; preferably alpha tocopherol acetate

[0046] Tocopheryl Acetate or Alpha Tocopheryl Acetate is commonly known as Vitamin E. It has the structure as given below: Alpha-tocopheryl acetate , also known as tocopheryl acetate, is a synthetic form of vitamin E. a- tocopheryl acetate is a fat-soluble vitamin E and considered the most stable and active form of vitamin E. Alpha tocopheryl acetate is known for protecting cells from oxidative stress induced damages.

[0047] Tocopheryl acetate can be found in many skincare products where it is used as a skinconditioning agent. It helps in preventing skin damages caused by excessive exposure to ultraviolet (UV) radiation emitted by the sun. This product is recommended for skin whitening / lightening applications, as well as anti-aging and anti-wrinkle products.

[0048] D-Alpha tocopherol acetate has the structure as give below. d-alpha-tocopherol is a natural active ingredient of Vitamin E, as it reduces oxidative stress induced damages in cells.

[0049] D alpha tocopherol succinate

[0050] D a-Tocopherol succinate is a fat-soluble vitamin which helps in reducing oxidative stress induced damages in cells.

[0051] It is also possible by way of the present invention that synthetic forms of vitamin E like DL-alpha tocopherol acetate and succinate may be included.

[0052] The above are non-limiting examples of Vitamin E or its derivative, It is also within the scope of the present invention to include other derivatives, esters and isomers of vitamin E. Vitamin E or its derivatives are available from BASF and Matrix Lifescience. BASF markets these materials under the names CopherolR1250 and Vitamin E acetate Care.

[0053] Vitamin E or its derivative is preferably included in 0.0001 to 0.2% by weight of the composition.

[0054] It has been found by way of the present invention that inclusion of starch in a soap bar composition enhances the combined anti-inflammatory benefit delivered by the vitamins alone. Starch is preferably included in 5 to 25%, more preferably 8 to 22%, further more preferably 10 to 20%, even further more preferably 10 to 18% by weight of the composition. Starch from any source such as corn, potato, sweet potato, rice, or wheat may be used but it is preferably corn starch. When obtained from corn, the starch is preferably obtained from the grain which is also known as the kernel. It is preferably obtained from the endorsperm of the kernel. The starch used preferably includes amylopectin with an average degree of polymerization (DP) higher than 70, more preferably higher than 100.

[0055] The composition of the invention preferably includes certain other skin care benefit agents like hydroxystearic acid. When included, it is preferred that the hydroxy stearic acid is 10- hydroxystearic acid, 12-hydroxystearic acid or trihydoxystearic acid (e.g. 9,10,13- trihydroxystearic acid) or trihydroxy stearin or compounds that yield one or more molecules of hydroxystearic acid or hydroxystearate on their breakdown like mono, di or tri ester of glycerol with hydroxystearic acid. Of these, 10-hydroxystearic acid, 12-hydroxystearic acid and 9,10,13- trihydroxystearic acid are more preferred, 12-hydroxystearic acid (12-HSA) being most preferred. 12-HSA has the structure as given below:

[0056] Hydroxystearic acid is preferably included in 0.001 to 1 %, more preferably 0.01 to 1 % by weight of the composition.

[0057] The composition of the invention preferably comprises a humectant which is preferably a polyhydric alcohol. Preferred polyhydric alcohols are selected from one or more of glycerol, 1 ,3- butylene glycol, propylene glycol, 1 ,3-propanediol, pentylene glycol, hexylene glycol, and sorbitol. It is most preferred to include glycerol as the humectant in the composition. When included it is present in 0.1 to 8%, preferably 1 to 5% by weight of the composition. The composition of the invention comprises soap. The soap is preferably a C8-C24 soap, more preferably C10-C20 soap and most preferably C12-C18 soap. The cation of the soap can be alkali metal, alkaline earth metal or ammonium. Preferably, the cation of the soap is selected from sodium, potassium or ammonium. More preferably the cation of the soap is sodium or potassium. Fatty acids derived from other suitable oils / fats such as groundnut, soybean, tallow, palm, palm kernel, etc. may also be used in other desired proportions. Soap, is present in an amount of 40 to 80%, preferably from 40 to 70%, by weight of the composition. The cleansing composition is preferably in solid form, most preferably in the shape of a soap bar.

[0058] Other anionic synthetic surfactants are preferably included in small amounts in the soap bar of the composition. Such anionic surfactants are preferably selected from one or more of alkyl ether sulphate, primary alkyl sulphate, secondary alkyl sulphonates, alkyl benzene sulphonates, ethoxylated alkyl sulphates and alpha olefin sulfonates. The anionic surfactant other than soap which is preferred in the cleansing composition is an alkyl ether sulphate preferably those having between 1 and 3 ethylene oxide groups, either from natural or synthetic source and / or sulphonic acid. Especially preferred are sodium lauryl sulphate. Alkyl polyglucoside may also be present in the composition, preferably those having a carbon chain length between Ce and C16. When included synthetic anionic surfactant may be included in 0.1 to 5 wt% preferably from 1 to 3 wt% of the composition.

[0059] The composition may also additionally comprise a free fatty acid other than hydroxy stearic acid. The free fatty acid is preferably included in 0.01 to 5% by weight of the composition. The free fatty acid may be one or more of C8-C24, preferably C10-C20 and most preferably C12-C18 fatty acid.

[0060] The soap bar of the invention includes water from 5 to 30 wt%, preferably from 8 to 25 wt%, most preferably from 10 to 22 wt%.

[0061] The soap bar composition of the invention may include other known ingredients such as perfumes, pigments, preservatives, emollients, sunscreens, gelling agents and thickening agents. The present invention also relates to a method of providing enhanced anti-inflammatory benefit to skin comprising the steps of applying a composition of the present invention on to skin preferably diluted with water, followed by rinsing the skin with water. The present invention also relates to a method of providing enhanced brightness to skin. The method is preferably cosmetic or non-therapeutic.

[0062] The invention will now be illustrated with the help of the following non-limiting examples.

[0063] Examples Examples A, B, 1 : Free radical scavenging activity of various combinations

[0064] Combination of actives as shown in table -1 below were prepared and their free-radical scavenging activity was measured using the procedure given below:

[0065] 20|jl of DPPH (2,2-Diphenyl-1-picrylhydrazyl) reagent (1mM stock) was added to the 96 well plate containing 1 SO I of test samples as shown in table 1 . Post 30 min incubation, a reading was taken at 517nm using TECAN instrument to measure the free radical scavenging activity of the samples. The combination of actives and the measured % scavenging activity is given in the table -1 below:

[0066] Table - 1 :

[0067] The P values are as given below:

[0068] Between Example A and Example 1 : < 0.005

[0069] Between Example B and Example 1 : <0.005

[0070] The data in the table above indicates that inclusion of starch synergistically improves the free- radical scavenging activity of the combination of Vitamin C and Vitamin E. It is to be understood that the concentration of the actives used in the above experiment are those that are expected to be present at the cellular level, which is usually about 1 to 3 orders of magnitude lower in concentration as compared to the concentration of the product sold to the consumer. The lowered concentration is due to the dilution with water as applied by the consumer and other reasons like diffusional resistances of the actives across the water and oil phases present in the multi-phase cleaning system.

[0071] Example - 2: Effect of inclusion of Vitamin C and Vitamin E in a soap bar containing starch on melanin content.

[0072] The effect of using a soap composition comprising starch and the vitamins as per the invention on mitigating the ill effects of free radical formation due to UV radiation and thereby on melanin formation in the skin was studied using the procedure as given below: Reconstructed human pigmented epidermis (RHPE) phototype IV were procured from Episkin, France. The tissues were equilibrated in the growth media at 37°C in a regular CO2 incubator overnight. The next day (Day 1), 10 pl of 8% soap solution was applied topically. Post 20 sec of product application, tissues were washed gently with distilled water for 30 seconds three times. After washing, tissues were exposed to UV light and incubated at 37°C in the CO2 incubator for 48 h. The change in media, application of soap and UV exposure was repeated on Day 3 and Day 5. On day 7, tissues were dissolved in solvable solution (Perkin Elmer) by heating at 100 degrees Celsius for 45 minutes and then the melanin content was measured at 490nm using TECAN instrument.

[0073] The soap bar used in the above experiment is as given in table - 2 below:

[0074] Table - 2:

[0075] The data on % melanin content is summarized in Table - 3 below:

[0076] Table - 3

[0077] Data in Table- 2 and 3 read with Table - 1 indicates that with use of a composition as per the invention, one is able to obtain enhanced free radical scavenging which can be used in a product like a soap bar to obtain reduction in pigmentation of skin which is affected by UV radiation (as evidenced by reduced melanin content).

Claims

Claims1. A soap bar composition comprising(i) 0.00001 to 0.1 wt% vitamin C or its derivative;(ii) 0.00001 to 0.5 wt% vitamin E or its derivative;(iii) 5 to 25 wt% starch;(iv) 40 to 80 wt% soap;(v) 5 to 30 wt% water; and wherein the vitamin C or its derivative is selected from one or more of ascorbic acid, sodium ascorbyl phosphate, 3-O-ethyl ascorbic acid, ascorbyl methylsilanol pectinate, magnesium ascorbyl phosphate, ascorbyl glucoside, and tetrahexyldecyl ascorbate; preferably ascorbic acid or sodium ascorbyl phosphate; and wherein Vitamin E or its derivative is selected from one or more of alpha tocopherol acetate, d-alpha-tocopherol acetate and d-alpha-tocopherol succinate; preferably alpha tocopherol acetate.

2. A composition as claimed in claim 1 comprising 0.0001 to 0.02 wt% vitamin C or its derivative.

3. A composition as claimed in claims 1 or 2 comprising 0.0001 to 0.2 wt% vitamin E or its derivative.

4. A composition as claimed in any one of the preceding claims wherein the starch is corn starch.

5. A composition as claimed in any one of the preceding claims comprising 10 to 18 wt% starch.

6. A composition as claimed in any one of the preceding claims additionally comprising 0.001 to 1 wt% hydroxystearic acid preferably 10 - or 12-hydroxystearic acid (12HSA).

7. A composition as claimed in any one of the preceding claims comprising a humectant preferably glycerol.

8. A method of providing enhanced anti-inflammatory benefit to skin comprising the steps of (i) applying a composition as claimed in any one of the preceding claims on to said skin preferably diluted with water, followed by (ii) rinsing said skin with water.

9. A method as claimed in claim 8 additionally providing enhanced brightness to skin.

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