One-pot synthesis of poly(alkyl methacrylate)-functionalized mesoporous silica hybrid nanocomposites for microencapsulation of poorly soluble phytochemicals

Silibinin (SBN), the major active constituent of milk thistle seeds indicated in liver conditions, has low oral bioavailability due to low solubility and degradation in gastric fluid. Hybrid mesoporous silica nanocomposites composed of polymerized alkyl methacrylate monomers (methyl methacrylate, butyl methacrylate or 1:1 mixture of methyl methacrylate and acrylic acid) were developed to enhance dissolution and antioxidant activity of SBN. Samples were worked up by calcination in oven or refluxing with ammonium nitrate. DLS, FE-SEM, AFM, TGA, FTIR, EDS, XRD and BET techniques were employed to characterize unloaded and SBN-loaded particles. Well-tuned hybrid nanoparticles exhibited spherical morphology, small size (~20 nm), large pore volumes (1.6 cm 3 g −1 ), high polymer functionality (~50%) and high SBN loading (19%). Importantly, in-vitro dissolution and DPPH antioxidant activity of SBN in acidic gastric medium increased remarkably after loading in the particles. Conclusively, well-tuned hybrid nanocomposites are suggested for modulating the oral bioavailability of poorly sluble phytochemicals.