Topical sunscreen formulation

1. A sunscreen formulation, comprising

a) a semifluorinated alkane;

b) a metal oxide selected from titanium dioxide, zinc oxide and mixtures thereof; and

c) optionally a co-solvent and/or an oil component and/or an active ingredient;

wherein the semifluorinated alkane is a compound of formula CF3(CF2)n(CH2)mCH3, wherein n and m are integers independently selected from each other from the range of 2 to 10.

2. The sunscreen formulation of claim 1 , wherein the formulation comprises a solid thickening agent.

3. The sunscreen formulation of claim 1 , wherein the metal oxide is present at a concentration of from 1 to 6 percent by weight based on the total weight of the formulation.

4. The sunscreen formulation of claim 1 , wherein the semifluorinated alkane is of the formula F(CF2)n(CH2)mH, wherein n is an integer selected from 4 to 6 and m is an integer selected from 5 to 10.

5. The sunscreen formulation of claim 1 , wherein the semifluorinated alkane is selected from 1-perfluorohexyl-octane (F6H8), 1-perfluorobutyl-pentane (F4H5), 1-perfluorohexyl-decane (F6H10), 1-perfluorobutyl-octane (F4H8), 1-perfluorobutyl-decane (F4H10), and combinations thereof.

6. The sunscreen formulation of claim 1 , wherein the formulation comprises 50-95 wt % of the semifluorinated alkane, based on the total weight of the formulation.

7. The sunscreen formulation of claim 1 , wherein the metal oxide particles have a mean particle diameter of between 1 nm and 100 nm.

8. The sunscreen formulation of claim 2 , wherein the formulation comprises 1 to 40 wt % of the solid thickening agent, based on the total weight of the formulation.

9. The sunscreen formulation of claim 2 , wherein the solid thickening agent is a natural or synthetic thickening agent selected from plant waxes, animal waxes, petroleum derived waxes, triglycerides, cetyl alcohol, tetradecanol, and combinations thereof.

10. The sunscreen formulation of claim 9 , wherein the wax is selected from the group consisting of bees wax, lanolin wool wax, carnauba wax, candelilla wax, castor wax, rice bran wax (rice wax), spermaceti wax, jojoba oil, bran wax, montan wax, kapok wax, bay berry wax, shellac wax, sugar cane wax, paraffin wax, and ceresin wax.

11. The sunscreen formulation of claim 1 , in form of an ointment.

12. The sunscreen formulation of claim 1 , wherein the formulation is water-free and/or preservative-free.

13. The sunscreen formulation of claim 1 , further comprising an active ingredient selected from panthenol, thymol, tea tree oil, retinol palmitate, and tocopherol.

14. A method for the prevention of skin cell damage caused by UV-radiation, comprising topically administering to the skin of a subject a composition according to claim 1 .

15. A method for the prevention of skin cancer, comprising topically administering to the skin of a subject a composition according to claim 1 .

16. A method for protecting the skin from sunburn, comprising topically administering to the skin of a subject a sunscreen formulation according to claim 1 .

17. A kit comprising a container for holding the sunscreen formulation according to claim 1 .

18. The sunscreen formulation of claim 1 , wherein the metal oxide is present at a concentration of 1 to 20 percent by weight based on the total weight of the formulation, or at a concentration of 1 to 10 percent by weight based on the total weight of the formulation.

19. The sunscreen formulation of claim 1 , wherein the formulation comprises a cosolvent selected from isopropanol, ethanol, liquid medium chain triglycerides, N-methyl-2-pyrrolidone, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethyl acetate, ethyl oleate, octyldodecanol, and diethyl sebacate.

20. The sunscreen formulation of claim 1 , wherein the formulation comprises an oil component which is an oily material selected from squalane, squalene, liquid triglycerides, silicone oils, and emollient vegetable oils.

21. The sunscreen formulation of claim 20 , wherein the formulation comprises the oily material squalene at a concentration of 1 to 45 percent by weight based on the total weight of the formulation.

22. The sunscreen formulation of claim 1 , wherein the formulation comprises an active ingredient selected from D-panthenol, retinol palmitate, and tocopherol, and esters of each of the foregoing.

23. The sunscreen formulation of claim 20 , wherein the silicone oils are selected from cyclomethicone and dimethicone.

24. The sunscreen formulation of claim 20 , wherein the emollient vegetable oils are selected from olive oil, coconut oil, jojoba oil, sesame oil, avocado oil, sunflower oil, safflower oil, borage oil, corn oil, and sea buckthorn oil.

25. The sunscreen formulation of claim 1 , wherein the formulation comprises an oil component which is an essential oil.

26. The sunscreen formulation of claim 1 , wherein the formulation is effective to deliver the metal oxide into the stratum corneum.

27. The method according to claim 14 , wherein the method provides for effective penetration of the metal oxide into the stratum corneum.

28. The method according to claim 15 , wherein the method provides for effective penetration of the metal oxide into the stratum corneum.

29. The method according to claim 16 , wherein the method provides for effective penetration of the metal oxide into the stratum corneum.