WO2000000167A1

WO2000000167A1 - Cosmetic skin care compositions

Info

Publication number: WO2000000167A1
Application number: PCT/EP1999/004274
Authority: WO
Inventors: Uma Santhanam; Ronni Lynn Weinkauf; Carol Annette Bosko; Laura Rose Palanker; Helene Marie Santanastasio
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 1998-06-26
Filing date: 1999-06-18
Publication date: 2000-01-06
Also published as: AU4899699A

Abstract

Cosmetic skin care compositions containing D-pipecolic acid and cosmetic method of improving the appearance of wrinkled, lined, dry, flacky, aged or photodamaged skin and improving skin thickness, elasticity, flexibility, radiance, glow and plumpness.

Description

COSMETIC SKIN CARE COMPOSITIONS

FIELD OF THE INVENTION

Cosmetic compositions containing D-pipecolic acid and the use of the compositions for improving the appearance and cosmetic condition of the skin.

BACKGROUND OF THE INVENTION

Cosmetic products which improve the appearance of skin are increasingly popular with consumers. These products aim to alleviate or delay the signs of aged or photoaged skin, such as fine lines and wrinkles, dry and sagging skin. Although the marketplace offers a variety of products, the cosmetic manufacturers continue the quest for alternative actives, in order to provide a consumer with a choice of products.

Pipecolic acid has been described in cosmetic compositions. For instance, US Patent 5,091,171 (Yu et al . ) discloses cosmetic compositions containg alpha-hydroxy acids and an amphoteric compound. Pipecolic acid is listed among suitable amphoteric compounds. Yu et al . , however, do not describe any enantiomers of pipecolic acid.

The present invention is based at least in part on the surprising discovery that D-pipecolic acid is significantly more effective than L-pipecolic acid at inhibiting keratinocyte differentiation and increasing glycosaminoglycan synthesis in the skin cells. This was unexpected, because with regard to other acids, it was the L-enantiomer, not the D-enantiomer, that was reported to be more effective. See for instance US Patent 5,702,711 (Parab) and Rawlings et al . , "Effect of Lactic Acid Isomers on keratinocyte synthesis, stratum corneum lipid levels and stratum corneum barrier function," Arch. Dermatol . Res. (1996), 288:383-390.

SUMMARY OF THE INVENTION

The present invention comprises a skin care composition comprising D-pipecolic acid in an amount of from 0.1 to 40 wt . % and a cosmetically acceptable vehicle.

The present invention also includes a cosmetic method of improving or preventing the condition of wrinkled, lined, dry, flaky, aged or photodamaged skin and improving skin thickness, elasticity, flexibility, radiance, glow and plumpness, which method includes applying to the skin the inventive composition. Compositions of the invention are intended for topical application to mammalian skin which is already dry, flaky, lined, wrinkled, aged, photodamaged, or the inventive compositions may be applied prophylactically to normal healthy skin to prevent or reduce the deteriorative changes.

The composition may be used in a cosmetic method to improve the production of glycosaminoglycans by fibroblasts and to inhibit keratinocyte differentiation.

The following detailed description and the examples illustrate some of the effects of the inventive compositions. DETAILED DESCRIPTION OF THE INVENTION

All amounts are by weight of the oil-in-water emulsion, unless otherwise specified.

The term "skin" as used herein includes the skin on the face, neck, chest, back, arms, hands and scalp.

For the avoidance of doubt 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 .

D-pipecolic acid is an essential ingredient of the inventive compositions.

D-pipecolic acid is used in the inventive compositions in an amount of from 0.1 to 40 %, preferably from 0.5 to 20%, most preferably from 1 to 10% . D-pipecolic acid may be obtained from Sigma Chemical Company.

The compositions according to the invention also comprise a cosmetically acceptable vehicle to act as a dilutant, dispersant or carrier for D-pipecolic acid in the composition, so as to facilitate its distribution when the composition is applied to the skin.

The vehicle may be aqueous, anhydrous or an emulsion. Preferably, the compositions are aqueous or an emulsion, especially water-in-oil or oil-in-water emulsion. Water when present will be in amounts which may range from 5 to 99%, preferably from 20 to 70%, optimally between 35 and 60% by weight .

Besides water, relatively volatile solvents may also serve as carriers within compositions of the present invention. Most preferred are monohydric Cι-C₃ alkanols. These include ethyl alcohol, methyl alcohol and isopropyl alcohol. The amount of monohydric alkanol may range from 1 to 70%, preferably from 10 to 50%, optimally between 15 to 40% by weight.

Emollient materials may also serve as cosmetically acceptable carriers. These may be in the form of silicone oils and synthetic esters. Amounts of the emollients may range anywhere from 0.1 to 50%, preferably between 1 and 20% by weight.

Silicone oils may be divided into the volatile and non-volatile variety. The term "volatile" as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms. Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25°C while cyclic materials typically have viscosities of less than about 10 centistokes. Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers . The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5 to about 25 million centistokes at 25°C. Among the preferred non-volatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 10 to about 400 centistokes at 25°C.

Among the ester emollients are:

(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate , isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.

(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.

(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di- fatty acid esters, polyethylene glycol

(200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly- fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters. (4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and arachidyl behenate.

(5) Sterols esters, of which cholesterol fatty acid esters are examples thereof.

Fatty acids having from 10 to 30 carbon atoms may also be included as cosmetically acceptable carriers for compositions of this invention. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erucic acids.

Humectants of the polyhydric alcohol -type may also be employed as cosmetically acceptable carriers in compositions of this invention. The humectant aids in increasing the effectiveness of the emollient, reduces scaling, stimulates removal of built-up scale and improves skin feel. Typical polyhydric alcohols include glycerol , polyalkylene glycols and more preferably alkylene polyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2, 6-hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. For best results the humectant is preferably propylene glycol or sodium hyaluronate . The amount of humectant may range anywhere from 0.5 to 30%, preferably between 1 and 15% by weight of the composition.

Thickeners may also be utilized as part of the cosmetically acceptable carrier of compositions according to the present invention. Typical thickeners include crosslinked acrylates (e.g. Carbopol 982), hydrophobically-modified acrylates (e.g. Carbopol 1382), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations of these gums. Amounts of the thickener may range from 0.0001 to 5%, usually from 0.001 to 1%, optimally from 0.01 to 0.5% by weight.

Collectively the water, solvents, silicones, esters, fatty acids, humectants and/or thickeners will constitute the cosmetically acceptable carrier in amounts from 1 to 99.9%, preferably from 80 to 99% by weight.

Optional Skin Benefit Materials and Cosmetic Adjuncts:

An oil or oily material may be present, together with an emulsifier to provide either a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average hydrophilic-lipophilic balance (HLB) of the emulsifier employed.

Surfactants may also be present in cosmetic compositions of the present invention. Total concentration of the surfactant will range from 0.1 to 40%, preferably from 1 to 20%, optimally from 1 to 5% by weight of the composition. The surfactant may be selected from the group consisting of anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a

C₁₀-C₂₀ fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C₂-C₁₀ alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di- fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di- C₈-C₂₀ fatty acids; block copolymers (ethylene oxide/propylene oxide) ; and polyoxyethylene sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty amides (e.g. methyl gluconamides) are also suitable nonionic surfactants .

Preferred anionic surfactants include soap, alkyl ether sulfate and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates,

C₈-C₂₀ acyl isethionates, acyl glutamates, C₈-C₂0 alkyl ether phosphates and combinations thereof.

Various types of additional active ingredients may be present in cosmetic compositions of the present invention. Actives are defined as skin benefit agents other than emollients and other than ingredients that merely improve the physical characteristics of the composition. Although not limited to this category, general examples include additional anti- oxidants, anti-aging ingredients and sunscreens.

Sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, avobenzophenone (Parsol 1789 ) octyl methoxycinnamate 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 compositions can vary depending upon the degree of protection desired from the sun's UV radiation.

Many cosmetic compositions, especially those containing water, must be protected against the growth of potentially harmful microorganisms. Preservatives are, therefore, necessary. Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds.

Particularly preferred preservatives of this invention are methyl paraben, propyl paraben, phenoxyethanol and benzyl alcohol. Preservatives will usually be employed in amounts ranging from about 0.1% to 2% by weight of the composition.

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

The composition according to the invention is intended primarily as a product for topical application to human skin, especially as an agent for improving skin's resilience and firmness, radiance and clarity and finish, and for preventing or reducing the appearance of lined, wrinkled, dry, aged or photoaged skin.

In use, a quantity of the composition, for example from 1 to 100 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.

Product Form and Packaging :

The cosmetic skin composition of the invention can be in any form, e.g. formulated as a gel, lotion, a fluid cream, or a cream. The composition can be packaged in a suitable 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 prope11ant-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 invention accordingly also provides a closed container containing a cosmetically acceptable composition as herein defined.

The composition may also be included in capsules such as those described in U.S. Patent No. 5,063,057, incorporated by reference herein. The following specific examples further illustrate the invention, but the invention is not limited thereto.

Example 1

This example measures the level of differentiation in cultured human keratinocytes.

Keratinocytes, the major cell type in the epidermis, undergo a program of differentiation leading to formation of corneocytes which form the stratum corneum and provide a protective barrier against water loss and entry of harmful substances and pathogens . A prominent feature of keratinocyte differentiation is the formation of a highly insoluble, cross-linked envelope (CE) immediately beneath the keratinocyte plasma membrane. The production of CE is catalyzed by the enzyme transglutaminase-K (also referred to as Tgase I) which cross-links certain precursor proteins in the cell.

Retinoic acid, an agent that is highly effective for improving the appearance of photoaged skin (Weiss etal JAMA, 259:527,1988), has been reported to decrease Tgase I in cultured human keratinocytes. Therefore, agents that reduce Tgase I activity have the potential of providing benefits to the skin.

Method for Keratinocyte Transglutaminase assay:

Normal human keratinocytes were seeded in 96-well plates at 4000 cells/well and grown in Keratinocyte Growth Medium (KGM) obtained from Clonetics Corp. until they reached 60- 70% confluency. Cells were treated with test compounds at various concentrations for 48 hours. 4-6 replicate wells were used for each test. At the end of the incubation period, two parameters were measured on the cells: (I) DNA amount, and (II) Transglutaminase protein.

I . DNA was measured using a method described by Rago et al Anal. Biochem 191:31-34,1990. Medium was aspirated from the plates, cells were washed 3 times with

Phosphate Buffered Saline (PBS) . Cells were frozen and thawed 2 times for 5-10 min each. lOOμl of Hoescht Dye (purchased from Calbiochem) solution (lμg/ml in PBS) was added to each well, plate was covered with foil and let sit at room temperature for 10 minutes. Readings were then taken on Millipore Fluorescence Miicroplate Reader (ex/em 360/450 nm) . Amount of DNA per well (a) was calculated using standards.

II. Transglutaminase protein amount was measured as follows :

Dye was removed and the cells were again rinsed 3 times with PBS to prepare for the Transglutaminase (Tgase) assay. 200μl of 5% Carnation Non-fat milk powder

("milk") in PBS (blocking solution) was added to each well and left for 1 hour at room temperature. This solution was then aspirated, and lOOμl of human αTgase 1 monoclonal Antibody (obtained from Biomedical Technologies Inc.) diluted 1/2000 in l%milk in PBS was added to each well. Plates were incubated for 2hrs at ambient temperature. The solutions were then removed and wells washed 4 times with l%milk/0.05% Tween in PBS. Anti- mouse Fab' conjugated with Horse Radish peroxidase (obtained from Amersham) was diluted 1:4000 in l%milk/0.05%tween/PBS and lOOμl of this solution was added to each well and incubated for 2 hours at 37°C. The solutions were aspirated, then washed 3 times with l%milk/0.05%Tween in PBS. Substrate solution was prepared by dissolving 2 mg O-Phenylenediamine (Sigma) in 5 mis of citrate buffer and adding 1.65 μl of 30% H₂O₂. lOOμl of this substrate solution was added to each well and incubated in the dark for 5 min. The reaction was stopped by adding 50μl of 4N H₂SO₄. Absorbance was measured at 490nm (b) .

Keratinocyte differentiation was expressed as transglutaminase absorbance (b) / μg DNA (a) . p-value was calculated using student's t-test. The results that were obtained are summarized in Table I.

Table 1

It can be seen from the results in Table 1 that D-pipecolic acid at 1 mM showed the maximum inhibition of keratinocyte differentiation and was significantly better than L- pipecolic acid at the same concentration.

Example 2

This example measures production of glycosaminoglycans by fibroblasts in response to treatment with various test compounds .

Glycosaminoglycans (GAGs) are a family of polysaccharides which (with the exception of hyaluronic acid (HA) ) can be linked to a protein core, forming a proteoglycan. The main GAGs in the dermis are HA and dermatan sulfate, with chondroitin-4-sulfate and chondroitin-6-sulfate present in small amounts. Made by both keratinocytes and dermal fibroblasts, GAGs are essential components of the extracellular matrix, although they make up only 0.2% of the dry weight of skin. GAGs hydrate in the skin (HA can hold up to lOOOx its mass in water) and maintain basement membrane integrity, regulate cellular interactions and nutrient transport, and are involved in collagen and possibly elastic fiber formation. The proportion of GAGs (especially HA) in the dermis has been shown to be diminished with aging. See Perlish et al , "The Role of Glycosaminoglycans in Aging of the Skin. " Retinoic acid, the benchmark anti-aging active, has been shown to increase GAG content of the spinous and granular layers of the epidermis and the papillary dermis of aged skin in vivo. See Kligman et al . , "Effects of topical tretinoin on non- sun-exposed protected skin of the elderly," J. Am Acad Dermatol 1993;29:25-33.

Protocol for measuring GAGs

Neonatal human dermal fibroblasts were purchased from Clonetics Corp., San Diego, CA and used in passages 5-10. All materials for cell culture were purchased from Life Technologies, NY. Cells were seeded at a density of approximately 50,000/well in a 12-well plate in a medium containing DMEM (Dulbecco's Modified Eagle's Medium), high- glucose supplemented with 2 mM L-glutamine, 10% fetal bovine serum, and antibiotic and antimycotic solutions. Cells were then grown to confluence for 2 days. At confluence, each well was rinsed in serum-free DMEM and the cells dosed with test compounds (in triplicate) in 750μL of serum-free DMEM.

Test compounds were used at a concentration indicated in

Table 2 below. Control did not contain any test compounds. After 24 hours, this medium was aspirated and the treatment step repeated. After a second 24 -hour period, this medium, containing the soluble GAGs, was collected and frozen until analysis .

A positively-charged Zeta Probe membrane was soaked in sterile water and placed into the Dot-Blot Apparatus (both Bio-Rad Labs, Hercules, CA) . lOOμL of water was applied to each well and pulled through using a vacuum. After thawing, lOOμL of test solution samples was applied to the membrane and allowed to gravity filter (about 1.5 - 2 hours) . GAGs were now bound to membrane. The membrane was blocked in 3% w/v fatty acid free bovine serum albumin (Sigma) in water for one hour. A dye solution of 0.5% w/v Alcian Blue dye (ICN Biochemicals, Cleveland, OH) in 3% acetic acid, pH approximately 2.3, was made. The membrane was washed twice in distilled water and then stained in the dye solution on a rotary shaker for 15 minutes. The dye was poured off and the membrane destained twice for 15 minutes each time in 3% acetic acid. The membrane was rinsed in water and left to dry overnight. The Bio-Rad GS 700 Image Analysis Densitometer was used to quantitate the intensity of color in each spot .

Fold increase over control was calculated as a ratio of densitometer reading for cells treated with a test compound over control. p-value was calculated using student's t- test . The results that were obtained are summarized in Table 2

Table 2

The results in Table 2 demonstrate that D-pipecolic acid was significantly better than L-pipecolic acid at inducing GAG synthesis in fibroblasts.

Examples 3-8 illustrate topical compositions according to the present invention. The compositions can be processed in conventional manner. They are suitable for cosmetic use. In particular the compositions are suitable for application to wrinkled, rough, dry, flaky, aged and/or UV-damaged skin to improve the appearance and the feel thereof as well as for application to healthy skin to prevent or retard deterioration thereof. Example 3

This example illustrates a high internal phase water-in-oil emulsion incorporating the inventive composition.

Brij 92 is polyoxyethylene (2) oleyl ether

Example 4

This example illustrates an oil-in-water cream incorporating the inventive composition.

* Brij 56 is cetyl alcohol POE (10) Alfol 16RD is cetyl alcohol Example 5

This example illustrates an alcoholic lotion incorporating the composition according to the invention.

Example 6

This example illustrates another alcoholic lotion containing the inventive composition.

Example 7

This example illustrates a suncare cream incorporating the composition of the invention:

Example 8

This example illustrates a non-aqueous skin care composition incorporating the inventive combination.

A dimethyl silicone polymer having a molecular weight of at least 50,000 and a viscosity of at least 10,000 centistokes at 25°C, available from GEC

Dimethyl siloxane cyclic pentamer, available from Dow

Corning Corp. ₃

Dimethyl siloxane tetramer, available from Dow Corning

Corp.

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

Claims

1. A cosmetic skin care composition comprising D-pipecolic acid in an amount of from 0.1 to 40 wt . % and a cosmetically acceptable vehicle.

2. A cosmetic method of improving the appearance of wrinkled, lined, dry, flaky, aged or photodamaged skin and/or improving skin thickness, elasticity, flexibility and plumpness, the method comprising applying to the skin the composition of claim 1.

3. A cosmetic method of inhibiting keratinocyte differentiation in human skin, the method comprising applying to the skin the composition of claim 1.

4. A cosmetic method of increasing gycosaminoglycans synthesis by fibroblasts in human skin, the method comprising applying to the skin the composition of claim 1.

5. Use of D-pipecolic acid in a cosmetic skin care composition for improving the appearance of wrinkled, lined, dry, flaky, aged or photodamaged skin and/or improving skin thickness, elasticity, flexibility and/or plumpness .