Influence of silica on intestinal absorption of solid self-microemulsifying drug delivery systems

Solid carriers had important effects on the properties of solid self-microemulsifying drug delivery systems (S-SMEDDS).  In order to make the basis for further development of S-SMEDDS, the influences of silica on the absorption of S-SMEDDS were investigated.  An in vitro lipolysis model was used to evaluate the influence of silica on self-microemulsifying drug delivery system digestion from intestinal tract.  S-SMEDDS containing silica were prepared by extrusion/spheronization.  The drug release and absorption were investigated.  The results showed that lipolysis rate and drug concentration in aqueous phase after intestinal lipolysis both increased by adding silica, which was benefit to drug absorption.  And silica was not benefit to absorption for slowing drug release.  Consistently, there was no significant influence of silica on intestinal absorption.  This study implied that the influences of silica on lipolysis rate and drug release were both amount dependent and it is suggested that silica could be used as the solid carrier but the proportion needs to be optimized.