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Background Colon cancer is one of the most common gastrointestinal malignant tumouts,and its incidence is increasing year by year.But the conventional chemotherapeutic drugs for colon cancer still display poor specificity in reaching tumour site, poor patient compliance,and inefficiency of clinical treatment and so on.To evade these problems, oral colon-specific drug delivery system (OCDDS) seems to be more promising.Objective This study was to prepare the GO/pectin/Ca2+-CUR composite hydrogel;in addition, in vitro release and in vivo study of the hydromel was executed.Method We adopted the repeated physical cross linking method to prepared composite hydrogel with Ca2+ as cross-linking agent and pectin and grapheme oxide for the network structure.The actual release behaviour of composite hydrogel on the targeted site-colon, is explored by simulate physiological environment of digestive tract in vitro.The GO/pectin /Ca2+-CUR composite hydrogel is labelled by fluorescence DiR in rat and non-invasive optical imaging technology was utilized.The in vivo analysis method of determined the concentration of CUR in rat was established, and the pharmacokinetics of the gastrointestinal tract was studied.Results The experiment results showed the cumulative drug release is no more than 10% in simulated gastric fluid, less than 20% in simulated small intestinal fluid and about 80% in simulated cercal fluid.The hydrogel is depended on the peptonise and the increase of pH value (Fig1).The in vivo study of the hydrogel showed that in our study the hydrogel just displayed prolonged circulation time (Fig2).In view of the determined results by high performance liquid chromatography (HPLC), the GO/ pectin /Ca2+-CUR composite hydrogel stayed for a long time in the rat, had lower amount of CUR release in the stomach and higher concentration in the colon(Fig3).Conclusion The hydrogel possessed enzyme-sensitive and pH-sensitive properties, which helped to protect CUR while passing stomach as an intact form to reduce toxicity and increase the drug concentration in colon.