Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
1999-12-30
2003-02-04
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S401000
Reexamination Certificate
active
06514485
ABSTRACT:
The present invention relates to combinations of sunscreens comprising at least one anti UV-B filter with triazine structure and at least one anti UV-A filter as defined in the following, and the compositions containing them.
It is well known that sun radiations ranging from 280 to 400 nm are noxious for human skin. Those with a wavelength from 280 to 380 nm, the so-called UV-B radiations, cause erythema and cutaneous sun-burns, whose severity depends on the kind of the skin and on the duration of the exposition to sunlight. Also radiations ranging from 320 to 400 nm, the so called UV-A radiations, which were considered innocuous and only responsible for skin tanning, are, as a matter of fact, harmful, in that they can cause damages to elastine and collagene, with consequent ageing of the skin as well as a number of phototoxic and photoallergic reactions. The damages to DNA structure induced by said radiations are known, as well.
Different combinations of anti UV-A and anti UV-B filters are described in the patent and non-patent literature. Thus, for instance, GB 2 198 944, WO 91/11989 and WO 94/04131 disclose combinations of benzylidenecamphor derivatives or cyanoacrylates (anti UV-B filters) and dibenzoylmethane derivatives (anti UV-A filters), for the purpose of preventing photodegradation of the latter which are known to be poorly stable to light (Int. J. Cosm. Science, 10, 53, 1988). Combinations of anti UV-B filters with triazine structure and dibenzoylmethane derivatives are also described in EP 0 800 813 and EP 0 845 260.
The kind of sunscreens and the amounts at which they are used, alone or in mixtures, are selected depending on the intended protection, as well as on the above mentioned remarks. In particular, an index of this protection is the so-called sun protection factor, (SPF), which is expressed as the ratio of the time of irradiation necessary to reach the erythematogenic threshold in the presence of the UV filter to the time necessary to reach the erythematogenic threshold in the absence of the UV filter.
There is, anyway, a demand for novel, more effective protection systems for those parts of the body which can be damaged by a more or less prolonged exposition to UV radiations, such as skin and hair, which demand is even more felt nowadays in view of the problems deriving from the holes in the ozone layer.
Therefore, the present invention relates to combinations of sunscreens comprising at least one anti UV-B filter selected from the compounds of formulae I and II:
and at least one anti UV-A filter selected from the compounds of formulae III, IV, V, VI and VII:
The compounds of formulae I and II are known in literature. Such compounds, as well as the processes for the preparation thereof, are specifically described in EP 0 570 838 and in EP 0 087 098, respectively. The compound of formula IV and the process for the preparation thereof are specifically described in EP 0 832 642, whereas the compounds of formulae III, V and VI are included in the general formula of EP 0 832 642. Finally, the compound of formula VII is included within the general formula of EP 0 832 641. The preparation of the compounds of formulae III, V, VI and VII, carried out according to procedures known in literature, will be reported in the following.
Both EP 0 832 641 and EP 0 832 642 generally claims that the disclosed anti UV-A filters can be combined, in cosmetic compositions, with the anti UV-B filters described in EP 0 570 838. However, nor specific combinations thereof neither cosmetic compositions containing specific combinations of anti UV-A and anti UV-B filters described in the respective EP-A- are specifically reported.
Neither EP 0 832 641 nor EP 0 832 642 disclose that the respective anti UV-A filters can be combined with the compounds of formula II.
Preferred combinations according to the invention comprise at least one anti UV-B filter selected from the compounds of formulae I or II, and at least one anti UV-A filter selected from the compounds of formulae III, IV, V and VI. Most preferred combinations are those comprising, as anti UV-B filter, the compound of formula I, and at least one anti UV-A filter selected from the compounds of formulae III, IV, V and VI.
In the combinations of the present invention, the ratio of the one or more anti UV-A filters to the one or more anti UV-B filters can range within wide limits, for example, it can range from about 0.05 to about 3, preferably from about 0.1 to about 2.
These combinations of sunscreens comprise compounds having a high specific extinction coefficient in the UV region specific for each of them. Moreover, they are resistant to photodegradation induced by sun radiations, and are particularly soluble in the solvents used for the preparation of cosmetic or dermatological compositions.
Therefore, the combinations of sunscreens of the present invention can be used in the protection of human body from the harmful effects of UV radiations, both as they are, dissolved in the suitable solvents, or, preferably, in cosmetic or dermatological compositions.
It has, in fact, surprisingly been found that presence of the anti UV-A filter in the combinations of the invention remarkably enhances the specific extinction in the VU-B region. It is therefore possible to prepare dermatological or cosmetic formulations with SPF (Sun Protection Factor) remarkably higher than that of a corresponding composition containing only the anti UV-B filter, which means that said combinations exert a synergistic effect as far as SPF is concerned.
As mentioned above, the combinations of the invention are particularly resistant to photodegradation induced by sunlight. This feature makes them particularly suitable to the protection of cosmetic compositions whose components can undergo degradation or undesired colour alterations induced by light, such as creams, shampoos, gel, nail lacquers, lotions, perfumes and the like.
On the other hand, such stabilising effect has also been observed when including the above mentioned combinations in photosensitive compositions different from the cosmetic and dermatological ones, such as polymers.
According to the invention, preferred compositions are cosmetic and dermatological compositions, containing said combinations in amounts ranging from about 0.05 to about 30% of the composition total weight: these compositions are a further object of the present invention.
A further object of the present invention is the use of the combinations defined above in the preparation of cosmetic and dermatological compositions for the protection of human skin from sun radiations.
Still a further object of the present invention is the use of the combinations of sunscreens described above for the stabilization of cosmetic and dermatological compositions, and of polymers.
In a preferred embodiment, the cosmetic compositions comprise a combination of sunscreens according to the invention in cosmetically acceptable excipients, such as oil-in-water, water-in-oil, oil-water-oil, water-oil-water, water-in-silicon, oily solutions, lipid fusions, hydro-alcoholic, anhydrous or aqueous gels, alcoholic or hydro-alcoholic solutions, and analogues. When an oily substance is necessary to dissolve or disperse one or more of the components of the selected combination, this substance is a compound advantageously selected from:
i) hydrocarbons, such as paraffin, mineral oils, and analogs;
ii) oils, butters and natural waxes, such as avocado oil, sunflower oil, almond oil, apricot-stone oil, karite butter, evening primrose oil, black currant oil, borage oil, jojoba oil, safflower oil, wheat germ oil, macadamia oil, rice bran oil, sesame oil, castor oil, coconut oil; unsaponifiable oils of olive, avocado, soya; cocoa butter, bees-wax, candelilla wax, carnauba wax, and analogs;
iii) silicone oils such as dimethicones, cyclomethicones, dimethiconols, alkyldimethicones, and analogs;
iv) esters of straight or branched, saturated or unsaturated aliphatic acids or of aromatic or alkylaromatic acids, having 1 to 25 carbon atoms, said acids being optionally hy
Malpede Alverio
Zanchi Giorgio
3V Sigma S.p.A.
Birch & Stewart Kolasch & Birch, LLP
Dees Jose′ G.
George Konata M.
LandOfFree
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