Evaluation and characterization of the encapsulation/entrapping process of octyl methoxycinnamate in ordered mesoporous silica type SBA-15

Encapsulating/entrapping UV filters into a SBA-15 matrix represents an interesting method to increase the photostability of filters. Octyl methoxycinnamate (OMC) is frequently used as an organic UVB filter in sun care products. However, this filter is unstable upon radiation and has the undesirable ability to permeate into the viable layers of the skin. Recognizing these issues, the aim of this research was to encapsulate/entrap OMC into SBA-15 and to characterize this material by physicochemical analytical techniques. Scanning electron microscopy proved to be an efficient tool to evaluate the structural morphology of SBA-15. The diffraction laser results showed that the particle size diameter of SBA-15 was 15.7 ± 0.46 µm. The decrease in the surface area and in mesoporous volume (V) observed in the nitrogen adsorption desorption isotherms of encapsulated/entrapped samples indicated that OMC was efficiently encapsulated/entrapped into SBA-15. Additionally, SAXS results showed that OMC did not affected the hexagonal structure of the mesoporous material and that OMC filled the SBA-15 pores. The FTIR spectrum of encapsulated/entrapped samples displayed characteristic absorption bands of free OMC, confirming the presence of this compound after loading. DTA curves of encapsulated/entrapped materials showed that the thermal stability of OMC was increased. On the other hand, DSC curves of encapsulated/entrapped materials demonstrated that thermal stability of OMC was not increased. Finally, thermogravimetric and elemental analysis were efficient tools to confirm the presence and the quantity of OMC into SBA-15.