M. Babazadeh - Department of Chemistry, Islamic Azad University, Tabriz Branch, Tabriz, Iran- Islamic Azad University, Bostanabad Branch, Bostanabad, Iran
L. Edjlali - Department of Chemistry, Islamic Azad University, Tabriz Branch, Tabriz, Iran
M. Yusefnejad - Department of Chemistry, Islamic Azad University, Tabriz Branch, Tabriz, Iran

Synthetic strategies and chemical structural of the synthesis of HPMA(2-hydroxypropyl methacrylat) copolymer conjugates with 5-amino salicylic acid (5-ASA) drug in treatment of inflammatory bowel diseases discussed in this research. In this work, first 5-ASA was refluxed in formic acid and added cold distilled water to obtain 5-formylaminosalicylic acid as a white precipitate. The precipitate was filtered, washed several times with cold water, and dried in vacuum. 5-formylaminosalicylic acid was linked to 2-hydroxypropyl methacrylate by carbodiimidazole (CDI) to obtain metachryloyloxy propyl 5-amino salicylate. The resulting acrylic derivative of 5-ASA was copolymerized with 2-hydroxypropyl ethacrylate and butyl acrylate by free radical polymerization method in DMF solution at 70 °C. The obtained polymers were characterized by FT-IR, 1HNMR, elemental analysis and gel permeation chromatography. Release studies of 5-amino salicylic acid were performed into dialysis bags by hydrolysis buffered solutions in different pH at 37 °C. Detection of hydrolysis by UV spectroscopy at selected interval showed that the drug can be released by selective hydrolysis of the ester bond at the side of drug moiety .The release profiles indicated that the hydrolytic behavior of polymeric prodrugs is strongly based on the hdyrophobicity of polymer and the pH of the hydrolysis solution.