Abstract: This invention describes a novel polysaccharide prodrug of 5-fluorouracil (5-FU) with enhanced target specificity for colorectal cancer treatment, and its preparation methods. The prodrug is synthesized by chemically linking anti-cancer drug 5-fluorouracil (5-FU) with a specially selected polysaccharide with molecular weight of 105˜107 Da containing galactose residues. Its distinctive characteristics are that it is a prodrug synthesized by chemically linking polysaccharides with 5-FU through different bridge links for the targeted treatment of colorectal cancer; that the polysaccharides in the chemical compound contain galactose residues; and that these polysaccharides are prepared from natural gums or plant materials. Due to these unique characteristics, as an oral preparation, the polysaccharide component of this novel prodrug can protect the active agent 5-FU from absorption (or metabolism) in the upper gastrointestinal tract and deliver a high concentration of the 5-FU to the colorectal area.

Abstract: This application discloses embodiments of a novel prodrug and its method of synthesis. The prodrug comprises a galactose-containing polysaccharide covalently linked to 5-fluorouracil (5-FU). The galactose residues that are part of the backbone of the galactose-containing polysaccharide mediate the binding between the prodrug and the lectin galectin-3 which is expressed in various cancers. The galactose-containing polysaccharide is isolated from various plant material and covalently bonded to 5-FU. Various formulations (parenteral, or other local or systemic forms) can be used to administer this 5-FU-releasing prodrug to target galectin-3 expressing cancers.