Gastro-protective protein-silica nanoparticles formulation for oral drug delivery: In vitro release, cytotoxicity and mitochondrial activity.

Our contribution aims to provide an efficient solution to one of the major challenges of oral delivery of gastro-sensitive drugs, namely preventing their premature release and degradation in the gastric fluid in order to maximize the absorption in the small intestine. Our results show that a pH-responsive protein, i.e., succinylated β-lactoglobulin (BL), together with the key attributes of mesoporous silica nanoparticles (MSNs), can synergetically reduce the release of the gastro-sensitive drug, omeprazole (OMP), in acidic pH and enhance the dissolution in intestinal pH conditions. Two families of MSNs were synthesized, MCM-48-based and dendritic-type MSNs, and both materials were additionally functionalized with trimethylsilyl groups to produce a hydrophobic surface that can further modulate the interaction of the MSNs with the succinylated protein in the nanoformulation. The methyl-functionalization of the MSNs also impacted on the physical state of the confined OMP and consequently on its release in near neutral pH. Our cytotoxicity screening revealed no particular mitochondrial dysfunction originating from the MSNs. Moreover, upon progressive release of the drug confined into dendritic-type MSNs, the cytotoxicity against tumorigenic and non-tumorigenic cells (Caco-2 and HCEC) was significantly lower in comparison to the drug pre-dissolved in DMSO.