Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1993-10-15
1997-02-04
Ivy, C. Warren
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568373, 568376, C07C 49437, C07C20700
Patent
active
056000073
DESCRIPTION:
BRIEF SUMMARY
This is the U.S. National Phase Application of PCT/EP93/00245 filed Feb. 3, 1993.
The invention relates to the use of .alpha.-hydroxyketoalkyl derivatives as light protection filters for cosmetic or pharmaceutical products, the .alpha.-hydroxyketoalkyl group being linked, if appropriate via a spacer, to a chromophoric group which has an absorption maximum in a wavelength range of between 280 and 400 nm and has a conjugated .pi.-electron system of at least 8 .pi.-electrons, and to new .alpha.-hydroxyketoalkyl derivatives, processes for their preparation and their use in cosmetic formulations, in particular for protection from solar radiation, and in pharmaceutical formulations for preventive treatment of inflammations and allergies of the skin or certain types of cancer.
As is known, the skin is sensitive to solar rays, which can cause common sunburn or erythema, but also burns of a greater or lesser degree.
However, solar rays also have other negative actions: they cause the skin to lose its elasticity and develop wrinkles, and therefore lead to premature aging. Dermatoses can also sometimes be observed. In the extreme case, skin cancer occurs in some humans.
It is also desirable to protect hair from photochemical damage, in order to prevent changes in color shades, bleaching or damage of a mechanical nature.
It is known that the components contained in cosmetic preparations are not always sufficiently stable to light and decompose under the action of light rays.
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 due to the presence of the ozone layer of the earth's atmosphere, which absorbs some of the solar radiation, the lower limit of ultraviolet rays which reach the earth's surface is at about 280 nm.
It therefore seems desirable to provide compounds which absorb UV rays in a wavelength range from 280 to 400 nm, that is to say also UV-B rays having a wavelength of between 280 and 320 nm, which play a decisive role in the development of solar erythema, and also UV-A rays having a wavelength of between 320 and 400 nm, which tan but also age the skin, promote initiation of an erythematous reaction or increase this reaction in certain people or can even trigger off phototoxic or photoallergic reactions.
The sunscreen filters customary at present in cosmetics are divided into UVA and UVB filters. While there are good filters in the UVB range (280-320 nm), with substances such as Eusolex.RTM. 6300 or Eusolex.RTM. 232, those in the UVA range (320-400 nm) present problems:
Dibenzoylmethanes, such as Parsol.RTM. 1789 or Eusolex.RTM. 8020 do not have an unlimited stability under UV irradiation, which on the one hand reduces the filtering effectiveness with time and on the other hand can promote photosensitizations of the skin in isolated cases. The benzophenones also used as UVA filters have only a limited solubility in the oils used in cosmetics, and they have a relatively low absorption. On the other hand, only few water-soluble UVA filters are currently known, but their UV absorption is low.
Similar benzylidenecamphor derivatives are known from EP 03 90 682. However, these have at least one hydroxyl group on the phenylene ring. Although these compounds can also be used as UV filters in sunscreen agents, they are more suitable as antioxidants because of the phenolic hydroxyl group. These compounds furthermore have only a limited solubility in conventional carriers for cosmetics, in particular in aqueous suspensions, so that in sunscreen agents, they usually have to be employed together with other UV filters.
The conventional light protection filters as a rule have a low or inadequate adhesion to the skin, which leads to a relatively short duration of the protective action of the filter and in particular to virtually complete removal of the filter during bathing.
It has been found that certain .alpha.-hydroxyketoalkyl derivatives, in particular 4-(1-oxo-2-hydroxyethyl)phenyl derivatives, have outstanding UVB filter pr
Heywang Ulrich
Kurz Thekla
Martin Roland
Schwarz Michael
Stein Ingeborg
Covington Raymond
Ivy C. Warren
Merck Gmbh
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