The objectives of the present investigation were to prepare the 5-Fluorouracil (5-FU) loaded chitosan microspheres for colon targeting and its in vitro cytotoxicity analysis on HT-29 human colon cancer cell lines. Chitosan microspheres prepared by the emulsion polymerization method were analyzed for morphology, mean particle size, drug polymer interaction, entrapment efficiency, in vitro drug release and cytotoxicity on HT-29 colon cancer cell lines. The mean particle size of unloaded microspheres underwent significant change with increase in concentration of chitosan solution. The stirring speed had a significant effect only at the lower level (i.e. 1000 to 4000 rpm). Entrapment efficiency increased with increase in drug concentration. The formation of chitosan microspheres was heeled by the use of differential stirring. With an increase in the concentration of water-soluble drug, there was an increase in entrapment efficiency and drug load over a large concentration range. Cytotoxicity study indicated that 5- FU loaded chitosan microspheres prolonged the cytotoxic effect on HT-29 colon cancer cell lines in comparison to free 5-FU
Key words: Chitosan microspheres, 5- Fluorouracil, Cytotoxicity.