Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2001-12-17
2002-10-01
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S060000, C424S400000, C424S401000
Reexamination Certificate
active
06458342
ABSTRACT:
The invention relates to the use of sunscreen combinations which comprise, as constituent which absorbs in the UV-A region, 2,2′-p-phenylenebis(3,1-benzoxazin-4-one), and at least one further sunscreen which absorbs in the UV-A region, in the UV-B region or in both regions, chosen from a group defined in detail below as photostable UV filter combination in cosmetic and pharmaceutical preparations for protecting the human epidermis or human hair against 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 degradation 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 has a proportion of UV-B radiation (280 to 320 nm) and of UV-A radiation (>320 nm), which are directly adjacent to the visible light region. The effect on the human skin becomes evident, particularly in the case of UV-B radiation, from 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 solar 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 would therefore suggest the need 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. Furthermore, 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 against 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 in one molecule using a connecting member. 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 linking 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 can be achieved advantageously by certain sunscreen combinations.
Accordingly, this object is achieved according to the invention by the use of sunscreen combinations comprising a
A) compound absorbing essentially in the UV-A region and
B) further compounds absorbing in the UV-A region, in the UV-B region and in both regions,
where the constituent absorbing in the UV-A region consists of
A) effective amounts of the compound of the formula
and the constituent
B) comprises effective amounts of one or more compounds chosen from the group consisting of
Ba) the compound of the formula II
Bb) the compound of the formula III
Bc) the compound of the formula IV
Bd) the compound of the formula V
Be) the compound of the formula VI
Bf) an organosiloxane benzalmalonate of the formula VIla
in which
V
1
′ is the group
V
1
is a methyl group or V
1
′, or of the formula VIIb
in which V
2
′ is the group of the structure
V
2
is a methyl group or V
2′
or mixtures of compounds of the formulae VIIa and VIIb,
where t is a value up to 100 and u is a value up to 20, with the proviso that u=0 if V
1
=V
1
′ and/or V
2
=V
2
′, and u is a value from 1 to 20 if V
1
=CH
3
and/or V
2
=CH
3
,
Bg) the compound of the formula VIII
Bh) the compound of the formula IX
Bi) the compound of the formula X
Bj) the compound of the formula XI
in which X is hydrogen, sodium, potassium, ammonium or triethanolammonium,
Bk) the compound of the formula XII
Bl) the compound of the formula XIII
Bm) the compound of the formula XIV
Bn) the compound of the formula XV
Bo) the compound of the formula XVI
Bp) zinc oxide (XVII) and/or titanium dioxide (XVIII)
as photostable UV filters in cosmetic and pharmaceutical preparations for protecting human skin or human hair against solar rays, optionally together with other compounds which absorb in the UV region and are known per se for cosmetic and pharmaceutical preparations.
The sunscreen combination of the compounds (A) and (B) can be used alone or in combination with other compounds which absorb in the UV region, although at least effective amounts of the compounds (A) and (B) should be present in the sunscreen preparations. “Effective amounts of the compounds (A) and of the compounds (B)” means generally in each case at least 0.1% by weight, in each case based on the cosmetic preparation.
In the sunscreen combinations according to the invention, the amount of compounds which absorb in the UV-B region usually predominates. Accordingly, the content of the compound (A) which absorbs in the UV-A region is generally 5 to 50% by weight, preferably 10 to 25% by weight, in each case based on sunscreen combination of (A) and (B).
The sunscreen combinations are characterized by their high photostability, and the preparations prepared with the sunscreen combinations by their pleasant feel on the skin.
The compound of the formula I has the CAS No. 018600-59-4 and is known under the name Cyasorb® 3638 (Cyasorb) as stabilizer for plastics. In addition, it is described in U.S. Pat. No. 5,234,681 as a constituent of cosmetic preparations. Moreover, column 5 of said patent specification, lines 54 to 58, mentions that it is possible to use the compound group to which the compound of the formula I belongs, together with known ultraviolet absorbers. However, it could not be concluded from these statements that particularly advantageous combinations can be obtained with certain selected UV absorbers.
The compounds (B) are all known and are characterized in more detail below:
Ba) The compound of the formula II has the CAS No. 5466-77-3
Heidenfelder Thomas
Tiefensee Kristin
Wünsch Thomas
BASF - Aktiengesellschaft
Dodson Shelley A.
Keil & Weinkauf
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