Silica-coated flexible liposomes as a nanohybrid delivery system for enhanced oral bioavailability of curcumin

Abstract

Abstract:We investigated flexible liposomes as a potential oral drug delivery system. However, enhanced membrane fluidity and structural deformability may necessitate liposomal surface modification when facing the harsh environment of the gastrointestinal tract. In the present study, silica-coated flexible liposomes loaded with curcumin (CUR-SLs) having poor water solubility as a model drug were prepared by a thin-film method with homogenization, followed by the formation of a silica shell by the sol-gel process. We systematically investigated the physical properties, drug release behavior, pharmacodynamics, and bioavailability of CUR-SLs. CURSLs had a mean diameter of 157 nm and a polydispersity index of 0.14, while the apparent entrapment efficiency was 90.62%. Compared with curcumin-loaded flexible liposomes (CURFLs) without silica-coatings, CUR-SLs had significantly higher stability against artificial gastric fluid and showed more sustained drug release in artificial intestinal fluid as determined by in vitro release assays. The bioavailability of CUR-SLs and CUR-FLs was 7.76-and 2.35-fold higher, respectively, than that of curcumin suspensions. Silica coating markedly improved the stability of flexible liposomes, and CUR-SLs exhibited a 3.31-fold increase in bioavailability compared with CUR-FLs, indicating that silica-coated flexible liposomes may be employed as a potential carrier to deliver drugs with poor water solubility via the oral route with improved bioavailability.

Liposil Nanocarriers for Pharmaceutical Applications: Synthesis Innovations

“…In clinic, for intravenous administration, there are already several pharmaceutical systems where drugs are encapsulated in liposomal structure [5]. However, when oral administration is envisaged and gastrointestinal tract mucus and epithelium barrier need to be overcome, the protection of liposomes from anticipated disruption becomes a promising strategy [6]. The emerging of silica-based drug delivery carriers for oral route administration was the leitmotiv for silica-coating of liposomes, Liposils for short.…”

“…Silica precursor molecules hydrolyze, yielding a sol, and then condense, to form a gel able to establish hydrogen-like/electrostatic bounding to the inner liposome structure. The silica-coating helps maintaining the aqueous interior in the liposome-core [6,[8][9][10][11][12], and improves the bioavailability of poorly water soluble drugs by enhancing their colloidal stability, retaining, at the same time, the liposome intrinsic advantage as drug carrier. Liposil were reported by Bégu et al [8] for the first time.…”

“…Until now, Liposil structures are difficult to produce due to large time-consuming coating protocols [6,[8][9][10][11][12]. Bégu et al [8] hydrolyze tetraethyl orthosilicate (TEOS) in phosphate-buffered saline solution (PBS), for two days long.…”

“…A total of 5 days is needed for the silica coating process. Li et al [6] add TEOS to a liposome suspension, and let the mixture stir for two days (2 days for the liposome coating). Mohanraj et al [12] propose the faster protocol (1 day), by adding an aqueous suspension of silica nanoparticles (NPs) to an ionically stabilized liposome suspension, and stay stirring overnight.…”

Silica-coated liposomes loaded with quantum dots as labels for multiplex fluorescent immunoassay

“…Synthesis of liposome-silica derivatives is a widely used method to stabilize the lipid bilayer [31][32][33][34].…”