Synthesis and chemical characterization of new silica polyethylene glycol hybrid nanocomposite materials for controlled drug delivery

A series of inorganic organic hybrid nanocomposite materials, containing indomethacin (IND) as a model drug, were synthesized using an inorganic precursor (tetraethoxysilane, TEOS) and an organic precursor (polyethylene glycol, PEG 400) through sol-gel chemistry. The various synthesized hybrids differed in PEG weight percentage (0, 6, 12, 24, and 50 % wt). On an equal PEG percentage, different amounts of the non-steroidal anti-inflammatory drug were loaded (5, 10, and 15 % wt). The bonding characteristics of the various composites were investigated via FT-IR spectroscopy, which suggests the formation of H-bonds between hybrids components. X-ray diffraction (XRD), used for the investigation of their atomic organization, and scanning electron microscopy (SEM) analysis confirmed the amorphous and nanocomposite structure of synthesized materials, which appeared morphologically homogeneous. The in vitro bioactivity evaluation was carried out by analyzing the apatite layers produced on the hybrid materials using SBF as incubation medium. The apatite formation was analyzed using SEM coupled to energy-dispersive electron X-ray spectroscopy. The in vitro release of indomethacin from the new drug-loaded bioactive materials was investigated by HPLC-UV-ESI MS/MS analysis. Data obtained allowed us to state that the drug release was markedly affected by the PEG percentage in investigated hybrid materials.