Synthesis and characterization of new biodegradable polyurethanes containing azo derivatives of 5-aminosalicylic acid

Abstract

The purpose of this study is to develop colon-specific drug delivery systems with
pH-sensitive drug release properties.The azo polyurethane were characterized, and the
drug content of the azo polyurethane was determined.Their behaviour and hydrolytic
degradation was studied in simulated gastric fluid (SGF, pH =4) and simulated
intestinal fluid (SIF, pH =7.8).
All synthesized monomers and polymers were characterized by FTIR, 1H-NMR
spectra.The release of 5-ASA under physiological conditions (pH = 7.8 and
pH = 4) was investigated at body temperature (37 ºC). The release rate of 5-ASA
increased with increasing pH (7.8 > 4).