FR2666226A1 - Composition for protecting the skin - Google Patents

Abstract

The invention relates to a composition for protecting the skin, which comprises the combination of a system that screens over the breadth of the range of wavelengths of light, at least one anti-free-radical component and at least one anti-elastase component.

Description

NEW PROTECTIVE SKIN COMPOSITIONS
The subject of the present invention is new protective compositions for the skin, intended to limit the factors of tissue degradation, in particular exogenous. It also relates to the process for the preparation of such products.

 With regard to exogenous causes, it aims in particular to eliminate harmful photobiological effects by limiting the incident light energy by reducing the quantity of photons admitted to reach the skin per unit area, and by modifying their spectral band, it being understood that the entire spectrum of incident light radiation must be taken into account (infrared, visible and ultra-violet spectrum).

The invention also relates to the reduction of endogenous abnormal factors and in particular that of elastase, as well as the deviations due to age which are manifested in particular by progressive destructuring.

 Numerous compositions have been known in the prior art which attempt to ensure as complete protection as possible of the skin against radiation, but, until now, all the solutions are far from leading to satisfactory effectiveness, and we always observe, despite the progress made and the precautions taken, sometimes serious and too often irreversible disorders; whether by prevention, that is to say by filtering or reflecting radiation, or by treatment intervening later and too often too late, the results remain disappointing in most cases.

It should be recalled that the effects of light radiation, to which we will limit ourselves here, that is to say the action of photons, is reflected in particular by various effects on the skin:
a) They cause, like most of the others
attacks, the formation of free radicals
destructive;
b) They promote the action of elastase and therefore the
destruction of the elastin layer;
c) They cause disorders at the vascular level
translating by erythema, edemas, etc., ...;
d) They activate, in the event of intense radiation,
certain genes in the germinal part of the epidermis
(melanocytes and to some extent keratinocytes),
which can result in many phenomena or
disorders essentially dependent on the efficiency of the
defense system of the organism considered.

 It is therefore essential, if we want to ensure as complete protection as possible, to take into account the points which have just been highlighted and to solve the problems raised by these phenomena under the action of photons, and in particular solar radiation. .

 However, it turns out that filtration by so-called "chemical" filters is still insufficient and that consequently, if we limit certain disorders, we are far from eliminating them, especially in the case of sensitive subjects such as those with low natural defense system, for example, subjects of photype I, which corresponds appreciably to the Celtic type with red hair and milky complexion, practically never tanning and remaining very subject to sunburn, ephelids and erythemas). The use of so-called "physical" screens or filters forms a safer shield but has drawbacks which will be discussed below.

 Experience has shown that it is possible, thanks to certain combinations of specific components, chosen and dosed in accordance with the invention, to results which have hitherto not been achieved by use, now classic, of filtering or reflecting agents associated with various other protective agents.

 We have also noticed that, up to now, thanks to filters, we have sought to attenuate or even obscure the radiation in certain ranges, especially ultraviolet, known to be particularly harmful without worrying about the fact that photochemical reactions or photobiological transformations occurred with radiation extending over almost the entire light spectrum, including in the visible and infrared region, and only to provide effective protection, especially of subjects with sensitive skin drunk for certain sensitive skin areas, it was important to provide more protection in the wavelength range.

 It will be recalled that under Planck's law, the energy of photons is proportional to their frequency and therefore inversely proportional to their wavelength, and that therefore, if we take into account low frequencies (lengths longest waves and therefore with the least energy according to Planck), that is to say essentially the ultraviolet, it is, a fortiori, more than desirable not to omit the frequencies which correspond to higher energy levels, i.e. the average frequencies of the visible spectrum (medium wavelengths) and the highest of the infrared (shortest wavelengths).

It will also be recalled that, in the order of decreasing frequencies and energies and therefore increasing wavelengths, the far infrared are in the frequency range of the light spectrum beyond 1,500 nm, the near infrared between 700 and 1,500 nm, the visible between 380 and 700 nm, the ultraviolet A between 315 and 380 nm, the ultraviolet B between 280 and 315 nm, and the ultraviolet C between 190 and 280 nm.

 However, experience has shown that such extended protection, combined with an anti-elastase action and with an anti-free radical or anti-free radical action carried out under adequate conditions, greatly exceeds the results of the most effective previous compositions.

 It is obvious that maximum protection could be easily obtained by external elements such as clothing, which is outside the cosmeto-dermatological field, but, for example, by topical applications of screens or filters "physical with a high content of opaque particles. forming, at least theoretically, a perfect screen with any light radiation, which requires a high particle density, a perfect homogeneity of distribution and, to the extent necessary, a sufficient thickness, but this leads to unsightly applications resulting most often by a uniform and generally white color, all the more unacceptable as most of the interested parties precisely seek the opposite coloring effect.

 The use of "physical" screens or other filters, as opposed to "chemical" filters, is therefore essentially limited by non-technical, but more generally aesthetic considerations, and, in some cases also, by legislative and regulatory aspects. .

 As has also been mentioned above, the invention seeks to oppose endogenous factors of degradation of the skin which are essentially and ultimately in the form of free radicals and elastase.

 One of the aims of the present invention is therefore to achieve compositions which do not alter the appearance of the skin or possibly improve it, while ensuring the maximum protection sought with respect to exogenous or endogenous factors the most significant, and remaining within the limits of legal and regulatory authorizations.

 A subject of the present invention is therefore novel compositions for protecting the skin, comprising the combination of a filtering system over the entire spectrum of photonic frequencies, combined with at least one anti-radical component, namely alpha-tocopherol or one of its derivatives, in particular one of its esters, and at least one antielastatic component.

 According to a preferred embodiment of the invention, as components of the filtering system, at least one "physical" screen or filter will be used, titanium oxide, microbeads, for example polymethyl methacrylate and mica, it being understood that one can also use in the context of the present invention, other substances such as talc, kaolin, or other oxides preferably of light color, to avoid the absorption of photonic energy. It is also possible to use at least one "chemical" filter.

With regard to the anti-free radical components, it should be emphasized, in particular, the use of vitamin
E which constitutes an important element in the combinations in accordance with the present invention: alpha-tocopherol and certain of its derivatives such as acetate or linoleate, have particularly important properties in the cosmeto-dermatological field. Vitamin E has essentially the following properties:
- it is first of all an antioxidant and, therefore,
prevents peroxidation, especially of lipids, reduces
disorders due to ultraviolet rays and, in particular,
acts against the formation of free radicals,
(favored in particular by ultraviolet A and B);
- it prevents the formation of nitrosamine with the effects
carcinogens, as well as prostaglandins, especially
from arachidonic acid, and inflammation and
the erythema they cause;
- it reduces the unfavorable activity of ornithine
decarboxylase, but protects that of the superoxide
dismutase and its anti-radical action;
- it hydrates and softens the skin, protects it, helps
tissue repair and scarring, and
has anti-inflammatory properties;
- it promotes the in vivo formation of other molecules
of vitamin E, and protects vitamin A.

 Experience has shown that, in accordance with the present invention, the proposed combinations potentiate the action of alpha-tocopherol and extend its field of action against photons and the disorders they may cause.

 It is also possible to use other anti-radical constituents such as acetylcysteine which causes the free radicals to be evacuated by the blood microcirculation.

 As regards the antielastatic components, according to a preferred embodiment of the invention, use is made of the flavonic compounds and the juglone which are found in many plants, which makes it possible to use extracts or essential oils. , such as walnut, mulberry or St. John's wort, which often have the advantage of exerting an anti-free radical action elsewhere, as is the case for vitamin P, the effects of which can be possibly reinforced by synergy with also antioxidant vitamin C.

 According to a preferred embodiment of the present invention, it is possible to combine with "physical" screens or filters "chemical" filters, such as, preferably, benzophenones and / or dibenzoylmethane and its derivatives whose spectrum of action is relatively broad, but it is also possible to use benzimidazoles, cinnamates, salicylates, as well as benzylidene-camphor and paraminobenzoic acid and their derivatives.

 The compositions according to the invention can also contain various agents and in particular anti-inflammatory agents.

 The invention also relates to the method for the manufacture of such compositions consisting in selecting filters and screens extending over the extent of the spectrum of photonic frequencies, in dosing them so as to oppose photons physical and in particular optical filtering which limits the width of the pass frequency bands and the pass energy, which depends in particular on the filters or screens chosen and on the surface density of distribution of the particles, itself a function of the concentration of these particles in the composition used.

 To better understand the technical characteristics and advantages of the present invention, we will describe embodiments thereof, it being understood that these are not limiting as to their mode of implementation and to the applications that can be made of them. to do.

Example 1: MELANOGENESIS INDUCTION CREAM
We use the following composition:
Oily phase% by mass polymethyl methacrylate microbeads 1.50 "phys." Filter titanium oxide 1.50 "phys." filter 2.00 mica "phys." filter alpha-tocopherol (vitamin E) 0.50 antiradic.

extract of walnut leaves, walnut husk and St. John's wort (juglone and fla- antiradic. and vonic) 0.50 antielastase vegetable oils 2.10 vaseline oil 19.20 mineral wax 3.00 isopropyl myristate 6.00 glycerol ester of vitamin F 0.20 palmitate of vitamin A 0.10 perfume 0.75
Oily complex concentrate of mulberry leaves 0.50 antiradic.

white petrolatum antielastase 35.00 lanolin 27.00
Demineralized water tanning base 0.10 soda 0.01 tanning complex 0.04
The fatty phase is prepared by conventional means with average stirring at 380 C; the fatty complex is also prepared in a conventional manner by melting and mixing, then it is emulsified with the fatty phase; finally, letting the temperature drop to around 250C, after incorporating it, incorporate the tanning base until homogenization, then continue mixing with moderate stirring. A composition is thus obtained having the appearance of a cream providing excellent protection against photons across the spectrum, thanks to filters and screens, protection considerably reinforced by the combination with the anti-free radical and anti-elastase components. It will be noted that the presence in this composition of a complex called "bronzing" allows, despite the very effective protection to initiate, without risk, melanogenesis.

Example 2: HIGH PROTECTION MILK
We start from the following composition:
Fat phase% by mass polymethyl methacrylate microbeads 1.50 "phys." Filter titanium oxide 1.50 "phys." filter 1.50 mica "phys." filter octyl methoxycinnamate 0.50 filter "chem." 3- (methyl-4-benzylidene) -camphor 0.50 filter "chem." hydroxy-2-methoxy-4-benzophenone 0.50 filter "chem." alphatocopherol (vitamin E) 0.50 antiradic.

extract of walnut leaves, walnut husk and St. John's wort (juglone and fla- antiradic. and vonic) 0.50 antielastase acetylcysteine 0.50 antiradic.

octyl-2-dodecanol 4.50 stearic acid + sorbitan oleate 1.50 liquid vaseline oil 6.00 vegetable oil 1.10 isopropyl myristate 3.00 vitamin A palmitate 0.10 glycerol ester of vitamin F 0, 30 perfume 0.40
Natural bio-flavonoids aqueous phase (vitamin P) 0.05 antielastase palmitate vitamin C 0.05 anti-radical.

demineralized water 66.00 glycerin 2.00 magnesium sulfate 0.65 soda 0.13
L-tyrosine 0.30 benzyl alcohol + methylchloroisothiazolinone + methylisothiazolinone 0.15 l, l'-methylene-bis (3- [3- (hydroxy-methyl) -2, 4-dioxo-5-imidazolidinyl] y-urea 0, 20 citric acid 0.05
The aqueous phase is prepared with gentle stirring at 380C; the fatty phase is carried out with medium stirring at room temperature, then the whole is emulsified while allowing to cool to around 300C. A highly protective milk is obtained against photons. And their various effects, and this across the entire spectrum, from ultra-violet to infrared.

EXAMPLE 3 CREAM AGAINST PHOTO INTOLERANCES
We start from the following composition:
Fat phase% by mass of titanium oxide 2.50 "phys." Filter mica 5.00 filter "phys." Polymethylmethacrylate microbeads 1.50 "phys." filter ethyl methoxycinnamate 2.00 "chem." filter hydroxy-2-methoxy-4-benzophenone 2.50 "chem." filter 3- (methyl-4-benzylidene) -chamber 2.50 "chem." Filter extract of walnut leaves, walnut husk and St. John's wort (juglone and fla- antiradic. and vonic) 0.50 antielastase acetylcysteine 0.50 antiradic.

alphatocopherol (vitamin E) 0.50 antiradic.

octyl-2-dodecanol 7.00 vegetable oil 1.00 sorbitan monostearate 2.00 sorbitan trioleate 2.00 glyceryl stearate 2.50 white petrolatum 4.00 myristyl myristate 4.00 stearin 5.00 caprylic triglycerides + capric 1.00 vitamin A palmitate 0.30 glycerol ester of vitamin F 0.10 perfume 0.20
Aqueous phase demineralized water 48.59 natural bioflavonoids (vitamin P) 0.10 antielastase
and antiradic.

vitamin C palmitate 0.10 allantoin 0.10 99% triethanolamine 0.21 chloro-5-methyl-2-isothiazoline-4-one-3 + methyl-2-isothiazoline-4-one-3 + magnesium chloride 0 , 10 1,1 '-methylene-bis3- [3- (hydroxy-methyl) -2,4-dioxo-5-imidazolidinyl]) - urea 0.20 propylene glycol 3.00 18beta-glycyrrhetinic acid 1.00
The aqueous phase is prepared hot with slow stirring and under slight vacuum, by mixing separately propylene glycol and 18beta-glycyrrhetinic acid; the fatty phase is prepared at 750C with medium stirring and the aqueous phase is added thereto under vacuum while emulsifying; the temperature is allowed to drop to 400C and the propylene glycol and 18betaglycyrrhetinic acid are added with moderate stirring while allowing to cool to ambient; a very protective cream is thus obtained against photons of the widest range, having more good anti-inflammatory properties.

Example 4: REPAIRING CREAM
We use the following composition:
Fat phase% by mass titanium oxide 1.25 "phys." Filter 1.50 mica "phys." filter 0.25 polymethyl methacrylate microbeads "phys." filter octyl methoxycinnamate 0.50 filter "chem." 3- (methyl-4-benzylidene) -camphor 0.50 filter "chem." alpha-tocopherol (vitamin E) 0.50 antiradic.

extract of walnut leaves, walnut husk and St. John's wort (juglone and fla- antiradic. and vonic) 0.50 antielastase vegetable oil 1.50 petroleum jelly oil 10.00 white beeswax 2.00 isopropyl myristate 2, 00 glyceryl stearate 4.50 polyethylene monostearate 2.50 octyl-2-dodecanol 5.00 cetyl palmitate 1.00 cetyl alcohol 2.00 hexadimethylsiloxane 0.50 repair complex 7.50 vitamin A palmitate 0.10 glycerol ester vitamin F 0.30 perfume 0.40
Aqueous phase demineralized water 48.40 natural bioflavonoids (vitamin P) 0.10 antielastase
and antiradic.

0.10 antiradic vitamin C palmitate.

N-acetyl-L-tyrosine 1.10 melanogenesis-inducing complex 3.05 99% triethanolamine 1.70 benzyl alcohol + methylchloroisothiazolinone + methylisothiazolinone 0.15 1,1'-methylene-bis {3- [3- (hydroxy- methyl) -2,4-dioxo-5-imidazolidinyl]) - urea 0.20
The aqueous phase is carried out at 800 with gentle stirring; the fatty phase is carried out at 750C with very slow stirring, with the exception of the repair complex; the whole is emulsified under vacuum, allowing to cool to 390, the temperature at which the repair complex is added; it is homogenized with moderate stirring, leaving the temperature to return to ambient. A cream is thus obtained which is both protective and repairing, suitable for damaged skin and nevertheless allowing the subjects to be reasonably exposed, for example, to solar radiation.

The resulting products were subjected to the following tests:
Ornithine decarboxylase and dialdehyde.de malonyl tests
They were conducted on the dorsal side of eight-week-old clipped mice. A quarter of an hour after application, they were subjected to solar radiation for one day. 18 hours later, an absence of disorder and a reduction of more than half of the activity of ornithine decarboxylase and of malonyl dialdehyde were observed with all the products of the above examples.

Erythema and superoxide dismutase tests
They were conducted on the shaved dorsal part of guinea pigs.

After application of the various products defined above to the examples given, the guinea pigs were exposed for one hour to solar radiation and, in all cases after 24 and 48 hours, only moderate redness, or even negligible. In addition, the number of cells with typical disorders resulting from the presence of free radicals was counted in 4 mm areas. Their number has been found to be negligible, even for abnormally high photonic energies. Furthermore, a very significant reduction in the activity of superoxide dismutase has been observed.

Claims (8)

1- A protective composition for the skin, characterized in that it comprises the combination of a filtering system over the whole range of light wavelengths, of at least one anti-radical component and of at least one antielastatic component. 2- Composition according to claim 1 characterized in that it comprises as anti-radical compound alphatocopherol (or vitamin E) and / or one of its derivatives. 3- Composition according to one of claims 1 or 2 characterized in that it comprises as anti-free radical acetycysteine and / or one of its derivatives. 4- Composition according to claim 2 characterized in that it contains vitamin C and / or one of its derivatives. 5- Composition according to one of claims 1 to 4 characterized in that it contains as anti-elastic vitamin P and / or one of its derivatives. 6- Composition according to one of claims 1 to 6 characterized in that it comprises as a component of the filtering system at least one "physical" filter or screen. 7- Composition according to one of claims 1 to 6 characterized in that it comprises as a component of the filtering system at least one "chemical" filter. 8- A method of manufacturing compositions according to one of claims 1 to 7 characterized in that it comprises a phase of selection of filters or screens consisting, according to their own characteristics of filtration according to the light wavelengths, adding them to concentrations such that the overall characteristic is distributed over the extent of the light spectrum.