title: An investigation of the photo-clastogenic potential of ultrafine titanium dioxide particles.
abstract: Ultrafine titanium dioxide is widely used in a number of commercial products including sunscreens and cosmetics. There is extensive evidence on the safety of ultrafine titanium dioxide. However, there are some published studies indicating that some forms at least may be photogenotoxic, photocatalytic and/or carcinogenic. In order to clarify the conflicting opinions on the safety of ultrafine titanium dioxide particles, the current studies were performed to investigate the photo-clastogenic potential of eight different classes of ultrafine titanium dioxide particles. The photo-clastogenicity of titanium dioxide was measured in Chinese hamster ovary (CHO) cells in the absence and presence of UV light at a dose of 750 mJ/cm(2). The treatments were short (3 h) followed by a 17-h recovery and achieved concentrations that either induced approximately 50% cytotoxicity or reached 5000 microg/ml if non-cytotoxic. None of the titanium dioxide particles tested induced any increase in chromosomal aberration frequencies either in the absence or presence of UV. These studies show that ultrafine titanium dioxide particles do not exhibit photochemical genotoxicity in the model system used.
authors.affiliation: Covance Laboratories Ltd, Otley Road, Harrogate, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Theogaraj
authors.forename: Susan
authors.initials: S
authors.lastname: Riley
authors.forename: Laurie
authors.initials: L
authors.lastname: Hughes
authors.forename: Monika
authors.initials: M
authors.lastname: Maier
authors.forename: David
authors.initials: D
authors.lastname: Kirkland
mesh_terms: D000818:Animals; D016466:CHO Cells; D002869:Chromosome Aberrations; D020552:Comet Assay; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D009153:Mutagens / Q000633:toxicity*; D053758:Nanoparticles; D010316:Particle Size; D013473:Sunscreening Agents / Q000633:toxicity*; D014025:Titanium / Q000633:toxicity*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D009153:Mutagens; D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium