The present invention relates to 5,6-diphenyl-1,2,4-triazine derivatives, and in particular to the use thereof as sun filters on human skin and hair or as light-protective agents in the synthetic materials industry such as plastics, glass and textiles. The present invention also has as an object cosmetic compositions containing the aforesaid derivatives.
As a brief review, the action of solar radiation on the skin depends primarily on the energy of the radiation which reaches the various cutaneous layers. Generally speaking, the most energetic radiation, i.e., having the shortest wavelength (E=hc/λ), cause erythemas or “sunburn”, whereas less energetic radiation only causes a simple browning of the skin. It is thus considered that a sun filter intended to be part of the composition of so-called “sunscreen” cosmetic preparations must absorb short wavelength radiation to the maximum degree possible while remaining transparent to radiation of longer wavelength.
Photobiologists typically divide the ultraviolet spectrum into three parts, called UV-A, UV-B and UV-C, which correspond to the decreasing wavelength ranges from 400 nm to 320 nm, from 320 nm to 280 nm and from 280 nm to 200 nm, respectively.
UV-B and UV-A allow the tanning of the human epidermis. UV-B causes erythemas and cutaneous burns which can harm the development of a natural tan. For these reasons, as well as for esthetic reasons, a constant demand exists for methods of controlling this natural tanning with a view to controlling the color of the skin. It is thus advisable to filter this UV-B radiation.
It is also known that UV-A rays are likely to induce a deterioration of the skin, in particular in the case of sensitive skin or skin continuously exposed to sun radiation. In particular, UV-A rays cause a loss of skin elasticity and the appearance of wrinkles which lead to premature aging. They cause the triggering of the erythematous reaction or amplify this reaction in certain subjects and can even be the cause of phototoxic or photoallergic reactions. It is thus desirable to UV filter-A radiation as well.
UV-C, which is the most highly energetic, causes photokeratitis. The ozone formed in the stratosphere generally absorbs a large part of this UV-C radiation which, on the other hand, is found in large amounts in the radiation emitted by artificial lamps, which are often responsible for serious cutaneous injuries. UV-B, which penetrates the skin layer and, in particular, the stratum mucosum of the epidermis, causes solar erythemas. Consequently, UV-B and UV-C radiation together constitute the so-called erythema spectrum with regard to which sun filters must act as a screen. UV-A produces the direct pigmentation of the skin (melanogenesis), i.e., the tanning of the skin.
Compounds derived from the benzotriazoles and/or the benzotriazoles are known as UV filters, in particular in the field of cosmetics. The patent application FR 2,803,194 thus disclosed S-triazine derivatives carrying phenylbenzothiazole or benzothiazole groups useful as UV filters in particulate form. These compounds cover the range of UV-A and of UV-B but they exhibit the major disadvantage of absorbing in the visible spectrum (wavelengths longer than 400 nm). Thus these products are heavily colored, which limits their use in cosmetic products.
The present invention proposes novel 5,6-diphenyl-1,2,4-triazine derivatives capable of absorbing in UV-A and/or UV-B and/or UV-C, without absorbing in the visible spectrum. Thus these compounds have the advantage of being lightly colored.
They also have the advantage of being capable of being specific to one of these spectra. This is advantageous when it is desired to filter a specific UV spectra (UV-A, UV-B or UV-C), for example to supplement the spectral effectiveness of a UV filter which exhibits a gap in this specific range.
These novel derivatives thus offer a varied range of specific UV filters which can also exhibit various degrees of absorbance. The combination of several of these filters selected according to their specificity and their degree of absorbance thus makes it possible to prepare all types of UV filters acting in the spectrum and with the absorbance desired.
These novel derivatives also have the advantage of being soluble in various pharmaceutically acceptable excipients and of exhibiting better photostability than certain commercial filters, which makes them particularly useful in cosmetic products, notably in sun protectors.
The present invention has as an object the use, as sun filters active in UV-A and/or UV-B and/or UV-C for human skin and/or hair, of 5,6-diphenyl-1,2,4-triazinic compounds of general formula (I):
wherein:
The present invention also has as an object the use of compounds such as previously defined as light-protective agents active in the UV-A and/or UV-B and/or UV-C spectra, useful in the synthetic materials industry, in particular as light-protective agents incorporated into the composition of plastics, glass or textiles.
These compounds, which are objects of the present invention, can thus be used to protect photosensitive materials.
The light-protective agent could be incorporated into a substratum with the goal of protecting said substratum against attack from ultraviolet rays, to prevent the modification of one or several physical properties of said substratum, such as, for example, discoloration, a change in resistance to tearing, an increase in brittleness, etc., and/or to prevent chemical reactions caused by ultraviolet rays, for example the oxidation process. In this case, the protective agent can be incorporated before and during the preparation of the substratum, or at a later time by a suitable process, for example a binding process analogous to dyeing.
The light-protective agent can also be incorporated into a substratum to protect one or more additional substances incorporated into the aforesaid substratum, for example dyes, auxiliary agents, etc.
The light-protective agent can also be incorporated into a filter layer that may be a solid (film, sheet) or semi-solid (cream, oil, wax) applied to a substratum for the purpose of protecting said substratum from ultraviolet rays.
The compounds of the present invention are suitable not only as light-protective agents for colorless materials, but also for pigmented materials. In this case, the protection against light is extended to the coloring agents, thus allowing in many cases a quite notable improvement of stability in light.
The present invention also has as an object the 5,6-diphenyl-1,2,4-triazinic compounds of general formula (Ia):
wherein:
Among the compounds of general formula (Ia), the following compounds have led to particularly advantageous practical results:
The present invention also has as an object cosmetic sunscreen compositions containing an effective quantity of at least one compound of formula (Ia) in combination with a cosmetically acceptable excipient, preferably between 0.1% and 20% by weight with respect to the total weight of the composition.
The cosmetic sunscreen compositions according to the invention may contain in addition one or more sun filters active in UV-A and/or UV-B and/or UV-C (absorbers), either hydrophilic or lipophilic. These additional filters may be selected among, in particular, cinnamic derivatives, dibenzoylmethane derivatives, salicylic derivatives, camphor derivatives and triazine derivatives other than those previously cited in the present invention.
The compounds of general formula (I) can be prepared from 1,2-diketones of formula (II), by conventional methods known to those skilled in the art, such as those described in the examples which follow.
in which R1 and R2 have the same significance as that given previously.
The diketones of formula (II) are available commercially (such as, for example, benzyl(diphenylethan-1,2-dione), 4,4′-dimethylbenzyl, 4,4′-dibromobenzyl, 4,4′-difluorobenzyl or 4,4′-dichlorobenzyl) or can be synthesized by conventional methods well known to those skilled in the art. For example, the following synthesis route can be used:
The examples which follow give other examples of syntheses of diketones of formula (II).
The present invention will be illustrated below by mentioning several nonrestrictive examples of the preparation of representative derivatives conforming to general formula (I).
The compounds prepared are summarized in table 1.
The compounds of formula (I) of table 1 can be synthesized in the following way:
wherein R1, R2=
wherein R′=chlorine,
DBM=Parsol 1789® (Roche Laboratories)
MCX=Parsol MCX® (Roche Laboratories)
C16H14O4 M=270.28 g/mol
Oxalyl chloride (4.71 ml, 55.2 mmol) at 0° C. is slowly added to a mixture of anisole (10.8 g, 100 mmol) and aluminum chloride (33.33 g, 250 mmol). The mixture is stirred at ambient temperature for 4 hours. After cooling, it is poured into iced water and extracted with dichloromethane. The organic phases collected are washed with 2 N HCl then with brine and are dried on magnesium sulfate. After filtration and concentration under reduced pressure, the residue is recrystallized in ethanol. The resulting precipitate is filtered, washed several times in ethanol and dried to yield 9.80 g (66%) of pure product in the form of a yellow solid. δH (200 MHz, CDCl3) 3.93 (s; 6H), 6.99 (d; J 7.8; 4H), 7.99 (d; J 7.8; 4H).
C22H28N2O2 M=352.48 g/mol
Oxalyl chloride (44.1 ml, 191.1 mmol) at 0° C. is slowly added to a mixture of N,N′-diethylaniline (60 g, 382.1 mmol) and aluminum chloride (30.57 g, 229.3 mmol). The mixture is stirred at ambient temperature for 4 hours. After cooling, it is poured into iced water and extracted with dichloromethane. The recombined organic phases are washed with 2 N HCl then with brine and are dried on magnesium sulfate. After filtration and concentration under reduced pressure, the residue is recrystallized in ethanol. The resulting precipitate is filtered, washed several times with ethanol and dried to yield 13.55 g (70%) of pure product in the form of a yellow solid. δH (200 MHz, CDCl3), 1.25 (t; 12H), 3.45 (q; 8H), 6.65 (d; J 7.8; 4H), 7.87 (d; J 7.8; 4H).
C22H29N5O M=391.52 g/mol
Semicarbazide hydrochloride (1.57 g, 14.2 mmol) and sodium acetate (1.41 g, 17.3 mmol) are added to a solution of 1,2-bis(4-diethylaminophenyl)-ethane-1,2-dione prepared according to example 2 (5 g, 14.2 mmol) in acetic acid (20 ml). The mixture is heated at reflux for 12 hours. After returning to ambient temperature, the reaction mixture is poured into water. The raw solid is collected by filtration and washed with water. The residue is recrystallized in acetic acid. After filtration and washing with water, 3 g (54%) of a yellow solid are obtained after drying. δH (200 MHz, CDCl3), 1.18 (t; 12H), 3.45 (q; 8H), 6.65 (d; J 7.8; 4H), 7.87 (d; J 7.8; 4H), 10.4 (s; 1H)
C23H19N3O3 M=385.42 g/mol
2-Hydroxyphenylhydrazide (2.23 g, 14.8 mmol) is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione prepared according to example 1 (4 mg, 14.8 mmol) in acetic acid (20 ml) in the presence of ammonium acetate. The mixture is heated at reflux for 5 hours. After returning to ambient temperature, the precipitate obtained is filtered, successively washed with acetic acid then with ethanol and is dried to yield a yellow solid. The residue is recrystallized in a dimethylformamide/ethanol mixture (95/5) to yield 2.90 g (51%) of a yellow solid. δH (200 MHz, CDCl3), 3.86 (s; 6H), 7.02 (m; 4H), 7.58 (d; J 7,8; 2H), 7.71 (m; 4H), 8.77 (d; J 8.7; 2H), 12.3 (s; 1H); MS (Electrospray) m/z 386 (MH+, 100%).
C23H19N3O3 M=385.42 g/mol
4-Hydroxyphenylhydrazide (2.23 g, 14.8 mmol) is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione prepared according to example 1 (4 mg, 14.8 mmol) in acetic acid (20 ml) in the presence of ammonium acetate. The mixture is heated at reflux for 6 hours. After returning to ambient temperature, the precipitate obtained is filtered, successively washed with acetic acid then with ethanol and is dried to yield a yellow solid. The residue is purified by chromatography on a silica gel (dichloromethane/ethanol: 95/5) to yield 2.56 g (45%) of a yellow solid. δH (200 MHz, CDCl3), 3.86 (s; 6H), 7.02 (m; 4H), 7.58 (d; J 7.8; 2H), 7.71 (m; 4H), 8.77 (d; J 8.7; 2H), 11.79 (s; 1H); MS (Electrospray) m/z 386 (MH+; 100%).
C21H15N3O M=325.37 g/mol
2-Hydroxyphenylhydrazide (3.17 g, 20.9 mmol) is added to a solution of benzyl (4 mg, 19 mmol) in acetic acid (20 ml) in the presence of ammonium acetate. The mixture is heated at reflux for 4.5 hours. After returning to ambient temperature, the precipitate obtained is filtered, successively washed with acetic acid then with ethanol and is dried to yield a yellow solid. The residue is recrystallized in a dimethylformamide/ethanol mixture (90/10) to yield 3.15 g (51%) of a yellow solid. δH (200 MHz, CDCl3), 7.02 (m; 5H), 7.58 (d; J 7.8; 2H), 7.71 (m; 4H), 8.77 (d; J 8.7; 2H), 12.6 (s; 1H); MS (Electrospray) m/z 359 (MH+; 100%), 673 (2M+Na+; 21%).
C21H15N3O M=325.37 g/mol
4-Hydroxyphenylhydrazide (3.17 g, 20.9 mmol) is added to a solution of benzyl (4 mg, 19 mmol) in acetic acid (20 ml) in the presence of ammonium acetate. The mixture is heated at reflux for 3 hours. After returning to ambient temperature, the precipitate obtained is filtered, successively washed with acetic acid then with ethanol and is dried to yield a yellow solid. The residue is purified by chromatography on a silica gel (dichloromethane/ethanol: 94/6) to yield 3.46 g (56%) of a yellow solid. δH (200 MHz, CDCl3), 7.02 (m; 5H), 7.58 (d; J 7.8; 2H), 7.71 (m; 4H), 8.77 (d; J 8.7; 2H), 11.79 (s; 1H); MS (Electrospray) m/z 326 (MH+, 100%).
C24H21N3O3 M=399.45 g/mol
4-Methoxyphenylhydrazide (2.23 g, 14.8 mmol) is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione prepared according to example 1 (4 g, 14.8 mmol) in acetic acid (20 ml) in the presence of ammonium acetate. The mixture is heated at reflux for 5 hours. After returning to ambient temperature, the precipitate obtained is filtered, successively washed with acetic acid then with ethanol and is dried to yield a yellow solid. The residue is purified by chromatography on a silica gel (dichloromethane/ethanol: 95/5) to yield 2.42 g (41%) of a yellow solid. δH (200 MHz, CDCl3), 3.86 (s; 6H), 3.90 (s; 3H), 7.02 (m; 4H), 7.58 (d; J 7.8; 2H), 7.71 (m; 4H), 8.63 (d; J 8.7; 2H); MS (Electrospray) m/z 460 (MH+, 100%).
C23H19N3O5 M=417.42 g/mol
3,4,5-Trihydroxyphenylhydrazide (2.5 g, 11 mmol) is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione prepared according to example 1 (3 g, 11 mmol) in acetic acid (20 ml) in the presence of ammonium acetate. The mixture is heated at reflux for 5.5 hours. After returning to ambient temperature, the precipitate obtained is filtered, successively washed with acetic acid then with ethanol and is dried to yield a yellow solid. The residue is purified by chromatography on a silica gel (dichloromethane/ethanol 90/10) to yield 200 mg (5%) of a yellow solid. δH (200 MHz, CDCl3, 3.86 (s; 6H), 7.02 (m; 4H), 7.58 (d; J 7.8; 2H), 7.71 (d; J 8.7; 2H), 8.70 (5; 2H), 7.71 (m; 4H), 8.77 (d; J 8.7; 2H), 11.79 (s; 1H), 11.90 (2H; s); MS (Electrospray) m/z 418 (MH+, 100%).
C35H43N3O3 M=553.74 g/mol
JR65 (7 g, 18.1 mmol) prepared according to example 5 is added to a solution of sodium hydroxide (872 mg, 21.8 mmol) in ethanol (50 ml). The mixture is stirred for half an hour. 1-Bromododecane (9.473 g, 38 mmol) is added to the solution. The whole is brought to reflux in ethanol for 12 hours. After returning to ambient temperature, the precipitate obtained is filtered and recrystallized twice in cyclohexane to yield 5.2 g (52%) of a yellow solid. δH (200 MHz, CDCl3), 0.92 (m; 3H), 1.20-1.40 (m; 19H), 1.50-1.87 (m; 2H), 3.91 (s; 6H), 4.00 (t; J 7.5, 2H) 6.95 (m; 4H), 7.65 (d; J 7.8; 2H), 7.82 (m; 4H), 8.63 (d; J 8.7; 2H); MS (Electrospray) m/z 554 (MH+, 100%).
C17H16N4O2 M=308.34 g/mol
Aminoguanidine (2.450 g, 2.21 mmol) is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione prepared according to example 1 (5 g, 18.5 mmol) in ethanol (50 ml). The mixture is heated at reflux for 12 hours. After returning to ambient temperature, the precipitate obtained is filtered, washed with ethanol and is dried to yield a yellow solid. The residue is purified by chromatography on a silica gel (dichloromethane/triethylamine 0.5%) to yield 3.7 g (65%) of a yellow solid. δH (200 MHz, CDCl3), 3.88 (s; 6H), 5.51 (s; 2H), 6.92 (m; 4H), 7.41 (m; 4H).
C24H28N4O2 M=404.50 g/mol
JR77 prepared according to example 11 (2 g, 6.5 mmol) and heptaldehyde (0.907 ml, 6.5 mmol) are placed in solution in glacial acetic acid and heated at reflux for 1.5 hours. After cooling, the raw reaction product is precipitated on crushed ice. The solid obtained is placed in solution in dichloromethane and filtered. The solvent is evaporated dry, 2 g of a yellow oil are obtained. δH (200 MHz, CDCl3), 0.92 (m; 3H), 1.29 (m; 6H), 1.59 (m; 2H), 2.34 (t; J 7.5, 2H) 3.86 (s; 6H), 6.77 (d; 2H) 6.89 (d; 2H), 7.44 (m; 4H); MS (Electrospray) m/z 405 (MH+, 100%).
C8H8N4 M=160.18 g/mol
A mixture of 1,2-dicyanobenzene (10 g, 78.1 mmol) and hydrazine monohydrate (50 ml) is placed under a nitrogen atmosphere. The mixture is stirred at ambient temperature for 12 hours. The yellow precipitate obtained is then filtered and placed in ethanol to recrystallize to yield 5 g (40%) of a yellow solid. δH (200 MHz, acetone-d), 3.53 (m; 4H), 7.72 (m; 1H), 8.05 (m; 2H), 8.58 (s; 1H).
C8H8N4 M=160.18 g/mol
A mixture of 1,3-dicyanobenzene (10 g, 78.1 mmol) and hydrazine monohydrate (50 ml) is placed under a nitrogen atmosphere. The mixture is stirred at ambient temperature for 12 hours. The yellow precipitate obtained is then filtered and placed in ethanol to recrystallize to yield 5.62 g (45%) of a yellow solid. δH (200 MHz, CDCl3), 3.53 (m; 4H), 7.50 (t; J 7.3; 1H), 7.67 (d; J 7.3; 2H), 7.95 (m; 1H).
C8H8N4 M=160.18 g/mol
A mixture of 1,4-dicyanobenzene (10 g, 78.1 mmol) and hydrazine monohydrate (50 ml) is placed under a nitrogen atmosphere. The mixture is stirred at ambient temperature for 12 hours. The yellow precipitate obtained is then filtered and placed in ethanol to recrystallize to yield 5.75 g (46%) of a yellow solid. δH (200 MHz, CDCl3) 3.51 (m; 4H) 7.70 (d; J 7.3; 2H), 7.95 (J; 7.3; 2H).
C22H14N4 M=334.00 g/mol
3-Cyanophenylcarboxamidehydrazone (1 g, 6.25 mmol) prepared according to example 14 is added to a solution of benzyl (2.14 g, 10.2 mmol) in dimethylsulfoxide (DMSO) (100 ml). The mixture is heated at reflux for 15.5 hours at 130° C. After returning to ambient temperature, the raw reaction product is precipitated in water, the precipitate obtained is filtered and then dried. The residue is purified by chromatography on a silica gel (dichloromethane) to yield 1.2 g (57%) of a yellow solid. δH (200 MHz, CDCl3), 7.35 (m; 5H), 7.65 (d; J 7.8; 2H), 7.82 (d; J 8.7; 2H), 8.63 (s; 4H); MS (Electrospray) m/z 335 (MH+, 100%).
C22H14N4 M=334.00 g/mol
2-Cyanophenylcarboxamidehydrazone (1 g, 6.25 mmol) prepared according to example 13 is added to a solution of benzyl (2.142 g, 10.2 mmol) in dimethylsulfoxide (DMSO) (100 ml). The mixture is heated at reflux for 15.5 hours at 130° C. After returning to ambient temperature, the raw reaction product is precipitated in water, the precipitate obtained is filtered and then dried. The residue is purified by chromatography on a silica gel (dichloromethane) to yield 1.1 g (55%) of a yellow solid. δH (200 MHz, CDCl3), 7.34 (m; 5H), 7.65 (m; 3H), 7.82 (s; 1H), 8.63 (s; 4H); MS (Electrospray) m/z 335 (MH+, 100%).
C24H18N4O2 M=394.43 g/mol
2-Cyanophenylcarboxamidehydrazone (1 g, 6.25 mmol) prepared according to example 13 is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione (2.75 g, 10.2 mmol) prepared according to example 1 in ethanol (20 ml). The mixture is heated at reflux for 9.5 hours. After returning to ambient temperature, the solvent is evaporated and the solid is purified by chromatography on a silica gel (dichloromethane/ethanol: 95/5). 1.653 g (40%) of an orange yellow product is obtained. δH (200 MHz, CDCl3), 3.86 (s; 6H), 6.88 (m; 4H), 7.58 (d; J 7.8; 2H), 7.82 (m; 4H), 8.77 (d; J 8.7; 2H); MS (Electrospray) m/z 395 (MH+, 100%).
C24H18N4O2 M=394.43 g/mol
3-Cyanophenylcarboxamidehydrazone (1.5 g, 9.37 mmol) prepared according to example 14 is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione (4.2 g, 15.6 mmol) prepared according to example 1 in ethanol (20 ml). The mixture is heated at reflux for 10 hours. After returning to ambient temperature, the solvent is evaporated and the solid is purified by chromatography on a silica gel (dichloromethane/ethanol: 96/4). After evaporation of the solvent, 963 mg (37%) of a yellow solid are obtained. δH (200 MHz, CDCl3), 3.91 (s; 6H), 6.95 (m; 4H), 7.65 (m; 3H), 7.82 (m; 4H), 8.63 (m; 2H); MS (Electrospray) m/z 395 (MH+, 100%).
C24H18N4O2 M=394.43 g/mol
4-Cyanophenylcarboxamidehydrazone (1 g, 6.25 mmol) prepared according to example 15 is added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione (2.81 g, 10.41 mmol) prepared according to example 1 in ethanol (20 ml). The mixture is heated at reflux for 12 hours. After returning to ambient temperature, the solvent is evaporated and the solid is purified by chromatography on a silica gel (dichloromethane/ethanol: 96/4). After evaporation of the solvent, 1.92 g (78%) of a yellow solid is obtained. δH (200 MHz, CDCl3), 3.91 (s; 6H), 6.95 (m; 4H), 7.65 (d; J 7.8; 2H), 7.82 (m; 4H), 8.63 (d; J 8.7; 2H); MS (Electrospray) m/z 395 (MH+, 100%).
C17H15N3O3 M=309.32 g/mol
Semicarbazide chlorohydrate (2.22 g, 20 mmol) and sodium acetate (1.80 g, 22 mmol) are added to a solution of 1,2-bis(4-methoxyphenyl)-ethane-1,2-dione (5.4 g, 20 mmol) prepared according to example 1 in acetic acid (25 ml). The mixture is heated at reflux for 12 hours. After returning to ambient temperature, the reaction mixture is poured into water. The raw reaction product is collected by filtration and washed with water. The residue is recrystallized in acetic acid. After filtration and washing in water, 5.9 g (95%) of a yellow solid is obtained after drying. δH (200 MHz, CDCl3), 3.86 (s; 6H), 6.94 (m; 4H), 7.67 (s; 4H).
C17H14N3O2 M=327.77 g/mol
JR99 (4.57 g, 14.8 mmol) prepared according to example 21 in solution in 23 ml of phosphorus oxychloride is brought to reflux for 1.5 hours. The cooled mixture is poured over crushed ice and extracted with diethyl ether. The extract is washed successively with a solution of 2% sodium hydroxide in water until the wash products are neutral. The ether extract is dried on anhydrous sodium sulfate and evaporated. The residue is taken up in ether and filtered. The filtrate is evaporated and yields 3.5 g (72%) of a yellow-brown solid. δH (200 MHz, CDCl3), 3.86 (s; 6H), 6.94 (m; 4H), 7.67 (s; 4H)
Below are found the physicochemical studies carried out on the compounds which are objects of the present invention, in comparison with the following commercial filters:
The calculation of the molar extinction coefficient (ε) is made from the Beer-Lambert law:
A=absorbance
Io=intensity of the incident light
I=intensity of the transmitted light
ε=molar extinction (or molar absorbance) coefficient in M−1 cm−1
l=path length in cm
c=concentration in mol/l
The molar extinction coefficient can be expressed with respect to a given mass of the product. It thus makes it possible to be able to compare the coefficients of extinction between products for the same given quantity. This quantity is 1% by weight. The molar extinction coefficient thus becomes the specific absorbance (A1cm1 %).
It is expressed as follows:
A1cm1 %=specific absorbance
ε=molar extinction coefficient
M=molar mass
The spectral characteristics of the compounds in comparison with commercial filters at a concentration of 10 μg/ml are summarized in tables 2-1 and 2-2.
Procedure: The products are dissolved in ethyl acetate to a concentration of 10 μg/ml. The spectra are measured using a dual-beam spectrophotometer (Varian CARY 50 Scan) between 290 nm and 400 nm.
The products tested are classified according to spectral distribution in UVA and UVB in a range from 290 nm to 400 nm.
It is possible to differentiate them according to their spectral distribution:
Products with a narrow spectrum:
Parsol 1789° only absorbs in UVA (see
JR18, JR70, JR65 and JR173 absorb in UVB (see
JR89, JR115, JR63, JR68 and JR77 absorb in UVB (280-320 nm) and UVA-II (280-340 nm) (see
JR107, JR113, JR114, Tinosorb S® and Tinosorb M® absorb in UVB and UVA (See
Table 3 summarizes the spectral distributions of the compounds tested.
The in vitro methods of determining the protective effectiveness of sun products consist of measuring by transmission spectrophotometry the absorption spectrum of the filter in solution or of the product applied on a substrate with the aim of simulating the surface of the skin. The effectiveness against UVB and/or UVA rays, or the effect on the cutaneous response, are then determined by calculation, taking into account or not the UV radiation action spectrum for the damage considered.
The Sayre/Agin and Diffey/Robson method, used since the 1990s, involves a comparative measurement, with the aid of an integrating-sphere spectroradiometer, of the transition from 290 nm to 400 nm in 5 nm steps, the sample being subjected to UV radiation from a stable known source covering the whole of the UV spectrum (unfiltered xenon).
Diffey and Robson evaluate the erythemal response by the following calculation:
E(λ)=spectral irradiation in W(m−2) (nm−1) at 40° N sun at 20° zenith angle
ε=erythematous capacity
N(λ)=number of values for a given wavelength
The Diffey and Robson formula makes it possible to determine SPF from the measurement of transmittance between 290 nm and 400 nm. Transmittance is measured in solution in ethyl acetate at a concentration of 10 μg/ml using a UV-visible spectrophotometer (Varian CARY 50 Scan).
T(λ)=transmittance at wavelength λ
The results of the measurements taken are summarized in table 5.
PMMA (polymethyl methacrylate) plates (50×50 mm, supplied by Europlast) were used.
The dose applied in the in vivo solar product evaluation protocols (2 mg/cm2) is too high for the type of substrate employed here. A study showed that the best correlations with SPF were obtained by the application of 1.2 mg/cm2.
Gels were formulated from the triazines that are objects of this invention and certain reference filters. The molecules are solubilized in Transcutol® CG in a water bath. The solution is then placed under magnetic stirring and a gelling agent, Klucel HF (hydroxypropyl cellulose), is added at a concentration of 2%. Stirring is maintained for 30 minutes. SPF is measured using a Labsphere UV-1000 S Transmittance Analyzer spectrophotometer (Labsphere, North Sutton, N.H., USA). The results of the measurements taken are summarized in table 5.
A Suntest CPS+ (Atlas, Linsengenicht/Altenhasslan, Germany) was used. The Suntest makes it possible to reproduce the solar spectrum and thus to carry out exposures inside at any time without weather constraints.
Setting the MED (minimal erythemal dose):
The radiance of the solar simulator was carefully measured with a spectroradiometer (MSS 2044, Bielefeld, Germany). UVB and UVA intensities were 0.49 mW/cm2 and 6.32 mW/cm2, respectively. The MED value defined by COLIPA is 5.6 J/cm2 in total UV (22). The UV total (UVA+UVB) accounts for 14.8% of the energy delivered by the lamp (power 460 W/m2). An irradiation dose equivalent to 1 MED corresponds to 37.83 J/cm2 (in total spectrum) delivered by the lamp.
The Suntest test duration is calculated using the following formula:
t=H/E
with:
E=illumination energy in W/m2
H=irradiation dose in J/m2
t=duration of the test in s
The setting of the MED on the Suntest and the correspondence with sun intensity at 3 seaside resorts are indicated in table 6.
The solutions of the compounds are prepared at a concentration of 500 μg/ml in methanol. 50 μl (25 μg) of each solution are deposited in a crystallizer, then irradiated in the Suntest at 5, 10 and/or 20 MED. A non-irradiated control is prepared (deposit of 50 μl of solution and addition of 2.450 ml of methanol). The solvent evaporates during irradiation and the products are taken up in 2.5 ml of methanol. After irradiation, the absorbance of each solution is measured with the UV-visible spectrophotometer (Varian CARY 50 Scan).
The photostability measurement results for the compounds of formula (I) are summarized in table 7.
The solubility results for solvents or excipients used in cosmetics are summarized in table 8.
Number | Date | Country | Kind |
---|---|---|---|
0404810 | May 2004 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/FR2005/01129 | 5/4/2005 | WO | 00 | 1/23/2007 |