Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2000-05-03
2001-02-13
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S060000, C424S400000, C424S401000, C106S436000
Reexamination Certificate
active
06187298
ABSTRACT:
The present invention relates to a cosmetic preparation which has ultraspectral protection or else broad-band protection against solar radiation. The invention also relates to novel light protection filters for the preparation of sunscreens and to the use in cosmetics.
While about 30 years ago sunlight was regarded as healing and safe because of its ability to synthesize vitamin D, in recent years the attitude in this respect has changed considerably, not only for medical reasons. There is increasing awareness of the potential dangers which are associated both with natural and also artificial solar irradiation. In particular, there has even been a change in behavior as a result of knowledge about the influence of sunlight on skin aging and the formation of skin cancer.
As is known, the skin is sensitive to solar rays, which may cause common sunburn or an erythema, but also burns of varying severity.
Solar rays do, however, also have other negative effects: they cause the skin to lose its elasticity and develop wrinkles and thus lead to premature aging. Dermatoses are also sometimes observed, and in extreme cases, skin cancer may result.
On the basis of this knowledge, there have been some developments in sun protection. While up to just a few years ago, the principal aim was an erythema-inhibiting UVB protection, protection against UVA radiation is now included in sunscreen formulations. UVA radiation is essentially a trigger for pigmenting the skin.
It is also desirable to protect hair against photochemical damage in order to avoid changes in shades, bleaching or damage of a mechanical nature.
As is known, the most dangerous part of solar rays comprises the ultraviolet rays having a wavelength of less than 400 nm. It is also known that as a result of the presence of the ozone layer in the Earth's atmosphere, which absorbs some solar radiation, the lower limit of ultraviolet rays which reach the Earth's surface is about 280 nm.
The main aim in the field of sun protection has thus to date actually been to ensure good protection against UVB and UVA radiation.
The wavelength region of sunlight, however, extends not only over the region of UVA and UVB radiation from 280 to 400 nm. The region perceptible to the eye extends to 800 nm and is delimited by the transition into the long-wave infrared radiation, which is perceived as thermal radiation. At the lower end, the radiation enters the short-wave UV region, also called UVC radiation. This is the wavelength region from 100 to 280 nm.
Sunlight in the wavelength region from 400 to 800 nm (VIS region) and above (IR region) can penetrate into the deeper layers of the skin and cause damage there, so that the effect of this light alone may also accelerate skin aging processes.
An object of the invention was thus to provide cosmetically well-tolerated light protection filters which also offer protection against sunlight in the wavelength region from 400 to 800 nm and in the IR wavelength region above 800 nm.
In addition, it was desirable to find an effective IR protection filter for the IR wavelength region above 800 nm which is not regarded negatively as a result of severe “whitening” on the skin, as has hitherto been the case.
An object of the invention was also to provide cosmetic formulations which offer protection against the damaging effect of sunlight both in the UV region and also in the long-wave region, the VIS and IR region. This means that formulations are to be provided which exhibit complete protection against the entire solar spectrum which reaches the Earth, as happens, for example, through clothing. The object was thus to provide cosmetically well-tolerated formulations which offer such broad-band or ultraspectral protection.
The object is achieved by light protection filters effective in the wavelength region from 400 to 800 nm (VIS region) and in the wavelength region above 800 nm (IR region), these being substances which are soluble or insoluble in cosmetic formulations or mixtures of soluble and insoluble substances.
The invention thus provides light protection filters effective in the wavelength region from 400 to 800 nm (VIS region) and in the infrared wavelength region (IR region) from 800 nm.
According to the invention, such filters may comprise pigments and/or dyes which reflect and/or absorb in the visible wavelength region (VIS reflecting). Such pigments may, in particular, be golden, red, orange-, copper- or body-colored interference pigments which resemble very closely the natural color of skin.
These interference pigments are preferably platelet-shaped or ground mica having a diameter of up to 15 &mgr;m, which is coated with SnO
2
and/or TiO
2
. Interference pigments whose carrier material does not consist of mica are, however, also suitable. The coatings may be doped in various ways, such as, for example, by iron or cerium.
In a particular embodiment of these pigments, the mica has a thin coating consisting of up to 18% by weight of SnO
2
, and a coating consisting of 50-70% by weight, preferably 54-60% by weight, of TiO
2
having a rutile structure.
The light protection filters may also be mica having a thin coating consisting of up to 1% by weight of SnO
2
, and a coating consisting of 50-70% by weight, preferably 54-60% by weight, of TiO
2
having an anatase structure, or mica having a coating consisting of 50-70% by weight, preferably 54-60% by weight, of TiO
2
having a rutile or anatase structure.
Suitable substances which may also be used as VIS and/or as IR filters are pearlizing pigments consisting of mica or other carrier materials which are coated with titanium dioxides or iron oxides; in particular, these are
Silver pigments (mica+TiO
2
) having particle sizes <200 &mgr;m, in particular <15 &mgr;m, such as, for example, Timiron MP 1005® or MP 1001® available commercially, or also coarser fractions
Interference pigments (mica+TiO
2
) having particle sizes <200 &mgr;m, in particular having particle sizes of from 5 to 25 &mgr;m, with golden, red, orange-, copper- or body-colored interference, such as, for example, Timiron Silk Red® or Silk Gold® or Super Red® or Super Gold® or Super Copper® or coarser fractions or other interference colors and mixtures thereof
Gold pigments (mica+TiO
2
and iron oxides) having particle sizes of <200 &mgr;m, in particular <5-25 &mgr;m or <15 &mgr;m; such a gold pigment is, for example, Timiron MP 20®, but coarser gold pigment fractions are also suitable
Colored pigments (mica+TiO
2
and iron oxides) having particle sizes of <200 &mgr;m, in particular <5-25 &mgr;m or <15 &mgr;m; suitable colored pigments are, for example, Dichrona® or Microna® matt.
Also suitable are VIS-absorbing or -reflecting fillers, such as, for example, mica coated with TiO
2
and/or BaSO
4
. These also include, for example, Biron® (BiOCl), Low Luster® or Extender W®, provided they are not 100% transparent.
The invention also provides mixtures of the pigments, pearlizing pigments, VIS-reflecting absorbing fillers or dyes given above and below as light protection filters according to the invention.
Normally used as UV filters, microfine ZnO and TiO
2
particles are also suitable as such, provided they also reflect or absorb in the VIS region. These are available commercially under the names Hombitec® or Sachotec®, Kemira M160®, Tioveil AQ® and, to a limited extent, Eusolex T-2000®, limited since it has very high transparency.
Suitable VIS filters can also be dyes approved in cosmetics, for example chosen from the “Blaue Liste” (Blue List) (list of dyes permitted in cosmetics)[“Blaue Liste” (Blue List) edition Cantor Verlag, editor H. P. Fiedler (1993)], which can be used either as they are or else in a mixture. These dyes can also be used as undissolved pigments. Those which are particularly suitable here are the red, yellow and blue dyes, which individually or in a mixture with the other additives give formulations which, when applied to the skin, have a natural color. It is thus also possible to use dyes from this list havin
Hitzel Sabine
Kurz Thekla
Wille Dorothee
Dodson Shelley A.
Merck Patent Gesellschaft mit beschrankter Haftung
Millen White Zelano & Branigan P.C.
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