Distribution And Excretion Of Chitosan In Mice After Gastric Infusion

Chitosan is the only alkaline polysaccharides in nature, and it has a good bioconsistency and biodegradable. It was reported that chitosan had many physiological functions such as hypolipidemic activity,anticancer effect,immuno-enhancing effect and so on.Although the application of chitosan in medicine was concerned widely,the metabolic pathway of chitosan was not clear yet in vivo.In this study,chitosan was labeled by fluorescein isothiocyanate,then its distribution and excretion were determined in mice after gastric infusion.This study was an importment foundation for the pharmacokinetics of chitosan,and provided important basis for its further application in medicine, it has great academic and economic significance.Fluorescein isothiocyanate was used to label chitosan with 5×105 of molecular weight and 90% of deacetylation degree under different reaction conditions.The results showed the labeling efficiency was significantly influenced by pH and temperature,and the labled rate increased with the increasing pH and temperature of the reaction,respectively.After fluorescein isothiocyanate and chitosan interacted in the solution of pH 9.0 at 25℃for 3 h,the product named fluorescein isothiocyanate labeled chitosan (FITC-CIS) was got at the labeling efficiency of 1.21%.The FITC-CIS was to use in experiments of distribution in tissues and excretion in mice.The concentration of FITC-CIS in tissue at the different time were observed following gastric infusion of FITC-CIS in mice.The distribution experiment indicated that the detection method was applicable to the pharmacokinetics study of FITC-CIS in vivo,FITC-CIS were mainly distributed in the liver,kidney and lung,and the concentration in the kidney was the highest while it was low in heart,spleen and serum.FITC-CIS stayed in the stomach for a long time which comfirmed that chitosan could increase the feeling of full.It was detected that there was higher fluorescence intersity in the intestine than the other tissues,witch may indicated that chitosan was mainly excreted through intestinal directly.The excretion of FITC-CIS in feces and urine at the different time were observed following gastric infusion in mice. The excretion experiment indicated that FITC-CIS was mainly excreted in feces with prototype drug through intestine, and the degradation of FITC-CIS was excreted in urine. The highest concentrations of FITC-CIS in feces and urine appeared at 6 h following gastric infusion.In this study, the reaction condition of fluorescein labeling was determined, and the distribution in tissues and excretion of chitosan were investigated by fluorospectrophotometer and HPLC,which were to explore the metabolic pathway of chitosan.The study was a foundation for the further development of chitosan in the medicine.