Preparation and characterization of glutaraldehyde cross-linked O-carboxymethylchitosan microspheres for controlled delivery of pazufloxacin mesilate

O-carboxymethylchitosan (OCMC) microspheres containing an antibiotic drug pazufloxacin mesilate (PM) have been successfully prepared by emulsion cross-linking using glutaraldehyde (GA). Various manufacturing parameters, including amount of cross-linking agent and OCMC:PM ratios were altered to optimize process variables during the microspheres production. The structure and morphology were characterized by Fourier transform infrared (FT-IR), wide-angle X-ray diffraction (WXRD) and scanning electron microscopy (SEM). The swelling and releasing behaviors of the microspheres at pH 1.2 and 7.4 media were investigated. The results revealed that the microspheres had a spherical, rough morphology and with a narrow size distribution. The degree of swelling of microspheres at pH 7.4 media was higher than that at pH 1.2 media. The microspheres proved to be successful in prolonging drug release. The release of PM was found to depend upon the extent of matrix cross-linking and drug loading. The release profiles of PM from OCMC microspheres were found to be biphasic with a burst release followed by a gradual release phase, and followed the Higuchi matrix model.