Methods for preparing a novel family of polysaccharride prodrugs for colonic delivery

摘要

This invention describes a novel family of polysaccharide prodrugs with enhanced colonic delivery advantage. The prodrugs are synthesized by chemically linking a parent compound with a specially selected polysaccharide (M.W. 105-107 Da) containing galactose residues. Its characteristics are that it is synthesized by chemically linking polysaccharides with the parent compound through different bridge links for targeted colonic delivery; that the polysaccharides contain galactose residues. Because of this, the polysaccharide component can protect the parent compound from absorption (or metabolism) in the upper gastrointestinal tract and deliver a high concentration of the bound compound to the colonic area. Upon reaching the colon, the active component of the parent drug will be released locally from the polysaccharide via enzymatic hydrolysis, allowing it to act locally for colonic disease such as inflammation or infection and/or taking advantage of the favorable microenvironment in the colon for steady and stable colonic drug absorption.