WO1999037281A1

WO1999037281A1 - Skin care cosmetic method and system

Info

Publication number: WO1999037281A1
Application number: PCT/EP1999/000335
Authority: WO
Inventors: Stephan Samuel Habif; Helen Elizabeth Knaggs; William Dwight Becker; Martha Ann Brown; Philip Edward Miner
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Lever Limited
Priority date: 1998-01-23
Filing date: 1999-01-21
Publication date: 1999-07-29
Also published as: AU2423099A; AR018736A1

Abstract

A cosmetic system and method for delivering a compound having an octanol/water coefficient log P in the range of from -2 to 6 to the skin. Also disclosed is a cosmetic method and system for protecting the skin from UV ray damage, after the skin has been stripped with an adhesive composition.

Description

- 1 -

SKIN CARE COSMETIC METHOD AND SYSTEM

FIELD OF THE INVENTION

The invention relates to a system and a method for cosmetic skin care.

BACKGROUND OF THE INVENTION

Cosmetic skin care compositions typically contain one or more active molecules which deliver a cosmetic benefit (e.g., anti-aging, moisturization, oil control) to the skin. To impart the benefit, an active molecule must be able to penetrate across the stratum corneum and the debris on the skin into the viable layers of the skin. The stratum corneum, however, is a good barrier and in general very little amount of active ingredients would find its way to the living tissues. To improve delivery, skilled formulators often use penetration enhancers which tend to reduce the barrier function of the stratum corneum. Delivery, however, is still not optimum. Thus, there exists the need to improve the delivery of a cosmetic benefit compound to ensure maximum efficacy.

Transdermal patches are often used by pharmaceutical companies for prolonged continuous delivery of medically active molecules across the skin into the blood stream where they will be transported to other regions of the body for benefits such as hormone replacement therapy or smoking cessation. The transdermal patch method consists in the application on a small region of skin of an adhesive patch which contains: (a) an active ingredient often diluted in a - 2 -

fluid carrier which may or may not contain penetration enhancers, (b) a backing or support made of a polymer which provides partial or total occlusion to the skin, and (c) an adhesive polymer which ensures that the patch sticks to the skin and that the active ingredient stays in close contact with the skin for the duration required for efficacy. Transdermal patches are kept on the skin for extended periods of time (several hours or days or weeks) .

Use of transdermal patches in a cosmetic field is undesirable: the patches are unsightly which precludes their prolonged use, especially on the face; their required prolonged use for efficacious delivery results in hyper- moisturization of the skin which leads to local irritation, and irritation is often exacerbated by the prolonged contact of the adhesive with the skin.

In the cosmetic field, beauty treatments consisting of applying to the skin a peelable mask, followed by application of other cosmetic compositions are known. Such peelable masks, however, do not sufficiently remove external layers of the skin to attain significantly improved penetration of the subsequently applied cosmetic benefit compound.

Adhesive strips to unclog pores and remove blackheads have been introduced into a cosmetic market recently (e.g., Pond's® Clear Pore Strips). See also U.S. Patent 5,512,277 (Uemura et al . ) . Unlike transdermal patches, cosmetic adhesive strips are usually applied to the skin for a short time (e.g., 10-15 minutes). Such products do not, however, include or suggest the use of any skin care cosmetic compositions following the removal of the strip. - 3 -

US Patent 4,752,472 (Kligman) discloses applying a layer of a liquid polymerizable adhesive (alpha-cyanocrylate) , then a strip of an adhesive is applied before the cyanocrylate is completely polymerized. After the cyanoacrylate coating is completely polymerized, the tape is removed from the skin. It is said that the materials on the surface of the skin and within the sebaceous glands are removed with the polymerized adhesive. A hyper-emollient cream may be applied to sooth any irritation. The process taught by Kligman has several disadvantages. The consumer may find it messy and inconvenient to apply a cyanoacrylate glue separately from the tape (e.g., the timing has to be carefully controlled); the cyanoacrylate glue is very strong and its application to the skin is likely to result in an excessive damage to the skin; and the cream applied to the skin after removal of the tape is merely an emollient cream, to reduce the cyanoacrylate glue irritation of the skin. The use of cyanoacrylate glue on the skin is not commercially desirable, and has to be carefully controlled as to the duration of each application and the total duration and frequency of repeated applications.

The stripping of the skin with an adhesive potentially makes the viable skin cells more susceptible to UV radiation, which is known to result in the appearance of wrinkled, dry, hyperpigmented and aged skin. The art does not appear to recognize this problem. Likewise, although the art recognizes the challenge of delivering compounds into the viable layers of the skin, the art does not offer the solution according to the present invention. The significant advantage of a sequential use of an adhesive- containing composition, followed by a delivery of a - 4 -

sunscreen or certain cosmetic benefit agents has not been realized prior to the present invention.

SUMMARY OF THE INVENTION

The present invention includes a cosmetic system for skin care comprising:

(i) a flexible substrate sheet comprising a backing formed from a mixture of hydrophilic and hydrophobic material, wherein the amount of the hydrophilic material is in the range of from 20 to 60 %, by weight of the backing, and the amount of hydrophobic material is in the range of from 40 to 80 % , by weight of the backing, and impregnated with an adhesive composition containing an anionic, cationic, nonionic, amphoteric or zwitterionic polymer; and

(ii) a cosmetic skin care composition comprising a compound selected from the group consisting of a sunscreen and a compound having a log P (log of the octanol/water partition coefficient) in the range of from -2 to 6, and mixtures thereof;

wherein the composition is contained in a separate unit from the sheet ;

(iii) instructions for a sequential application to the skin of the sheet followed by the composition.

The present invention also includes two cosmetic methods: (i) a cosmetic method for delivering a compound having a log P in the range of from -2 to 6 to the skin, and (ii) a cosmetic method of protecting the skin from UV radiation. According to the inventive methods, the sheet is used first over the desired area of the skin. This step is generally carried out for a relatively brief interval of time. After the sheet is removed, a skin care composition containing a sunscreen and/or a compound having a log P in the range of from -2 to 6 is applied to the same area of the skin.

This consecutive but not concomitant use of the sheet and the cosmetic benefit formulation allows for a brief use of the adhesive sheet, typically no more than fifteen to thirty minutes, a duration more acceptable to skin care consumers and which results in very limited skin irritation potential compared to the transdermal patch. The use of the adhesive sheet unclogs the pores and removes blackheads . The use of the specific hydrophilic/hydrophobic sheets according to the invention also improves the delivery of certain actives to the skin.

The present invention is based at least in part on the discovery that the use of adhesive sheets on the skin presents a problem and an advantage at the same time: it increases the potential damage to the viable layers from the environmental exposure (hence, the advantageous use of sunscreen) , yet the delivery of some cosmetic benefit agents to the viable layers is improved.

DETAILED DESCRIPTION OF THE INVENTION

Adhesive Sheet:

An essential part of the inventive system and method is a flexible substrate sheet impregnated with an adhesive - 6 -

composition containing an anionic, cationic, nonionic, amphoteric or zwitterionic polymer. In a dry state, the composition preferably but not necessarily is non-tacky to the touch. The sheet included in the present invention is formed of a mixture of hydrophilic and hydrophobic materials. This mixture may be in the form of a single layer or multiple layers. When multiple layers are employed, a dual hydrophilic/ hydrophobic character of the sheet may be achieved by using alternating hydrophilic and hydrophobic layers, or each layer may be a blend of a hydrophilic and hydrophobic materials.

Suitable hydrophilic materials include but are not limited to: cotton, flax, wool, rayon, silk and acetate.

Suitable hydrophobic materials include but are not limited to: polyethylene, polypropylene, polyester, polystyrene, vinyl, polyolefins .

These materials may be woven or nonwoven, or a foam. Materials formed from combinations of cellulosic with thermoplastic fibers may also be employed. For instance, a hydrophilic polypropylene/rayon combination can be employed for the present invention.

Also, the materials for the hydrophobic layer and the hydrophilic layer may be treated with a surface active agent selected from a fatty acid ester-type nonionic surface active agent, a polyglycerol fatty acid ester, an alkyl ether sulfate, a higher alcohol sulfate, a metal salt of alkylphosphate and mixtures thereof to give the material hydrophilic property as occasion demands. - 7 -

The preferred flexible sheet backing is formed of a mixture of rayon (20-40%) and polypropylene (60-80%) .

The impregnated substrate sheet is preferably sealably enclosed in a pouch, particularly a laminated foil package to control moisture level (to prevent the adhesive from getting brittle and crumbling off the sheet) .

The sheet may be shaped to accommodate the desired area of the application, e.g., as a circle, as a nose strip, as a rectangle.

If the sheet is enclosed in a pouch, the pouch is normally of the laminated foil variety. These are heat sealed and utilize foils with very low vapor (e.g., moisture) transmission rates (a rate of transmission less than 5% per day, preferably less than 1% per day volatile fluid gain or loss) . Walls suitable for the pouch may utilize polyester, polyethylene or polypropylene sheets, several layers of which can be laminated together. These layers may also be provided with a coating of wax or other volatile fluid impermeable material .

The sheet is used by either directly wetting the composition on the sheet or indirectly by wetting the face in areas to be contacted by the composition. In either instance, the wetting agent interacts with the composition so it becomes tacky and sufficiently mobile to adhere to the skin. If the sheet is in a pouch, it must be removed therefrom prior to wetting; the time between removal of strip from the pouch and use may be anywhere from 5 seconds to several hours, using from 10 to 20 seconds. Water is the preferred wetting agent. However, other liquid systems or gels could be - 8 -

employed. Suitable wetting agents would include alcohols such as ethanol, propanol, propylene glycol, polyethylene glycol, polypropylene glycol and especially mixtures of these alcohols with water. Gels would normally consist of structured liquids (particularly water) thickened with structuring agents such as Carbomer.

Subsequent to wetting, the sheet composition is allowed to dry over the area of treatment. During drying, the skin stickingly adheres to the sheet composition. Advantageously the drying period ranges from 1 minute to 5 hours, preferably from 5 minutes to 1 hour, optimally from 10 to 20 minutes. Thereafter, the dried composition with adhered keratotic and accumulated dead superficial skin cells plugs is peeled from the skin.

The composition includes an adhesive polymer which may either be anionic, cationic, nonionic, amphoteric, zwitterionic or mixtures thereof. Mixtures may be of polymers within any one category or between different category types. Illustrative of the latter is a combination of an anionic and nonionic polymer.

Examples of nonionic polymers suitable for adhesive film deposition are the copolymers of vinyl acetate and crotonic acid, terpolymers of vinyl acetate, crotonic acid and a vinyl ester of an alpha-branched saturated aliphatic monocarboxylic acid such as vinyl neodecanoate; copolymers of methyl vinyl ether and maleic anhydride (molar ratio about 1.1) wherein such copolymers are 50% esterified with a saturated alcohol containing from 1 to 4 carbon atoms such as ethanol or butanol; and acrylic copolymers, terpolymers, etc., containing acrylic acid or methacrylic acid esters of - 9 -

acrylic or methacrylic acid with one or more saturated alcohols having from 1 to 22 carbon atoms such as methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, t-butyl acrylate, t-butyl methacrylate, n-butyl methacrylate, n-hexyl acrylate, n-octyl acrylate, lauryl methacrylate and behenyl acrylate, glycols having from 1 to 6 carbon atoms such as hydroxypropyl methacrylate and hydroxyethyl acrylate, styrene, vinyl caprolactam, vinyl acetate, acrylamide, alkyl acrylamides and methacrylamides having 1 to 8 carbon atoms in the alkyl group such as methacry1amide, t-butyl acrylamide and n-octyl acrylamide, and other compatible unsaturated monomers. One specific example is the emulsion polymerized terpolymer of methacrylic acid, n-butyl acrylate and ethyl acrylate (e.g., in a weight percent ratio of 31:42:27, respectively).

Further examples of nonionic adhesive polymers are homopolymers of N-vinylpyrrolidone and copolymers of N-vinylpyrrolidone with compatible nonionic monomers such as vinyl acetate and terpolymers of ethyl acrylate, butyl methacrylate and methyl methacrylate. Nonionic polymers containing N-vinylpyrrolidone in various weight average molecular weights are available commercially from ISP Corporation such as homopolymers of N-vinylpyrrolidone having an average molecular weight of about 630,000 under the trademark PVP K-90 and those having an average molecular weight of about 1,000,000 sold under the trademark of PVP K-120. Particularly preferred is poly (methyl vinyl ether/maleic anhydride) as an unneutralized resin available from ISP Corporation under the trademark Gantrez® S-97 BF .

Anionic adhesive polymers often are derived from the nonionic types which include carboxylic acid functions. - 10 -

Alkaline agents are employed to neutralize the carboxylic acid or anhydride transforming them into anionic salts. Examples of suitable neutralizing agents include 2-amino-2-methyl-l, 3-propanediol (AMPD) ; 2-amino-2-ethyl-l, 3-propanediol (AEPD) ;

2-amino-2-methyl-l-propanol (AMP) ; 2-amino-l-butanol (AB) ; monoethanolamine (MEA) ; diethanolamine (DEA) ; triethanolamine (TEA) ; monoisopropanolamine (MIPA) ; diisopropanolamine (DIPA) ; triisopropanolamine (TIPA) ; and dimethyl stearamine (DMS) . Most preferred is AMP.

Particularly preferred anionic polymers are the salts of poly (methyl vinyl ether/maleic anhydride) and polystyrene sulfonic acid. The former is obtained by at least partial neutralization of Gantrez® S-97 BF and the latter available from the National Starch & Chemical Company under the trademarks Versa TL-501 and Flexan® 130 having respective molecular weights of about 500,000 and 100,000. Other polymer films which may be employed and are commercially available as listed in Table A below.

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TABLE A

POLYMER TRADEMARKS CTFA DESIGNATIONS (SUPPLIER)

Resyn® 28-1310 (NSC) Vinyl acetate/crotonic acid copolymer

Resyn® 28-2930 (NSC) Vinyl acetate/crotonic acid/vinyl neodecanoate copolymer

Resyn® 28-2913 (NSC) Vinyl acetate/crotonic acid/vinyl neodecanoate copolymer

Versatyl® 40 (NSC) Octylacrylamide/acrylates copolymer

Versatyl® 42 (NSC) Octylacrylamide/acrylates copolymer

Experimental Resin Vinyl acetate/vinyl (NSC) neodecanoate/maleic half-ester

Ultrahold-8® (BASF) Acrylate/acrylamide copolymer

Luviset® CAP (BASF) Vinyl acetate/crotonic acid/vinyl propionate copolymer

PVP K-30 (ISP) PVP

PVP/VA E-335 (ISP) PVP/Vinyl acetate copolymer

PVP/VA E-735 (ISP) PVP/Vinyl acetate copolymer

Gantrez® ES-225 (ISP) Ethyl ester of PVM/MA copolymer

Gantrez® ES-425 (ISP) Butyl ester of PVM/MA copolymer

Gaffix® VC-713 (ISP) Vinyl caprolactam/PVP/dimethyl aminoethyl methacrylate copolymer

Cationic adhesive polymers suitable for the present invention may be prepared as homo- or copolymers from monomers including:

Dimethyl aminoethyl acrylate (DMAEA) , Dimethylaminoethyl methacrylate (DMAEMA) , Dimethylaminopropylacrylamide

(DMAPAAm) , and Dimethylaminopropyl methacrylamide (DMAPMAAm) - 12 -

which are all (meth) acrylamides or (meth) acrylic acid esters having a dialkylamino group;

Dimethylaminostyrene (DMASt) and Dimethyaminomethylstyrene (DMAMSt) and the like which are styrenes having a dialkylamino group;

4-Vinyl pyridine and 2-vinyl pyridine which are vinyl pyridines ; and

Quaternized products of these with a known quaternizing agent such as alkyl halide, benzyl halide, alkyl or aryl sulfonic acid, or dialkyl sulfate.

Among suitable amphoteric adhesive polymers are those derived from monomers such as :

N- (3-sulfopropyl) -N-acryloyloxyethyl-N,N-dimethylammonium betaine, N- (3-sulfopropyl) -N-methacroylamidepropyl-N,N- dimethylammonium betaine, N- (3-carboxymethyl) -N- methacroylamidepropyl-N,N-dimethylammonium betaine and N- carboxymethy1-N-methacroyloxyethy1-N,N-dimethylammonium betaine.

When the salt forming group of the cationic and amphoteric polymers is not ionized, it is preferred to ionize it via neutralization with known acids such as hydrochloric acid and sulfuric acid which are inorganic acids; acetic acid, propionic acid, lactic acid, succinic acid, glycol acid which are organic acids, or with known bases such as triethylamine, trimethylamine which are tertiary amines; ammonia; or sodium hydroxide. - 13 -

Suitable adhesive compositions for sheets are also described by Uemura et al . , (U.S. Patent 5,512,277), which is incorporated by reference herein.

Milder adhesives are preferred, so that the skin is not damaged and made raw. Yet the adhesive must be sufficiently strong to remove unwanted substances from stratum corneum and weaken the stratum corneum barrier function. For this reason, glues such as cyanoacrylates are preferably not used.

It is advantageous to employ a ratio of composition to substrate sheet in amount ranging from 0.1:1 to 1,000:1, preferably 0.5:1 to 100:1 and optimally 0.8:1 to 10:1 by weight. The polymer ordinarily will constitute from 50 to

100%, preferably from 75 to 99%, optimally from 85 to 95% by weight of the composition deposited onto the substrate sheet .

- The sheet may, and preferably does include additional ingredients (in addition to an adhesive) to improve blackhead removal, while also improving the active delivery to the skin. The preferred additional ingredients include

- 14 -

- opacifying agents (0-1% by weight of the mixture, e.g. silica, titanium dioxide) ;

- materials which aid in spreading the adhesive on the skin by lowering the surface tension of the composition, such as dimethicone copolyol, ethyleneglycol, polyethylene glycols, propylene glycol, polypropylene glycols, butylene glycol, glycerols, sugar alcohols, ethylene oxides, fatty acid esters, branched alkyl ethers, and other polyols (0- 0.5% by weight of the mixture); - a preservative (0.001-0.01%, by weight of the mixture).

Although the sheet may also carry a cosmetic active ingredient, which may or may not be chosen from those listed below, the invention includes a cosmetic skin care composition which is in a separate unit from the sheet.

Cosmetic Skin Care Composition:

Cosmetic skin care compositions included in the present invention contain a compound selected from the group consisting of a sunscreen, a compound having an octanol/water log P in the range of from -2 to 6 to the skin, and mixtures thereof.

Log P is a value that reflects the polarity of a compound. The higher the number, the less polar the compound. Log P may easily be determined experimentally, using the following procedure :

Octanol/water log P is most conveniently measured in the laboratory using a radiolabeled test compound added to the non-radiolabeled compound of interest. It is - 15 -

imperative that the test compound (s) , water, and n- octanol be of the highest purity available.

Prior to the partitioning test, the n-octanol phase is saturated with water, and vice versa, by gently mixing equal volumes of the solvents by slowly inverting on a rotator overnight. Four 15-ml glass screw cap centrifuge tubes each containing 6 ml each of water and n-octanol is a convenient means to provide sufficient solvent to perform one log P determination in triplicate. The mixture is separated by centrifuging and carefully isolating the two phases, discarding a generous interface region between the layers, and re-centrifuging where necessary. If the test material is ionizable, sufficient acid or base, must be added to the aqueous phase to maintain the test material in its unionized form at the anticipated test compound concentration (0.005-0.01 M) prior to the solvent saturation step.

For the partitioning step, pure non-labeled test compound plus radiolabeled test compound is added to either the octanol-saturated aqueous phase or the water-saturated octanol phase to yield a concentration in the range of about 0.005 to 0.01 Molar, with the material being added to the solvent in which it has the greater solubility. (It must be completely soluble in this phase at the starting concentration.) Twenty (20) ml is a reasonable volume to prepare for one log P determination in triplicate.

Radioisotope concentration of about 0.5 μCi/ml would be sufficient for most materials. Aliquots of this original solution should be counted prior to initiating the partitioning step for future reference. For the actual partitioning, precisely equal volumes of the radiolabeled - 16 -

phase and of the alternate phase are combined and gently equilibrated overnight . Total ten-ml mixtures, i.e., five- ml aqueous phase plus five-ml n-octanol phase slowly rotated in 15-ml glass screw cap centrifuge tubes, in triplicate, are convenient.

To assay for test compound in the equilibrated phases, the tubes are centrifuged and triplicate aliquots, e.g., 100 μL, of the upper octanol phase are removed using a positive displacement pipet and weighed into scintillation vials.

The remaining n-octanol phase is removed from each tube and the underlying aqueous layers re-centrifuged. Any traces of octanol are carefully removed and discarded, and triplicate aliquots of the aqueous phase e.g., 100 μL, are weighed into scintillation vials. For water soluble test compounds, an aqueous base liquid scintillation cocktail such as Ecolume (ICN Biomedicals, Inc., Irvine, CA) is added directly to the water phase aliquots. For the octanol phas^'e, a ml of water should be added to the octanol aliquots and the samples treated in a sonic bath for 30 minutes before addition of aqueous-based liquid scintillation cocktail. For highly lipophilic materials alternative cocktails and sample treatment may be appropriate.

The log P value is calculated by dividing the test compound concentration, or dpm, in the octanol layer by the test compound concentration, or dpm, in the aqueous layer, and expressing the quotient as the base 10 logarithm.

Examples of the compounds having log P within the range of - 2 to 6 include but are not limited to the following compounds : - 17 -

Molecule Molecular Weight log P

Ascorbic Acid 176.12 -1.64

Glycolic Acid 76.05 -1.11

Succinic Acid 118.09 -0.59

Salicylic Acid 138.12 2.26

Retinol 286.44 5.68

The term "retinol" includes the following isomers of retinol all-trans-retinol, 13-cis-retinol, 11-cis-retinol, 9-cis- retinol, 3 , 4-didehydro-retinol . Preferred isomers are all- trans-retinol, 13-cis-retinol, 3 , 4-didehydro-retinol, 9-cis- retinol . Most preferred is all-trans-retinol, due to its wide commercial availability.

When the compound is a hydroxy acid and when stereo isomers exist, L-isomer is most preferred.

It is to be understood that depending on the pH of the composition, the hydroxy acid may be present as a salt, e.g., ammonium or potassium or sodium salt. Hydroxy acid may also be present as an ester.

Sunscreens include those materials employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, octyl methoxycinnamate, avobenzone (Parsol 1789^®) and 2- hydroxy-4-methoxy benzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone are commercially available under the trademarks, Parsol MCX and Benzophenone-3 , respectively. The exact amount of sunscreen employed in the emulsions can vary depending upon the degree of protection desired from the sun's UV radiation. - 18 -

Preferably the amount of the sunscreen or the compound with log P of from -2 to 6 is from 0.0001 to 20%, more preferably from 0.001 to 10% and most preferably from 0.01 to 5% by weight .

The cosmetic skin care composition also includes a cosmetically acceptable vehicle or a carrier which is inert, usually an ingredient present in the highest amounts, and functioning to deliver active ingredients. The composition may be solid, aqueous liquid or anhydrous.

Vehicles other than or in addition to water can include liquid or solid emollients, solvents, humectants, thickeners and powders. An especially preferred nonaqueous carrier is a polydimethyl siloxane and/or a polydimethyl phenyl siloxane. Silicones of this invention may be those with viscosities ranging anywhere from about 10 to 10, 000,000mm^2/s(centistokes) at 25°C. Especially desirable are mixtures of low and high viscosity silicones. These silicones are available from the General Electric Company under trademarks Vicasil, SE and SF and from the Dow Corning Company under the 200 and 550 Series. The cosmetically acceptable vehicle will usually form from 5% to 99.9%, preferably from 25% to 80% by weight of the composition, and can, in the absence of other cosmetic adjuncts, form the balance of the composition.

Preferably, water comprises at least 50 wt.% of the inventive emulsion, most preferably from 60 to 80 wt.%, by weight of the composition. - 19 -

Optional Skin Benefit Materials and Cosmetic Adjuncts

An oil or oily material may be present, together with an emulsifier to provide either an oil-in-water or water-in-oil emulsion.

Emollients are often incorporated into cosmetic compositions of the present invention. Levels of such emollients may range from 0.5% to 50%, preferably between 5% and 30% by weight of the total composition. Emollients may be classified under such general chemical categories as esters, fatty acids and alcohols, polyols and hydrocarbons.

Esters may be mono- or di-esters. Acceptable examples of fatty di-esters include dibutyl adipate, diethyl sebacate, disopropyl dimerate, and dioctyl succinate. Acceptable branched chain fatty esters include 2-ethyl-hexyl myristate, isopropyl stearate and isostearyl palmitate. Acceptable tribasic acid esters include triisopropyl trilinoleate and trilauryl citrate. Acceptable straight chain fatty esters include lauryl palmitate, myristyl lactate, oleyl eurcate and stearyl oleate. Preferred esters include coco- caprylate/caprate (a blend of coco-caprylate and coco- caprate) , propylene glycol myristyl ether acetate, diisopropyl adipate and cetyl octanoate.

Suitable fatty alcohols and acids include those compounds having from 10 to 20 carbon atoms. Especially preferred are such compounds such as cetyl, myristyl, palmitic and stearyl alcohols and acids.

Among the polyols which may serve as emollients are linear and branched chain alkyl polyhydroxyl compounds. For - 20 -

example, propylene glycol, sorbitol and glycerin are preferred. Also useful may be polymeric polyols such as poly-propylene glycol and polyethylene glycol . Butylene and propylene glycol are also especially preferred as penetration enhancers .

Exemplary hydrocarbons which may serve as emollients are those having hydrocarbon chains anywhere from 12 to 30 carbon atoms. Specific examples include mineral oil, petroleum jelly, squalene and isoparaffins .

Another category of functional ingredients within the cosmetic compositions of the present invention are thickeners. A thickener will usually be present in amounts anywhere from 0.1 to 20% by weight, preferably from about 0.5% to 10% by weight of the composition. Exemplary thickeners are cross-linked polyacrylate materials available under the trademark Carbopol from the B.F. Goodrich Company. Gums may be employed such as xanthan, carrageenan, gelatin, karaya, pectin and locust beans gum. Under certain circumstances the thickening function may be accomplished by a material also serving as a silicone or emollient. For instance, silicone gums in excess of 10 centistokes and esters such as glycerol stearate have dual functionality.

Powders may be incorporated into the cosmetic composition of the invention. These powders include chalk, talc, kaolin, starch, smectite clays, chemically modified magnesium aluminum silicate, organically modified montmorillonite clay, hydrated aluminum silicate, fumed silica, aluminum starch octenyl succinate and mixtures thereof . - 21 -

Other adjunct minor components may also be incorporated into the cosmetic compositions. These ingredients may include coloring agents, opacifiers and perf mes. Amounts of these other adjunct minor components may range anywhere from 0.001% up to 20% by weight of the composition.

The cosmetic composition is contained in a separate unit from the adhesive sheet (i.e., it is not on the sheet).

According to the present invention, the cosmetic system of the present invention includes the flexible sheet and the cosmetic composition as described above and the instructions for a sequential use of the sheet followed by the composition.

The sheet, the composition, and the instructions are preferably part of the same package, e.g., a kit. The package may include several or a plurality of sheets and a regular size container of the cosmetic composition; or it may include a single sheet and a small supply (e.g., three days' amount) of the cosmetic composition.

According to the cosmetic method of the present invention, the flexible sheet containing an adhesive is applied to the desired area of the skin. Generally, the sheet is applied for a relatively brief period, i.e., from 1 minute to 5 hours, preferably from 5 minutes to 1 hour. The sheet is then peeled off and the cosmetic skin care composition is applied within the next 72 hours, preferably within the next 48 hours, before the stratum corneum recovered its integrity, most preferably right after or within 1-30 minutes after the removal of the sheet. The composition is preferably repeatedly applied during the 72 hour period, e.g., at least - 22 -

once every 8 hours. The sheet is preferably applied to the skin once every 5-7 days to maximize the efficacy while minimizing the potential discomfort occasioned by the stripping.

The skin care cosmetic composition, for example from 1 to 10 ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then spread over and/or rubbed into the skin using the hand or fingers or a suitable device.

The composition can be packaged in a container to suit its viscosity and intended use by the consumer. For example, a lotion or fluid cream can be packaged in a bottle or a roll- ball applicator, or a capsule, or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar.

The following specific examples further illustrate the invention, but the invention is not limited thereto.

- 23 -

EXAMPLE 1

The delivery of various compounds with and without adhesive stripping of the skin was assessed.

Procedure:

RADIOLABEL SKIN PENETRATION METHOD

SUMMARY

The skin penetration tests used to determine delivery enhancement effects of pore cleansing strip treatment were performed using piglet skin, Bronaugh flow-through penetration cells and radiolabeled test materials. The skin was pretreated by applying the pore strip products as directed on the packages, then dosed with radiolabeled test actives in a cosmetic base. After six hours of unoccluded skin: product contact, excess product was washed off with water and the skin layers collected and counted for radioactivity. Details follow.

MATERIALS

Nolvasan-washed three-four (3-4) week old female dorsal piglet skin was obtained from Buckshire Corporation, Perkasie, PA. The skins were shipped on wet ice and stored at -70°C until use. A Norelco electric shaver model 815RX, and a Padgett Dermatome^R, model 250, Padgett Instruments, Kansas City, MO, were used to prepare the skin for testing. A ServoMed EPl evaporimeter, Stockholm, Sweden, was used to assess skin integrity prior to testing. 24 -

Teflon 'Bronaugh' flow-through penetration cells with 9-mm diameter orifices, heated cell blocks and Isco Retriever IV fraction collectors were purchased as a complete testing assembly from Crown Bio-Scientific, Somerville, NJ . The cell blocks were heated by means of a Haake constant temperature bath and Haake Cl immersion circulator from Cole Parmer, Niles, IL. Receptor fluid was pumped through the cell reservoirs via a Masterflex peristaltic pump, model 7518-10, and two Omnifit 8-way manual Teflon valves, also from Cole Parmer.

Receptor fluid was prepared using Hank's Balanced salt solution (Sigma H8264) and HEPES free acid (Sigma 9136) .

Samples were counted by liquid scintillation spectrometry using a Beckman LS 6500 Scintillation System, Beckman Instruments, Inc., Fullerton, CA. Borosilicate scintillation vials, 28-ml capacity, were purchased from Fisher Scientific, Springfield, NJ. All samples except dermis were counted in Ecolume™ liquid scintillation cocktail, ICN Biomedicals, Inc., Irvine, CA. Dermis samples were digested in NCSII™ tissue solubilizer, Amersham Corporation, Life Science Division, Arlington Heights, IL., then counted in Scinti-Verse BD cocktail from Fisher Scientific.

Skin pre-treatment was performed using 3M Scotch^R brand cellophane tape, or flexible adhesive sheets A and B, having a formulation as described in Table 1.

All test molecules were applied to the skin from cream base as described in Table 2. - 25 -

TABLE 1

Flexible sheet A - "Biore Pore Strip" Composition adhesive (cationic) silica glycerin dimethicone copolyol

Ti02 preservative

Non-woven alternating sheet backing hydrophilic/hydrophobic bilayer

Flexible sheet

B

Composition 87.8% gantrez (anionic) 3.98% propylene carbonate 0.76% silica 0.6% Ti02 0.25% Abil 8852 0.006 % glydant plus 6.624% water Blend backing

Non-woven a fiber blend of 30% rayon sheet backing (hydrophilic) and 70% polypropylene (hydrophobic)

ID

O TABLE 2 r_ o © σ. Height Percent in Formulation o\ Q* Chemical Name Trade Name/% Active ascorbic glycolic succinic salicylic retinol retinyl

63 acid acid acid acid palmitate

H υ disodium EDTA Sequesterene Na2 0.05 0.05 0.05 0.05 0.05 0.05

P. magnesium aluminium Veegum Ultra 0.60 0.60 0.60 0.60 0.60 0.60 silicate methyl paraben methyl paraben 0.15 0.15 0.15 0.15 0.15 0.15 simethicone Antifoam Emulsion 0.01 0.01 0.01 0.01 0.01 0.01 butylene glycol-1,3 butylene glycol-1,3 3.00 3.00 3.00 3.00 3.00 3.00 hydroxymethylcellulose Natrosol 250HHR 0.50 0.50 0.50 0.50 0.50 0.50 glycerin USP glycerin USP 2.00 2.00 2.00 2.00 2.00 2.00 xanthan gum Keltrol M 0.20 0.20 0.20 0.20 0.20 0.20 triethanolamine 99% TEA 99% 1.20 1.20 1.20 1.20 1.20 1.20 stearic acid Pristeren 4911 3.00 3.00 3.00 3.00 3.00 3.00 glyceryl hydroxy stearate Naturechem GMHS 1.50 1.50 1.50 1.50 1.50 1.50 stearyl alcohol Lanette 18DE0 1.50 1.50 1.50 1.50 1.50 1.50 cholesterol NF cholestrol NF 0.50 0.50 0.50 0.50 0.50 0.50 sorbitan stearate sorbitan stearate 1.00 1.00 1.00 1.00 1.00 1.00

CM PEG-100 stearate MYRJ 59 2.00 2.00 2.00 2.00 2.00 2.00 isostearyl palmitate Protache ISP 6.00 6.00 6.00 6.00 6.00 6.00

C12-C15 alchoholic Hetester FAO 3.00 3.00 3.00 3.00 3.00 3.00 octanoate sodium stearoyl lactylate Pationic SSL 0.50 0.50 0.50 0.50 0.50 0.50 1 dimethicone silicone Fluid 200 (50cts) 1.00 1.00 1.00 1.00 1.00 1.00 1 tocopheryl acetate vitamin E acetate 0.10 0.10 0.10 0.10 0.10 0.10 1 butylated hydroxytoluene Embanox BHT 0.05 0.05 0.05 0.05 0.05 0.05 propylparaben NF propylparaben NF 0.10 0.10 0.10 0.10 0.10 0.10 alpha-bisabolol alpha-bisabolol 0.20 0.20 0.20 hydroxycaprillicacid hydroxycaprillic acid 0.10 0.10 0.10 retinyl palmitate vitamin A Palmitate 84% 0.06 0.06 0.06 0.16 ascorbic acid vitamin C 2.00

00 glycolic acid glycolic acid 8.00 t- succinic acid succinic acid 8.00 salicylic acid salicylic acid 0.20 o retinol vitamin A 0.10 ammonium hydroxide 29% ammonium hydroxide 29% 0.53 2.5 1.22 0.1 water DI water DI 69.15 61.18 62.46 71.74 71.94 71.88 final pH: 3.8 3.8 3.8 4.3 7.6 7.6

27

The test materials were present in the base formulation in the amounts indicated in Table 3 and Table 2, replacing an equal weight of water. The radiolabeled test materials were purchased at 1 mCi/ml from American Radio-labeled Chemicals, Inc., St. Louis, MO, or DuPont New England Nuclear, Wilmington, DE, or Moravek Biochemicals , Brea, CA, as indicated in Table 4 as ARC (or ART) , NEC, or MC, respectively.

TABLE 3 Non-Radiolabeled Test Molecules

Weight Per Cent Formula Molecular

Non-Radiolabeled Test Molecule Supplier in pH Weight ^aLog P Formulation

Ascorbic Acid Sigma 2.0% 3.8 176.12 -1.64

Glycolic Acid Sigma 8.0% 3.8 76.05 1.11

Succinic Acid Sigma 8.0% 3.8 118.09 -0.59

Salicylic Acid Sigma 0.2% 4.3 138.12 2.26

Retinol Roche 0.1% 7.6 286.44 5.68

Retinyl Palmitate

B BAASSFF 0.1% 7.6 524.88 ^b15.51

TABLE 4 Radiolabeled Test Molecules

Specific

Radiolabeled Test Supplier/ Activity Solvent

Molecule Number

Ascorbic Acid[l-14C] NEC-146 8 mCi/mmol crystals

Glycolic Acid[2-14C] , Ca ARC-486 50 mCi/mmol water salt

Succinic Acid[2 , 3-14C] NEC-201 58 mCi/mmol EtOH/water 1

Salicylic Acid[7-14C] MC-1123 55 mCi/mmol EtOH/water 2

Retinol [15-3H] ART-556 20 Ci/mmol ethanol

Retinyl Palmitate [15-

ART-558 15 Ci/mmol toluene

3H] - 28 -

METHOD

Test Sample Preparation

Fully formulated non-radiolabeled test products were labeled with radioactive test material at least one day before the test by adding 30 μL of radiolabeled test material (1 mCi/ml) to a 1-gram sample of formulation to yield a 30 μCi/gram test product. The formulation was mixed with a closed-end capillary and equilibrated overnight. Radiolabel homogeneity was demonstrated by counting six (6) 2-μL aliquots taken from the top, middle, and bottom of the vial.

Skin Preparation and Flexible Adhesive Sheet Pre-treatment

On the day of the experiment, ca . 5xl5-cm skin sections were thawed at room temperature, shaved gently with an electric shaver, and sliced to either 380 or 510 μm thickness using a Padgett DermatomeN Tape stripping was performed by pressing fresh Scotch tape to one end of each skin section thirteen (13) times and then punching out equal numbers of 18-mm discs from the stripped and untreated sides of the skin. Flexible Adhesive Sheet pre-treatment was performed in two different ways. In the first method, the moist adhesive sheets were applied to one half of each dermatomed skin section, the sheets were permitted to dry until moderate resistance was met when the edges of the sheets were pulled gently away from the skin (15-30 minutes) , the sheets were removed, and equal numbers of 18-mm discs cut from the treated and untreated sides of the skin. In the second method, the discs were cut out first, randomized into two groups, and half of them applied to moistened flexible - 29

adhesive sheets, dried, etc. Individual test conditions are shown in Table 5.

Log P = Log of octanol: water partition coefficient. Except as noted, data from L.Hansch, A. Leo, D. Hoekman: Exploring QSAR Hydrophobic, Electronic, and Steric Constants, American Chemical Society, Washington, DC 1995. Example experimental method attached in Appendix B

Calculated, unrealistic in nature (KOWWIN Software, Syracuse Research Corporation, North Syracuse, NY)

TABLE 5 Individual Test Conditions

Test Skin

Test Pre-Treatment Compound Thickness Application Method

1 13XScotch Succinic 380 μm half-skin Tape

2 13XScotch Glycolic 380 μm half-skin Tape

3 Flexible Glycolic 510 μm half-skin Sheet A

4 Flexible Glycolic 510 μm half-skin Sheet A

5 Flexible Ascorbic 510 μm half-skin Sheet A

6 Flexible Retinol 510 μm half-skin Sheet A

7 Flexible Ret. Palm. 510 μm half-skin Sheet A

8 Flexible Glycolic 510 μm half-skin Sheet B

9 Flexible Glycolic 510 μm randomized Sheet B

10 Flexible Salicylic 510 μm randomized Sheet B

11 Flexible Retinol 510 μm randomized

Sheet B - 30 -

Skin Penetration Measurement Set-Up

Seven each of the pre-treated and untreated 18-mm skin discs were mounted in fourteen Bronaugh diffusion cells in two 32°C heating blocks. The discs were alternated in the blocks such that each block contained approximately equal numbers of pre-treated and untreated discs. HEPES Hank's balanced salts buffer, pH 7.4, was pumped through the cells, beneath and in contact with, the dermal (underside) skin surface at a rate of 5 ml/min. After 30 minutes equilibration, transepidermal water loss was determined using a ServoMed EPl evaporimeter .

The skin discs were dosed with 2 μL of the radiolabeled product using a 10-μL displaced volume pipet (Gilson M10) . The dose was rubbed evenly onto the 9-mm diameter exposed skin surface with a latex finger cot stretched over a cotton tip applicator. The finger cots were retained for radioisotope counting and the '100% applied dose' determined by subtracting the cot value from the 2-μL aliquot dpm value obtained during the homogeneity check in the test sample preparation section above.

The products were left in contact with the skin for six (6) hours, unoccluded, with receptor fluid being sampled at 1- hour intervals in 28-ml borosilicate scintillation vials (Fisher Scientific) . At the end of the six (6) hours, the skin surface was rinsed with triplicate ~l-ml aliquots of water, the skin discs were removed from the apparatus, and blotted with 1/3 of a Kim Wipe. The upper surface of each skin disc was tape-stripped by pressing 9 times with fresh Scotch transparent tape to obtain the stratum corneum, or in the case of the pre-treated skin, the upper 9 layers of - 31 -

residual stratum corneum plus epidermis. In some early studies the pre-treated skin was not tape-stripped for stratum corneum . When taken, tape strip dpm's from pre- treated skin were ultimately combined with the lower epidermal counts for uniformity in data presentation. Epidermis and dermis were separated with a scalpel identically for both pre-treated and untreated skin.

All samples except dermis were counted in Ecolume aqueous- based liquid scintillation cocktail. These included finger cot applicators, rinse solutions, Kimwipes, Scotch tape strips, epidermis, and receptor fluids. Epidermis samples were first sonicated for 30 minutes in one (1) ml of either water or ethanol (ethanol for retinol and retinyl palmitate only) . Ecolume was added to all samples to about 5 mm below the shoulder of the vials. Dermis samples were digested in 3 ml NCSII tissue solubilizer for 48 hours or until completely liquefied, and 100-μL aliquots of the dermal digests counted in ScintiVerse organic based liquid scintillation cocktail.

Samples were counted in a Beckman LS6500 scintillation system using the appropriate ¹⁴carbon or tritium factory- installed automated quench correction program.

Samples were counted for 10 minutes or to 2σ error of 1% .

Calculations

Calculations were performed in Lotus 123 spreadsheets. Data were reported as percent of applied dose present in each tissue compartment and in total receptor fluid for each - 32 -

sample. Disintegrations per minute (dpm) in the theoretical 100% applied dose was determined by subtracting the material retained on the finger cot applicator from the average measured radioactivity from the six (6) 2-μL aliquots of the radiolabeled test product described in Test Sample

Preparation section above. Percent of dose in each tissue compartment and receptor fluid sample was determined by dividing the dpm in the tissue or fluid sample by the dpm in the 100% theoretical dose. (Background dpm were subtracted from all samples and standards prior to any other calculations.) For dermis, dpm in the NCS dermis digest aliquots were multiplied by 30, after background subtraction, to account for the full dermis sample. Percent of dose in each tissue compartment or receptor fluid sample was averaged for the seven (7) samples in each test group to obtain the final figures presented in the results table. Suspected outliers were eliminated only if they met *Q-test criteria. Statistics were performed in the Lotus 123 spreadsheets using a homoscedastic Student's T-Test if F- test results were greater than 0.2, or a heteroscedastic T- Test if F-values were less than 0.2.

Delivery data are presented in the results table as delivery to combined skin tissue compartments, delivery to receptor fluid, and delivery to total tissue plus fluid delivery. Final test-to-control ratio percent was calculated by dividing total delivery to treated tissues by total delivery to untreated tissues and multiplying by 100.

*To perform the Q-test on suspected outliers:

1. Calculate the difference between the greatest and smallest value in the set. - 33 -

Calculate the difference between the suspected outlier and its nearest neighbor.

Divide the answer in Step 2 by the answer in Step 1 (result = ' Q' ) .

The suspected outlier may be rejected with 90% confidence if the result exceeds the value below:

No. of

Observation Q s 3 0.94

4 0.76

5 0.64

6 0.56

7 0.56

The results that were obtained are summarized in Table 6

V. r. o © ay

TABLE 6

63 H U 0-

Percent of Dose Delivered

Test Pre-Treatment Test Active Active Total Receptor Total Ratio Percent Ratio Compound Log P Mol.Wt Tissue Fluid Delivery Test :Untreated Percent p-value

1 Untreated 13xScotch Tape Succinic -0.59 118 5.5 0.3 5.8 143 0.0038 Treated 6.1 2.2 8.3

2 Untreated 13xScotch Tape Glycolic -1.11 76 4.7 0.6 5.3 309 0.0042 Treated 5.6 10.8 16.4

3 Untreated Flexible Sheet A Glycolic -1.11 76 5.8 0.3 6.1 174 0.0001 j Treated 9.9 0.7 10.6

4 Untreated Flexible Sheet A Glycolic -1.11 76 5.8 4.4 10.2 120 0.1873 Treated 7.2 5.0 12.2

1 5 Untreated Flexible Sheet A Ascorbic -1.64 176 2.7 1.0 3.7 170 0.0826 Treated 3.6 2.7 6.3

6 Untreated Flexible Sheet A Retinol 5.68 286 5.8 0.7 6.5 128 0.0200

1 Treated 7.8 0.5 8.3

7 Untreated Flexible Sheet A Ret . Palm 15.5 525 4.2 0.3 4.5 96 0.8756 Treated 4.0 0.3 4.3

8 Untreated Flexible Sheet B Glycolic -1.11 76 4.3 0.8 5.1 118 0.0622 Treated 5.0 1.0 6.0

9 Untreated Flexible Sheet B Glycolic -1.11 76 5.3 1.4 6.7 148 0.0012 Treated 6.3 3.6 9.9

10 Untreated Flexible Sheet B Salicylic 2.26 138 8.0 0.6 8.6 286 0.0002 Treated 22.6 2.0 24.6

11 Untreated Flexible Sheet B Retinol 5.68 286 5.8 0.6 6.4 114 0.1494 Treated 6.5 0.8 7.3

00 tn

O

- 35 -

It can be seen from the results in Table 6 that both Flexible Sheet A and Flexible Sheet B significantly enhanced delivery of compounds having a partition coefficient log P in the range of from -2 to 6 to the skin, with the exception of Sheet B/retinol combination.

EXAMPLE 2

A variety of polymers were evaluated for their adhesive effects in removing keratotic plugs from the skin. The polymers listed in Table 7 below were coated onto a non- woven resin bonded rayon (1 ounce/square yard) . A knife- over-roll was utilized in the coating operation. After coating, the non-woven polymer impregnated substrate sheets were dried at 75°C in a convection oven. They were then cut into small patches.

The test patches were applied to the face of panelists in an area containing several plugged pores . The plugged pores were counted. Water was applied to the patch and it was then placed over the test area with wet side down. Next, the patch was allowed to dry whereupon it was peeled off. The number of plugs removed were counted as they appeared on the adhesive patch. Percentage of plugs removed were calculated to reflect efficiency of the test product.

36

TABLE 7

POLYMER % DRIED % PLUGS POLYMER ON REMOVED NON-WOVEN

Dextrine 409 5-15

Polyvinyl Alcohol 441 10-20

Polyvinyl Acetate 347 30-40

PolyacrylamidomethyIpropane Sulfonic 119 5-15 Acid

PolyacrylamidomethyIpropane Sulfonic 275 25 Acid

Poly (methyl vinyl ether/maleic 113 90-100 anhydride)

98% Poly (methyl vinyl ether/maleic 116 80-95 anhydride) + 2% 2-amino-2-methyl-l- propanol

90% Poly (methyl vinyl ether/maleic anhydride) 145 90-100

10% Polyacrylamido methyIpropane

Sulfonic Acid

It should be understood that the specific forms of the invention herein illustrated and described are intended to be representative only.

Claims

- 37 -CLAIMS

1. A cosmetic system for skin care comprising:

(i) a flexible substrate sheet comprising a backing formed from a mixture of hydrophilic and hydrophobic material, wherein the amount of the hydrophilic material is in the range of from 20 to 60 %, by weight of the backing, and the amount of hydrophobic material is in the range of from 40 to

80 %, by weight of the backing, and impregnated with an adhesive composition containing an anionic, cationic, nonionic, amphoteric or zwitterionic polymer; and

(ii) a cosmetic skin care composition comprising a compound selected from the group consisting of a sunscreen and a compound having an octanol/water log P in the range of from -2 to 6, and mixtures thereof;

wherein the composition is contained in a separate unit from the sheet;

2. The system of claim 1 wherein the sheet, the composition and the instructions are packaged together in a single kit. - 38 -

3. A cosmetic method of delivering a compound having a log P in the range of from -2 to 6 to the skin, the method comprising:

(a) applying to the skin a flexible substrate sheet comprising a backing formed from a mixture of hydrophilic and hydrophobic material, wherein the amount of the hydrophilic material is in the range of from 20 to 60 %, by weight of the backing, and the amount of hydrophobic material is in the range of from 40 to 80 %, by weight of the backing, and impregnated with an adhesive composition containing an anionic, cationic, nonionic, amphoteric or zwitterionic polymer;

(b) removing the sheet;

(c) applying to the same area of the skin a cosmetic skin care composition comprising a compound having a log P in the range of from -2 to 6 to the skin .

4. A cosmetic method of protecting the skin from UV radiation , the method comprising:

(a) applying to the skin a flexible substrate sheet comprising a backing formed from a mixture of hydrophilic and hydrophobic material, wherein the amount of the hydrophilic material is in the range of from 20 to 60 %, by weight of the backing, and the amount of hydrophobic material is in the range of from 40 to 80 %, by weight of the backing, and impregnated with an adhesive composition - 39 -

containing an anionic, cationic, nonionic, amphoteric or zwitterionic polymer;

(b) removing the sheet;

(c) applying to the same area of the skin a cosmetic skin care composition comprising a sunscreen compound .

5. The method according to claim 3 or claim 4, wherein step (c) is carried out within a time period of from 30 minutes to 72 hours after step (b) .

6. The method according to claim 3 or 4, wherein step (a) is carried out once every week.