Sol-gel-processed silica/polydimethylsiloxane/calcium xerogels as polymeric matrices for Metronidazole delivery system

Silica, silica/polydimethylsiloxane and silica/polydimethylsiloxane/calcium xerogels were examined as polymeric carriers for the controlled release of drug-Metronidazole. Characterization assays comprised analysis of the matrix by Fourier transform infrared spectroscopy (FTIR), determining the specific surface area of solids (BET) and scanning electron microscope (SEM) techniques and further monitoring in the ultraviolet and visible light regions (UV-Vis) of the in vitro release of the drug over time. Using tetramethoxysilane (TMOS) as a precursor of silica matrix and polydimethylsiloxane (PDMS) and calcium ions as additives, xerogels with different morphology and physical properties were obtained. The applied modifications diminished the porosity and hydrophilicity of the silica matrix as well as reduced the release of drug. Based on the presented results of this study, it may be stated that applied xerogel matrices, pure silica (SiO2) and modified silica (SiO2-CaO, SiO2-PDMS and SiO2-CaO-PDMS), could be promising candidates for the formulation in local delivery systems.