Abstract
At the present study, paclitaxel loaded chitosan microspheres were prepared by an emulsification technique and crosslinked with tripolyphosphate. The effect of chitosan molecular weight and the pH of the crosslinking medium on physicochemical characteristics of the prepared microparticles were investigated. Particle size, size distribution, zeta potential, entrapment efficiency, powder X-ray diffraction, thermal analysis and in vitro release profile were determined for each formula. The particle sizes showed a wide range of variability ranging from 1.206 to 8.727 mu m depending on the chitosan composition and the pH of the formulations. All formulae showed narrow particle size dispersion except TM7, TH3 and TH7. Zeta potential values ranged between +7.81 to +30.72 mV. Formulae TL5, TM3 and TM5 exhibited the highest three entrapment efficiencies among all the prepared formulae with values equal to 83%, 83.7% and 73.7%, respectively. Both X-ray diffractomy and DSC confirmed the amorphous state of the encapsulated paclitaxel. The release profile showed tremendous enhancement in the cumulative % released for formulae TM3 and TM5 reaching a magnitude around 90%.