Controlled release of retinol from silica particles prepared in O/W/O emulsion: the effects of surfactants and polymers.

Spherical silica particles containing retinol were fabricated by using O/W/O multiple emulsion and sol-gel method. In this study, when both hydroxypropyl cellulose (HPC) and surfactants such as Tween 20 and Span 80 were used, multiple emulsion encapsulating retinol was prepared successfully. The size of water droplets and the amount of released retinol depended on the concentration of surfactants and PEG polymer. In addition, PEG, PVP, and Pluronic P123 were introduced as a stabilizer in the water phase to investigate the effect of polymers on the encapsulation efficiency. In the case of PVP, encapsulation efficiency of retinol in the silica particles was 7.35% and the lowest. On the other hand, in the case of Pluronic P123, it was 30.89% and the highest among obtained silica particles. The morphologies of multiple emulsion and silica particles were observed by optical microscope (OM) and field emission scanning electronic microscope (FE-SEM). In vitro release test and encapsulation efficiency were characterized by HPLC.