Publication Date: 2002-Feb-12
The IP.com Prior Art Database
The objective of care cosmetic is to protect the skin against environmental influences, which lead to permanent damage and thus ageing of the skin. This protection can be provided by encapsulated organic UV filters. Encased in suitable capsules, regular organic UV filters can act advantageously in different formulation mediums
A suntan of the skin to whatever degree is regarded in today's society as attractive and as an expression of vigour and sportiness. As well as this desired effect of the sun on the skin, a number of undesired secondary
effects arise, such as sunburn or premature skin ageing and the development of wrinkles. In the meantime, a number of high performance UV filters have been developed which, applied to the skin in the form of creams, lotions, sprays or gels, can effectively delay the development of sunburn even when the incidence of solar rays is relatively high. This is
due to the UV filter, present in the pharmaceutical or cosmetic composition, forming a film or a layer on the surface of the skin. Known UV filters or sun protection agents thus act by absorbing certain regions of sunlight, meaning that this radiation cannot penetrate into deeper layers of the skin. As it is known, the most hazardous part of solar radiation is
formed by the ultraviolet rays having a wavelength of less than 400 nm. The lower limit of the ultraviolet rays, which reach the surface of the earth is limited by the absorption in the ozone layer to about 280 nm. The sun protection filters, which are nowadays customary in cosmetics absorb in a wavelength range from 280 to 400 nm. This range includes UV-B rays
having a wavelength between 280 and 320 nm, which play a decisive role in the formation of a solar erythema, and also UV-A rays, having a wavelength between 320 and 400 nm, which tan the skin but also contribute to the skin's ageing process, favour the triggering of an erythematous reaction or can exacerbate this reaction at certain people or
even trigger phototoxic or photoallergic and irritative reactions.
Wherever possible, it is the objective of care cosmetics to obtain the impression of a youthful skin. In principle, there are various ways of achieving this. For example, existing skin damage, such as irregular
pigmentation or the development of wrinkles can be smoothed out by covering powders or creams. Another approach is to protect the skin against environmental influences, which lead to permanent damage and thus ageing of the skin. The idea is therefore to intervene in a preventative manner and thus to delay the ageing process. One example of this are the
UV filters already mentioned above, which as a result of absorption of certain wavelength regions, prevent or at least reduce skin damage. Depending on the position of their absorption maxima, UV absorbers for cosmetic and dermatological compositions are divided into UV-A and UV-B
absorbers. UV-A absorbers also absorbing in the UV-B region are being referred to as broadband absorbers or broadband filters.
It is known that inorganic UV filters such as Titanium dioxide do not penetrate the skin, while several sunscreen compositions comprising
soluble organic UV filters are said to penetrate the skin. Furthermore it is desired to induce a protective...