Sol-gel silicon alkoxides-polyethylene glycol derived hybrids for drug delivery systems

The potential application of hybrid systems based on silicon alkoxides and polyethylene glycol 400 as drug delivery systems was studied. They were synthesized using the sol-gel technique, using ketoprofen as a model drug. The preparation of the materials and their characterization by X-ray diffraction, infrared spectroscopy, thermogravimetric analysis are reported. Drug loading was performed during the gelation of the sols. Drug release studies were performed at pH 1.2 and 7.5 mimicking gastrointestinal environments. Drug release was affected by the presence of polyethylene glycol in the formulation: a faster release was observed for polyethylene glycol hybrids. The results suggest that these devices should guarantee long durability after implantation and could be suitable for sustained release: after a first period of release by diffusion, complete release will be reached by bioerosion of the matrix.