Preparation, characterization and utilizations of chitosan-sepiolite biocomposite

Chitosan-clay biocomposites have been prepared in which Sepiolite (SEP) is used as nanofiller and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and sepiolite respectively. The effect of SEP loadings in biocomposites and drug release has been investigated. Chitosan/SEP biocomposites were characterized with different methods (FTIR, TGA, XRD and SEM) of analysis. The FTIR and SEM results indicated the formation of a phase separated microcomposite structure at low and high sepiolite content. Surface functional groups of biocomposites were also investigated by Boehm?s titration technique. The point of zero charge was determined as neutral pH. The thermal behavior of the samples was examined by TGA/DTG. The dispersed clay improves the thermal stability of the matrix systematically with the increase of clay loading. The release of Tetracycline (TC) from CS/SEP biocomposites was studied in a batch system as function of pH conditions, clay content and contact time at 37°C. The release of drug into the aqueous solution depends on the clay content. The maximum release at equilibrium was observed at %1 clay content by plotting the amount of TC released by CS/SEP biocomposites versus time. Release of TC from biocomposites which have different clay contents showed that increase in the clay content of the composite resulted decrease in the release of TC. This result is due to the interaction of the silanol groups (-SiOH) of the clay and the ?OH groups of the drug by the formation of the hydrogen bonding. Diffusion rate of TC to aqueous medium decreased by increasing clay content.