Simple ultraviolet and high-performance liquid chromatography methods for the evaluation of sunscreen efficacy

• Published in: Journal of the American Academy of Dermatology 2011-08, Vol.65 (2), p.328-335
• Main Authors: Maw, Khin Lay, BS, Caton-Williams, Julianne, PhD, Salon, Jozef, PhD, Huang, Zhen, PhD
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chromatography, High Pressure Liquid; Dermatology; Diseases of the skin. Cosmetics; DNA Damage - radiation effects; Female; high-performance liquid chromatography; Humans; Male; Materials Testing; Medical sciences; method to analyze sunscreen; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Reference Values; Sensitivity and Specificity; Skin - radiation effects; Skin Neoplasms - prevention & control; Spectrophotometry - methods; sunlight; Sunscreening Agents - chemistry; Sunscreening Agents - therapeutic use; sunscreens; thymidine-thymidine dinucleotide; ultraviolet; ultraviolet irradiation; ultraviolet photolesion; Ultraviolet Rays
• ISSN: 0190-9622; 1097-6787
• DOI: 10.1016/j.jaad.2010.05.038

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. Limitations 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. Conclusion In conclusion, we have established a simple strategy to analyze the effectiveness of sunscreens and the quality of these potential cancer-preventive products.