Linear type azo-containing polyurethanes for colon-specific drug delivery

Abstract

New biodegradable polyurethanes containing azo-linked polymeric prodrugs of 5-aminosaheylic acid (5-ASA) in the main chain were prepared by reacting 1,6-Hexamethylenediisocyanate (HDI) with 3,3'-azobis(6-hydroxy benzoic acid) (ABHB) and 5-[4-(hydroxyl phenyl) azol salicylic acid (HPAS) as azo derivatives of 5-ASA. The polymers were characterized by FTIR and H-1-NMR spectroscopy. The hydrolysis of polyurethane containing azo-derivatives of 5-ASA was carried out in cellophane membrane dialysis bags containing aqueous buffer solution (pH = 8.5 and pH = 1) at 37degreesC. Detection of the hydrolysis product by UV spectroscopy showed that ABHB and HPAS were released by the hydrolysis of the urethane bond in the polymer chain.