WO2017042748A1

WO2017042748A1 - Moisturizing cosmetic composition

Info

Publication number: WO2017042748A1
Application number: PCT/IB2016/055418
Authority: WO
Inventors: Nunziatino RAVIDA'; Roberta SCOLLO; Jacopo GUALANDI
Original assignee: Coswell S.P.A.
Priority date: 2015-09-10
Filing date: 2016-09-12
Publication date: 2017-03-16
Also published as: ITUB20153542A1

Abstract

The present invention relates to a cosmetic composition having a moisturizing action comprising, in a physiologically acceptable medium and in parts by weight based on the total weight of the composition: a) from 0.001 to 0.007 parts by weight of at least one cosmetically acceptable salt of lactic acid; b) from 0.002 to 0.014 parts by weight of at least one amino acid selected from: L- serine, glycine, leucine, lysine, proline, valine, tyrosine, glutamic acid, alanine, aspartic acid, arginine, tryptophan, histidine, phenylalanine, ornithine, threonine, and mixtures thereof; c) from 0.001 to 0.007 parts by weight of trehalose; and d) from 0.0005 to 0.005 parts by weight of at least one cosmetically acceptable salt of zinc. The invention also relates to a method for the cosmetic treatment of the skin and a cosmetic product comprising such a composition.

Description

MOISTURIZING COSMETIC COMPOSITION

DESCRIPTION

Background of the invention

The present invention relates to a cosmetic composition having a moisturizing action, a method for the cosmetic treatment of the skin and a cosmetic product comprising such a composition.

More particularly, the present invention relates to a composition and to a cosmetic product having a preferred though not exclusive use in the field of cosmetics for infants. As known, the skin is an organ consisting of two parts: the epidermis and the dermis which represent a keratinized stratified squamous coating epithelium and a connective support tissue, respectively.

The epidermis is in turn formed by five layers that correspond to the same type cells, keratinocytes, in different moments of their life cycle. The layers, from the deepest to the most superficial one, are: basal, spiny, granular, lucid and horny.

Keratinocytes have the peculiarity of changing from being living cells to thin sheets of dead cellular elements, devoid of the core, very flattened and rich in keratin, a filamentous protein rich in sulfur. The cellular elements making up the horny layer cell are sometimes referred to by the name of horny lamellae or, more improperly, corneocytes.

Therefore, the layers of the epidermis have an increasing state of keratinization moving away from the dermis into the horny layer. The epidermis is therefore by its nature subject to a continuous change which takes about four weeks.

The horny layer, which ranges from a few to several hundreds of layers (for example in the hand palm and the foot sole areas) of said keratinized cellular elements containing a very low percentage of water, plays a significant role in controlling the level of moisturization of the skin.

In particular, the corneocytes of the horny layer contain keratin tonofilaments embedded in a matrix derived from the transformation of keratohyalin and eleidin.

The eleidinic cementing material (produced by the deepest layers of the epidermis), sebum and the aqueous component of sweat together produce a skin hydrolipidic film, in other words a slightly acidic protective emulsion able to retain moisture within the skin and also having a bactericidal action.

In particular, a large number of low molecular weight compounds (defined as a Natural Moisturizing Factor, NMF) is present in this layer, especially free amino acids resulting from the degradation of filaggrin and pyrrolidone carboxylic acid (PCA).

Proper moisturization, in particular of the horny layer, it is extremely important to have a soft, flexible and healthy skin. Dry and cracked skin is largely the result of an insufficient level of moisturization of the horny layer which can be a result of cleansing, exposure to the elements (pollution, wind, cold, air conditioning) and physiological phenomena of dehydration.

The moisturization level of the skin depends on a number of factors. Among these, the binding potential of water of the horny layer, the rate at which water is supplied to the inner layers of the horny layer, and the rate at which water is lost from the outer surface of the skin.

In this regard, it is known that babies' skin is very delicate and particularly susceptible to the action of environmental factors, therefore in cosmetics and especially in the cosmetics industry for infants and newborns, the need to identify compositions able not only to moisturize the skin effectively, but also to exert a lasting protective action as well as of sustaining adequate levels of moisturization is particularly felt.

Related art

The French patent application FR 2 877 222 discloses a cosmetic composition comprising, in a physiologically acceptable medium: (a) at least one moisturizing agent; and (b) at least one hydroxyalkyl urea of formula:

(ί)

wherein Ri, R₂, R₃ and R₄ are each independently hydrogen, a C1-C4 alkyl group or a C₂- C₆ hydroxyalkyl group which may contain from 1 to 5 hydroxyl groups, at least one of radicals R1-R1 representing a hydroxyalkyl group and salts, solvates and isomers thereof.

According to this patent application, the moisturizing agent may be indifferently selected from: amino acids and N-acyl derivatives thereof, urea, pyrrolidone carboxylic acid and salts and N-acyl derivatives thereof, sugars and alkyl esters and ethers thereof, heterogeneous polysaccharides, trehalose, ectoin, glycosaminoglycans and sulfates thereof, phospholipids and polymers containing phosphorylcholine groups, cholesterol, phytosterols, essential fatty acids, cinnamic acid, an extract of Theobroma cacao, dehydroepiandrosterone (DHEA) and 7-oxidised and 17-alkylated derivatives thereof, (dihydro)jasmonic acid alkyl-esters, agents that increase the differentiation of keratinocytes, gamma-aminobutyric acid, a mixture of surfactants comprising: (a) a C₆- C₂₂ fatty acid and glyceryl ester, (b) a fatty acid C₆-C₂₂ and citric acid and glycerol diester, (c) a Cio-C₃o fatty alcohol and (d) a gemini surfactant of formula (II):

wherein R and R₃ indicate, independently of each other, an alkyl radical having 1 to 25 carbon atoms; R₂ indicates a spacer group consisting of a linear or branched alkylene chain having 10 to 12 carbon atoms; X and Y are, independently of each another, a (C₂H40)a-(C₃H60)bZ group, where:

- Z indicates a hydrogen atom or a -CH₂-COOM, -S0₃M, -P(0)(OM)₂, C₂H₄-S0₃M, C₃H₆-S0₃M o CH₂(CHOH)4CH₂OH radical, wherein M represents H or an alkali or alkaline earth metal ion or an ammonium or alkanolammonium ion,

- a is from 0 to 15,

- b is from 0 to 10,

- the sum of a + b is 1 to 25; and

- n is from 1 to 10.

Moisturizing compositions are also known on the market comprising trehalose, sodium lactate and one or more amino acids, such as the products of the lines Homeo Beau, Perricone MD Cosmoceuticals, Favorina, Elmiplant Bioten Skin Moisture, Fruit & Passion Lavender Shades, Fruit & Passion Tonic Freshness, Laura Mercier Flawless Skin Infusion de Rose, Laboratoires Filorga.

Summary of the invention

The Applicant has surprisingly found that a particular combination of moisturizing agents in specific and limited amounts allows obtaining a moisturizing composition wherein such agents cooperate in a synergistic way so as to have a particularly effective moisturizing effect, an effective inhibiting action of the growth of microorganisms (bacteria and yeasts) which increases the physiological defenses against the latter, and this without having totally undesirable cytotoxic effects in the cosmetic products for infants and newborns.

More particularly, according to a first aspect thereof, the present invention relates to a moisturizing cosmetic composition comprising, in a physiologically acceptable medium and in parts by weight based on the total weight of the composition:

a) from 0.001 to 0.007 parts by weight of at least one cosmetically acceptable salt of lactic acid;

b) from 0.002 to 0.014 parts by weight of at least one amino acid selected from: L- serine, glycine, leucine, lysine, proline, valine, tyrosine, glutamic acid, alanine, aspartic acid, arginine, tryptophan, histidine, phenylalanine, ornithine, threonine, and mixtures thereof;

c) from 0.001 to 0.007 parts by weight of trehalose; and

d) from 0.0005 to 0.005 parts by weight of at least one cosmetically acceptable salt of zinc.

In a particularly preferred embodiment, the present invention relates to a moisturizing cosmetic composition comprising, in a physiologically acceptable medium and in parts by weight based on the total weight of the composition:

a) from 0.001 to 0.004 parts by weight of sodium lactate;

b) from 0.002 to 0.008 parts by weight of at least one amino acid selected from: L- serine, glycine, leucine, lysine, proline, valine, tyrosine, glutamic acid, alanine, aspartic acid, arginine, tryptophan, histidine, phenylalanine, ornithine, threonine, and mixtures thereof;

c) from 0.001 to 0.004 parts by weight of trehalose; and

d) from 0.0005 to 0.003 parts by weight of a pyrrolidone carboxylic acid zinc salt (PCA).

Within the scope of the present description and in the following claims, all numerical values indicating amounts, parameters, percentages and so on are to always be intended as preceded by the term "about", if not otherwise stated. Moreover, all numerical value ranges include all possible combinations of the maximum and minimum numerical values and all possible intermediate ranges, besides those specifically indicated below. In the present description and subsequent claims, the term: moisturizing agent is meant to denote a compound or a mixture of compounds having a moisturizing action when applied to the skin.

In the present description and subsequent claims, the expression: cosmetically acceptable salt is meant to denote a salt compatible with the skin and/or its integuments so as to be suitable for a topical application to the skin.

The Applicant has experimentally found that with the above specific combination of moisturizing agents in said specific and limited amounts, the following advantageous technical effects can be achieved:

- reconstituting the hydrophilic part of the skin hydrolipidic film which is lost during cleansing, or by the action of atmospheric agents, or as a result of the physiological dehydration phenomena;

- exerting a lasting protective action on the skin;

- maintaining a proper degree of moisture of the horny layer, enhancing the action of the natural moisturizing factor by exogenously bringing a degree of moisture such as to maintain the skin in good state of health;

- exerting an effective inhibitory action of the growth of microorganisms (e.g. bacteria and yeasts) which increases the physiological defenses of the skin against the latter;

- stimulating cell proliferation, thereby promoting the renewal of the epidermal cell population and thus carrying out a regenerating action on the same.

The present invention can have, in one or more of the above aspects, one or more of the preferred features described hereinafter, which can be combined with one another as desired depending on the application requirements.

In a preferred embodiment, said cosmetically acceptable salt of lactic acid preferably is sodium lactate. Preferably, the cosmetic composition comprises from 0.001 to 0.006 parts by weight, more preferably from 0.001 to 0.004 parts by weight and even more preferably from 0.0015 to 0.0035 parts by weight, of at least one cosmetically acceptable salt of lactic acid on the total weight of the composition.

In a particularly preferred embodiment, the cosmetic composition comprises from 0.0015 to 0.0035 parts by weight of sodium lactate on the total weight of the composition.

Preferably, the cosmetic composition comprises from 0.002 to 0.010 parts by weight, more preferably from 0.002 to 0.008 parts by weight and even more preferably from 0.003 to 0.007 parts by weight, of said at least one amino acid on the total weight of the composition.

In a preferred embodiment of the invention, the cosmetic composition comprises from 0.003 to 0.007 parts by weight of the said at least one amino acid on the total weight of the composition.

Preferably, the cosmetic composition comprises from 0.001 to 0.006 parts by weight, more preferably from 0.001 to 0.004 parts by weight and even more preferably from 0.0015 to 0.0035 parts by weight, of trehalose on the total weight of the composition. In a preferred embodiment of the invention, the cosmetic composition comprises from 0.0015 to 0.0035 parts by weight of trehalose on the total weight of the composition. The Applicant has in fact observed that by using one or more of the above preferred ranges, it is advantageously possible to achieve an effective moisturizing effect and a lasting skin protection action even with very small amounts of one or more of said moisturizing agents.

In a preferred embodiment of the invention, said at least one amino acid is selected from L-serine, glycine, and mixtures thereof.

By using these specific amino acids, a particularly strong skin nutritive effect has in fact been advantageously observed, even at very low amounts of this ingredient.

Moreover, an advantageous effect of connective tissue reinforcement has been observed, so these specific amino acids effectively contribute to keep the skin soft and replenished.

In a preferred embodiment of the invention, the cosmetic composition comprises in parts by weight on the total weight of the composition:

- from 0.001 to 0.007, preferably from 0.001 to 0.004 parts by weight, more preferably from 0.0015 to 0.0035 parts by weight, of L-serine; and

- from 0.001 to 0.007, preferably from 0.001 to 0.004 parts by weight, more preferably from 0.0015 to 0.0035 parts by weight, of glycine.

Advantageously, the Applicant has observed that the above technical effects related to the use of these specific amino acids are expressed in a particularly effective way by employing the above amounts of these ingredients.

In a preferred embodiment of the invention, the cosmetic composition further comprises from 0.0007 to 0.005 parts by weight, more preferably from 0.001 to 0.004 parts by weight, even more preferably from 0.0015 to 0.0035 parts by weight, on the total weight of the composition of hydrolyzed rice proteins.

In the present description and subsequent claims, the term: hydrolyzed rice proteins is meant to denote a number of plant soluble and cosmetic grade protein, extracted from rice bran ("Oryza Sativa").

Preferred hydrolyzed rice proteins for the purposes of the invention are for example those available on the market under the designation of Gluadin® R Benz (BASF).

The Applicant has experimentally found that by the use of the hydrolyzed rice proteins - in the above specific and limited amounts - in synergistic combination with the moisturizing agents described above, again in very limited amounts, it is possible to both increase the moisturizing effect of the composition and increase the protective action on the skin, extending the hydration effects over time.

Although the Applicant does not wish to be bound to any theory, it is believed that these advantageous technical effects can be ascribed to the formation of a kind of mechanical barrier on the epidermis by the rice proteins, or to a synergistic combination thereof with the moisturizing agents described above, which barrier is able to "confine" the moisturizing agents within the horny layer, thereby increasing the effects and their rate of absorption by the skin.

In a preferred embodiment, said cosmetically acceptable salt of zinc is preferably selected from the group comprising pyrrolidone carboxylic acid zinc salt, zinc citrate, zinc chloride, zinc gluconate and mixtures thereof.

In a particularly preferred embodiment, said cosmetically acceptable salt of zinc is pyrrolidone carboxylic acid zinc salt. In this way, it is advantageously possible to increase the moisturizing effect of the composition.

Preferably, the cosmetic composition comprises from 0.0005 to 0.004 parts by weight, more preferably from 0.0005 to 0.003 parts by weight and even more preferably from 0.0010 to 0.0025 parts by weight, of said cosmetically acceptable salt of zinc on the total weight of the composition. In a particularly preferred embodiment of the invention, the cosmetic composition comprises from 0.0005 to 0.003 parts by weight, more preferably from 0.0010 to 0.0025 parts by weight, on the total weight of the composition of a pyrrolidone carboxylic acid (PCA) zinc salt.

Hereinafter in the present description and subsequent claims, this salt will be also referred to as zinc-PCA or Zn-PCA.

The Applicant has experimentally found that by the use of said cosmetically acceptable salt of zinc and in particular of Zn-PCA in the above specific and limited amounts in synergistic combination with the moisturizing agents described above and, if present, in synergistic combination with hydrolyzed rice proteins, ingredients which are also present in very small amounts, the following further advantageous technical effects can be achieved:

- achieving an effective inhibitory action of the growth of microorganisms (e.g. bacteria and yeasts) by increasing the physiological defenses against the latter; and

- increasing the moisturizing effect of the composition.

In particular, the Applicant has surprisingly found that said inhibiting action is particularly effective on one of the most common bacteria on human skin (Staphylococcus aureus) and on one of the fungi responsible for infant mycosis (Candida albicans), thereby being particularly useful for cosmetic products for infants and newborns.

The Applicant has also unexpectedly observed, as will become apparent in the following description, a further synergistic effect - in terms of inhibitory action for the growth of micro-organisms - between Zn-PCA and the moisturizing agents in combination with the hydrolyzed rice proteins.

In the present description, the moisturizing agents described above and, if present, the hydrolyzed rice proteins and Zn-PCA, will also be indicated by the term: "active ingredients". The composition according to the invention preferably comprises a cosmetically acceptable carrier, that is, compatible with the skin and/or its integuments so as to be suitable for a topical application to the skin.

Such a cosmetically acceptable carrier is preferably a dermatologically acceptable carrier, in particular a dermatologically acceptable carrier compatible with the delicate skin of a newborn or an infant.

Preferably, the dermatologically acceptable carrier may act as a diluent, dispersant or carrier for the active ingredients.

Preferably, the carrier is a liquid selected from those commonly used in cosmetic products for skin care.

Preferably, the carrier is water or a cosmetically acceptable aqueous buffer having a pH of about 7.0 to about 7.4, and, more preferably, water or the aqueous buffer is purified and/or sterile.

The dermatologically acceptable carrier may constitute from about 40% to 90% by weight, more preferably from 45% to 85% by weight, of the total weight of the cosmetic composition, depending on its specific formulation.

The composition according to the invention may be in any cosmetic form conventionally used for topical application and, in particular, in the form of dispersions of the lotion or aqueous gel type, emulsions of liquid or semiliquid consistency of the milk type, obtained by dispersing a fatty phase in an aqueous phase (oil-in-water or O/W) or vice versa (water-in-oil or W/O), or suspensions or emulsions of soft, semisolid or solid consistency of cream or gel type, or alternatively multiple emulsions (W/O/W or 0/W/O).

These compositions are prepared according to conventional methods known in the art. Depending on the selected cosmetic form, the man skilled in the art is able to dose and determine the content of the active ingredients according to analytical methods known for the purpose in the field of cosmetic compositions (such as HPLC or ICP atomic emission spectroscopy).

According to a preferred embodiment of the invention, the composition comprises an aqueous phase and is more preferably present in the form of an emulsion and especially an oil-in-water emulsion (O/W).

Preferably, the composition as a whole according to the invention has a pH of between 4 and 8 and, more preferably, between 5 and 7.

The composition may further contain, depending on the specific use, one or more ingredients selected from those commonly used in cosmetics, such as surfactants, emulsifiers, thickeners and/or gelling agents, humectants, oils and/or lipids, absorbing and/or texturing agents, antioxidants, preservatives, sequestering agents, perfumes, chelating agents, solubilizing agents and the like.

Preferred surfactants/emulsifiers for the purposes of the invention include: anionic, cationic, nonionic and amphoteric surfactants, including polyoxy ethyl enethers, cetyl alcohol derivatives, in particular ethers, cetearyl alcohol, cetearyl alcohol derivatives (ceteareths), lanolin alcohol derivatives (laneths), myristyl alcohol derivatives (myreths), such as sodium myreth sulfate, lauryl alcohol derivatives (laureths), stearates, cetyl alcohol derivatives, glyceryl palmitate, glyceryl stearate, nonoxyols, octo-oxyols, oleths, castor oil, poloxamers (e.g. poloxamer 407), poloxamines, polysorbates, sodium laurate, ammonium lauryl sulfate, sodium lauroyl glutamate, sodium lauroyl sarcosinate, sodium lauroyl taurate, sodium lauryl sulfate, sodium cocoyl/olivoil, sodium oleoyl methyl taurate, nonoxynol sodium sulfate, sodium cetyl sulfate, sodium cetearyl sulfate, sodium cocoate, sodium cocoyl isethionate, coconut betaine, fructosil cocoate/olivate, sodium cocoyl sarcosinate, glyceryl oleate, glyceryl stearate, coconut glucoside, glycol distearate, and mixtures thereof. Other suitable surfactants/emulsifiers are known to the man skilled in the art and are listed in the CTFA International Cosmetic Ingredient Dictionary and Handbook, Vol. 2, 7th edition (1997).

More preferably, the surfactants include coconut betaine, sodium myreth sulfate, sodium cocoyl/olivoil, fructosil cocoate/olivate, sodium lauroyl glutamate, laureth-2, glyceryl stearate, PEG-90, cetearyl olivate, sorbitan olivate, cetyl palmitate, cetearyl alcohol, lauryl olivate, polyglyceryl-2-di-polyhydroxystearate, glyceryl oleate, and mixtures thereof.

Preferred thickeners and/or gelling agents for the purposes of the invention include: cellulose and derivatives, xanthan gum, guar gum and derivatives, carrageenans, alginates, locust bean gum, acrylic derivatives, hydrocarbon derivatives, amorphous silicas and silicates, and mixtures thereof.

More preferably, thickeners and/or gelling agents include xanthan gum.

Preferred humectants for the purposes of the invention include: glycerine, sorbitol, panthenol, butyl ene glycol, dipropylene glycol, PEG-4, PEG-6, PEG-8-PEG-12, and mixtures thereof.

More preferably, humectants include glycerine, panthenol, and mixtures thereof.

Preferred oils and/or lipids for purposes of the invention include: paraffin, isoparaffin, dicaprylyl ether, PPG- 15 stearyl ether, beeswax, candelilla wax, carnauba wax, ethylhexyl stearate, caprylic/capric triglycerides, cetyl lactate, stearyl stearate, isononyl isononanoate, octyldodecanol, hexyldecanol, squalene, natural triglycerides such as cherry kernel oil {Prunus Cerasus), Persea Gratissima oil, Carthamus Tinctorius seed oil, Macadamia Ternifolia seed oil, cocoa butter {Theobroma Cacao), Butyrospermum Parkii butter and mixtures thereof.

More preferably, the oils and/or lipids include: cocoa butter (Theobroma Cacao), cherry kernel oil {Prunus Cerasus), squalene, beeswax, ethylhexyl stearate, caprylic/capric triglycerides, and mixtures thereof.

Preferred absorbing and/or texturizing agents for the purposes of the invention include: modified maize starch, silica, talc, zinc stearate, magnesium sulfate, zinc oxide, calcium and aluminum borosilicate, starches and derivatives, polyurethanes, and mixtures thereof.

More preferably, the absorbing and/or texturizing agents include: modified maize starch, talc, zinc stearate, magnesium sulfate, zinc oxide, and mixtures thereof.

Preferred antioxidants for the purposes of the invention include: tocopherol, butylhydroxytoluene, butylhydroxyanisole, carnosinic acid, and mixtures thereof.

Preferred preservatives for the purposes of the invention include: gluconolactone, sodium benzoate, calcium gluconate; other ester preservatives of parahydroxybenzoic acid, phenoxyethanol, chlorhexidine digluconate, alkyl trimethylammonium bromide, and mixtures thereof.

Preferred sequestering and/or chelating agents for the purposes of the invention include: sodium phytate, EDTA and salts thereof, tetrasodium glutamate di acetate, pentasodium pentetate, and mixtures thereof.

More preferably, the sequestering and/or chelating agents include: sodium phytate. Perfumes suitable for the purposes of the invention include the fragrances commonly used for cosmetic products.

Preferred solubilizing agents for the purposes of the invention include: polysorbates, PEG-30/40, castor oil, Laureth-23, PPG-26-Buteth-26, Trideceth-9, and mixtures thereof.

According to a preferred embodiment, the composition is in the form of liquid, emulsion, suspension, gel or solid.

More preferably, the composition is selected from the group comprising: shampoo, shower gel, cream, cleansing milk, paste, gel, lotion, serum.

For a more extensive discussion on the formulation of a cosmetic composition, reference may also be made to Harry's Cosmeticology, 7th edition, 1982, edited by J.B. Wilkinson and R.J. Moore. According to a second aspect thereof, the present invention relates to a method for the cosmetic treatment of the skin comprising a step of applying a cosmetic composition having a moisturizing action as described above to the skin.

The application is carried out using standard techniques, for example by the application of shampoo, shower gel, cream, cleansing milk, paste, gel, lotion, serum to the skin to be treated, or the dissolution of a predetermined amount of the composition in water and the subsequent use of water thus admixed or of the foam formed for cleansing or skin treatment.

According to a third aspect thereof, the present invention relates to a cosmetic product comprising:

a) a container delimiting at least one compartment closed by a respective closure element; and

b) a cosmetic composition having a moisturizing action as described above, arranged within said compartment.

The container may have any appropriate form. It may in particular be in the form of a bottle, a tube, a capsule, a can, a jar, a box or a bag.

The closure element may be in the form of a removable stopper, lid, ribbon, or tearing sheet. It may also be in the form of a dispensing element, in particular a pump, a valve or a cap with a spray nozzle.

The moisturizing composition may be contained directly or indirectly in the container. For example, the composition may impregnate a support, in particular in the form of a pad, placed (either individually or multiple layers) in a box or in a bag.

The closure element may be coupled to the container in any way known in the art, such as by a screw, bayonet, snap coupling, by welding, gluing or by magnetic attraction. The container may be at least partially made of plastics. Suitable exemplary plastic materials include polypropylene or polyethylene.

Alternatively, the container may be made of a material other than plastics, for example glass or metal (or metal alloy).

The container may have rigid walls or deformable walls, in particular in the form of a tube or a tubular bottle.

The container may comprise means for causing or facilitating the distribution of the composition. For example, the container may have deformable walls so as to cause the dispensing of the composition in response to a pressure exerted on the walls of the container itself.

Brief description of the figures

In the figures:

- Fig. 1 shows a photograph of a Petri dish used in a test of bactericidal efficacy on which a pad soaked in aqueous solution of a moisturizing complex including the active ingredients according to the invention has been applied;

- Fig. 2 shows a photograph of a Petri dish used in the same test of bactericidal efficacy on which a pad soaked in aqueous solution of Zinc-PCA and preservative (comparison) has been applied;

- Fig. 3 shows a photograph of a Petri dish used in a test of antifungal efficacy on which a pad soaked in aqueous solution of a moisturizing complex including the active ingredients according to the invention has been applied;

- Fig. 4 shows a photograph of a Petri dish used in the same test of antifungal efficacy on which a pad soaked in aqueous solution of Zinc-PCA and preservative (comparison) has been applied.

Detailed description of the currently preferred embodiments

Further features and advantages of the invention will appear more clearly from the following description of some preferred embodiments thereof, made hereinafter by way of a non-limiting example with reference to the following exemplary examples of cosmetic compositions according to the invention.

In these examples, unless otherwise stated, quantities are expressed as percentages by weight.

EXAMPLE 1

(Shampoo)

A cosmetic composition in the form of shampoo was prepared by methods known to a man skilled in the art, having the composition shown in Table 1 below.

TABLE 1

* = Geogard® ULTRA (Lonza)

**= Gluadin® R Benz (BASF)

The composition had the physical characteristics shown in the following Table 2.

TABLE 2

Viscosity at 20 °C 2.000 - 8.000 mPa'S

Density 1.020 +/- 0.01

The method of using the shampoo is: wet your hair with warm water; apply a small amount of shampoo on the hair and massage gently. Let stand 1-2 minutes and rinse with plenty of water.

EXAMPLE 2

(Shower gel)

A cosmetic composition in the form of shower gel was prepared by methods known to a man skilled in the art, having the composition shown in Table 3 below.

TABLE 3

* = Geogard® ULTRA (Lonza)

**= Gluadin® R Benz (BASF)

The composition had the physical characteristics shown in the following Table 4. TABLE 4

The method of using the shower gel is: wet your body and hair with warm water; apply a small amount of product on your hand and rub until a light foam forms. Alternatively, dilute the product in a bathtub. Rinse with plenty of water.

EXAMPLE 3

(Body and face cream)

A cosmetic composition in the form of body and face cream was prepared by methods known to a man skilled in the art, having the composition shown in Table 5 below.

TABLE 5

* = Geogard® ULTRA (Lonza)

**= Gluadin® R Benz (BASF)

The composition had the physical characteristics shown in the following Table 6.

TABLE 6

The method of using the cream is: apply morning and evening on clean skin after cleansing. Rub in gently.

EXAMPLE 4

(Cleansing milk)

A cosmetic composition in the form of cleansing milk was prepared by methods known to a man skilled in the art, having the composition shown in Table 7 below.

TABLE 7

Trehalose 0.0020

* = Geogard® ULTRA (Lonza)

**= Gluadin® R Benz (BASF)

The composition had the physical characteristics shown in the following

TABLE 8

The method of using the cream is: apply to the skin, preferably with a cotton ball. Do not rinse.

EXAMPLE 5

(Protective paste for babies)

A cosmetic composition in the form of protective paste was prepared by methods known to a man skilled in the art, having the composition shown in Table 9 below.

TABLE 9

Fragrance 0.8

Hydrolyzed rice proteins** 0.0030

Zinc-PCA 0.0020

Sodium Lactate 0.0020

L-Serine 0.0020

Glycine 0.0020

Trehalose 0.0020

* = Geogard® ULTRA (Lonza)

**= Gluadin® R Benz (BASF)

The composition had the physical characteristics shown in the following Table 10.

TABLE 10

The method of using the protective paste is: apply on clean, dry skin of the baby at every diaper change. Rub in gently.

Tests carried out by the Applicant have shown that in the cosmetic compositions having a moisturizing action described above, the active ingredients of the same (sodium lactate, L-serine, glycine, trehalose, hydrolyzed rice proteins and Zinc-PCA) cooperate synergistically in providing a particularly effective moisturizing action without cytotoxicity effects.

Furthermore, such cosmetic compositions have been able not only to moisturize the skin effectively, but also to exert a lasting protective action and sustaining adequate moisturization levels over time.

EXAMPLE 6

(Evaluation of the antimicrobial activity of the active ingredients of examples 1-5) The overall antimicrobial activity of a moisturizing complex including:

a) the active ingredients of examples 1-5, namely: sodium lactate, L-serine, glycine, trehalose, hydrolyzed rice proteins and Zinc-PCA;

b) glycerin; and

c) the preservative used in the formulations described above in such examples (Geogard® Ultra - Lonza);

was evaluated with respect to the combination of Zinc-PCA and preservative alone, ingredients with documented antibacterial and antifungal properties.

Specifically, the tested moisturizing complex had the composition shown in the following Table 11.

TABLE 11

* = Geogard® ULTRA (Lonza)

**= Gluadin® R Benz (BASF)

The tests were conducted on microorganisms mainly present on the skin surface (Gram positive bacteria) and/or responsible for minor diseases of infants' skin, such as skin fungus (yeast), in order to give real evidence of the antimicrobial function of the substances tested.

In particular, the tests to evaluate the antibacterial activity were carried out using the Gram-positive bacterial strain Staphylococcus Aureus ATCC 6538, while the tests to evaluate the antifungal activity were carried out using the yeast strain Candida albicans ATCC 10231.

The bacterial strains and yeasts used were in lyophilized form, as refrigerated gelatin pellets. The development of viable cells was obtained at room temperature after the dissolution of the pellets in appropriate nutrient culture broth, respectively Tryptone Soy Broth for the bacteria and Buffered Peptone Water for yeasts, for at least 30 minutes. 1 ml of respective culture broths with the revitalized microorganisms was then inoculated into a Petri dish containing a nutrient and non-selective agar medium (15 ml of Tryptone soya agar for Gram-positive bacteria and Sabouraud dextrose agar for yeasts).

The culture medium was distributed as evenly as possible so as to allow a uniform and optimal growth of the microorganism cells on the whole surface of the Petri dish.

Subsequent to solidification of the agar, a metered quantity (1 ml) of the following was applied in a central position in the Petri dish inoculated with microorganisms:

- a liquid sample including 3% by weight of demineralized water of hydrating the moisturizing complex having the composition shown in the above Table 11; and as a comparison

- a liquid sample including 3% by weight of Zinc-PCA and 1% by weight of preservative (Geogard® ULTRA - Lonza) in demineralized water.

The application of the liquid samples was performed using sterile cellulose pads (2 cm diameter) adequately soaked with 1 ml of sample to be tested by exerting a light pressure on the culture medium after placing the pad so as to allow the sample to adhere well and penetrate radially into the agar by diffusion.

The Petri dishes with the pad soaked in the sample were incubated in the thermostat at the optimal growth temperature of the microorganism used, specifically at 37 °C for 48h for Staphylococcus aureus and 25 °C for 72h for Candida albicans.

After incubation, the dishes were read-observed for the presence and extent of inhibition areas of the microorganism growth.

The following Fig. 1-4 show as many pictures of the dishes after incubation with the tested samples. In particular:

- Fig. 1 shows a photograph of a Petri dish used in the bactericidal efficacy test against the Staphylococcus aureus and on which the disk soaked in aqueous solution at 3% by weight of the moisturizing complex including the active ingredients according to the invention and having the composition shown in Table 11 was applied;

- Fig. 2 shows a photograph of a Petri dish used in the same test of bactericidal efficacy on which the pad soaked in aqueous solution at 3% by weight of Zinc-PCA and 1% by weight of preservative (comparison) has been applied;

- Fig. 3 shows a photograph of a Petri dish used in the antifungal efficacy test against the Candida albicans and on which the disk soaked in aqueous solution at 3% by weight of the moisturizing complex including the active ingredients according to the invention and having the composition shown in Table 11 was applied;

- Fig. 4 shows a photograph of a Petri dish used in the same test of antifungal efficacy on which the pad soaked in aqueous solution at 3% by weight of Zinc-PCA and 1% by weight of preservative (comparison) has been applied.

A comparison of the inhibition area of the microorganism growth around the pad clearly shows that the antimicrobial activity of the active ingredients according to the invention is clearly superior to that of the combination of zinc-PCA and preservative, showing an unexpected synergistic effect between the active ingredients and the Zinc- PCA/preservative combination.

EXAMPLE 7

(Evaluation of the moisturizing activity of the active ingredients of examples 1-5) The moisturizing activity of the active ingredients was evaluated by subjecting a culture of human keratinocytes (the keratinocytes used in this assay are derived from a human cell line [HaCat, BS code CL 168] from I.Z.L.E.R. [Istituto Zooprofilattico

Sperimentale della Lombardia e deU'Emilia Romagna]) to a quantitative evaluation of aquaporin-3 expression by the ELISA technique in the presence of the moisturizing complex having the composition shown in the above Table 11.

Aquaporin-3 is an essential molecule for water distribution in the skin, which has recently been shown to have a role in cell proliferation and migration (Schrader et al, 2010): for the purpose of this test, an increased aquaporin-3 expression in HaCat cells was therefore associated with an enhanced moisturizing action of the composition. In order to perform the assay, run in two replicates, HaCat cells were seeded homogeneously in 96-well plates at the concentration of l,8xl0⁴ cells per well and incubated at 37 °C, 5% C0₂. After 24 h from seeding, 3 h treatments were performed with the composition shown in the above Table 1 1, diluted in a complete medium consisting of D-MEM High Glucose supplemented with 10% fetal bovine serum (FBS), 1 mM L-glutamine and antibiotics (100 IU/ml penicillin and 100 μg/ml streptomycin) at a concentration of 0.019% by volume.

In order to evaluate the expression of aquaporin-3, an ELISA protocol was used directly on cells seeded in the plate. The treated cells were fixed and a process of permeabilization of cell membranes was carried out. Subsequently, it was incubated with the primary antibody, specific for the recognition of the molecule aquaporin 3 (AQP-3), and with the secondary antibody, which is able to provide a quantitative assessment of the expression levels of the target molecule being tested. The plates were subsequently subjected to spectrophotometric reading with a microplate reader (Tecan Sunrise) at a wavelength of 450 nm. The aquaporina-3 expression was calculated by measuring the difference in optical density between each of the concentrations tested compared to controls.

Similar comparison measurements were carried out on the same culture of HaCat cells, not subjected to any treatment.

The results obtained show that the composition after 3 h treatment shown in the above Table 11 increases the synthesis of aquaporin-3 by about 2% in human keratinocytes HaCat, compared to the control consisting of untreated cells, thereby giving evidence of a significant moisturizing action. EXAMPLE 8

(Evaluation of the regenerating activity of the active ingredients of examples 1-5)

The regenerating activity on the epidermis, that is, to stimulate cell proliferation, thereby promoting the renewal of the epidermal cell populations, of the active ingredients was evaluated by subjecting a culture of human keratinocytes (the keratinocytes used in this assay are derived from a human cell line [HaCat, BS CL code 168] coming from I.Z.L.E.R. [Istituto Zooprofilattico Sperimentale della Lombardia e deU'Emilia Romagna]) to a Real Time Cell Analysis (RTCA) assay, monitoring the behavior of the seeded cells in real time, in terms of growth and adhesion, using the RTCA system ICelligence (Acea Biosciences) in the presence of the moisturizing complex having the composition shown in the above Table 11.

In this test, cells are seeded in plates (E-plates L8) provided with microelectrodes that measure the impedance values caused by the adherence of the cells thereon: for the purposes of the present test, a higher impedance in the seeded cells was therefore associated to an increased cell proliferation and therefore a greater regenerating activity of the composition.

For the tests, carried in two replicates, the HaCat cells were seeded at a concentration of 2xl0⁴ in each well of an E-plate L8 plate. Cells were made to adhere to the bottom of the wells for a period of 20 minutes and, thereafter, positioned in an incubator at 37 °C, 5% C0₂. After 24 hours from seeding, 3 cells were treated with the composition shown in the above Table 11, diluted in a complete medium consisting of D-MEM High Glucose supplemented with 10% fetal bovine serum (FBS), 1 mM L-glutamine and antibiotics (100 R7/ml penicillin and 100 μg/ml streptomycin) at a concentration of 0.039% by volume.

As a negative control for cell proliferation stimulation, untreated cells were used.

The measurement of cell growth was obtained through repeated measurements at regular intervals of 15 minutes for a period of 72 hours from the start of the treatment. The Normalized Cell Index (CI) values were examined to analyze the cell growth. The quantitative measurement of the regenerating action was carried out in the plateau region of the recorded impedance values (during the present test the in treatment time of between 60 hours:08 minutes:36 seconds and 69 hours:08 minutes:36 seconds from the start of the treatment).

The results obtained show that the composition shown in the above Table 11 increases cell impedance by about 161% in human keratinocytes HaCat, compared to the control consisting of untreated cells, thereby demonstrating a highly significant regenerating action.

It is clear that a man skilled in the art may make several changes and variants to the finding described hereinbefore in order to meet specific and incidental application requirements, changes and variants in any case falling within the scope of protection defined in the following claims.

Claims

1. Cosmetic composition having a moisturizing action comprising, in a physiologically acceptable medium and in parts by weight based on the total weight of the composition: a) from 0.001 to 0.007 parts by weight of at least one cosmetically acceptable salt of lactic acid;

c) from 0.001 to 0.007 parts by weight of trehalose; and

2. Cosmetic composition according to claim 1, wherein said cosmetically acceptable salt of lactic acid is sodium lactate.

3. Cosmetic composition according to any one of claims 1 to 2, wherein said cosmetically acceptable salt of zinc is selected from the group comprising pyrrolidone carboxylic acid zinc salt, zinc citrate, zinc chloride, zinc gluconate and mixtures thereof.

4. Cosmetic composition according to claim 3, wherein said cosmetically acceptable salt of zinc is pyrrolidone carboxylic acid zinc salt.

5. Cosmetic composition according to any one of claims 1 to 4, comprising:

a) from 0.001 to 0.004 parts by weight of sodium lactate;

b) from 0.002 to 0.008 parts by weight of at least one amino acid selected from: L- serine, glycine, leucine, lysine, proline, valine, tyrosine, glutamic acid, alanine, aspartic acid, arginine, tryptophan, histidine, phenylalanine, ornithine, threonine, and mixtures thereof; and

c) from 0.001 to 0.004 parts by weight of trehalose;

6. Composition according to any one of claims 1 to 5, wherein said at least one amino acid is selected from L-serine, glycine and mixtures thereof.

7. Composition according to claim 6, comprising, in parts by weight based on the total weight of the composition:

- from 0.001 to 0.007 parts by weight of L-serine; and

- from 0.001 to 0.007 parts by weight of glycine.

8. A composition according to any one of the preceding claims, further comprising from 0.0007 to 0.005 parts by weight based on the total weight of the composition of hydrolyzed rice proteins.

9. A composition according to any one of the preceding claims, further comprising at least one preservative selected from the group comprising: gluconolactone, sodium benzoate, para-hydroxybenzoic acid esters, phenoxyethanol, chlorhexidine digluconate, alkyl trimethylammonium bromide, and mixtures thereof.

10. A composition according to any one of the preceding claims, having a pH comprised between 4 and 8.

11. A composition according to any one of the preceding claims, in the form of a liquid, emulsion, suspension, gel or solid.

12. A composition according to claim 1 1, selected from the group comprising: shampoo, shower gel, cream, cleansing milk, paste, gel, lotion, serum.

13. Method for the cosmetic treatment of the skin comprising a step of applying to the skin a cosmetic composition having a moisturizing action according to any one of claims from 1 to 12.

14. Cosmetic product comprising:

b) a cosmetic composition having a moisturizing action according to any one of claims 1 to 12 arranged within said compartment