CH634987A5 - Cosmetic light-stabilising agent for the UV-A region - Google Patents

Description

The invention relates to a cosmetic light stabilizer for the UV-A range with a content of pyruvic acid or levulinic acid condensation products which, when used tropical on the skin, protect against the damaging effects of the longer-wave UV-A component of sunlight under prolonged exposure grant.

The preparations generally used as cosmetic sunscreens or light stabilizers contain components which prevent or reflect the short-wave UV-B component of sunlight to prevent sunburn. They reduce the dose of short-wave radiation that penetrates the outer layers of the skin and thus prevent the development of severe erythema without preventing the tanning caused by the longer-wave portion. This longer-wave portion of the sunlight, which covers the range of 320-400 nm, not only enables the pleasant tanning of the skin, but is also made responsible for the chronically damaged skin. This damage was formerly considered age-related; people generally spoke of the skin of the age. Today, however, it is known that they essentially depend on the total duration and intensity of the exposure to light. Such damage to the skin is manifested by increased wrinkling of the skin due to loss of elasticity, thinning of the epidermis, yellow-brown coloring of the facial skin, pigment shifts and finally by keratosis, which can lead to cancer precursors and skin cancer, such as spinaliomas and basalomas.

There is therefore a need, not only from a purely aesthetic point of view, for cosmetic agents which prevent the harmful side effects of a too long and intensive exposure to the longer-wave UV-A component of sunlight. The agents must also be toxicologically and dermatologically harmless, have good light and heat stability and adhere well to the skin.

It has now been found that cosmetic light stabilizers containing pyruvic acid or levulinic acid condensation products of the formula

O

R-CH = CH-C- (CH2) n-COOR1

in which n is the number 0 or 2, Rj is hydrogen, an alkyl radical having 1-4 carbon atoms or a salt-forming cation from the group of the alkali or alkaline earth metals, the ammonium or substituted ammonium cation, the optionally alkyl-substituted urea or allantoin and R the radicals Ar or -CH = CH-Ar, where Ar is an aryl radical, in particular a phenyl radical, which may be replaced by one or more C1-C4-alkyl radicals, one or more hydroxyl groups, one or more Cj-Q.-alkoxy groups, one or more amino - or di- (C1-C4) alkylamino groups, one or more halogen atoms or a methylenedioxy group is substituted, largely meet the requirements.

The pyruvic acid or levulinic acid condensation products used in the cosmetic light stabilizer according to the invention are preparations known from the literature, the production of which by E.D. Stecher and H.F. Ryder in J. Am. Chem. Soc. 74, p. 4392ff. (1952) or by S.H. Zaheer, J.K. Kacker and N. Shanmukha Rao in Chem. Ber. 89, pp. 354ff. (1956) is described in detail.

Examples of pyruvic acid or levulinic acid condensation products which can be used in the cosmetic light stabilizer according to the invention are benzylidene pyruvic acid, methyl benzylidene pyruvate, ethyl benzylidene pyruvate, benzylidene benzyl benzylbenzate, 4-benzylbenzate hydroxybenzate, 4-benzylidene benzylbenzate -lidene-pyruvic acid methyl ester, 4-methoxy-benzylidene-pyruvic acid, 3,4-dimethoxy-benzylidene-pyruvic acid methyl ester, 4-methoxy-benzylidene-pyruvic acid ethyl ester, 4-chloro-benzylidene-pyruvic acid, 3,4-dichlorobenzyl -pyruvic acid, 4-amino-benzylidene-pyruvic acid methyl ester, 4-dimethyl-amino-benzylidene-pyruvic acid ethyl ester, 3,4-methylenedioxy-benzylidene-pyruvic acid, cinnamylidene-pyruvic acid benzyl acid, cinnamylidene-benzene benzylidenidyl acid, benzinnyl methylene acid , Isopropyl benzylidene vulcanic acid , Butyl benzylidene levulinate, 4-hydroxy-benzylidene levulinate, 3,4-di-hydroxy-benzylidene levulinic acid, 4-methoxy-benzylidene levulinic acid, 4-methoxy-benzylidene levulinic acid butyl ester, 3,4-dimethoxy-benzylidene levulinic acid, 3,4-dimethoxy-benzylidene-levulinic acid ethyl ester, 3-methoxy-4-hydroxy-benzylidene-levulinic acid, methyl 4-chloro-benzylidene-levulinic acid, 3,4-dichlorobenzylidene-levulinic acid, 4-amino-benzylidene -Levulinic acid methyl ester, 4-dimethylamino-ben-zyliden-levulinic acid, 4-dimethylamino-benzylidene-levulinic acid butyl ester, 3,4-methylenedioxy-benzylidene-levulinic acid and the sodium, potassium, ammonium, ethylammonium, ethanol ammonium - To call urea, diethylurea and allantoin salts of the substituted pyruvic acids and levulinic acids.

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

634 987

When used in cosmetic light stabilizers, the pyruvic acid or levulinic acid condensation products described can be incorporated into liquid, pasty or solid cosmetic preparations, such as, for example, aqueous suspensions, emulsions, solutions in organic solvents, oils, ointments, creams, sticks or powder. When used as a light stabilizer against the longer-wave UV-A radiation, the pyruvic acid or levulinic acid condensation products are used, for example, in amounts of 0.5 to 20 percent by weight, preferably 2 to 10 percent by weight, based on the total cosmetic agent.

In addition to the sole use in cosmetic light stabilizers, the use in common with conventional UV-B filter substances which serve to prevent sunburn can be in the foreground of use. With this use, the pyruvic acid or levulinic acid condensation products described can be used in combination with conventional UV-B filter substances, such as, for example, ethyl p-aminobenzoate, propyl ester, butyl ester, isobutyl ester, monoglycerol ester, ethyl p-dimethylamino benzoate, amyl ester, p-diethylaminobenzoic acid, ethyl ester, amyl ester, salicylic acid methyl ester, homomethyl ester, ethyl tonic ester, glycerol ester, -2-ethylhexyl ester, tert-butyl ester, -bornyl ester, -phenyl ester, triethanolammonium salt, p-salanyl acid, menthyl ester, antioxidant, salonic acid, menthyl ester, -Methoxycinnamic acid-3-ethoxy-ethyl ester, -2-ethyl hexyl ester, p-acetamido cinnamic acid iso-

propyl ester, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxy-benzophenone, 4-phenylbenzophenone, 2-hydroxy-4-meth-oxy- benzophenone-5-sulfonic acid, isooctyl 4-phenylbenzophenone-2-5 carboxylic acid, 7-ethylamino-4-methylcoumarin, 7,8-dihydroxycoumarin, 6,7-dihydroxycoumarin, 7-hydroxycoumarin, 4-methyl-7-hydroxycoumarin , 2-phenylbenz-imidazole-5-sulfonic acid, sodium 3,4-dimethoxyphenyl glyoxylate, butylbenzalacetone, benzalacetophenone, 3-ben-lo cylidene-D, L-camphor, 3- (p-methyl-benzylidene) -D, L-cam-pher and urocanic acid.

The amount of UV-B filter substances in these products based on a combination of UV-A and UV-B protective substances is, for example, 1 to 10% by weight, preferably 2 to 6% by weight, based on the total cosmetic light stabilizer.

When applied topically, such sunscreens not only provide effective protection against the dreaded sunburn, but also against the chronic effects of longer-lasting effects of the longer-wave UV-A components of sunlight.

The following examples are intended to show the protective properties of the pyruvic acid or levulinic acid condensation products described and their suitability for use in cosmetic light stabilizers.

In addition to the name of the products, the absorption characteristics are listed in Table 1 below.

Table 1

No.

product

Xmax. (nm)

Ige

1

Benzylidene pyruvic acid

299

4.2

2nd

Ethyl benzylidene pyruvate

311

4.0

3rd

4-methoxy-benzylidene-pyruvic acid

331

4.3

4th

Cinnamylidene pyruvic acid

336

4.4

5

3,4-methylenedioxy-benzylidene-pyruvic acid

347

4.1

6

Cinnamylidene pyruvic acid ethyl ester

348

4.4

7

Ethyl 4-methoxy-benzylidene-pyruvate

350

4.4

8th

4-methoxy-benzylidene levulinic acid

319

4.5

9

4-methoxy-benzylidene levulinic acid butyl ester

320

4.3

10th

4-Hydroxy-benzylidene levulinic acid butyl ester

327

4.3

11

3,4-dimethoxy-benzylidene levulinic acid

334

4.3

12

3,4-Dimethoxy-benzylidene-levulinic acid ethyl ester

335

4.2

13

3,4-methylenedioxy-benzylidene levulinic acid

337

4.2

14

3-methoxy-4-hydroxy-benzylidene levulinic acid

340

4.2

15

4-dimethylamino-benzylidene levulinic acid

383

4.5

16

4-Dimethylamino-benzylidene-levulinic acid butyl ester

385

4.3

Some examples of embodiments of the cosmetic light stabilizer according to the invention containing pyruvic acid or levulinic acid condensation products are listed below:

Examples

1. To prepare a light protection oil, 80 g of ethyl 4-methoxy-benzylidene-pyruvate are very finely suspended in 100 g of paraffin oil with heating, and then the following further constituents are added at about 25 ° C.

300 g vegetable oil containing lecithin 400 g olive oil 100 g isopropyl myristate 100 g purcellin oil mixed intimately.

2. To prepare a light protection powder, 150 g of ethyl cinnamylidene pyruvate are dissolved in a

55 nem powder mixer intensively with 350 g rice starch 350 g colloidal clay 100 g lycopodium 100 g talc 60 brought into homogeneous distribution.

3. 40 g of glycerol monostearate are used to produce a light protection cream

160 g beeswax 420 g mineral oil 65 50 g ceresin

50 g of an absorption base based on cholesterol,

Beeswax, stearyl alcohol and Vaseline 90 g 3,4-methylenedioxy-benzylidene-levulinic acid

634 987

melted together at 65 C. A mixture of 247 g of water and 13 g of borax heated to the same temperature is added to this warm mixture

2 g of methyl p-oxybenzoate are incorporated with vigorous stirring, and the cream obtained is stirred further until room temperature is reached.

4. To prepare a light protection emulsion, the mixture is heated to about 80 ° C.

20 g glycerol monostearate 70 g stearic acid 30 g oleic acid 20 g cetyl alcohol

80 g of 3,4-dimethoxy-benzylidene-levulinic acid ethyl ester are added to a mixture of 800 g of water, 10 g of glycerol and 9 g of triethanolamine with vigorous stirring. The lotion obtained is then stirred cold.

The above emulsion can also be packaged using a propellant in a volume ratio of 80 parts lotion: 20 parts propellant in aerosol form.

5. To make a sunscreen oil

80 g of 3,4-methylenedioxy-benzylidene-pyruvic acid 40 g of p-methoxycinnamic acid-2-ethylhexyl ester while heating is very finely suspended in 100 g of paraffin oil, and then the following further constituents are added at about 25 ° C.

300 g vegetable oil containing lecithin 360 g olive oil 100 g isopropyl myristate 100 g purcellin oil mixed intimately.

6. 40 g of glycerol monostearate are used to produce a sun protection cream

150 g beeswax

390 g mineral oil 50 g ceresin

50 g of an absorption base based on cholesterol, beeswax, stearyl alcohol and petroleum jelly s 90 g of 3-methoxy-4-hydroxy-benzylidene-levulinic acid 40 g of 3- (p-methylbenzylidene) -D, L-steamer melted together at 65 ° C. A mixture of 247 g of water and 13 g of borax heated to the same temperature is added to this warm mixture

2 g of methyl p-oxybenzoate are incorporated with vigorous stirring, and the cream obtained is stirred further until room temperature is reached.

15 7. To prepare a sunscreen emulsion, add 70 g stearic acid 30 g oleic acid 20 20 g cetyl alcohol to a mixture of 20 g glycerol monostearate heated to approx. 80 ° C

80 g of 3,4-dimethoxy-benzylidene-levulinic acid 40 g of 2-ethylhexyl p-dimethylaminobenzoate were added to a mixture of 800 g of water, 10 g of glycerol and 9 g of triethanolamine with vigorous stirring. The lotion obtained is then stirred cold.

The above emulsion can also be packaged using a propellant in a volume ratio of 80 parts lotion: 20 parts propellant in aerosol form.

Instead of the pyruvic acid or levulinic acid condensation products used in the recipes mentioned above, the other pyruvic acid or levulinic acid condensation products listed above can also be used, and the 35 others can be used instead of the UV-B filter substances mentioned in the recipes UV-B filter substances occur.

Claims (3)

634 987 1. Cosmetic light stabilizer for the UV-A range, characterized in that it contains at least one pyruvic acid or levulinic acid condensation product of the formula R-CH = CH-C-CCH ^ n-COORj in which n is zero or 2, Rx is hydrogen, an alkyl radical with 1-4 carbon atoms or a salt-forming cation from the group of the alkali or alkaline earth metals, the ammonium or substituted ammonium cation, or, if appropriate alkyl-substituted urea or of allantoin and R is the radical Ar or -CH = CH-Ar, where Ar is an aryl radical, optionally by one or more QG ^ alkyl radicals, one or more hydroxyl group (s), one or more C1-C4 Alkoxy group (s), one or more amino or di (C1-C4) alkylamino group (s), one or more halogen atom (s) or a methylenedioxy group is substituted. 2. Light stabilizer according to claim 1, characterized in that it contains the pyruvic acid or levulinic acid condensation product in an amount of 0.5 to 20 percent by weight, preferably 2 to 10 percent by weight, based on the total cosmetic agent. 2nd PATENT CLAIMS 3. Light stabilizer according to claim 1 or 2, characterized in that it also contains UV-B filter substances in an amount of 1 to 10 percent by weight, preferably 2 to 6 percent by weight, based on the total cosmetic agent.