RU2793323C2 - Method for treatment and/or prevention of keratin damages - Google Patents

Abstract

FIELD: cosmetics.

SUBSTANCE: group of inventions relates to the treatment or prevention of keratin damage in keratin-containing tissue. A method for treating or preventing damage to keratin in a keratin-containing tissue comprises applying a cosmetic composition comprising molecules bearing at least one photosensitive functional group and at least one photoinitiator to the said keratin-containing tissue; keeping for processing with exposure to the specified keratin-containing tissue of light having a wavelength suitable for the activation of at least one specified photoinitiator, while photosensitive functional groups are selected from acrylates, methacrylates, vinylbenzene, alkynes and combinations thereof; moreover, molecules bearing at least one photosensitive functional group are obtained by functionalization of amino acids, saccharides and/or fatty acids, and/or their residues; wherein the keratin-containing tissue is human or animal hair. Also a cosmetic composition is disclosed, its use for the treatment or prevention of keratin damage, a set of components for the treatment or prevention of keratin damage.

EFFECT: group of inventions provides a long-term effect on the hair, which lasts for at least six months.

11 cl, 4 dwg, 12 ex

Description

The technical field to which the invention belongs

The present invention relates to the field of cosmetics and to a method for the treatment and/or prevention of keratin damage, in particular in hair, skin and/or nails.

State of the art

Keratin is a fibrous structural protein that makes up hair, nails, and the outer layer of human skin. Keratin monomers assemble to form intermediate filaments and have a structure showing a central domain of 310 residues with four segments in an alpha helical conformation that are separated by three short linker segments in a beta sheet conformation. Keratin molecules coil into a supercoil, forming a stable left-handed supercoil motif for multimerization, forming filaments composed of multiple copies of the keratin monomer.

Keratin contains many cysteine residues that are rich in sulfur-containing functional groups, namely thiol groups (-SH), which form covalent bonds with other thiol groups in the sulfur-containing functional groups on adjacent filaments. These strong cross-links involving two sulfur atoms (S-S) are known as disulfide bonds.

Human hair contains 14% cysteine. Depending on the frequency of such disulfide bonds and their distribution in the hair, they contribute to the definition of the curvature of the hair and hence its shape as well as its texture. These covalent bonds are stable in the presence of water, and as a result, wet hair regains its original shape after drying.

Other weaker bonds are also present between keratin filaments, such as van der Waals bonds, hydrogen bonds, and Coulomb interactions. Unlike stronger disulfide bonds, these compounds are cleaved by water. New bonds are then formed after the water evaporates. Therefore, for example, wet hair is easier to style than dry hair.

Hair is a filamentous biomaterial with a thickness of 20-180 microns, consisting mainly of keratin. The structure of the human hair shaft consists of a medulla in the center of the hair, surrounded by a cortex that contains keratins (40-60 kDa) and lipids. The cortex is surrounded by the cuticle, an outer layer of scaly-shaped dead cells that protects the hair. In healthy looking hair, the cuticle has a smooth and glossy appearance. This is due to the fact that the cuticle layer is tightly closed on the hair shaft (see Fig. 2b). The surface of the hair is coated with covalently bound 18-methyl-arachidic acid.

The keratin-containing cortex makes up most of the hair. It consists of loosely packed, spindle-shaped cortical cells filled with keratin filaments running parallel to the length of the hair and an amorphous matrix of high sulfur proteins.

The cuticle can be damaged (or "aged") by mechanical forces, such as the friction of combing the hair, or chemically, such as by oxidation, typical of bleaching or permanent styling procedures. Excess sunlight and heat also cause damage. Damaged hair usually exhibits an open cuticle, with the cuticle rising above the hair shaft and may crack and flake off (see Fig. 2a).

Damaged hair suffers from low lipid content, which affects its hydrophobicity, while being more porous than healthy-looking hair. Damaged hair is also weak and prone to premature cracking, longitudinal splitting (ie split ends), separation of the hair cortex, loss of strength and loss of shine. Such damage ultimately leads to cleavage of the cysteine disulfide bonds leading to the exposure of free thiols.

In skin and nails, damage to the disulfide bonds of keratin causes the skin to look dry and unhealthy and nails to break easily.

Hair conditioners have been developed to prevent hair damage and improve hair shine. Their main action is to restore the hydrophobicity of the hair shaft and eliminate negative charges on the hair fibers (responsible for unruly hair due to static electricity) by creating an oily coating on the cuticle. Conditioners typically contain polymers (typically polyquaternium polymers), oils, waxes, hydrolyzed amino acids and/or cationic molecules. However, conditioners can also make hair too oily and prone to dirt sticking. Moreover, the positive effect of the conditioner is temporary, since with each use of the shampoo, the oil coating is washed off by surfactants.

Therefore, there is a need in the art for a method and a cosmetic composition that provides for the treatment and/or prevention of keratin damage, in particular in hair, skin and/or nails, in an effective and lasting manner.

Thus, the technical problem underlying the present invention is to provide an accessible method as well as a composition for treating and/or preventing damage to keratin, in particular in hair, skin and/or nails, more specifically in hair, even more specifically hair on the human scalp that has a long-lasting effect, such as an effect on hair that lasts at least six months.

Another technical object underlying the present invention is to provide such an accessible method and composition that does not leave undesirable residues on the hair shaft, which can adversely affect the shine and silkiness of the hair.

Another technical object underlying the present invention is to provide such an affordable method and composition that also further improves the overall appearance of the hair, for example by improving moisture to prevent dry hair as a result and by increasing the volume of the hair.

Another technical object underlying the present invention is to provide such an affordable method and composition that also helps to protect and repair hair from damage of a chemical or physical nature, such as, for example, after dyeing, bleaching, straightening or styling procedures, which also facilitates application of such procedures.

Another technical object underlying the present invention is to provide such an affordable method and composition that can be easily incorporated into existing methods of coloring and styling hair, both in the professional field (for example, in hairdressing) and at home, as well as in products for hair care, such as, for example, conditioners, hair dyes and hair sprays.

Another technical problem underlying the present invention is to provide such an affordable method and composition that is also environmentally friendly.

The essence of the invention

Such a problem has been solved, according to the present invention, by a method for treating and/or preventing damage to keratin in a tissue containing keratin, which includes the following steps:

a) applying to the keratin-containing tissue a cosmetic composition comprising molecules bearing at least one photosensitive functional group and at least one photoinitiator; And

b) exposing the keratin-containing tissue to light having a wavelength suitable for activating at least one photoinitiator.

The above method according to the present invention will also be referred to as the "first method".

By "keratin-containing tissue" is meant body tissue that typically exhibits the presence of disulfide bonded keratin filaments, such as, for example, human hair or animal hair, human skin and nails, or animal skin and claws or hooves.

Preferably, the keratin-containing tissue is selected from human or animal hair, human or animal skin, and/or (human) nails, more preferably human or animal hair, even more preferably human scalp hair.

The term "hair" refers to one or more strands of hair.

Preferably the cosmetic composition is a flowable composition, more preferably a liquid.

In a preferred embodiment, the cosmetic composition is in the form of a suspension or emulsion, more preferably a suspension.

The cosmetic composition may, for example, be in the form of a liquid, lotion, milk, mousse, spray, gel, cream, shampoo or conditioner.

Preferably, the cosmetic composition is applied from the outlet of a plastic bottle, or by spraying, or by any other method known in the art, depending on convenience.

By "photosensitive functional group" is meant a functional group that can be activated by light comprising a wavelength of 10 nm to 100 µm, more preferably 300 nm to 1400 nm, even more preferably 360 nm to 800 nm, in the presence of a suitable photoinitiator, to form reactive intermediates capable of forming covalent bonds with target sites, namely free thiols (also called thiol groups).

In the present description, the word "light" is used to mean "electromagnetic radiation". Throughout the text of the description, the expression "electromagnetic radiation" and the word "light" are also referred to as "radiation".

In the present invention, ultraviolet (UV) radiation refers to radiation having a wavelength of 300 nm to 400 nm; visible radiation means radiation (having a wavelength >400 nm - 700 nm, near infrared radiation (NIR) means radiation having a wavelength > 700 nm - 1400 nm.

Preferably photosensitive functional groups are selected from acrylates, methacrylates, vinylbenzene, alkynes and combinations thereof, more preferably alkynes.

Preferably, molecules bearing at least one photosensitive functional group, where the functional group is acrylate, methacrylate or vinylbenzene, carry at least two of said photosensitive functional groups.

Hereinafter, the expression "reactive molecules" will also be used to mean "molecules bearing at least one light-sensitive functional group". Similarly, "reactive molecule" will also be used to refer to "a molecule bearing at least one photosensitive functional group".

Preferably the reactive molecules have a degree of substitution greater than 5%, more preferably greater than 20%, even more preferably greater than 30%, even more preferably greater than 40%, even more preferably greater than 50%, most preferably greater than 55%.

The degree of substitution can be adjusted based on the molar ratio between parent molecule and substituent groups. As an example, the parent molecule and the substituent groups are respectively gelatin and methacrylic anhydride (MAA) in the preparation of methacrylate-functionalized gelatin (see Example 1).

The expression "degree of substitution" of a reactive molecule according to the present invention means the percentage of functional groups (for example, amino groups, carboxyl or hydroxyl groups) of the original molecule that have been functionalized with the specified photosensitive functional groups, of the total number of functional groups (for example, amino groups, carboxyl or hydroxyl groups) participating in the functionalization reaction of the specified initial molecule. The degree of substitution can be determined by any method known in the art, such as, for example, NMR (Nichol., J. W. et al. (2010) Biomaterials, 31 (21) 5536-5544); trinitrobenzoic acid assay (Yoon, H.J. et al. (2016) PLoS ONE 11(10) 1-18); or the Habeeb method (Habeeb, AF. (1966) Anal. Biochem, 14, 328-336); preferably NMR.

In NMR, for example, a sample containing functionalized molecules is dissolved in deuterated solvents, such as D ₂ O (deuterated) or dDMSO (deuterated dimethyl sulfoxide), and examined by ¹ H-NMR spectroscopy using, for example, a Varian 300 MHz spectrometer (Varian Inc., Palo Alto, California, US). Comparing the results with a non-functionalized sample allows you to determine the percentage of total potential functional groups that have been functionalized.

Preferably, reactive molecules are obtained by functionalizing the main chain, side chain(s) and/or end(s) of the original molecules.

Preferably, reactive molecules in which the photosensitive functional group is an alkyne are obtained by functionalization of the main chain, side chain(s) and/or end(s) of the parent molecules, more preferably the side chain(s).

Preferably, reactive molecules in which the photoactive functional group is an acrylate, methacrylate or vinylbenzene are obtained by functionalizing the side chain(s) of the parent molecules.

Preferably, in the reactive molecules, the photosensitive functional group(s) are covalently bonded.

Preferably, the reactive molecules are compatible with aqueous or solvent-containing cosmetic delivery systems, more preferably aqueous cosmetic delivery systems.

Preferably, the reactive molecules of the present invention are selected on the basis of their chemical compatibility with keratin-containing tissue, more preferably human or animal hair, even more preferably human scalp hair, most preferably also on the basis of their suitability for being washable from keratin-containing tissue, typically water, if present in excess.

In a preferred embodiment according to the present invention, reactive molecules are obtained by functionalization of amino acids, saccharides and/or fatty acids and/or their residues. In other words, the parent molecules are preferably amino acids, saccharides and/or fatty acids and/or their residues.

Preferably the amino acids, saccharides and/or fatty acids and/or their residues are natural amino acids, saccharides and/or fatty acids and/or their residues. The expression "natural amino acids, saccharides and/or fatty acids and/or residues thereof" is used herein to refer to naturally occurring amino acids, saccharides and/or fatty acids and/or residues thereof.

The amino acid may be a free amino acid or may be linked via a peptide bond to other amino acids in the form of branched or linear polypeptide chains or proteins.

Preferably the branched or linear polypeptide chain has a chain length of 2 to 3000 amino acid residues.

Preferably the proteins have a molecular weight of 0.1 kDa to 800,000 kDa, more preferably 1 kDa to 100,000 kDa, even more preferably 2 kDa to 300 kDa.

Preferably the proteins are selected from collagen, gelatin, keratin and albumin.

In a preferred embodiment, the proteins and amino acids are selected from vegetable proteins and amino acids, i.e. proteins and amino acids from a plant source.

Preferably, the vegetable proteins are selected from hydrolyzed soy protein, hydrolyzed wheat protein, hydrolyzed rice protein, hydrolyzed quinoa protein, hydrolyzed barley protein, hydrolyzed vegetable protein, and mixtures thereof.

Preferably, the vegetable amino acids are a mixture of amino acids, a mixture that mimics the properties of keratin, such as, for example, solutions containing wheat and soy amino acids (for example, sold under the trade name Fision KeraVegl8 TRI-K Industries Inc, India).

Examples of reactive molecules obtained by protein functionalization are methacryloyl gelatin, acrylate gelatin, methacrylamide/methacrylate gelatin, vinylbenzene gelatin, and glycidyl methacrylate-modified gelatin.

Functionalization of proteins and/or residues thereof can be performed according to methods known in the art. In particular, the functionalization of proteins at their side chains with acrylates or methacrylates can be performed according to methods known in the art, such as, for example, Nichol, JW. et al. (2010, Nichol, JW. et al. (2010) Biomaterials, 31(21):5536-5544); Gaude ID. and Shreiber, D.I. (2012, Gaudet ID. and Shreiber, DI. (2012) Biointerphases, 2012, 7:25); Brinkman, W.T. et al. (2003, Brinkman, WT. et al. (2003) Biomacromolecules, 4, 890-895); Teramoto et al. (2012, Teramoto et al. (2012), Materials, 5, 2573-2585); Van Den Bulcke et al. (2000, Van Den Bulcke et al. (2000) Biomacromolecules, 1, 31-38).

Preferably the saccharides are in a form selected from monosaccharides, disaccharides, branched or linear oligosaccharides, and branched or linear polysaccharides.

Preferably, the polysaccharides have a molecular weight of 0.1 kDa to 800,000 kDa, more preferably 1 kDa to 300,000 kDa, even more preferably 2 kDa to 300 kDa.

Preferably the polysaccharides are selected from hyaluronic acid, alginates, dextrose, cellulose and its derivatives. For example, the polysaccharide may be a salt, preferably a salt of hyaluronic acid.

Preferably the monosaccharides are selected from dextrose, glucose and fructose.

The functionalization of saccharides and/or their residues can be carried out according to methods known in the art. In particular, the functionalization of saccharides with acrylates or methacrylates or alkynes can be carried out according to methods known in the art, such as Smeds KA. et al. (2001, Smeds KA. et al. (2001) Journal of Biomedical Material Research, 54, 115-121); Fenn D. et al. (2009, Fenn D. et al. (2009) Reactive & Functional polymers 69, 347-352); Yin, R. et al. (2010, Yin, R. et al. (2010) Carbohydrate polymers, 82, 412-418); Roy, B. and Mukhopadhyay, B. (2007, Roy, B. and Mukhopadhyay, B. (2007) Tetrahedron Letters, 48, 3783-3787).

Preferably the fatty acids are free fatty acids or associated with the formation of lipids, for example, esterified with glycerol to form glycerides or phospholipids, or associated with the formation of other lipids. The fatty acids may be in the form of saturated or unsaturated fatty acids.

Preferably the fatty acids contain a number of carbon atoms ranging from 2 to 100, more preferably from 5 to 70, even more preferably from 7 to 25.

Preferably the fatty acids are selected from stearic acid, oleic acid, palmitic acid, lauric acid, linoleic acid.

The functionalization of fatty acids and/or residues thereof can be carried out according to methods known in the art. In particular, the functionalization of fatty acids with acrylates, methacrylates or alkynes can be carried out according to methods known in the art, such as, for example, Adekunle, K. et al. (2009, Adekunle, K. et al. (2009) Journal of Applied Polymer Science, 115, 6, 3137-3145); Thiele, C et al. (2012, Thiele, C et al. (2012) ACS Chemical Biology, 7, 2004-2011); Tronci et al. (2013, Tronci et al. (2013) J. Mater. Chem. B. Mater. Biolo. Med., 1(30), 2705-3715), La Scala, J.J. et al. (2004, La Scala, J. J. et al. (2004) Polymer 45, 7729-7737).

Alternatively or additionally, reactive molecules are obtained from the functionalization of synthetic polymers, more preferably synthetic polymers bearing at least one alkyne functional group. In other words, the parent molecules are preferably synthetic polymers, more preferably synthetic polymers bearing at least one alkyne functional group.

Synthetic polymers are selected from polymers suitable for cosmetic use and include homo and copolymers of polyvinylpyrrolidone, polyvinyl acetate, polyacrylates, polymethacrylates, polyamides, polyvinylamides, polyurethanes and polysiloxanes.

Preferably the synthetic polymers are functionalized with alkyne functional groups.

Examples of reactive molecules obtained by the functionalization of synthetic polymers with alkynes are functionalized amino acids or peptides such as, for example, poly-L-lysine hydrobromide grafted alkyne (functionalized either in the side chain or at the end) and L-homoproparglycine.

Examples of reactive molecules obtained by functionalizing synthetic polymers with backbone alkynes, also called ynamides, are benzenesulfonamides, oxazolidinone and pyrrolidinones such as 4-methyl-N-(2-phenylethynyl)-N-(phenylmethyl)-benzenesulfonamide, 3-( 1-octyn-1-yl)-2-oxazolidinone, 3-(2-phenylethynyl)-2-oxazolidinone, 1-(2-phenylethynyl)-2-pyrrolidinone, (R)-4-phenyl-3-(2- phenylethynyl)oxazolidin-2-one and TMS-N-ethynyl-N,4-dimethylbenzenesulfonamide ≥95%.

Other examples of alkyne-functionalized synthetic polymers are alpha-methyl-poly-(2-ethyl-2-oxazoline)-omega-alkyne (Me-PEtOx-alkyne), (dicyclohexylammonium) salt (S)-(-)-2-azido -6-(Boc-amino)hexanoic acid, cyclohexylammonium salt of (S)-2-azido-3-(4-tert-butoxyphenyl)propionic acid, (S)-5-azido-2-(Fmoc-amino)pentanoic acid , L-azidohomoalanine hydrochloride, cyclohexylammonium salt (S)-2-azido-3-(3-indolyl)propionic acid, cyclohexylammonium salt (S)-2-azido-3-methylbutyric acid, salt (dicyclohexylammonium) (S)-2 -azido-3-phenylpropionic acid, (R)-2-(Boc-amino)-5-hexic acid, (dicyclohexylammonium) salt Boc-3-azido-Ala-OH, (dicyclohexylammonium) salt N-Boc-4-azido -L-homoalanine, (dicyclohexylammonium) salt N-Boc-6-azido-L-alpha-norleucine, Boc-4-azido-Phe-OH, Boc-propargyl-Gly-OH, Boc-(R)-4-( 2-propynyl)-L-proline, salt of (dicyclohexylammonium) (S)-(-)-4-tert-butyl 2-azidosuccinic acid, N2-[(1,1-dimethylethoxy)carbonyl]-N6-[(2- propynyloxy)carbonyl]-L-lysine 90%, Fmoc-β-azido-Ala-OH, Fmoc-(R)-propargyl-Ala-OH, Fmoc-(S)-propargyl-Ala-OH, L-homopropargylglycine hydrochloride.

The cosmetic composition according to the present invention may include a mixture of any of the reactive molecules described above, namely reactive molecules obtained by functionalization of: amino acids and/or their residues; saccharides and/or residues thereof; fatty acids and/or residues thereof; and synthetic polymers, in any combination thereof.

For example, the cosmetic composition may include reactive molecules obtained by the functionalization of amino acids and/or their residues, and reactive molecules obtained by the functionalization of synthetic polymers; or it may include reactive molecules obtained by the functionalization of amino acids and/or their residues, and reactive molecules obtained by the functionalization of saccharides and/or their residues; or it may include reactive molecules obtained by the functionalization of amino acids and/or their residues, reactive molecules obtained by the functionalization of saccharides and/or their residues, and reactive molecules obtained by the functionalization of synthetic polymers; or any other combination of the above reactive molecules.

Reactive molecules according to the present invention can be synthesized according to methods known in this field. In addition, reactive molecules according to the present invention may be commercially available.

Preferably, in the method of the present invention, the damaged keratin in the keratin-containing tissue comprises at least two free thiol groups, more preferably at least 2 µmol of free thiol groups per gram of keratin-containing tissue, most preferably from 2 to 1000 µmol of free thiol groups per gram of keratin-containing tissue.

Preferably, in the method according to the present invention, the keratin-containing tissue is human or animal hair, even more preferably human scalp hair, which comprises at least 2 µmol, more preferably at least 20 µmol, even more preferably at least 200 µmol, most preferably 200 µmol to 1000 µmol free thiol groups per gram of keratin-containing tissue.

Determination of the concentration of the number of thiol groups per gram of keratin-containing tissue can be performed according to any method known in this field, for example, according to the method described in Xu et al. (2017), Green and sustainable technology for high-efficiency and low-damage manipulation of densely crosslinked proteins, ACS Omega, 2, 1760-1768, in the paragraph "Titration of Sulfhydryl Groups, Carboxyl Groups, and Amine Groups" under Materials and methods.

Preferably, the damaged keratin-containing tissue is human or animal hair, more preferably human scalp hair, wherein the hair exhibits one or more of the following: dry texture, dull appearance, low sheen, brittleness, breaks, split ends, and decreased surface lipids.

Preferably, the damaged keratin-containing tissue is human or animal skin, wherein the skin exhibits one or more of the following: dryness, itching, wrinkles, and decreased surface lipids.

Preferably, the damaged keratin-containing tissue is (human) nails, wherein the nails exhibit one or more of the following: brittleness, porosity, softness, the presence of white lines, and a decrease in surface lipids.

Preferably, in the cosmetic composition of step a), the reactive molecules are present in a concentration, in percent by weight based on the volume of the composition, of at least 0.01%, more preferably from 0.05% to 20%, even more preferably from 0.1% 15%, most preferably 0.5 to 10%.

Preferably in step a) the keratin-containing tissue is selected from human or animal hair; human or animal skin; and/or (human) nails, more preferably human or animal hair, even more preferably human scalp hair, wherein the keratin contains at least two free thiol groups. In other words, keratin is damaged keratin.

Preferably, in step a) of the first method, the keratin is damaged keratin.

Preferably the hair and/or skin of the animal is the hair and/or skin of a mammal, more preferably the hair and/or skin of domestic animals such as, for example, cats, dogs, rabbits and horses.

The person skilled in the art can adjust the amount of the applied composition and its concentration, for example, depending on the degree of damage to the keratin and the desired result.

Preferably in step a), the keratin-containing tissue is human or animal hair, more preferably human scalp hair, and is wet. Wet hair does indeed allow better penetration of reactive molecules compared to dry hair.

A photoinitiator is a molecule that converts absorbed ultraviolet, visible, or near infrared radiation into chemical energy in the form of initiating molecules (ie, the photoinitiator is activated), such as free radicals or cations.

Preferably, the photoinitiator is activated (or excited) at a wavelength of 10 nm to 100 µm, more preferably 300 nm to 1400 nm, even more preferably 360 nm to 800 nm, most preferably 360 nm to 400 nm.

Preferably the photoinitiator is a radical photoinitiator.

The at least one photoinitiator may be a one-component, two-component or multi-component system, preferably a one-component system.

Preferably the photoinitiator is water soluble.

According to one embodiment of the invention, the photoinitiator is activated (or excited) by exposure to ultraviolet radiation and is preferably selected from alpha-hydroxy ketones or derivatives thereof, such as, for example, benzoin esters, benzyl ketals, alpha-dialkoxy-alkylphenones, alpha-hydroxy-alkylphenones, alpha- amino-alkylphenones, acyl-phosphine oxides, benzophenones and thio-xanthones.

Examples of suitable UV photoinitiators are bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ( ^Irgacure® 819), bis(eta-5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro -3-(1H-pyrrol-1-yl)-phenyl)titanium ( ^Irgacure® 784), 1-[4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-l-propane-1- he ( ^Irgacure® 2959).

According to another preferred embodiment of the invention, the photoinitiator is activated (or excited) by visible light. Examples of suitable photoinitiators in the visible spectrum are 2',4',5',7'-tetrabromofluorescein (EosinY), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide disodium salt (VA-086 ), salt of monoacylphosphine oxide and salt of bisacylphosphine oxide, titanocenes.

According to another preferred embodiment of the invention, the photoinitiator is activated (or excited) by exposure to near infrared radiation and is preferably selected from benzylidene ketone based cyclic initiators.

Preferably, the photoinitiator is present in the cosmetic composition at a percentage by weight, based on the total volume of the cosmetic composition, of 0.01% to 10%, more preferably 0.1% to 5%, even more preferably 0.5% until 3%.

Preferably the cosmetic composition has a pH of 4 to 9, more preferably 6 to 7.4.

Preferably, the cosmetic composition further comprises one or more excipients selected from water, phosphate buffered saline (PBS) and oil, preferably water.

Preferably the water is ultra high purity water, eg Milli ^Q® water (Millipore Corporation, Darmstadt, Germany).

Preferably, the cosmetic composition further comprises one or more ingredients, more preferably selected from humectants, acidity regulators, oils, surfactants, lubricants, sequestrants, antistatic agents, antimicrobials, preservatives, emulsifiers, thickeners, emollients, and sunscreens, and /or flavorings.

Preferably, the cosmetic composition further comprises at least one coloring agent, preferably selected from a pigment, a dye, and combinations thereof.

Preferably, the coloring agent is present in the cosmetic composition at a percentage by weight, based on the volume of the cosmetic composition, of 0.0001 to 1%, more preferably 0.001 to 0.1%.

In a preferred embodiment, the colorant is capable of emitting light when exposed to radiation having a wavelength of 10 nm to 100 µm, more preferably 300 nm to 1400 nm, even more preferably 360 nm to 800 nm, most preferably 360 to 400 nm.

Preferably the colorant is a fluorescent dye or a non-fluorescent dye, more preferably a fluorescent dye.

Fluorescein is an example of a fluorescent dye that can be used in the present invention.

Preferably the colorant is physically or covalently bonded to the molecules, more preferably physically bonded, eg via van der Waals forces or hydrogen bonds.

Preferably, in step a), the cosmetic composition is uniformly applied to the keratin-containing tissue.

Preferably, the keratin-containing tissue is human or animal hair, more preferably human scalp hair, and the cosmetic composition is applied with a brush or comb.

The presence of a coloring agent, in particular a fluorescent one, allows the user to determine, for example, by exposing the hair to ultraviolet radiation, whether the cosmetic composition is evenly applied to the hair. It is known that mechanical stress, such as excessive combing of the hair, especially when wet, leads to hair damage. The ability to determine when the composition is evenly applied thus has the double benefit of optimizing the uniformity of the result, while at the same time avoiding any unnecessary treatment of the hair when the composition is already evenly distributed.

In the present invention, the term "keeping" in step b) means that the cosmetic composition is left in contact with the keratin-containing tissue.

Preferably in step b) the composition is left to act during treatment for a period of at least 5 minutes, more preferably for a period of 7 to 40 minutes, even more preferably for a period of 10 to 30 minutes, most preferably for a period of 15 to 20 minutes .

Preferably in step b) the temperature of the environment surrounding the keratin-containing tissue is from 4 to 35°C, more preferably from 10 to 30°C, most preferably from 20 to 25°C.

Preferably, in step b), the keratin-containing tissue is exposed to radiation having a wavelength of 360 to 800 nm, more preferably 360 to 400 nm (UV radiation).

Preferably, in step b), the keratin-containing tissue is exposed to radiation for a period of at least 5 minutes, more preferably a period of 7 to 40 minutes, even more preferably a period of 10 to 30 minutes, most preferably a period of 15 to 20 minutes.

Preferably, in step b), the keratin-containing tissue is exposed to radiation during the treatment period.

The keratin-containing tissue may be exposed to radiation using any known suitable light emitting device known in the art, such as, for example, irradiating lamps or light emitting combs.

Preferably in step b), the keratin-containing tissue is human or animal hair, more preferably human scalp hair, and the hair is combed or combed, more preferably with a light emitting comb or brush, even more preferably with a UV-A comb or laser comb.

Preferably, the light emitting comb or brush emits radiation having a wavelength of 360 nm to 400 nm, more preferably 360 to 380, even more preferably 370 nm.

Preferably, the light emitting comb or brush emits UV and NIR radiation, preferably when switching between UV and NIR during use.

Preferably in step b) the hair is combed during the treatment period.

Preferably, step b) is followed by step c) of rinsing the keratin-containing tissue, preferably human or animal hair, more preferably human scalp hair.

Preferably step c) of rinsing is carried out with water until excess residues are completely removed from the keratin-containing tissue, preferably unreacted reactive molecules.

As stated above, damaged keratin is characterized in that the disulfide (or rather disulfide) bridges on and between the keratin filaments are broken, resulting in the formation of exposed free thiols.

The present invention provides a solution to the technical problem by providing functional groups that covalently bind to free thiols, forming cross-links between them. This in turn restores the smooth and healthy appearance typical of healthy looking keratin containing tissue such as human or animal hair, human or animal nails and skin. Provided that the total amount of supported reactive molecules is in sufficient quantity, all free thiols can be crosslinked in one application of the composition.

In fact, the reactive molecules of the present invention, when activated with a photoinitiator, allow functional groups, in particular acrylates, methacrylates, vinylbenzene and/or alkynes, to covalently bind to free thiols on damaged hair, resulting in cross-linking. This reaction is a radical-mediated thiolene (in the case of acrylates, methacrylates and vinylbenzene) or thioline (in the case of alkyne) coupling. An overview of the reactions used in the crosslinking of alkenes and alkynes is presented in Konuray et al. (2018, Konuray et al. (2018) Polymers, 10, 178).

In the case of acrylate, methacrylate or vinylbenzene functionalities, one alkene may be linked to one free thiol. Cross-linking (ie, bridging a broken disulfide bond) between two free thiol groups requires at least two such functional groups in the same reactive molecule. On the other hand, in the case of alkynes, one such functional group in the reactive molecule will be sufficient to bind to two thiols and form a bridge between them.

Figure 1 schematically shows the mechanism by which the process of the invention repairs damaged keratin, for example in hair.

In Figure 1a, in a schematic representation to the left of the arrow, keratin filaments of healthy hair are shown, which show natural disulfide bonds (or bridges). As a result of exposure to environmental or chemical factors (represented by the arrow), disulfide bonds are broken, resulting in the formation of free thiols, as shown schematically to the right of the arrow in Figure 1a.

The method of the present invention provides reactive molecules that, in the presence of light, bind to free thiols to form crosslinks between adjacent free thiols. This is shown in Figure 1b with specific reference to a reactive molecule bearing at least two acrylate or methacrylate functional groups. Figure 1c shows crosslinking between adjacent free thiols according to the method of the invention in the case of a reactive molecule bearing at least one alkyne functional group.

Since crosslinking is based on a strong covalent bond, the effect of the method is stable and lasts for at least 30 days, more preferably at least 6 months, even more preferably at least one year, most preferably at least 18 months.

In order to prevent further damage to keratin, to treat any new damage to keratin and/or to maintain the result longer, in particular in human or animal hair, more preferably in human scalp hair, the above method according to the present invention can be repeated one or more times before. treated keratin-containing tissue.

Thus, in a preferred embodiment according to the present invention steps a) to c) of the method according to the present invention are repeated.

Hereinafter, the repetition of the method according to the present invention in accordance with this preferred embodiment will also be referred to as the "second method".

Preferably, in step a) of the second method, the cosmetic composition is applied to a keratin-containing tissue, more preferably human or animal hair, even more preferably human scalp hair, comprising keratin filaments covalently bonding to said reactive molecules.

Preferably keratin-containing tissue, more preferably human or animal hair, even more preferably human scalp hair containing keratin filaments covalently linked to reactive molecules, has previously been subjected to the method of treating and/or preventing hair damage according to the present invention (i.e., the first method ).

In accordance with this embodiment of the invention, the cosmetic composition may be formulated as a hair conditioning composition. This can be achieved, for example, by adding hair conditioning agents to a cosmetic composition according to the invention, or by adding a cosmetic composition according to the invention to an existing hair conditioning composition.

In the present invention, "conditioner" means a cosmetic ingredient that is used in conditioning compositions to soften, smooth or change the shine of the hair. Suitable conditioning agents include, but are not limited to, polycationic polymers, such as polyquaternium polymers or quaternium-8 siloxane; alcohols, for example oleyl alcohol, stearyl alcohol, cetyl alcohol, panthenol; oils such as meadowfoam seed oil, mango seed oil, grape seed oil, jojoba seed oil, sweet almond oil; polyols; and other ingredients such as hydrolysed wheat and/or soy protein amino acids, rice bran wax, hydroxyethyl behenamidopropyldimonium chloride, aloe leaf extract, aloe vera leaf juice, phytantriol, retinyl palmitate, behentrimonium methosulfate, cyclopentasiloxane, quaternium-91, stearamidopropyl dimethylamine, which improve the appearance of hair, for example, increasing shine and silkiness, reducing static electricity and increasing smoothness.

As used herein, a "conditioning composition" is a composition containing an effective amount of one or more conditioning agents that is applied to the hair to soften, smooth or change the shine of the hair.

The conditioning composition or conditioner may be of any of the known types, namely mask, exit, regular and fixative.

Preferably, according to this preferred embodiment (ie, in the second method), step (b) is performed within 5-10 minutes, more preferably 8-12 minutes.

Preferably in step b) of the second method, the keratin-containing tissue, more preferably human or animal hair, even more preferably human scalp hair, is exposed to light for 5-15 minutes, more preferably 8-12 minutes.

Preferably, according to this preferred embodiment, step c) is preceded by step c') of exposing the keratin-containing tissue, more preferably human or animal hair, even more preferably human scalp hair, to a radiation-free treatment for at least 5 minutes, more preferably 10-45 minutes, even more preferably 20-40 minutes.

Preferably, the first method according to the present invention is repeated after a period of time ranging from 1 week to 6 months, more preferably from 1 to 3 months.

For optimal results, the second method according to the present invention can be carried out at a frequency of 1-20 times a month, more preferably 1-4 times a week, most preferably 1-2 times a week, more preferably for 4-8 weeks.

After treatment according to the first method according to the present invention, it is indeed good practice to repeat the method (ie, perform the second method of the invention) one or two months after the previous treatment. One repetition is usually enough to save the desired results. However, the second method can be repeated several times, and with a higher frequency, depending on the results to be obtained.

Preferably, according to this preferred embodiment, in the second method, the keratin-containing tissue is human or animal hair, even more preferably human scalp hair, which is exposed to light with an irradiation comb or an irradiation brush.

Hereinafter, the expressions "irradiation comb" and "irradiation brush" should be used interchangeably.

In another preferred embodiment according to the present invention, steps a) to c) of the first method according to the present invention are repeated, wherein the concentration of reactive molecules in the cosmetic composition is lower than the concentration in the cosmetic composition in the first method and/or the second method.

Hereinafter, the repetition of the first method according to the present invention in accordance with this additional preferred embodiment will also be referred to as the "third method".

The third method according to the present invention can be repeated once or twice a week, more preferably for 1-8 weeks.

Preferably, according to this more preferred embodiment, in the third method, keratin-containing tissue, more preferably human or animal hair, even more preferably human scalp hair, is exposed to light with an irradiating comb or exposed to visible light.

In fact, the third method is especially suitable for doing at home.

Preferably, the third method according to the invention is carried out after the first method and/or the second method according to the invention.

Preferably, according to this more preferred embodiment (third method), the cosmetic composition comprises at least one conditioning agent.

The present invention also relates to said cosmetic composition comprising said reactive molecules and at least one photoinitiator.

The cosmetic composition is stable for at least six months, preferably at least 12 months, even more preferably at least 2 years, when stored between 4 and 25°C. By "stable" is meant that more than 30% of the molecules are intact and sensitive to light in the presence of a suitable photoinitiator.

The present invention also relates to the use of the cosmetic composition according to the present invention on a keratin-containing tissue, preferably human or animal hair, human or animal nails and/or human or animal skin, more preferably human or animal hair, even more preferably human scalp hair, comprising at least at least two free thiol groups for the treatment and/or prevention of keratin damage.

The present invention also relates to the use of the cosmetic composition according to the present invention on a keratin-containing tissue, preferably human or animal hair, human or animal nails and/or human or animal skin, more preferably human or animal hair, even more preferably human scalp hair, comprising at least at least two free thiol groups to form a cross-link between at least two free thiol groups (ie, the formation of a disulfide bridge). Cross-linking is the result of covalent bonding between at least one photosensitive functional group of reactive molecules and free thiols.

The present invention also relates to the use of the cosmetic composition of the present invention on human or animal hair, even more preferably human scalp hair, comprising at least two free thiol groups, to close the hair cuticle.

Preferably, said keratin-containing tissue is a damaged keratin-containing tissue.

The present invention also relates to the use of the composition of the present invention on keratin-containing tissue, preferably human or animal hair, more preferably human scalp hair, comprising keratin filaments covalently linked to reactive molecules.

Preferably, keratin-containing tissue, preferably human or animal hair, more preferably human scalp hair, comprising keratin filaments covalently linked to reactive molecules, has previously been subjected to the method of treating and/or preventing damaged hair according to the present invention.

Preferably, the cosmetic composition according to the present invention is used in combination with light exposure of keratin-containing tissue.

Preferably, the cosmetic composition according to the present invention is used in combination with another cosmetic product, such as, for example, a hair conditioning composition, a coloring product/hair dye or hairspray, as well as hand creams or body creams.

The cosmetic composition according to the present invention may also be a composition for bleaching, straightening, curling, curling or coloring hair.

In fact, the reactive molecules of the cosmetic composition are compatible with other molecules for various hair treatments.

The present invention also relates to the use of a coloring agent, preferably a fluorescent coloring agent, more preferably covalently bound to reactive molecules, in a cosmetic composition according to the present invention to visualize the uniformity of application of the cosmetic composition according to the invention. In particular, the coloring agent can be detected by exposing the keratin-containing tissue to radiation having a suitable wavelength.

In addition or alternatively, a staining agent as described above can also be used to permanently stain keratin-containing tissue.

The method according to the present invention provides a number of advantages.

The main advantage of the method according to the present invention is that it produces a lasting effect.

The optimal result is enhanced by the fact that covalent binding to keratin occurs only under the influence of radiation. In cases where it is used, after washing the keratin-containing tissue with the removal of all residues, including the photoinitiator, the covalently bound molecules no longer react with radiation. Thus, the result obtained is stable in time, and the method is safe.

The covalent bond between reactive molecules and free thiols, as well as the repair of damage to the keratin filament, also provides a protective layer against future mechanical and chemical undesirable effects. Such a protective layer can make the keratin-containing tissue healthier, and in the case of hair, it can add volume to the hair, making it look even healthier.

In addition, the protective layer may have a moisturizing effect, thus preventing, for example, dry hair and dry skin.

In addition, reactive molecules according to the invention, as well as any other component in the composition used in the method according to the present invention, having an organic and natural origin, can be selected. As a consequence, the composition can be environmentally friendly and safe to handle.

The reactive molecules of the present invention are particularly storage stable. This is due to the fact that the functional groups are covalently bonded. This ensures long shelf life of the composition.

The method according to the present invention can also be easily carried out and does not require expensive equipment.

It can be performed by professionals (eg professional hairdressers) but can also be adapted for home use, such as using a UV comb, laser comb, or by exposing the hair to visible light during the treatment period.

Thus, the present invention relates to a kit of components for treating and/or preventing damage to keratin in human or animal hair, preferably human scalp hair, comprising first and second compositions of a cosmetic composition containing reactive molecules according to the invention.

At least one of the first and second compositions may include a conditioning agent. Alternatively, at least one of the first and second formulations may be added to the conditioning composition.

The first formulation is a formulation suitable for repeating the method of the invention on the hair, which includes reactive molecules (ie the second method of the present invention). The second formulation has a lower concentration of reactive molecules than the first formulation and can be applied once or twice a week. The second composition is suitable for carrying out the third method according to the present invention.

The first and second composition may be a bleaching, straightening, curling, curling or coloring composition.

The kit may also include a third cosmetic formulation for use in the method of the invention, wherein the formulation has a higher or higher concentration of reactive molecules than the first formulation and is suitable for application to damaged hair, preferably which does not include reactive molecules on keratin filaments. Thus, the third composition is suitable for carrying out the first method according to the present invention.

In a preferred embodiment, the cosmetic composition includes at least one photoinitiator that is activated in the visible spectrum.

In an alternative preferred embodiment, the cosmetic composition includes at least one photoinitiator that is activated in the UV spectrum.

The set may also include an irradiating comb.

Brief description of the drawings

Figure 1 is a schematic representation of keratin hair filaments. Figure 1a shows the effect of keratin damage on disulfide bonds between keratin filaments. Figure 1b shows the effect of the method according to the present invention on damaged keratin, where the functional groups of the reactive molecules are acrylates or methacrylates. Figure 1c shows the effect of the method according to the present invention on damaged keratin, where the functional groups of the reactive molecules are alkynes.

Figure 2 shows electron microscope images of DTT-damaged hair (2a) and hair restored according to the treatment method of the invention (2b).

Figure 3 shows two photographs comparing the hair of a volunteer before (3a) and after (3b) treatment with the method according to the invention.

Figure 4 shows a photograph of hair irradiated with UV radiation after application of a cosmetic composition in the treatment according to the invention, where the composition contains a fluorescent dye.

Detailed description of the invention

Hereinafter, the present invention will be described further with reference to the examples below as illustrative and non-limiting cases.

Example 1

Preparation of a composition comprising methacrylate-functionalized gelatin.

20% w/v fish gelatin (Weishardt International, France) was dissolved in 500 ml distilled water at 55°C. The pH was adjusted to 8.5-9 using 3N sodium hydroxide (Sigma). Methacrylic anhydride (MAA, obtained from Sigma-Aldrich (Sweden)) was added to the solution with continuous vigorous stirring, in a 3-fold molar excess relative to the side groups of gelatin lysine (i.e., in a ratio of 1:3 mole percent of gelatin lysines to methacrylic anhydride ), without changing pH and temperature, to obtain the functionalization of gelatin with methacrylic groups on the side chains. After 1 hour, the reaction mixture was dialyzed against water (pH>8-9) for 24 hours using dialysis membranes (12,000-14,000 kDa cut-off) obtained from Spectrum Laboratories, Inc. (CA, US) at room temperature (approximately 25°C) to remove unreacted methacrylic anhydride and other reaction by-products.

Then the reaction product was freeze-dried. The degree of substitution (DS) was determined using NMR. NMR analyzes showed more than 50% modification of the gelatin. In other words, more than 50% of the amino groups of lysines were replaced by methacrylate groups.

Example 2

Preparation of a composition comprising acrylate-functionalized gelatin.

The method of Example 1 was carried out by replacing methacrylic anhydride with acrylic anhydride (MP Biomedicals, USA). NMR analyzes showed more than 55% modification of the gelatin.

Example 3

Obtaining a composition comprising glycidyl methacrylate-functionalized gelatin.

The method of Example 1 was carried out by replacing the methacrylic anhydride with glycidyl methacrylate (Sigma-Aldrich, Sweden), where the pH of the solution was adjusted to 3.5-4 using 1M HCl. Thereafter, 6 ml of glycidyl methacrylate was added dropwise to the solution. The reaction was carried out at 50°C for 24 h and the product was purified by dialysis against Milli-Q water (Millipore Corporation, Darmstadt, Germany) using the above dialysis membrane at 40°C for five days. NMR analyzes showed more than 40% modification of the gelatin.

Example 4

Obtaining a composition comprising vinylbenzene-functionalized gelatin.

The method of Example 1 was carried out by replacing methacrylic anhydride with 4-vinylbenzyl chloride (VBC) (Sigma-Aldrich, Sweden) solubilized in 0.5 M hydrochloric acid and the pH of the solution was neutralized to pH 7.4-8, after which VBC was added in a molar excess at a 1:5 molar ratio to the amino groups of lysine in gelatin (i.e., a 1:5 mole percent ratio of gelatin lysines to VBC). The reaction was carried out at 50°C for 24 h and the product was purified by dialysis against Milli-Q water (Millipore Corporation, Darmstadt, Germany) using the above dialysis membrane at 40°C for five days. NMR analyzes showed >30% modification of gelatin.

Example 5

Obtaining a composition comprising alkyne-functionalized gelatin.

The method of Example 1 was carried out by replacing methacrylic anhydride with propargyl ester of N-hydroxysuccinimide (Sigma-Aldrich, Sweden) solubilized in a minimum amount of dimethyl sulfoxide (DMSO) (Sigma), in molar excess at a molar ratio of 1:5 to the mole percent of amino groups of lysine in gelatin (i.e. 1:5 mole percent of gelatin lysines to N-hydroxysuccinimide propargyl ester), which was added dropwise at 50-55° C. with stirring for 3 hours. The reaction mixture was dialyzed against distilled water (>pH 8) using a 12-14 kDa cutoff dialysis tube (Spectrum Laboratories, Inc., CA, US) for 2 days to remove reaction by-products. NMR analyzes showed a modification of gelatin >25-30%.

Example 6

Getting the composition for the hair.

A 5% (w/v) composition of the product of Example 1 was prepared by dissolving appropriate amounts in distilled water mixed with 1% Irgacure ^2959® photoinitiator (supplied by Sigma-Aldrich, Sweden) which had previously been dissolved in hot water at 80°C. Preservatives including sodium benzoate and phenoxyethanol were also added as antimicrobial agents. The composition showed a shelf life of >12 months.

Example 7

Hair treatment (first method according to the invention)

Healthy hair of four volunteers was damaged by the application of dithiothreitol (DTT), 200 mM dissolved in phosphate-buffered saline (PBS, pH 7.4) in an amount sufficient to cover all hair for two hours. The action of DTT is shown schematically in Figure 1b. The composition of Example 6 was applied to damaged hair while combing with ultraviolet radiation (385-400 nm) for 15 minutes using a Dibotech UV flashlight (Kjell & Company, Sweden). The composition was then washed off the hair with water and dried. The action of the composition is schematically shown in Figure 1b.

Using a scanning electron microscope, an electron microscopic image of the hair after treatment was obtained. It was compared with a previously obtained image of DTT-damaged hair. The results are shown in Figure 2, which shows a comparison of hair damaged after exposure to DTT (Figure 2a) and hair restored after applying the treatment method according to the present invention (Figure 2b). It can be seen that if in Figure 2a the cuticle has a rough and uneven surface, then in Figure 2b the cuticle is smooth.

After treatment, the hair began to look smoother and shinier. They also looked enlarged. Hair after treatment also became more silky to the touch.

Figure 3 shows a comparison of the appearance of the hair before (3a) and after (3b) treatment. It can be seen that after treatment, the hair becomes more shiny, uniform and not so dry.

When examined after 4 weeks, it was determined that the hair retained a healthy appearance in all volunteers.

Example 8

Post-treatment of the hair (second method according to the invention)

After the hair treatment in Example 7, a second treatment according to Example 7 was performed on the same four volunteers, with the difference that the composition applied to the hair was a mixture of the composition 1:5 (by weight) of Example 6 and the conditioning composition containing no sulfates, phosphates and parabens and having the following composition: water, behentrimonium chloride, cetearyl alcohol, stearamidopropyl dimethylamine, PPG-3 benzyl ether myristate, PEG-40 castor oil, glycerin, cetrimonium chloride, hydrolyzed vegetable protein PG-propylsilanetriol, Argania spinosa (argan) oil, Simmondsia chinensis (jojoba) seed oil, Persea gratissima (avocado) oil, keratin amino acids, hydrolyzed keratin, sodium pyrrolidone carbonate, silk amino acids, Rosmarinus officinalis (rosemary) leaf extract, Lavandula angustifolia (Lavender) flower extract, Chamomilla recutita (chamomile officinalis) flower extract ), Amodimethicone, Tridecet-12, C11-15 Paret-7, Laureth-9, Panthenol, Isopropyl Alcohol, Propylene Glycol Dicaprylate/Dicaprate, PPG-1, Tridecet-6, Hydroxypropyl Guar, Hydroxypropyl Trimonium Chloride, Polyquaternium-37, Propylene Glycol, Cinnamidopropyl Trimonium Chloride, EDTA disodium, fragrance (perfume), phenoxyethanol, ethylhexylglycerin, citric acid, yellow 5 (CI 19140), red 33 (CI 17200), butylphenylmethylpropional, hydroxyisohexyl-3-cyclohexenecarboxaldehyde, linalool, alpha-isomethylionone. After applying the composition, the hair was left to be treated for 10 minutes with irradiation, as in Example 7. After the treatment time, the hair was left for another 10 minutes without exposure to radiation. Then the hair was thoroughly rinsed.

After checking, it was determined that the hair had a healthy appearance in all volunteers.

Example 9

Post-conditioning (third method of the invention)

Volunteers were given a 100 ml bottle of a 1:5 (w/w) mixture of the composition prepared according to Example 6, with the difference that the reactive molecules were present at a concentration of 0.8% (w/v) with EosinY; and the conditioning composition described in Example 8.

The volunteers were instructed to use the mixture once every two weeks to continue the treatment of Example 7 and Example 8. The volunteers were instructed to apply the conditioner and expose the hair to sunlight for 15 minutes and then rinse. After 8 weeks, the hair of the volunteers was examined. The hair of all volunteers retained a healthy appearance.

Example 10

Hair composition containing a fluorescent dye

The composition was prepared according to Example 6 with the difference that Ebest Fluorescein LTC (purchased from Fastcolors, UK) was also added to the mixture (at a concentration in percent by weight, based on the volume of the entire composition, 0.001%). The composition was then applied to the volunteer's hair according to Example 7.

It was observed that when the hair was illuminated with UV radiation (385-400 nm), the hair composition glowed, which made it possible to detect areas of the hair to which the composition was not applied. See Figure 4.

Example 11

Obtaining a composition comprising alkene-functionalized hydrolyzed soy protein.

5% (w/v) hydrolyzed soy protein powder (Kelisema, Italy) was dissolved in Milli Q water to 100 ml and gently mixed. The pH was adjusted to 7.5-8.5 using 2N NaOH (Sigma). Then, methacrylic anhydride (Sigma-Aldrich, Sweden) was added dropwise to the solution at room temperature (25°C) in a 5:1 mole ratio to the mole percent of lysine amino groups in soy protein to modify the hydrolyzed soy protein with reactive methacrylate functional groups. After 1 hour, the reaction mixture was subjected to dialysis against water (pH>8-9) for 24 hours using dialysis membranes (paternal molecular weight 100-500 Da) obtained from Spectrum Laboratories, Inc. (CA, US) at room temperature (about 25°C) to remove unreacted methacrylic anhydride and other by-products of the reaction.

Then the reaction product was freeze-dried. The degree of substitution (DS) was determined by NMR comparing the original hydrolyzed soy protein and hydrolyzed soy protein methacrylate.

NMR analyzes showed more than 50% modification of hydrolyzed soy protein by methacrylic groups.

Example 12

Obtaining a composition comprising an alkyne-functionalized hydrolyzed soy protein.

5% (w/v) hydrolyzed soy protein powder (Kelisema, Italy) was dissolved in Milli Q water to 100 ml and gently mixed. The pH was adjusted to 7.5-8.5 using 2N NaOH (Sigma). Then propargyl ester of N-hydroxysuccimide (Sigma-Aldrich, Sweden) solubilized in a minimum amount of dimethyl sulfoxide (DMSO, Sigma) was added dropwise to the solution with stirring for three hours at room temperature (25°C) in a molar excess at a molar ratio of 1 :5 to mole percent amino groups of lysine in hydrolysed soy protein (i.e., at a ratio of 1:5 mole percent of hydrolyzed soy protein lysines to N-hydroxysuccimide propargyl ester) to modify the hydrolyzed soy protein with reactive methacrylate functional groups. After 1 hour, the reaction mixture was dialyzed against water (pH>8-9) for 24 hours using dialysis membranes (100-500 Da molecular weight cutoff) obtained from Spectrum Laboratories, Inc. (CA, US) at room temperature (about 25°C) to remove unreacted methacrylic anhydride and other by-products of the reaction.

Then the reaction product was freeze-dried. The degree of substitution (DS) was determined by NMR comparing the original hydrolyzed soy protein and hydrolyzed soy protein methacrylate.

NMR analyzes showed more than 50% modification of hydrolyzed soy protein by methacrylic groups.

Claims (14)

1. A method for treating or preventing damage to keratin in a keratin-containing tissue, comprising the following steps: a) applying to said keratin-containing tissue a cosmetic composition comprising molecules bearing at least one photosensitive functional group and at least one photoinitiator; And b) exposure to treatment with exposure to said keratin-containing tissue of light having a wavelength suitable for activating said at least one photoinitiator, while photosensitive functional groups are selected from acrylates, methacrylates, vinylbenzene, alkynes and combinations thereof; moreover, molecules bearing at least one photosensitive functional group obtained by functionalization of amino acids, saccharides and/or fatty acids, and/or their residues; wherein the keratin-containing tissue is human or animal hair. 2. The method of claim 1, wherein the keratin-containing tissue is hair on the human scalp. 3. The method according to claim. 1 or 2, in which in the cosmetic composition of step a) molecules bearing at least one photosensitive functional group are present in a concentration, in percent by weight based on the volume of the composition, of at least 0.01 %, preferably 0.05 to 20%, more preferably 0.1 to 15%, most preferably 0.5 to 10%. 4. The method according to any one of paragraphs. 1-3, wherein the photoinitiator is activated at a wavelength of 10 nm to 100 µm, preferably 300 to 1400 nm, more preferably 360 to 800 nm, most preferably 360 to 400 nm. 5. The method according to any one of paragraphs. 1-4, in which the cosmetic composition further comprises at least one coloring agent, preferably selected from a pigment, a dye, and a combination thereof, more preferably capable of emitting light when exposed to radiation having a wavelength of from 10 nm to 100 μm, even more preferably from 300 to 1400 nm, even more preferably 360 to 800 nm, most preferably 360 to 400 nm. 6. Cosmetic composition for the treatment or prevention of damage to keratin in keratin-containing tissue, containing molecules that carry at least one photosensitive functional group, and at least one photoinitiator; while the reactive molecules are present in a concentration expressed in weight percent relative to the volume of the composition, from 0.01 to 20%; wherein the photosensitive functional groups are selected from acrylates, methacrylates, vinylbenzene, alkynes, and combinations thereof; while the molecules bearing at least one photosensitive functional group obtained by functionalization of amino acids, saccharides and/or fatty acids, and/or their residues. 7. Use of the cosmetic composition according to claim 6 on keratin-containing tissue with at least two free thiol groups for the treatment or prevention of damage to keratin. 8. Use according to claim 7, wherein the keratin-containing tissue is human or animal hair. 9. Use according to claim 7, wherein the keratin-containing tissue is hair on the human scalp. 10. A set of components for the treatment or prevention of keratin damage in human or animal hair, including the first and second compositions of a cosmetic composition, including molecules bearing at least one photosensitive functional group, according to claim 6. 11. The kit of claim 10, wherein the human hair is hair on the human scalp.

Images