title: Simple ultraviolet and high-performance liquid chromatography methods for the evaluation of sunscreen efficacy.
abstract: BACKGROUND
  To prevent DNA damage caused by the ultraviolet (UV) radiation of sunlight, sunscreens are commonly used to protect human skin. Current analysis of sunscreens' effectiveness is done through complicated procedures, including human exposure.
  
  
  OBJECTIVE
  We sought to design a simple system using thymidine-thymidine (TT) dinucleotides to analyze the effectiveness of sunscreens.
  
  
  METHODS
  We can directly analyze sunscreen effectiveness and the formation of TT photolesions simply by using UV spectrophotometry and high-performance liquid chromatography (HPLC). Efficient sunscreen has protective effects against UV irradiation damage.
  
  
  RESULTS
  We have developed a simple method using TT dinucleotide, UV, and HPLC for the analysis of sunscreen effectiveness. Our research indicates that the analytical results from UV are consistent with those of HPLC, which is used to monitor the formation of the TT photolesions. Moreover, both UV and HPLC analyses indicate that TT dinucleotides are better protected against UV damage, using the sunscreens with higher UVB sun protection factor (SPF) value, and that sunscreens with higher SPF lead to reduced photolesion formation. Our UV and HPLC analyses confirm the SPF grading of commercial sunscreens.
  
  
  CONCLUSIONS
  In this experiment, only sunscreens were tested. The experiment, therefore, does not apply to other commercial products, such as cosmetic materials that claim UV protection as a secondary benefit.
  
  
  CONCLUSIONS
  In conclusion, we have established a simple strategy to analyze the effectiveness of sunscreens and the quality of these potential cancer-preventive products.
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia.
authors.forename: Khin Lay
authors.initials: KL
authors.lastname: Maw
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia.
authors.forename: Julianne
authors.initials: J
authors.lastname: Caton-Williams
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia.
authors.forename: Jozef
authors.initials: J
authors.lastname: Salon
authors.affiliation: Department of Chemistry, Georgia State University, Atlanta, Georgia. Electronic address: Huang@gsu.edu.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huang
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004249:DNA Damage / Q000528:radiation effects; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D012016:Reference Values; D012680:Sensitivity and Specificity; D012867:Skin / Q000528:radiation effects; D012878:Skin Neoplasms / Q000517:prevention & control*; D013053:Spectrophotometry / Q000379:methods; D013473:Sunscreening Agents / Q000737:chemistry* / Q000627:therapeutic use; D014466:Ultraviolet Rays
chemical_list: D013473:Sunscreening Agents