Encapsulation and Release of Moxifloxacin Hydrochloride in Chitosan-Dextran Sulphate Microcapsules

In the present work, multilayer microcapsules of size 350 nm were prepared with layer-by-layer assembly of oppositely charged chitosan and dextran sulphate on silica template. The monodisperse silica particles (310 nm) with fine spherical shape were successfully synthesized by Stober's method. Dissolution of silica particles in HF leads to the formation of hollow capsules. The resulting capsules were found to be able to effectively load moxifloxacin hydrochloride in the interior of the capsules under modest conditions without addition of other reagents, as demonstrated by scanning electron microscopy. Parameters affecting loading and release such as pH and initial concentrations were investigated. Release studies were performed in in-vitro mode with a semi-automatic release protocol, with different pH solutions in water and phosphate buffered saline. The size of silica particles was analysed by dynamic light scattering method. Scanning electron microscopy and energy dispersive X-ray spectroscopy measurements proved the surface morphology and purity of the hollow capsules from the core material. The kinetics of drug release mechanism was studied using Peppas and Higuchi models.