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 octy lmethoxycinnamate and its possible modifications after light exposure. OMC cis and trans isomers in solution were assessed by liquid chromatographic a nd ATR/FT-IR validated methods. An in vivo quantification model was built f rom ATR/FT-IR measurements on the naked skin. This model reveals, suitable for evaluating, the formation of cis-OMC from trans-OMC after sun irradiati on. Moreover, the results obtained from trans-OMC testify to the suitabilit y of the method for studying in vivo the degradation and the percutaneous p enetration of this molecule. After topical application, the disappearance o f OMC over the surface of the skin was studied. Simultaneously, the kinetic s of percutaneous penetration were established using the stripping method. Both results are in accordance with previous published works.