WO2012130606A1

WO2012130606A1 - A sunscreen composition

Info

Publication number: WO2012130606A1
Application number: PCT/EP2012/054345
Authority: WO
Inventors: Mohan Vijaykumar Chavan; Charu Duggal; Kumar Gaurav; Janhavi Sanjay Raut; Ashish Anant Vaidya
Original assignee: Unilever Nv; Unilever Plc; Hindustan Unilever Limited
Priority date: 2011-03-29
Filing date: 2012-03-13
Publication date: 2012-10-04
Also published as: AR085723A1

Abstract

The invention relates to a sunscreen composition. Known compositions do not provide enhanced SPF while using low amounts of organic sunscreens. It is thus an object of the present invention to provide high SPF photo-protective sunscreen compositions using relatively low amounts of sunscreen agents thereby keeping costs low.

Description

A SUNSCREEN COMPOSITION

Field of the invention

The invention relates to a sunscreen composition. The invention more particularly relates to a sunscreen composition that not only provides enhanced sun protection but does that over a sustained period of time after topically applying the composition to skin.

Background of the invention

Solar radiation includes ultraviolet (UV) radiation, wavelength of which is between 200 nm and 400 nm. Exposure of skin to UV-A (320 to 400 nm) and UV-B (290 to 320 nm) causes various problems like reddening of the skin, localized irritation, sunburn, melanoma and formation of wrinkles. UV radiation is also known to cause damage to hair. Therefore, it is desirable to protect the skin and other keratinous substrates of the human body from the harmful effects of both UV-A and UV-B radiation.

SPF (Sun Protection Factor) is a measure of the protection from solar radiation. In order to achieve this, formulators generally include high amounts of UV-A and UV-B. The present inventors have found that even with small amount of sunscreen agents with inclusion of a specific class of non-ionic surfactant in a cosmetic base comprising fatty acids, it is possible to provide high SPF.

Non-ionic surfactants have been disclosed in the past for use in skin compositions. WO 2008/022946 (Unilever) discloses a photostable cosmetic composition comprising 0.1 to 10 % dibenzoylmethane or its derivative, 0.1 to 10 % by weight p-methoxycinnamic acid or its derivative, 0.5 to 8 % by weight C8 to C18 fatty alcohol ethoxylate and 0.5 to 8 % polyalkyleneglycol. Published Indian Patent Application No. 514/MUM/2006 (Hindustan Unilever Ltd) discloses stable sunscreen compositions with novel silicone sunscreens where one of the sunscreens is an allyloxy functionalised cyanoacrylate sunscreen. US 2009/039322 (Hallstar) discloses alkoxy polyester compounds and methods to increase the photostability of UV-degradable photoactive compounds.

While the above references are directed to improving stability of sunscreen containing compositions, the references do not disclose a sunscreen composition resulting in prolonged and enhanced SPF while using low amounts of organic sunscreens as claimed in the present invention.

It is thus an object of the present invention to obviate the drawbacks of the prior art and provide high SPF photo-protective sunscreen compositions.

Another object of the present invention is to achieve the above object using relatively low amounts of sunscreen agents thereby keeping costs low. Summary of the Invention

The present invention provides for a sunscreen composition comprising, a) 0.05 to 15 % by weight compound of formula;

A where R1 and R2 are each independently hydrogen or straight or branched chain C1 -C30 alkoxy group, where R1 and R2 are not simultaneously hydrogen;

and R3 is a straight or branched chain C1 -C30 alkyl group;

(b) 0.01 to 10 % by weight a non-ionic surfactant;

(c) a cosmetically acceptable base comprising 1 to 25 % by weight fatty acid. Detailed description of the Invention

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, 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. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description and claims 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.

By "A Sunscreen Composition" as used herein, is meant to include a composition for topical application to sun-exposed areas of the skin and/or hair of mammals, especially humans. Such a composition may be generally classified as leave-on or rinse off, and includes any product applied to a human body for also improving appearance, cleansing, odor control or general aesthetics. It is more preferably a leave-on product. The composition of the present invention can be in the form of a liquid, lotion, cream, foam, scrub, gel, or toner, or applied with an implement or via a face mask, pad or patch. Non-limiting examples of such sunscreen compositions include leave-on skin lotions, creams, antiperspirants, deodorants, lipsticks, foundations, mascara, sunless tanners and sunscreen lotions. "Skin" as used herein is meant to include skin on the face and body (e.g. , neck, chest, back, arms, underarms, hands, legs, buttocks and scalp) and especially to the sun exposed parts thereof. The composition of the invention is also of relevance to applications on any other keratinous substrates of the human body other than skin e.g. hair where products may be formulated with specific aim of providing photoprotection. An advantage of the present invention is that the sunscreen composition is capable of providing an SPF higher than 8, more preferably higher than 12, further more preferably higher than 15. It is preferred that the composition comprises less than 10 %, preferably less than 8 %, more preferably less than 7 %, further more preferably less than 6 % total organic sunscreens by weight of the composition.

The composition of the invention comprises 0.05 to 15 % by weight compound of formula;

A

where R1 and R2 are each independently hydrogen or straight or branched chain C1 -C30 alkoxy group, where R1 and R2 are not simultaneously hydrogen; and R3 is a straight or branched chain C1 -C30 alkyl group. R3 is preferably a C2-C20 alkyl group.

R1 and/or R2 are preferably straight or branched chain C1 -C8 alkoxy group. Most preferably R1 and/or R2 are a methoxy group or a polymer anchored through an alkoxy group.

A highly preferred aspect provides for R1 to be methoxy, R2 to be hydrogen and R3 to be an ethyl hexyl group. In this case the compound is known as ethylhexyl methoxycrylene (EHMC):

Another useful compound of formula A is when R1 is allyloxy when it is known as ethyl allyloxycrylene.

Yet another useful compound of formula A is when R1 is polysiloxane covalently linked via propyloxy (-OCH2CH2CH2-polysiloxane) and the compound is then known as polymeric propyloxycrylene:

Polysiloxane chain

Compound of formula A is preferably present in 0.1 to 10 %, more preferably 0.1 to 4% by weight of the composition.

An important ingredient that contributes to benefits of the present invention is a non-ionic surfactant. The non-ionic surfactant for use in the composition of the present preferably has an HLB value of at least 9 as measured by the Griffin method.

The non-ionic surfactant is preferably selected from the following five classes:

(a) fatty alcohol ethoxylates with saturated carbon chain and having HLB higher than 15.5; or

(b) fatty alcohol ethoxylates with unsaturated carbon chain with HLB higher than 12.

(c) alky I phenol ethoxylates having HLB higher than 15; (d) polyoxyethylene sorbitan alkyl esters with saturated C12 to C16 carbon chain and having HLB higher than 12;

(e) polyoxyethylene sorbitan alkyl esters with unsaturated C18 carbon chain and having HLB higher than 9;

Suitable examples of (a) are Brij 35 (a C12E023 compound) or Brij 700 (C18EO100). Suitable examples of (b) are Brij 97 (unsaturated C18E012), or Brij 99 (unsaturated C18EO20). Suitable examples of (c) are Triton X 165, Triton X 305, Triton 405, or Triton X 705. Suitable examples of (d) and (e) are Tween 20, Tween 21 , Tween 40, Tween 80, Tween 81 or Tween 85 trioleate. The non-ionic surfactant is included in 0.1 to 5 %, preferably 0.2 to 4%, more preferably 0.2 to 3% by weight of the composition. Especially useful non-ionic surfactant is a polyoxyethylene/ polyoxypropylene based surfactant. The composition of the invention comprises a cosmetically acceptable base comprising 1 to 25 % fatty acid. The cosmetically acceptable bases are preferably in a cream, lotion, gel or emulsion format. A more preferred format is a cream, further more preferably a vanishing cream. Vanishing cream base is one which comprises 1 to 25 %, more preferably 5 to 20 % fatty acid. The fatty acids may be saturated or unsaturated fatty acids. The base preferably comprises 0.1 to 10 %, more preferably 0.1 to 3 % soap. C12 to C20 fatty acids are especially preferred in vanishing cream bases, further more preferred being Cu to C18 fatty acids. In creams, the fatty acid is preferably substantially a mixture of stearic acid and palmitic acid. Soaps in the vanishing cream base include alkali metal salt of fatty acids, like sodium or potassium salts The soap is preferably the potassium salt of the fatty acid mixture. The fatty acid in vanishing cream base is often prepared using hystric acid which is substantially (generally about 90 to 95 %) a mixture of stearic acid and palmitic acid. Thus, inclusion of hystric acid and its soap to prepare the vanishing cream base is within the scope of the present invention. It is particularly preferred that the composition comprises at least 6 %, preferably at least 10 %, more preferably at least 12 % fatty acid. The cosmetically acceptable base is usually from 10 to 99.9 %, preferably from 50 to 99 % by weight of the composition. It has been observed that use of higher levels of fatty acid in combination with the selective non-ionic surfactant contributes to increased SPF of the composition and in many cases doubling the SPF that can be obtained with compound of formula A alone. The cosmetically acceptable base preferably includes water. Water is preferably included in 35 to 90 %, more preferably 50 to 85 %, further more preferably 50 to 80 % by weight of the composition.

The composition of the invention preferably comprises a UV-A or a UV-B sunscreen. Organic sunscreens of these two types are generally available from the following major groups: benzophenones, anthranilates, dibenzoylmethanes, salicylates, cinnamates, camphores, and triazins.

The composition of the invention preferably comprises a UV-A sunscreen which is a dibenzoylmethane or its derivative. Preferred dibenzoylmethane derivative are selected from 4-tert-butyl-4'-methoxydibenzoylmethane, 2- methyldibenzoylmethane, 4-methyl-dibenzoyl-ethane, 4-isopropyldibenzoyl- methane, 4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane, 2,5- dimethyldibenzoylmethane, 4,4'-diisopropyl-dibenzoylmethane, 2-methyl-5- isopropyl-4'-methoxydibenzoylmethane, 2-methyl-5-tert-butyl-4'-methoxy- dibenzoyl methane, 2,4-dimethyl-4'- methoxy dibenzoylmethane or 2,6-dimethyl- 4-tert-butyl-4'-methoxy-dibenzoylmethane. The most preferred dibenzoylmethane derivative is 4-tert.-butyl-4'-methoxydibenzoylmethane. The composition of the invention preferably comprises 0.1 to 5 %, more preferably 0.2 to 5 %, further more preferably 0.4 to 3 %, by weight dibenzoylmethane based on total weight of the composition and including all ranges subsumed therein.

An oil soluble UV-B organic sunscreen is preferably included in the composition of the invention for further increasing the SPF. Oil soluble UV-B sunscreen is preferably selected from the class of cinnamic acid, salicylic acid, diphenyl acrylic acid or derivatives thereof. A few of the preferred oil soluble UV-B sunscreens which are commercially available and useful for inclusion in the composition of the invention are Octisalate™, Homosalate™, NeoHelipan™, Octocrylene™, Oxybenzone or Parsol MCX A surprising aspect of the present invention is that high SPF values can be obtained even when the total amount of organic UV- A and organic UV-B sunscreens (excluding the compound of formula A) are present in small amounts which may be in the range of 0.1 to 7 %, preferably from 0.5 to 6 %, more preferably 1 to 5 %, by weight of the composition. Alternately, a water soluble organic UVB sunscreen is preferably included in the composition of the invention. Preferred water soluble organic UVB sunscreen is Phenyl benzimidazole sulfonic acid. It is preferred that oil-soluble sunscreens are included in the composition of the invention in preference to water soluble sunscreens. These water soluble sunscreens may however be incorporated in small amount, preferably less than 1 %, further more preferably less than 0.5 %, even further more preferably less than 0.1 % by weight of the composition.

Photostabilizers may be included in the composition of the present invention. Suitable photostabilising compounds are of the diphenylacrylate, benzylidene camphor, napthalate, triazine, fluorene or diarylbutadiene class.

Other useful sun-protective agents e.g. inorganic sun-blocks may be preferably used in the present invention. These include, for example, zinc oxide, iron oxide, silica, such as fumed silica, or titanium dioxide. The total amount of sun block that is preferably incorporated in the composition according to the invention is from 0.1 to 5 % by weight of the composition.

The composition of the invention may additionally comprise a skin lightening agent. The skin lightening agent is preferably chosen from a vitamin B3 compound or its derivative e.g. niacin, nicotinic acid, niacinamide or other well known skin lightening agents e.g. aloe extract, ammonium lactate, azelaic acid, kojic acid, citrate esters, ellagic acid, glycolic acid, green tea extract, hydroquinone, lemon extract, linoleic acid, magnesium ascorbyl phosphate, vitamins like vitamin B6, vitamin B12, vitamin C, vitamin A, a dicarboxylic acid, resorcinol derivatives, hydroxycarboxylic acid like lactic acid and their salts e.g. sodium lactate, and mixtures thereof. Vitamin B3 compound or its derivative e.g. niacin, nicotinic acid, niacinamide are the more preferred skin lightening agent as per the invention, most preferred being niacinamide. Niacinamide, when used, is preferably present in an amount in the range of 0.1 to 10 %, more preferably 0.2 to 5 % by weight of the composition.

The composition according to the invention may also comprise other diluents. The diluents act as a dispersant or carrier for other materials present in the composition, so as to facilitate their distribution when the composition is applied to the skin. Diluents other than water can include liquid or solid emollients, solvents, humectants, thickeners and powders.

The composition of the invention may comprise a conventional deodourant base as the cosmetically acceptable carrier. By a deodorant is meant a product in the stick, roll-on, or propellant medium which is used for personal deodorant benefit e.g. application in the under-arm or any other area which may or may not contain anti-perspirant actives.

Deodorant compositions can generally be in the form of firm solids, soft solids, gels, creams, and liquids and are dispensed using applicators appropriate to the physical characteristics of the composition.

The compositions of the present invention can comprise a wide range of other optional components. The CTFA Cosmetic Ingredient Handbook, Second Edition, 1992, which is incorporated by reference herein in its entirety, describes a wide variety of non-limiting cosmetic and pharmaceutical ingredients commonly used in the skin care industry, which are suitable for use in the compositions of the present invention. Examples include: antioxidants, binders, biological additives, buffering agents, colorants, thickeners, polymers, astringents, fragrance, humectants, opacifying agents, conditioners, exfoliating agents, pH adjusters, preservatives, natural extracts, essential oils, skin sensates, skin soothing agents, and skin healing agents. The invention is now further described by way of the following non-limiting examples.

Examples

Examples 1 to 5

Photoprotective personal care vanishing cream compositions as shown in table 1 were prepared and the Invitro-SPF was measured using the Optometries 290S instrument model in accordance with standard ISO/WD 24445. The substrate used was a 8 cm Transpore tape (3M Company). The sample was applied at 2 mg/cm² The SPF as measured is shown in table 1 .

Table 1

Ingredients Example 1 Example Example Example Example

2 3 4 5

Hystric acid 17.00 17.00 17.00 17.0 17.0

KOH 0.60 0.60 0.60 0.60 0.6

Ethylhexyl methoxycrylene 5.0 5.0 5,0 7.0 5.0

Brij 35 (HLB = 17) 0 2.00 5.0 2.0 2.0

Parsol MCX 0 0 0 0 2.25

Water To 100 To 100 To 100 To 100 To 100

SPF 5.1 11.0 10.5 14.8 28

The data in table 1 indicates that compositions as per the invention (examples 2 to 5) provide for high SPF while the composition outside the invention (example 1 ) does not.

Examples 6 to 8: Effect of fatty acid concentration

Photoprotective personal care cream compositions as shown in table 2 were prepared and the Invitro-SPF was measured in accordance with ISO/WD 24445. The SPF values as measured are shown in table 2.

Table 2

Ingredients Example Example Example

6 7 8

Hystric acid 0 5 10

KOH 0.6 0.6 0.6

Carbopol® ETD 2020 Polymer: INCI Name: Aery lates/C 10-30 Alkyl Acrylate Crosspolymer The data in table 2 indicates that inclusion of fatty acid within the claimed concentration range provides for the enhanced SPF

Examples 9 to 1 1 : Effect of various non-ionic surfactants

Compositions similar to example 2 were prepared except that the non-ionics as per table 3 were used instead of Brij-35. The Invitro-SPF values were measured in accordance with ISO/WD 24445 and the data is presented in table 3.

Table 3

Span Series:

= Group consisting of carbon chain of 2 to 24; Rl

Span 60

Span 65

The data in table 3 indicates that many other non-ionic surfactants can be used in the composition of the invention but higher SPF values are obtained when non- ionic surfactant having HLB higher than 9 are used. The present invention thus provides for a high SPF photo-protective sunscreen composition. All this is achieved using low amounts of sunscreen agents thereby keeping costs low.

Claims

1. A sunscreen composition comprising,

a) 0.05 to 15 % by weight compound of formula;

where R1 and R2 are each independently hydrogen or straight or branched chain C1 -C30 alkoxy group, where R1 and R2 are not simultaneously hydrogen;

and R3 is a straight or branched chain C1 -C30 alkyl group;

(b) 0.01 % to 10 % by weight a non-ionic surfactant; and

(c) a cosmetically acceptable base comprising 1 to 25 % by weight fatty acid.

2. A composition as claimed in claim 1 wherein the cosmetically acceptable base comprises 0.1 to 10% by weight soap.

3. A composition as claimed in claim 1 or claim 2 wherein said non-ionic surfactant has an HLB value of at least 9.

4. A composition as claimed in claim 3 wherein said non-ionic surfactant is selected from the class comprising

(b) fatty alcohol ethoxylates with unsaturated carbon chain with HLB higher than 12

(c) alkyl phenol ethoxylates having HLB higher than 15;

(d) polyoxyethylene sorbitan alkyl esters with saturated C12 to C16 carbon chain and having HLB higher than 12; or (e) polyoxyethylene sorbitan alkyl esters with unsaturated C18 carbon chain and having HLB higher than 9.

5. A composition as claimed in any one of the preceding claims further comprising 0.01 to 10 % by weight of a UVA and/or UVB sunscreens.

6. A composition as claimed in claim 5 wherein said UVA sunscreen is a dibenzoylmethane derivative.

7. A composition as claimed in claim 6 wherein said dibenzoylmethane derivative is 4-tert-butyl-4'-methoxydibenzoylmethane.

8. A composition as claimed in any one of claims 5 to 7 wherein said UV-B organic sunscreen is selected from the group consisting of cinnamic acid, salicylic acid, diphenyl acrylic acid and derivatives thereof.

9. A composition as claimed in claim 8, wherein said UV-B sunscreen is 2- ethyl-hexyl-4-methoxy cinnamate.

10. A composition as claimed in any one of the preceding claims comprising less than 10 % by weight total organic sunscreens.

1 1 . A composition according to any one of the preceding claims further comprising a fatty acid, preferably 1 -25 % fatty acid, more preferably 5-20 % fatty acid.