Silica-coated ethosome as a novel oral delivery system for enhanced oral bioavailability of curcumin

The aim of this study is to investigate the feasibility of silica-coated ethosome as a novel oral delivery system for the poorly water-soluble curcumin (as a model drug).  The silica-coated ethosomes loading curcumin (CU-SE) were prepared by alcohol injection method with homogenization, followed by the precipitation of silica by sol-gel process.  The physical and chemical features of CU-SEs, and curcumin release were determined in vitro.  The pharmacodynamics and bioavailability measurements were sequentially performed.  The mean diameter of CU-SE was (478.5 ± 80.3) nm and the polydispersity index was 0.285 ± 0.042, while the mean value of apparent drug entrapment efficiency was 80.77%.  In vitro assays demonstrated that CU-SEs were significantly stable with improved release properties when compared with curcumin-loaded ethosomes (CU-ETs) without silica-coatings.  The bioavailability of CU-SEs and CU-ETs was 11.86- and 5.25- fold higher, respectively, than that of curcumin suspensions (CU-SUs) in in vivo assays.  The silica coatings significantly promoted the stability of ethosomes and CU-SEs exhibited 2.26-fold increase in bioavailablity relative to CU-ETs, indicating that the silica-coated ethosomes might be a potential approach for oral delivery of poorly water-soluble drugs especially the active ingredients of traditional Chinese medicine with improved bioavailability.