Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2000-05-24
2001-08-28
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
06280712
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to sun protection compositions containing dialkyl carbonates and UV filters and to the use of the dialkyl carbonates as solvents or dispersants for UV filters.
In the production of sun protection compositions, it is important inter alia to dissolve or disperse the insoluble UV filters so reliably that sedimentation is avoided, even in the event of prolonged storage. It is known from the customer information booklet “INFORMATION Kosmetik No. III/97 of Henkel KGaA (January 1997) that coconut fatty acid glycerides commercially available as Myritol 331 have good dissolving properties for crystalline UV filters and increase UV absorption by comparison with non-polar UV filters. Sun protection compositions containing these substances are also known, for example, from DE-A1 19631792 (Henkel). Besides the stability of the compositions, however, an equally important quality feature so far as the consumer is concerned is that the compositions should spread quickly and lastingly on the skin which requires the presence of a carefully balanced mixture of oil components from various spreading ranges. In the case of sun protection compositions, relatively high percentages of quick-spreading oils are required to support the rapid and uniform spreading of the sensorially heavy UV filters.
Accordingly, the complex problem addressed by the present invention was to provide oil components which would be high-spreading, which would have good dissolving or dispersing properties for UV filters and which, at the same time, would synergistically support UV absorption.
DESCRIPTION OF THE INVENTION
The present invention relates to sun protection compositions containing
(a) dialkyl carbonates and
(b) UV filters.
It has surprisingly been found that, in contrast to other high-spreading oils, for example dialkyl ethers or cyclomethicone, dialkyl carbonates, more particularly di-n-octyl carbonate and di-2-ethylhexyl carbonate have a distinctly higher dissolving power for UV filters and, in addition, synergistically enhance UV absorption. The expert is thus able to build up a spreading “cascade” of high- and medium-spreading oils which are capable of converting large amounts of UV filters into stable solutions or dispersions. In addition, the concentration in which the filters are used, as calculated for the required protection factor, can be reduced which, ultimately, leads to a reduction in the raw material costs for the same performance.
Dialkyl Carbonates
Formally, dialkyl carbonates are esters of carbonic acid and preferably correspond to formula (I):
R
1
O—CO—OR
2
(I)
in which R
1
and R
2
independently of one another represent linear or branched alkyl and/or alkenyl groups containing 1 to 22 carbon atoms, with the proviso that they contain in all at least 12, preferably 12 to 50 and more preferably 15 to 25 carbon atoms. The compounds are obtained by transesterifying dimethyl or diethyl carbonate, for example, with the corresponding fatty alcohols in known manner. Accordingly, the fatty carbonates may be symmetrical or non-symmetrical. However, carbonates in which R
1
and R
2
are the same and represent C
6-16
alkyl groups are preferably used. Transesterification products of dimethyl or diethyl carbonate with octanol, 2-ethylhexyl alcohol, decanol, cetyl alcohol, cetearyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, behenyl alcohol and/or erucyl alcohol in the form of their mono- and diesters or technical mixtures and Guerbet alcohols containing 8 to 24 carbon atoms are particularly preferred. From the performance point of view, it has proved to be effective to use di-n-octyl carbonate or di-2-ethylhexyl carbonate which have a Zeidler spreading value of 1600 mm
2
/10 mins. The dialkyl carbonates may be used in quantities of 1 to 30% by weight, preferably 5 to 20% by weight and more preferably 8 to 10% by weight, based on the composition.
UV Filters
UV filters in the context of the invention are organic substances which are capable of absorbing ultraviolet radiation and of releasing the energy absorbed in the form of longer-wave radiation, for example heat. UV-B filters can be oil-soluble or water-soluble. The following are examples of oil-soluble substances:
3-benzylidene camphor or 3-benzylidene norcamphor and derivatives thereof, for example 3-(4-methylbenzylidene)-camphor as described in EP-B1 0693471;
4-aminobenzoic acid derivatives, preferably 4-(dimethylamino)-benzoic acid-2-ethylhexyl ester, 4-(dimethylamino)-benzoic acid-2-octyl ester and 4-(dimethylamino)-benzoic acid amyl ester;
esters of cinnamic acid, preferably 4-methoxycinnamic acid-2-ethylhexyl ester, 4-methoxycinnamic acid propyl ester, 4-methoxycinnamic acid isoamyl ester, 2-cyano-3,3-phenylcinnamic acid-2-ethylhexyl ester (Octocrylene);
esters of salicylic acid, preferably salicylic acid-2-ethylhexyl ester, salicylic acid-4-isopropylbenzyl ester, salicylic acid homomenthyl ester;
derivatives of benzophenone, preferably 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4′-methylbenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone;
esters of benzalmalonic acid, preferably 4-methoxybenzalmalonic acid di-2-ethylhexyl ester;
triazine derivatives such as, for example, 2,4,6-trianilino-(p-carbo-2′-ethyl-1′-hexyloxy)-1,3,5-triazine and Octyl Triazone as described in EP-A1 0818450;
propane-1,3-diones such as, for example, 1-(4-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione;
ketotricyclo(5.2.1.0)decane derivatives as described in EP-B1 0694521.
Suitable water-soluble substances are
2-phenylbenzimidazole-5-sulfonic acid and alkali metal, alkaline earth metal, ammonium, alkylammonium, alkanolammonium and glucammonium salts thereof;
sulfonic acid derivatives of benzophenones, preferably 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and salts thereof;
sulfonic acid derivatives of 3-benzylidene camphor such as, for example, 4-(2-oxo-3-bornylidenemethyl)-benzene sulfonic acid and 2-methyl-5-(2-oxo-3-bornylidene)-sulfonic acid and salts thereof.
Typical UV-A filters are, in particular, derivatives of benzoyl methane such as, for example, 1-(4′-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione, 4-tert.butyl-4′-methoxydibenzoyl methane (Parsol 1789) or 1-phenyl-3-(4′-isopropylphenyl)-propane-1,3 dione. The UV-A and UV-B filters may of course also be used in the form of mixtures. Besides the soluble substances mentioned, insoluble pigments, i.e. finely dispersed metal oxides or salts, for example titanium dioxide, zinc oxide, iron oxide, aluminium oxide, cerium oxide, zirconium oxide, silicates (talcum), barium sulfate and zinc stearate, may also be used for this purpose. The particles should have a mean diameter of less than 100 nm, preferably between 5 and 50 nm and more preferably between 15 and 30 nm. They may be spherical in shape although ellipsoidal particles or other non-spherical particles may also be used. Other suitable UV filters can be found in P. Finkel's review in SOFW—Journal 122, 543 (1996).
Besides the two groups of sun protection factors mentioned above, secondary sun protection factors of the antioxidant type may also be used. Secondary sun protection factors of the antioxidant type interrupt the photochemical reaction chain which is initiated when UV rays penetrate into the skin. Typical examples are amino acids (for example glycine, histidine, tyrosine, tryptophane) and derivatives thereof, imidazoles (for example urocanic acid) and derivatives thereof, peptides, such as D, L-camosine, D-carnosine, L-carnosine and derivatives thereof (for example anserine), carotinoids, carotenes (for example &agr;-carotene, &bgr;-carotene, lycopene) and derivatives thereof, chlorogenic acid and derivatives thereof, liponic acid and derivatives thereof (for example dihydroliponic acid), aurothioglucose, propylthiouracil and other thiols (for example thioredoxine, glutathione, cysteine, cystine, cystamine and glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl,
Ansmann Achim
Gondek Helga
Kawa Rolf
Tesmann Holger
Cognis Deutschland GmbH
Dodson Shelley A.
Drach John E.
Trzaska Steven J.
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