O-Carboxymethylchitosan-based novel gatifloxacin delivery system

The increase in the treatment efficacy due to the enhanced permeability and retention properties and the decrease in the minimum inhibitory concentration (MIC) are the vital challenges related to the administration of the antibiotic drugs. In the present paper, we describe a novel delivery system of gatifloxacin (GFLX) from O-carboxymethylchitosan (OCMCS). GFLX is a fourth-generation fluoroguinolone, which has shown promise with excellent activity against both Gram-positive cocci and Gram-negative bacteria both in vitro and in vivo. OCMCS is a biocompatible amphiphilic derivative of chitosan. GFLX could be entrapped into OCMCS by the interaction between OCMCS and GFLX, which was characterized by fluorescence spectrum, transmission electron microscope, and dynamic light scattering techniques. The release behaviors of GFLX from this proposed delivery system in phosphate-buffered saline (PBS) solution at 37 °C were studied by fluorescence spectroscopy. The MIC of OCMCS formulation was evaluated. The results demonstrate that the release of GFLX from OCMCS formulation is slower than that from GFLX solution. In vitro bacteria antiproliferative activity assay confirms that the MIC of OCMCS formulation against Gram-negative bacteria is fourfold lower than the system without OCMCS. However, it seems that OCMCS has insignificant effect against Gram-positive bacteria. These results suggest that OCMCS matrix has obvious “transmission effect” on Gram-negative bacteria.