Abstract: AIM: To study the promotion of chitosan on Evans blue absorption via nasal mucosa and the nasal toxicity.METHODS: After nasal administration of Evans blue solution, the distribution of Evans blue in the brain of the mice was observed by fluorescence microscope.The content of Evans blue in the brain was determined by UV methods.The nasal toxicity of chitosan solution was studied by pathology sections. RESULTS: The absorption of water-soluble drugs such as Evans blue via nasal mucosa could be promoted by chitosan.Evans blue could be distributed in the front, middle and back of the brain.Chitosan had little toxicity to the mucosa of the rat.CONCLUTION: Chitosan is the good carrier to water soluble drugs absorbed from nasal mucosa.

Key words: chitosan, Evansblue, nasalabsorption, nasalmucosa, toxicity, braintargeting