Photostabilization of organic UV-absorbing and anti-oxidant cosmetic components in formulations containing micronized manganese-doped titanium oxide.
Micronized titanium oxide (TiO(2)) and manganese-doped titanium oxide (TiO(2):Mn) particles have been incorporated into a variety of oil-in-water (O/W) and water-in-oil-in-water (W/O/W) emulsions in conjunction with the UV-absorbing organic compounds butyl methoxydibenzoylmethane (BMDM) and octyl methoxycinnamate (OMC) and with the anti-oxidants vitamin E and vitamin C. The retention of the organics under solar exposure has been shown to be significantly enhanced by the addition of TiO(2):Mn to the formulation. In the case of BMDM and OMC, the retention is increased from 20% and 24% to 63% and 83%, respectively, after two hours of solar exposure. In this system, TiO(2) particles are shown to provide only limited protection relative to BMDM and OMC. Vitamin E and vitamin C are actively degraded by the presence of TiO(2) in the emulsion during solar exposure. This effect is reversed with TiO(2):Mn, the use of which can protect >90% of anti-oxidants in both the oil and water phases of the formulation. The absence of reactive oxygen species (ROS) generation and surface scavenging of ROS by TiO(2):Mn is responsible for a significantly reduced ROS load on the organic components and consequent photostabilization of the emulsion.
Wakefield
G
G
Oxonica Healthcare, 7 Begbroke Science Park, Sandy Lane, Yarnton, Oxford OX5 1PF, UK.
Stott
J
J
D000975:Antioxidants / Q000737:chemistry*; D003358:Cosmetics / Q000737:chemistry*; D004655:Emulsions; D008345:Manganese / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays
D000975:Antioxidants; D003358:Cosmetics; D004655:Emulsions; D009930:Organic Chemicals; C009495:titanium dioxide; D008345:Manganese; D014025:Titanium