Contribution of ATR/FT-IR spectroscopy for studying the in vivo behavior of octylmethoxycinnamate (OMC) after topical application

This work aims to evaluate the contribution of ATR/FT-IR spectroscopy as an in vivo analytical tool for following the percutaneous penetration of octylmethoxycinnamate and its possible modifications after light exposure. OMC cis and trans isomers in solution were assessed by liquid chromatographic and ATR/FT-IR validated methods. An in vivo quantification model was built from ATR/FT-IR measurements on the naked skin. This model reveals, suitable for evaluating, the formation of cis-OMC from trans-OMC after sun irradiation. Moreover, the results obtained from trans-OMC testify to the suitability of the method for studying in vivo the degradation and the percutaneous penetration of this molecule. After topical application, the disappearance of OMC over the surface of the skin was studied. Simultaneously, the kinetics of percutaneous penetration were established using the stripping method. Both results are in accordance with previous published works.