Use of amino-substituted hydroxybenzophenones as photostable...

Details Use of amino-substituted hydroxybenzophenones as photostable... Use of amino-substituted hydroxybenzophenones as photostable...

2000-04-20

2002-06-25

Higel, Floyd D. (Department: 1626)

Drug, bio-affecting and body treating compositions

Topical sun or radiation screening, or tanning preparations

C424S060000, C424S070100, C514S428000, C514S534000, C514S619000, C548S573000, C560S043000, C562S441000, C564S067000

Reexamination Certificate

active

06409995

ABSTRACT:

The invention relates to the use of amino-substituted hydroxybenzophenones as photostable UV filters in cosmetic and pharmaceutical preparations for protecting the human epidermis or human hair from UV radiation, specifically in the range from 320 to 400 nm.
The sunscreens employed in cosmetic and pharmaceutical preparations have the task of preventing, or at least diminishing the consequences of, harmful effects of sunlight on the human skin. However, these sunscreens also serve to protect other ingredients from decomposition or -breakdown by UV radiation. In hair cosmetic formulations the aim is to reduce damage to the keratin fibers by UV rays.
The sunlight reaching the surface of the earth contains proportions of UV-B radiation (280 to 320 nm) and UV-A radiation (>320 nm), which are directly adjacent to the visible light region. The effect on the human skin is manifested, particularly in the case of UV-B radiation, by sunburn. Accordingly, the industry offers a relatively large number of substances which absorb UV-B radiation and thus prevent sunburn.
Dermatological investigations have now shown that UV-A radiation is also perfectly capable of causing skin damage and allergies by, for example, damaging the keratin or elastin. This reduces the elasticity and water storage capacity of the skin, i.e. the skin becomes less supple and tends to form wrinkles. The noticeably high incidence of skin cancer in regions where the sun's radiation is strong shows that damage to the genetic information in the cells is evidently also caused by sunlight, specifically by UV-A radiation. All these findings therefore make it appear necessary to develop efficient filter substances for the UV-A region.
There is a growing demand for sunscreens for cosmetic and pharmaceutical preparations which can be used in particular as UV-A filters and whose absorption maxima ought therefore to be in the range from about 320 to 380 nm. In order to achieve the required effect using the minimum amount, sunscreens of this type ought additionally to have a high specific absorbance. Sunscreens for cosmetic products must also meet a large number of other requirements, for example good solubility in cosmetic oils, high stability of the emulsions produced with them, toxicological acceptability, and low intrinsic odor and low intrinsic color.
Another requirement which sunscreens must meet is adequate photostability. However, this is only inadequately ensured, if at all, with the UV-A-absorbing sunscreens hitherto available.
French Patent No. 2 440 933 describes 4-(1,1-dimethylethyl)-4′-methoxydibenzoylmethane as a UV-A filter. It is proposed to combine this specific UV-A filter, which is sold by GIVAUDAN under the name “PARSOL 1789”, with various UV-B filters in order to absorb all UV rays having a wavelength from 280 to 380 nm.
However, this UV-A filter does not have sufficient photochemical stability, when used alone or in combination with UV-B filters, to ensure sustained protection of the skin during sunbathing for prolonged periods, which means that repeated applications at regular and short intervals are required if effective protection of the skin from all UV rays is desired.
For this reason, EP-A-0 514 491 discloses the stabilization of the insufficiently photostable UV-A filters by adding 2-cyano-3,3-diphenylacrylic esters which themselves act as filters in the UV-B region.
It has furthermore already been proposed in EP-A-0 251 398 and EP-A-0 416 837 to combine chromophores absorbing UV-A radiation and UV-B radiation into one molecule using a linker. This has the disadvantage that firstly a free combination of UV-A and UV-B filters in the cosmetic preparation is no longer possible, and that difficulties in the chemical linkage of the chromophores allow only certain combinations.
It is an object of the present invention to propose sunscreens for cosmetic and pharmaceutical purposes-which absorb in the UV-A region with high absorbance, which are photostable, have low intrinsic color, i.e. a sharp band structure, and are soluble in oil or water depending on the substituent.
We have found that this object is achieved by the use of amino-substituted hydroxybenzophenones of the formula I
in which the variables independently of one another have the following meanings:
R
1
and R
2
are hydrogen, C
1
-C
20
-alkyl, C
2
-C
10
-alkenyl, C
3
-C
10
-cycloalkyl, C
3
-C
10
-cycloalkenyl, where the substituents R
1
and R
2
together with the nitrogen atom to which they are bonded can form a 5- or 6-membered ring;
R
3
and R
4
are C
1
-C
20
-alkyl, C
2
-C
10
-alkenyl, C
3
-C
10
-cycloalkyl, C
3
-C
10
-cycloalkenyl, C
1
-C
12
-alkoxy, C
1
-C
20
-alkoxycarbonyl, C
1
-C
12
-alkylamino, C
1
-C
12
-dialkylamino, aryl, heteroaryl, optionally substituted, substituents which confer solubility in water, chosen from the group consisting of a nitrile group, carboxylate, sulfonate or ammonium radicals;
x is hydrogen, COOR
5
, CONR
6
R
7
;
R
5
to R
7
are hydrogen, C
1
-C
20
-alkyl, C
2
-C
10
-alkenyl, C
3
-C
10
-cycloalkyl, C
3
-C
10
-cycloalkenyl, —(Y—O)
o
—Z, aryl;
Y is —(CH
2
)
2
—, —(CH
2
)
3
—, —(CH
2
)
4
—, —CH(CH
3
)—CH
2
—;
Z is —CH
2
13
CH
3
, —CH
2
13
CH
2
13
CH
3
, —CH
2
—CH
2
—CH
2
—CH
3
, —CH(CH
3
)—CH
3
;
m is from 0 to 3;
n is from 0 to 4;
o is from 1 to 20
as photostable UV filters in cosmetic and pharmaceutical preparations for protecting the human skin or human hair from the sun's rays, alone or together with compounds which absorb in the UV region and are known per se for cosmetic and pharmaceutical preparations.
Alkyl radicals R
1
to R
7
which may be mentioned are branched or unbranched C
1
-C
20
-alkyl chains, preferably 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, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl or n-eicosyl.
Alkenyl radicals R
1
to R
7
which may be mentioned are branched or unbranched C
2
-C
10
-alkenyl chains, preferably vinyl, propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, 3-methyl-1-butenyl, 1-hexenyl, 2-hexenyl, 1-heptenyl, 2-heptenyl, 1-octenyl or 2-octenyl.
Cycloalkyl radicals which may be mentioned for R
1
to R
7
are preferably branched or unbranched C
3
-C
10
-cycloalkyl chains such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, 1-methylcyclopropyl, 1-ethylcyclopropyl, 1-propylcyclopropyl, 1-butylcyclopropyl, 1-pentylcyclopropyl, 1-methyl-1-butylcyclopropyl, 1,2-dimethylcyclopropyl, 1-methyl-2-ethylcyclopropyl, cyclooctyl, cyclononyl or cyclodecyl.
Cycloalkenyl radicals which may be mentioned for R
1
to R
7
are preferably branched or unbranched C
3
-C
10
-cycloalkenyl chains with one or more double bonds such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, cycloheptenyl, cycloheptatrienyl, cyclooctenyl, 1,5-cyclooctadienyl, cyclooctatetraenyl, cyclononenyl or cyclodecenyl.
The cycloalkenyl and cycloalkyl radicals may be unsubstituted or substituted by one or more, e.g. 1 to 3, radicals such as halogen, e.g. fluorine, chlorine or bromine, cyano, nitro, amino, C
1
-C
4
-alkylamino, C
1
-C
4
-dialkylamino, hydroxyl, C
1
-C
4
-alkyl, C
1
-C
4
-alkoxy or other radicals, or contain 1 to 3 heteroatoms such as sulfur, nitrogen, whose free valences can be saturated by hydrogen or C
1
-C
4
-alkyl, or oxygen in the ring.
Suitable alkoxy radicals for R
3
and R
4
are those having 1 to 12 carbon atoms, preferably havin

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