Patent Application
20240130944
The present invention relates to use of certain amidino substituted amino acid derivatives as lecithin retinol acyltransferase inhibitors (LRAT inhibitors), to cosmetic compositions comprising said amino acid derivatives as well as the use thereof for the treatment of skin ageing.
Retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it and encompass inter alia retinoic acid, retinol as well as esters thereof. Retinoids have many important functions throughout the body including roles in vision, regulation of cell proliferation and differentiation, growth of bone tissue, immune function, and activation of tumor suppressor genes. Originally, used as an anti-acne treatment, Albert Kligman first identified the anti-wrinkle benefits of oral retinoids. Today, retinoids are considered as the “golden standard” for topical treatment of premature skin ageing. Tretinoin (all-trans retinoic acid) is the benchmark prescription topical therapy for improving fine facial wrinkles. Retinol as well as esters thereof are used as cosmetic agents for the prevention or treatment of skin ageing. However, the susceptibility of retinoids to degradation upon storage is still a limiting factor for their widespread use.
Retinoic acid mediates its effect via binding to its nuclear transcription factors. Two main types of nuclear retinoid receptor exist: retinoic acid receptor (RAR) which binds all trans retinoic acid (RA) and its stereoisomer 9-cis RA; and the more recently described retinoid X receptor (RXR) which binds 9-cis RA.
A common feature of these receptors is that they bind to certain regions of DNA known as hormone response elements and thereby initiate ligand dependent gene transcription. The retinoid transcription factors bind to a retinoic acid response element (RARE) in the promoter of genes composed of a six base pair sequence (AGGTCA). RAR's and RXR's are known to contain at least 3 different subtypes, alpha, beta & gamma each of which have several isoforms. The RXR's predominate in human skin, especially RXRalpha. Of the RAR's 87% are RARgamma & 13% RARalpha.
In the epidermis, retinol is metabolized to retinoic acid. However, substantial amounts of retinol are also converted to retinyl esters as storage reserves. Two enzymes are known to be responsible for the formation said retinyl esters: ARAT (acyl-CoA: retinol acyltransferase) transfers the fatty acyl group from a fatty acyl-CoA to retinol, while LRAT (lecithin: retinol acyltransferase) transfers the sn-1 fatty acyl group from phosphatidyl choline to retinol. Recent work has shown that while ARAT is mainly responsible for retinol esterification in non-proliferative, differentiated keratinocytes, LRAT is mainly responsible for retinol esterification in the basal proliferating keratinocytes (Kurlandsky et al. Cell Biology and Metabolism, Vol 271, Issue 25, 15346-15352). Thus, inhibition of LRAT allows more retinol to be available for subsequent conversion to retinoic acid making LRAT an attractive target for the development of alternative anti-ageing skin actives.
Type I and III collagens are formed in human skin in a higher proportion relative to other types and are maintained in a fixed proportion relative to one another in normal skin tissue. They are the main constituents of the dermal extracellular matrix and play a major role in skin elasticity and aspect. Collagen fibers in the dermis are composed by 80-85% of collagen I and by 10-15% of collagen III. Collagen I is the main component of collagen fibers, while collagen III is implicated mainly in their reticulation. Collagen III is a fibrillar collagen associated with collagen I and collagen V in order to form collagen fibers. However, type I and III collagen respective contents and distribution in skin vary as a function of age and therefore to quantity of both collagen I and III are key markers for skin age. In studies involving skin from donors with ages 18 up to 50, it was shown that the mean content of type I and III and type I/III collagen ratio in skin differed significantly among age groups (p<0.05), with the lowest levels of type I, III, and the highest ratio of type I/III observed in the elderly age group. It was concluded that the amount of collagen III significantly diminishes with age. During the physiological ageing different enzymes, including collagenase, neutral protease and lysosomal cathepsins, can degrade collagens. So during skin ageing collagen I and collagen III content decrease, with a faster decrease of collagen III compared to collagen I. Retinoids are well known to stimulate the synthesis of collagen I and III in skin.
Due to significant side effects, the cosmetic use of retinoic acid is not allowed. Thus, the cosmetic industry relies on the use of retinol (ROH), retinaldehyde (RA) or retinylesters (RE). However, as all of the cosmetically acceptable retinoids, need to be metabolized to retinoic acid to mediate their effects, the benefits, that can be derived from these agents, are obviously less potent than with retinoic acid.
Thus, there is an ongoing desire in the cosmetic industry to boost the efficacy of (endogenous) retinol in order to be able to reduce the concentration thereof in topical compositions and thus to overcome stability issues associated therewith.
Surprisingly it has now been found, that certain amidino substituted amino acid derivatives are highly effective LRAT inhibitors and are in particular suitable to enhance the beneficial skin-ageing effects of retinol, reflected by an increased epidermal thickness and increased collagen levels. Furthermore, they are stable upon formulation in topical compositions and thus particularly suitable for the use in cosmetic anti-ageing products.
Various publications disclose the use of benzamidine type structures as thrombin inhibitors (WO96/05189, EP0739886, Stürzenbecher et al, J. Med. Chem 1997, Vol 40, No. 19, p. 3091-3099). U.S. Pat. No. 4,049,645 discloses N2naphthalenesulfonyl-L-arginine esters and amidines as antithrombotic active ingredients. U.S. Pat. No. 5,518,735 discloses certain phenylalanine derivatives as new proteas inhibitors.
Thus, in a first embodiment, the present invention relates to a cosmetic use of a topical composition comprising at least one compound formula (I) or (II).
In a second embodiment, the present invention is directed to the use of a compound of formula (I) or (II) or a cosmetically acceptable salt thereof as an inhibitor for LRAT (lecithin: retinol acyltransferase), in particular for increasing the collagen level, such as in particular collagen III level in the skin and/or to increase the epidermal thickness, most in particular in aged, senescent and/or photo damaged skin.
In a third embodiment the present invention is directed to the a method to increase the effectiveness of endogenous retinol by inhibiting retinol esterification in (preferably the basal proliferating) keratinocytes (and accordingly increase the concentration of free, endogenous retinol), in particular in the treatment of skin ageing, said method comprising the step of topically applying a compound or a composition according to the present invention with all the definitions and preferences given herein, optionally together with one or more cosmetically acceptable retinoids, to the skin, and when compared to an untreated control.
As increased levels of collagen and/or an increased epidermal thickness lead to a reduction of the visible manifestations of skin ageing such as in particular of wrinkles, fine lines, sagging, and laxity, another subject matter of the invention is directed to a method for preventing and/or treating skin ageing, preferably to smoothen wrinkles and fine lines, to decrease their volume and depth, to treat skin sagging and/or to improve skin firmness said method comprising the step of topically applying a compound of formula (I) or (II) or a cosmetically acceptable salt thereof according to the present invention with all the definitions and preferences given herein to the affected area and optionally appreciating the effect.
In a further embodiment, the present invention also relates to cosmetic topical compositions comprising a at least one compound formula (I) or (II).
In addition, the present invention also relates to cosmetic compositions comprising a retinoid and at least one compound formula (I) or (II)
wherein the dotted line represents the connection to the carbonyl group and R3 is selected from H, a C1-C1salkylsulfonyl group or a C1-C5acyl group;
It is well understood, that all compositions according to the present invention are intended for topical application, which is to be understood as the external application to keratinous substances, such as in particular the skin. Particularly preferred cosmetic compositions are topical compositions.
For sake of clarity, some terms as been used in the present document are defined as follows:
The term ‘cosmetic composition’ as used herein refers to compositions, which are topically applied and which are used to treat, care for or improve the appearance of (i.e. beautify) the skin.
The term ‘prevention of skin ageing’ as used herein refers to a prophylactic use to reduce the risk to develop visible manifestations of skin ageing such as in particular wrinkles, fine lines, sagging, and laxity.
The term ‘treatment of skin ageing’ as used herein refers to a reduction of the visible manifestations of skin ageing such as in particular wrinkles, fine lines, sagging, and laxity.
The term ‘cosmetically acceptable carrier’ as used herein refers to all carriers and/or excipients and/or diluents conventionally used in cosmetic compositions such as in particular in skin care preparations.
It is well understood by a person skilled in the art, that the amidino residue (R4HN—C═NR5) in formula (I) is either in ortho (2), meta (3) or para (4) position of the phenyl residue, preferably, in all embodiments of the present invention the amidino residue is either in meta or in para position.
In the present document, a “Cx-y” refers to a group comprising x to y carbon atoms, i.e., for example, a C1-3alkyl group is an alkyl group comprising 1 to 3 carbon atoms.
The term ‘Cx-Cyalkyl group’ is used herein refers to monovalent straight or branched hydrocarbyl groups having from X to Y carbon atoms. Depending on the definition of ‘x’ and ‘y’ suitable Cx-Cyalkyl groups according to the present invention encompass methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, 2,4,4-trimethylpentyl and 3,5,5-trimethylhexyl groups, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, myristyl, palmityl, stearyl and eicosyl. Preferred in all embodiments of the present invention are straight chain (linear) Cx-Cyalkyl groups.
The term ‘aryl group’ as used herein refers to monovalent, aromatic, cyclic hydrocarbyl groups, such as phenyl or naphthyl (e.g. 1-naphthyl or 2-naphthyl). In general, the aryl group may be a monocyclic or polycyclic fused ring aromatic group. Preferred aryl groups in all embodiments of the present invention are C6-C14 aryl, more preferably C6-C10aryl, most preferably naphtyl, such as in particular 2-naphtyl.
The term ‘C1-C5alkoxy group’ is used herein to refer an —O—C1-C5alkyl group—with all the definitions and preferences for Cx-Cyalkyl as given above, such as in particular methoxy (—OMe) or ethoxy (—OEt). Most preferred in all embodiments of the present invention is methoxy.
The term ‘C1-C20alkylsulfonyl group’ is used herein to refer to a —S(O2)C1-C1salkyl group—with all the definitions and preferences for Cx-Cyalkyl as given above. Preferred in all embodiments of the present invention is a —S(O2)C1-C12alkyl group, more preferred a —S(O2)C1-C10alkyl group, most preferred —S(O2)CH3(—S(O2)Me) or —S(O2)C7H14CH3 (—S(O2)Octyl).
The term ‘thioCx-Cyalkoxyl group’ is used herein to refer to a —S—Cx-Cyalkyl group—with all the definitions and preferences for Cx-Cyalkyl as given above. Preferred in all embodiments of the present invention is a —S—C1-C5alkyl group, more preferred a —S—C1-C3alkyl group, most preferred —SCH3(—SMe).
The term ‘C1-C5acyl’ refers to a —C(O)C1-C5alkyl group—with all the definitions and preferences for Cx-Cyalkyl as given above such as e.g. acetyl, propionyl, n-butyryl, iso-butyryl and pentanoyl. Preferred C1-C5acyl groups in all embodiments according to the present invention are C1-C3acyl groups. Most preferred in all embodiments of the present invention is acetyl.
The term ‘alkylene group’ is used herein to refer to divalent saturated, linear or branched hydrocarbon groups. Exemplary alkylene groups include —CH2—, —(CH2)2—, —(CH2)3—, —C(CH3)2CH2— and —C(CH3)H—CH2—. Preferred alkylene groups are saturated linear ones having from 1 to 4 carbon atoms, more preferably from 2 to 3 carbon atoms, most preferably 2 carbon atoms (i.e. ethylene (—(CH2)2—)). Furthermore it is even more preferred if none of the carbon atoms is replaced by a heteroatom as defined herein.
The term ‘alkenylene group’ is used herein to refer to divalent linear or branched hydrocarbon groups, comprising at least one double bond. Exemplary alkenylene groups include —CH=CH—, —CH=CHCH2—, and —CH2 CH═CH—. The most preferred alkenylene group is ethenylene (i.e. —CH═CH—).
Preferably, in all embodiments of the present invention R1 is linear C8-C3alkyl group or an C6-C10aryl group, more preferably a linear C10-C12alkyl group or naphth-2-yl, most preferably dodecyl.
Preferably, in all embodiments of the present invention R2 is OH, a linear C1-C3alkoxy group or a residue of formula (III) wherein R3 is selected from a linear C1-C12alkylsulfonyl group or a linear C1-C3acyl group, most preferably R2 is OH, OMe or a residue of formula (III) wherein R3 is a linear C1-C10alkylsulfonyl group.
Preferably, in all embodiments of the present invention R4 is H and R5 is H, NH2 or a C1-3alkyl group or R4 and R5 together are a linear C1-4alkylene or a linear C1-4alkenylene group, most preferably R5 is H, NH2 or methyl or R4 and R5 together are ethylene.
Particular advantageous compounds of formula (I) or (II), respectively cosmetically acceptable salts thereof in all embodiments of the present invention are the ones, wherein
Even more advantageous compounds of formula (I) or (II), respectively cosmetically acceptable salts thereof in all embodiments of the present invention are the ones, wherein
wherein the dotted line represents the connection to the carbonyl group and R3 is selected from a linear C1-C10alkylsulfonyl group;
Particularly preferred compounds of formula (I) in all embodiments of the present invention are compounds of formula (Ia) or (Ib)
wherein the dotted line represents the connection to the carbonyl group and R3 is selected from a linear C1-C12 alkylsulfonyl group, preferably a linear C1-C10alkylsulfonyl group;
Particularly preferred compounds of formula (II) in all embodiments of the present invention are compounds of formula (IIa)
wherein
wherein the dotted line represents the connection to the carbonyl group and R3 is selected from a C1-C12alkylsulfonyl, preferably a C1-C5alkylsulfonyl, most preferably methylsulfonyl;
Most preferred in all embodiments according to the present invention are the compounds listed in table 1 as well as the respective chloride, iodide or acetate salts thereof.
The compounds according to the present invention can be prepared by standard methods in the art such as e.g. by reacting the respective amino acid (e.g. arginine) with the respective sulfonyl chloride (e.g. 1-dodecylsulfonyl chloride or 2-naphthalenesulfonyl chloride) in the presence of a base and/or as outlined in WO96/05189A.
It is well understood, that the present invention encompasses the compounds of formula (I) or (II) as optically pure isomers such as e.g. as pure enantiomers or stereoisomers as well as mixtures of different isomers such as e.g. as racemates, or mixtures of diastereoisomers.
It is furthermore well understood, that the respective amidino groups encompasses the respective cis/trans as well as tautomeric forms as outlined below:
The term ‘or a cosmetically acceptable salt thereof’ refers to compounds of formula (I) or (II) with all the definitions and preferences as given herein in the form of an acid addition salt such as in the form of a triflate, a chloride, an iodide, an acetate or a trifluoroacetate salt.
Most preferred, in all embodiments of the present invention, are the compounds of formula (I) or (II) as such or in the form of their acetates, chlorides or iodides. Such salts are easily prepared by a person skilled in the art.
It is well understood, that the at least one compound of formula (I) or (II) or the respective salts thereof are generally applied to skin in the form of compositions suitable for the topical application to human skin (topical compositions) such as in particular in the form of cosmetic compositions.
The amount of the compound of formula (I) or (II) or the respective salts thereof in the compositions according to the present invention can easily be adjusted by a person skilled in the art in order to achieve the desired beneficial effect. Preferably, the amount of the compound of formula (I) or (II) or the respective salts thereof is at least 1 ppm based on the total weight of the composition. In all embodiments of the present invention the amount of the compound of formula (I) or (II) or the respective salts thereof is preferably selected in the range from 0.0001 to 5.0 wt.-%, more preferably in the range from 0.001 to 1.0 wt.-%, most preferably in the range from 0.01 to 0.1 wt.-% based on the total weight of the composition. Further preferred ranges encompass 0.0001 to 1.0 wt.-%, 0.0001 to 0.5, 0.0001 to 0.1 wt.-%, 0.001 to 1.0 wt.-%, 0.001 to 0.5, 0.001 to 0.1 wt.-%, 0.01 to 1.0 wt.-%, 0.01 to 0.5, 0.01 to 0.1 wt.-%.
As the compositions according to the invention are intended for cosmetic application, it is well understood that they comprise a cosmetically acceptable carrier i.e. a physiologically acceptable medium, i.e. a medium compatible with keratinous substances, such as the skin, mucous membranes, and keratinous fibres.
Particular advantageous compositions in all embodiments of the present invention are skin care compositions.
Suitable carriers are well known in the art and are selected based on the end-use application. Preferably, the carriers of the present invention are suitable for application to skin (e.g., sunscreens, creams, milks, lotions, masks, serums, hydrodispersions, foundations, creams, creamgels, or gels etc.). Such carriers are well-known to one of ordinary skilled in the art, and can include one or more compatible liquid(s) or solid filler diluent(s), excipient(s), additive(s) or vehicle(s) which are suitable for application to skin. The exact amount of carrier will depend upon the level of the compound of formula (I) or (II) respectively the salts thereof and any other optional ingredients that one of ordinary skilled in the art would classify as distinct from the carrier (e.g., other active components). The compositions of the present invention preferably comprise from about 75% to about 99.999%, more preferably from about 85% to about 99.99%, still more preferably from 90% to about 99%, and most preferably, from about 93% to about 98%, by weight of the composition, of a carrier.
The exact amount of carrier will depend upon the actual level of the compound of formula (I) or (II) respectively a salt thereof and any other optional ingredients that one of ordinary skill in the art would classify as distinct from the carrier (e.g., other active ingredients).
In a particular advantageous embodiment, the carrier consists furthermore of at least 30 wt. %, more preferably of at least 40 wt.-%, most preferably of at least 45 wt.-% of water, such as in particular of 50 to 90 wt.-% of water.
The compositions of the present invention can be formulated into a wide variety of product types, including creams, waxes, pastes, lotions, milks, mousses, gels, oils, tonics, and sprays. Preferably the compounds of formula (I) or (II) respectively the corresponding salts thereof are formulated into lotions, creams, gels, and tonics. These product forms may be used for a number of applications, including, but not limited to, hand and body lotions, facial moisturizers, anti-ageing preparations, make-ups including foundations, and the like. Any additional components required to formulate such products vary with product type and can be routinely chosen by one skilled in the art.
If the compositions of the present invention are formulated as an aerosol and applied to the skin as a spray-on product, a propellant is added to the composition.
The compositions according to the present invention can be prepared by conventional methods in the art such as e.g. by admixing a compound of formula (I) or (II) or the corresponding salts thereof with all the definitions and preferences given herein with the cosmetically acceptable carrier.
The compositions of the invention (including the carrier) may comprise further conventional cosmetic adjuvants and additives, such as preservatives/antioxidants, fatty substances/oils, water, organic solvents, silicones, thickeners, softeners, emulsifiers, antifoaming agents, aesthetic components such as fragrances, surfactants, fillers, anionic, cationic, nonionic or amphoteric polymers or mixtures thereof, propellants, acidifying or basifying agents, dyes, colorings/colorants, abrasives, absorbents, chelating agents and/or sequestering agents, essential oils, skin sensates, astringents, pigments or any other ingredients usually formulated into such compositions.
Preferred compositions according to the present invention include a retinoid, preferably in an amount selected in the range from 0.001 to 10 wt.-%, preferably from about 0.005 to about 0.5.-%, most preferably from about 0.03 to about 0.3 wt.-%, based on the total weight of the composition of a retinoid.
Suitable retinoids include retinol as well as retinyl esters such as in particular retinyl linoleate, retinyl palmitate, retinyl oleate, retinyl propionate, retinyl laurate, retinyl octanoate, retinyl phenylbutyrate, retinyl alkyl carbonate, retinoxytrimethylsilane, (all trans)-retinal or its acetals, or methoxy PEG-12 retinamide and retinyl acetate, retinol being most preferred. Also suitable are all kind of encapsulated retinoids such as for example Cyclasphere® retinol.
Further preferred compositions according to the present invention include one or more hydroxystearic acid, such as in particular 12-hydroxystearic acid, 10-hydroxystearic acid and 9-hydroxystearic acid, preferably in an amount selected in the range from 0.05 to wt.-%, preferably from about 0.1 to 2.5.-%, most preferably from about 0.25 to 1.5 wt.-%, based on the total weight of the composition of a hydroxystearic acid.
In accordance with the present invention, the compositions according to the invention may also comprise further cosmetically active ingredients conventionally used in cosmetic compositions. Exemplary active ingredients encompass further skin lightening agents; UV-filters, agents for the treatment of hyperpigmentation; agents for the prevention or reduction of inflammation; firming, moisturizing, soothing, and/or energizing agents as well as agents to improve elasticity and skin barrier.
The compositions of the invention (including the carrier) may comprise conventional adjuvants and additives, such as preservatives/antioxidants, fatty substances/oils, organic solvents, silicones, thickeners, softeners, emulsifiers, antifoaming agents, aesthetic components such as fragrances, surfactants, fillers, anionic, cationic, nonionic or amphoteric polymers or mixtures thereof, propellants, acidifying or basifying agents, dyes, colorings/colorants, abrasives, absorbents, chelating agents and/or sequestering agents, essential oils, skin sensates, astringents, pigments or any other ingredients usually formulated into such compositions.
If nothing else is stated, the excipients, additives, diluents, etc. mentioned in the following are suitable for sunscreen compositions according to the present invention. The necessary amounts of the cosmetic and dermatological adjuvants and additives can, based on the desired product, easily be determined by the skilled person.
The additional ingredients can either be added to the oily phase, the aqueous phase or separately as deemed appropriate. The mode of addition can easily be adapted by a person skilled in the art.
Examples of cosmetic excipients, diluents, adjuvants, additives as well as active ingredients commonly used in the skin care industry which are suitable for use in the cosmetic compositions of the present invention are for example described in the International Cosmetic Ingredient Dictionary & Handbook by Personal Care Product Council (http://www.personalcarecouncil.org/), accessible by the online INFO BASE (http://online.personalcarecouncil.org/jsp/Home.jsp), without being limited thereto.
The cosmetically active ingredients useful herein can in some instances provide more than one benefit or operate via more than one mode of action.
Of course, one skilled in this art will take care to select the above mentioned optional additional ingredients, adjuvants, diluents and additives and/or their amounts such that the advantageous properties intrinsically associated with the combination in accordance with the invention are not, or not substantially, detrimentally affected by the envisaged addition or additions.
Exemplary compositions according to the invention are skin care preparations, decorative preparations, and functional preparations, skin care preparations and functional preparations being particularly preferred.
Examples of skin care preparations are, in particular, light protective preparations, anti-ageing preparations, preparations for the treatment of photo-ageing, body oils, body lotions, body gels, treatment creams, skin protection ointments, skin powders, moisturizing gels, moisturizing sprays, face and/or body moisturizers, skin-tanning preparations (i.e. compositions for the artificial/sunless tanning and/or browning of human skin), for example self-tanning creams as well as skin lightening preparations.
Examples of decorative preparations are, in particular, lipsticks, eye shadows, mascaras, dry and moist make-up formulations, rouges and/or powders.
Examples of functional preparations are cosmetic or pharmaceutical compositions containing active ingredients such as hormone preparations, vitamin preparations, vegetable extract preparations, anti-ageing preparations, and/or antimicrobial (antibacterial or antifungal) preparations without being limited thereto.
The compositions according to the present invention may be in the form of a suspension or dispersion in solvents or fatty substances, or alternatively in the form of an emulsion or micro emulsion (in particular of oil-in-water (O/W) or water-in-oil (W/O) type, silicone-in-water (Si/W) or water-in-silicone (W/Si) type, PIT-emulsion, multiple emulsion (e.g. oil-in-water-in oil (O/W/O) or water-in-oil-in-water (W/O/W) type), pickering emulsion, hydrogel, alcoholic gel, lipogel, one- or multiphase solution or vesicular dispersion or other usual forms, which can also be applied by pens, as masks or as sprays.
If the composition according to the present invention is an emulsion, such as in particular an O/W, W/O, Si/W, W/Si, O/W/O, W/O/W multiple or a pickering emulsion, then the amount of the oily phase present in such cosmetic emulsions is preferably at least 10 wt.-%, such as in the range of 10 to 60 wt.-%, preferably in the range of 15 to 50 wt.-%, most preferably in the range of 15 to 40 wt.-%, based on the total weight of the composition.
In one embodiment, the compositions according to the present invention are advantageously in the form of an oil-in-water (O/W) emulsion comprising an oily phase dispersed in an aqueous phase in the presence of an O/W emulsifier. The preparation of such O/W emulsions is well known to a person skilled in the art.
If the composition according to the invention is an O/W emulsion, then it contains advantageously at least one O/W- or Si/W-emulsifier selected from the list of, glyceryl stearate citrate, glyceryl stearate SE (self-emulsifying), stearic acid, salts of stearic acid, polyglyceryl-3-methylglycosedistearate. Further suitable emulsifiers are phosphate esters and the salts thereof such as cetyl phosphate (e.g. as Amphisol® A from DSM Nutritional Products Ltd.), diethanolamine cetyl phosphate (e.g. as Amphisol® DEA from DSM Nutritional Products Ltd.), potassium cetyl phosphate (e.g. as Amphisol® K from DSM Nutritional Products Ltd.), sodium cetearyl sulfate, sodium glyceryl oleate phosphate, hydrogenated vegetable glycerides phosphate and mixtures thereof. Further suitable emulsifiers are sorbitan oleate, sorbitan sesquioleate, sorbitan isostearate, sorbitan trioleate, cetearyl glucoside, lauryl glucoside, decyl glucoside, sodium stearoyl glutamate, sucrose polystearate and hydrated polyisobutene. Furthermore, one or more synthetic polymers may be used as an emulsifier. For example, PVP eicosene copolymer, acrylates/C10-30 alkyl acrylate crosspolymer, and mixtures thereof.
The at least one O/W, respectively Si/W emulsifier is preferably used in an amount of 0.5 to 10 wt. %, in particular in the range of 0.5 to 6 wt.-%, such as more in particular in the range of 0.5 to 5 wt.-%, such as most in particular in the range of 1 to 4 wt.-%, based on the total weight of the composition.
Particular suitable O/W emulsifiers to be used in the compositions according to the invention encompass phosphate ester emulsifiers such as advantageously 8-10 alkyl ethyl phosphate, C9-15 alkyl phosphate, ceteareth-2 phosphate, ceteareth-5 phosphate, ceteth-8 phosphate, ceteth-10 phosphate, cetyl phosphate, C6-10 pareth-4 phosphate, C12-15 pareth-2 phosphate, C12-15 pareth-3 phosphate, DEA-ceteareth-2 phosphate, DEA-cetyl phosphate, DEA-oleth-3 phosphate, potassium cetyl phosphate, deceth-4 phosphate, deceth-6 phosphate and trilaureth-4 phosphate.
A particular suitable O/W emulsifier to be used in the compositions according to the invention is potassium cetyl phosphate e.g. commercially available as Amphisol® K at DSM Nutritional Products Ltd Kaiseraugst.
Another particular suitable class of O/W emulsifiers are non-ionic self-emulsifying systems derived from olive oil e.g. known as (INCI Name) cetearyl olivate and sorbitan olivate (chemical composition: sorbitan ester and cetearyl ester of olive oil fatty acids) sold under the tradename OLIVEM 1000.
In one particular embodiment, the invention relates to compositions with all the definitions and preferences given herein in the form of O/W emulsions comprising an oily phase dispersed in an aqueous phase in the presence of an O/W emulsifier wherein the O/W emulsifier is potassium cetyl phosphate. The amount of oily phase in such O/W emulsions is preferably at least 10 wt.-%, more preferably in the range of 10 to 60 wt.-%, most preferably in the range of 15 to 50 wt.-%, such as in the range of 15 to 40 wt.-%, based on the total weight of the composition.
The compositions according to the invention in general have a pH in the range of 3 to 10, preferably a pH in the range of 4 to 8 and most preferably a pH in the range of 4 to 7.5. The pH can easily be adjusted as desired with suitable acids, such as e.g. citric acid, or bases, such as sodium hydroxide (e.g. as aqueous solution), triethanolamine (TEA Care), Tromethamine (Trizma Base) and Aminomethyl Propanol (AMP-Ultra PC2000), according to standard methods in the art.
The amount of the composition according to the present invention to be applied to the skin is not critical and can easily be adjusted by a person skilled in the art. Preferably the amount is selected in the range of 0.1 to 3 mg/cm2 skin, such as preferably in the range of 0.1 to 2 mg/cm2 skin and most preferably in the range of 0.5 to 2 mg/cm2 skin.
In accordance with the invention is the use of the compounds of formula (I) and (II) respectively the corresponding cosmetically acceptable salts thereof with all the definitions and preferences as given herein or the composition comprising said compounds according to the present invention as an agent for stimulating the synthesis of collagen in skin, thickening the epidermis, conditioning and smoothening the skin and/or preventing or reducing the appearance of wrinkled or aged skin.
Finally, a subject-matter of the invention is a method of mimicking the effect of topical retinoic acid, said method comprising applying a compound of formula (I) or (II) respectively a cosmetically acceptable salt thereof or the composition according to the present invention comprising said compound to an area of the skin in need thereof.
The following examples are provided to further illustrate the compositions and effects of the present invention. These examples are illustrative only and are not intended to limit the scope of the invention in any way.
The following buffer was prepared and stored at 4° C.: 0.05 M potassium phosphate, 2.5 mM dithioerythritol, pH 7.0(PO4/DTE). On the day of the assay, 1 mg BSA per mL of buffer was added to give a P04/DTE/BSA working buffer. Retinol substrate (Fluke, 1 mM) was prepared in acetonitrile (Riedel-de-Haen, Chromasolv) and stored in amber bottles under nitrogen gas at −20° C. Solutions of 4 mM dilauroyl phosphatidyl choline in ethanol were prepared and stored at −20° C. Inhibitors were prepared as 10 mM stock solutions according their solubilities in H2O, ethanol, acetonitrile, DMSO or acetic acid. The quenching solution was prepared using pure ethanol containing 50 μg/mL butylhydroxytoluene (Aldrich, BHT) A pentane solution containing 50 μg/mL BHT was used for the extractions.
To a 2 dram glass vial, the following were added in order: P04/DTT/BSA buffer to give a total volume of 500 μL, 5 μL acyl donor (dilauroyl phosphatidyl choline), 5 μL inhibitor or solvent blank (10 mM stock or further dilutions) followed by 2 μg recombinant LRAT enzyme (Abnova, H00009227-PO1). The mixture was incubated for 5 min. at 37° C. to equilibrate the reaction temperature and then 5 μL of a 1 mM retinol solution was added. The vials were capped, vortexed for 5 seconds and incubated for 60 minutes at 37° C. The reaction was quenched by adding 0.5 mL of a ethanol/BHT quenching solution. The retinoids were extracted by adding 1 mL pentane/BHT, vortexing the tubes for several seconds and centrifuging the tubes at 4000 rpm in a bench-top centrifuge for 5 min. to quickly separate the layers. The upper pentane layer was removed into a clean vial, and the aqueous layer re-extracted twice with another 1 mL pentane/BHT, as described above. The organic layers were combined, and the pentane evaporated by drying at 37° C. in a speed-vac centrifuge (Eppendorf). The dried residue was stored at −20° C. and directly analyzed by HPLC. The amount of retinyl laurate was quantified for LRAT activity by integration of the HPLC or UPLC signal as described below. Note that the incubation solution contains 40 μM acyl donor, 100 uM inhibitor, 10 uM retinol, approximately 2 μg LRAT protein, and 0.05 M P04/, 2.5 mM DTT, 1 mg/mL BSA at pH 7. All steps subsequent to the addition of retinol were done in the dark or under amber lights.
Two HPLC protocols were used for retinoid analysis. The separation of retinol and retinol esters was performed with a reverse-phase analytical column (Waters Symmetry (R), 75×4.6 mm, 3.5 μm; Eluent A: 0.07% trifluoroacetic acid TFA in water, B: 0.07% TFA in acetonitrile (AcN), linear gradient from 1% B to 99% B in 6 min, 24 min on 99% B) or ACQUITY UPLC BEH Phenyl 1.7 μm 2.1×50 mm (0.02% TFA in water and eluent B, 0.02% TFA in AcN with a gradient of 2% to 99% B in 0.9 min, 99% B for 1 min, from 99% to 2% B in 0.1 min and flow rate 0.5 ml/min at 40° C. The eluate was monitored with a PDA detector for absorbance at 325 nm. Quantification of the retinol and retinylester peak was based on references retinoic acid and retinyl acetate (Fluke). The inhibition [%] was calculated relative to the product yield from the non-inhibited control reaction. The results are outlined in table 2.
On an abdoplasty coming from a 45-year-old Caucasian woman with a type II phototype, 51 circular skin explants of 11±1 mm in diameter were prepared. The explants were kept for survival in BEM culture medium (BIO-EC's Explants Medium, Longjumeau, France) at 37° C. in a humid, 5% CO2 atmosphere
Each morning on day 0, 1, 4 and 6 the test products (except retinol) were applied topically on the basis of 2 pl/ explants (2 mg/cm2) of the concerned skin explants and spread using a small spatula. Each evening on day 0, 1, 4, 6 the retinol was applied topically on the basis of 2 μl/ explants (2 mg/cm2) of the concerned skin explants and spread using a small spatula. The vehicle V (DMSO 100%) was applied topically (same protocol as for products) in the morning and in the evening on day0, 1, 4, 6. The culture medium was refreshed on dayl, 4 and 6.
On day 0, 3 explants from the batch at day 0 were collected and cut in two parts. Half was fixed in buffered formalin solution and half was frozen at −80° C. On day 8, 3 explants from each experimental condition were collected and processed in the same way as on day 0.
After fixation for 24 hours in buffered formalin, the samples were dehydrated and impregnated in paraffin using a Leica PEARL dehydration automat. The samples were embedded using a Leica EG 1160 embedding station. 5-μm-thick sections were made using a Leica RM 2125 Minot-type microtome, and the sections were mounted on Superfrost® histological glass slides. The frozen samples were cut at 7-μm thickness with a Leica CM 3050 cryostat. The sections were then mounted on silanized glass slides Superfrost® Plus. The microscopical observations were realized using a Leica DMLB or Olympus BX43 microscope. Pictures were digitized with a numeric DP72 Olympus camera with cellSens storing software.
The cell viability of the epidermal and dermal structures was controlled on formalin-fixed paraffin-embedded (FFPE) skin sections after to Masson's trichrome staining, Goldner variant. The cell viability was assessed by microscopical observation.
Collagen III immunostaining was realized on frozen skin sections with an anti-collagen III polyclonal antibody (SBA, ref. 1330-01), diluted at 1:200 in PBS-BSA 0.3% and incubated for 1 hour at room temperature with a biotin/streptavidin amplifying system and revealed with VIP (Vector laboratories, Ref. SK-4600), a substrate of peroxidase giving a violet staining once oxidized. The staining was assessed by microscopical observation
The viability assessment of the skin explants after 8 days in culture showed good results for all experimental conditions. The results of the epidermal thickness and the modulation of collagen III protein are shown in table 3.
The test compounds LRAT-IA and B are:
The control tissues showed both at day0 and day8 the same staining intensity.
As can be retrieved from table 3, the LRAT inhibitors alone lead to an increase in the epidermal thickness and/or the collagen III level, which effect is particularly pronounced in the presence of retinol respectively for the dodecyl derivative.
Table 4 outlines exemplary O/W emulsions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21157280.5 | Feb 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/053021 | 2/8/2022 | WO |
