Influence of Titanium Dioxide Particle Size on the Photostability of the Chemical UV-Filters Butyl Methoxy Dibenzoylmethane and Octocrylene in a Microemulsion

Cosmetics

Jutta Kockler¹  Michael Oelgemöller²  Sherryl Robertson² 

[1] School of Pharmacy and Molecular Sciences, James Cook University, Townsville 4811, QLD, Australia;

关键词: photostability;    titanium dioxide;    particle size;    nano-TiO₂;    microemulsion;    butyl methoxy dibenzoylmethane;    octocrylene;    high performance liquid chromatography (HPLC);   

DOI  :  10.3390/cosmetics1020128

来源: mdpi

【 摘 要 】

Sunscreen products often contain combinations of ultraviolet (UV)-filters in order to achieve broad spectrum protection from exposure to sunlight. The inclusion of both chemical and physical UV-filters in these products, however, increases the possibility for both photolytic and photocatalytic reactions to occur. This study investigated the effect of titanium dioxide (TiO₂) particle size on the photostability of the chemical UV-filters butyl methoxy dibenzoylmethane (BMDM) and octocrylene (OC) formulated in a microemulsion. The International Conference on Harmonisation (ICH) Guideline Q1B for photostability testing of new active substances and medicinal products was applied. BMDM and OC in the microemulsion were irradiated with simulated sunlight in the presence of nano- (<25 nm) and micro-TiO₂ (~0.6 μm) and their concentrations determined using a validated high performance liquid chromatography (HPLC) method. For the combination of BMDM and OC, the photodegradation for BMDM was found to be 12% higher in the presence of nano-TiO₂ as compared to that of the micro-TiO₂. This enhanced photodegradation is attributed to the larger surface area of the nano-TiO₂ and the increased generation of reactive oxygen species (ROS). Because of these findings, sunscreen products containing chemical UV-filters and nano-TiO₂ should be regarded with caution, due to the potential loss of photoprotection.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.