The Colon-specific Release Based On Polysaccharide Drug Delivery System And Its Treatment For Ulcerative Colitis In Rat

AIM Glucocorticoid prodrugs were synthesized with different molecular weight dextran and polysaccharide fraction of traditional Chinese medicine. Our aims were to: (1) study the characteristics of different molecular weight dextran used as drug carrier; (2) explore the possibility of polysaccharide fraction of traditional Chinese medicine used as drug carrier; (3) explore the synergism between Glucocorticoid and polysaccharide fraction of traditional Chinese medicine with prodrug used in treatment for ulcerative colitis; and (4) explore new method for seeking new drug carriers and prodrugs with good properties in every aspect.METHODS (1) Rude polysaccharide was obtained by circumfluencing the residue of plant DG in distilled-water with lipophilic fraction completely removed and depositing the polysaccharide-enriched fraction by ethanol. After the removal of the protein fraction, the rude polysaccharide was purified with Sephacryl S-400 column into three polysaccharide fractions (DG1,DG2,DG3). (2) With succinate as a cross-linker and DG1, DG2 and dextran of different molecular weight as drug carriers, we synthesized the prodrug of DS and PL. The incubation of the prodrugs with diluted contents of different parts of rats gastrointestinal (GI) tract at 37℃ resulted in the release of DS, DSH, PL and PLH, which were determined by HPLC. (3) DS prodrug and DS were respectively administrated to rat by oral gavage at the dose of 5μmol/kg. The distribution of DS, DSH in the contents and mucosa of different parts of rat GI tract between different intervals, and the fluctuation of DS...