Long lasting waterproof sunscreen comprising metal oxide and peptide conditioner
View Patent ↗The disclosure provides a sunscreen formulation comprising a peptide-based metal oxide sunscreen agent, such as titanium dioxide nanoparticles, and a fluid vehicle.
1. A sunscreen formulation comprising:
(a) a peptide-based metal oxide sunscreen agent having a general structure selected from the group consisting of:
(i) (SBP) n -SSA, and
(ii) [(SBP) m -S] n - SSA,
wherein:
(A) SBP is a skin-binding peptide,
(B) S is a spacer having first and second ends,
(C) SSA is a metal oxide sunscreen agent,
(D) n ranges from 1 to about 1,000, and
(E) m ranges from 1 to about 50; and
(b) a fluid vehicle.
2. The sunscreen formulation of claim 1 wherein the metal oxide of the peptide-based metal oxide sunscreen agent is selected from the group consisting of titanium dioxide, zinc oxide, cerium oxide and iron oxide and combinations thereof.
3. The sunscreen formulation of claim 1 wherein the metal oxide of the peptide-based metal oxide sunscreen agent comprises metal oxide nanoparticles selected from the group consisting of titanium dioxide, zinc oxide, cerium oxide and iron oxide and combinations thereof.
4. The sunscreen formulation of claim 1 wherein the metal oxide of the peptide-based metal oxide sunscreen agent comprises titanium dioxide nanoparticles.
5. The sunscreen formulation of claim 1 wherein the metal oxide of the peptide-based metal oxide sunscreen agent is treated with a source of silica or alumina or a combination thereof.
6. The sunscreen formulation of claim 5 wherein the metal oxide of the peptide-based metal oxide sunscreen agent is treated in the presence of a densifying agent.
7. The sunscreen formulation of claim 6 wherein the densifying agent is citric acid.
8. The sunscreen formulation of claim 7 wherein the metal oxide of the peptide-based metal oxide sunscreen agent is titanium dioxide nanoparticles.
9. The sunscreen formulation of claim 1 wherein the peptide-based metal oxide sunscreen agent comprises up to 25 wt % of the total weight of the sunscreen formulation.
10. The sunscreen formulation of claim 1 wherein n is 1 to about 50.
11. The sunscreen formulation of claim 1 wherein m is 1 to about 10.
12. The sunscreen formulation of claim 1 wherein the spacer comprises a protease caspase cleavage site having SEQ ID NO: 9.
13. The sunscreen formulation of claim 1 wherein the spacer is selected from alkyl chains, phenyl compounds, ethylene glycol, amides, and esters.
14. The sunscreen formulation of claim 1 wherein the spacer is hydrophilic and has a chain length from 1 to about 100 atoms.
15. The sunscreen formulation of claim 1 wherein the spacer is hydrophilic and has a chain length about 2 to about 30 atoms.
16. The sunscreen formulation of claim 1 wherein the spacer is selected from ethanol amine, ethylene glycol, polyethylene with a chain length of 6 carbon atoms, polyethylene glycol with 3 to 6 repeating units, phenoxyethanol, propanolamide, butylene glycol, butyleneglycolamide, propyl phenyl, ethyl, propyl, hexyl, steryl, cetyl, and palmitoyl alkyl chains.
17. The sunscreen formulation of claim 1 wherein the spacer is covalently attached to the SBP and SSA and comprises reactive groups.
18. The sunscreen formulation of claim 17 wherein the spacer and reactive groups comprise a bifunctional cross-linking agent.
19. The sunscreen formulation of claim 18 wherein the bifunctional cross-linking agent is selected from the group of diamines, dialdehydes, bis N-hydroxysuccinimide esters, diisocyanates, bis oxiranes, and dicarboxylic acids.
20. The sunscreen formulation of claim 18 wherein the reactive groups on each end of the spacer are different.
21. The sunscreen formulation of claim 18 wherein the crossliniking agent has the following structure:
wherein R 1 is H or a substituent group selected from —SO 3 Na, —NO 2 , and —Br; and
R 2 is a spacer comprising —CH 2 CH 2 (ethyl), —(CH 2 ) 3 (propyl), or—(CH 2 ) 3 C 6 H 5 (propyl phenyl).
22. The sunscreen formulation of claim 18 wherein the crossliniking agent is 3-maleimidopropionic acid N-hydroxysuccinimide ester.
23. A method for treating skin or hair comprising applying the sunscreen formulation of claim 1 to the skin or hair.
24. The sunscreen formulation of claim 1 wherein the metal oxide of the peptide-based metal oxide sunscreen agent is in a crystalline form having a crystal lattice and said crystal lattice is doped with an element which is different from the metal of the metal oxide to modify the color of the metal oxide.
25. The sunscreen formulation of claim 24 wherein the lattice is doped with iron or manganese.
26. The sunscreen formulation of claim 1 wherein the metal oxide of the peptide-based metal oxide sunscreen agent is in a crystalline form having a crystal lattice and said crystal lattice is doped with an element which is different from the metal oxide to decrease the photoactivity of the metal oxide.
27. The sunscreen formulation of claim 26 wherein the crystal lattice of the metal oxide is doped with manganese, iron, vanadium, or chromium.
28. The sunscreen formulation of claim 24 or 26 in which the element doped in the crystal lattice is present in an amount ranging from about 0.01% to about 5% based on the entire weight of the metal oxide.
29. The sunscreen formulation of claim 1 wherein the spacer is a peptide spacer comprising from 1 to about 50 amino acids.
30. The sunscreen formulation of claim 29 wherein the peptide spacer comprises amino acids selected from the group consisting of glycine, alanine, serine, and mixtures thereof.