Anti-inflammatory entrapment in polycaprolactone/silica hybrid material prepared by sol-gel route, characterization, bioactivity and in vitro release behavior

Abstract

A novel organic/inorganic hybrid material, based on poly(ε-caprolactone) (PCL) and silica (SiO₂), were synthesized by the sol-gel method. An anti-inflammatory agent (indomethacin) was incorporated into the hybrid material to verify its local controlled drug delivery system. The structure of the interpenetrating network was investigated by Fourier transform infrared spectroscopy. The morphology of the materials was studied by scanning electron microscopy. The structure of a molecular level dispersion was disclosed by atomic force microscopy. The bioactivity of the synthesized hybrid materials was revealed by the formation of a layer of hydroxyapatite on the surface of samples soaked in a simulated body fluid (SBF). Release kinetics in SBF were subsequently investigated. The amount of drug released was detected by UV-VIS spectroscopy. Pure anti-inflammatory agent exhibited linear release with time; in contrast, sol-gel silica entrapped drugs were released with a logarithmic time dependence starting with an initial burst effect followed by a gradual decrease. SiO₂/PCL (3, 6, 9 and 12 %wt) materials, prepared via sol-gel process, are organic/inorganic hybrid and bioactive materials. All the materials showed a good release and therefore could be used as drug delivery system.