Stability tests of 5-Aminosalicylic acid containing solutions and chitosan-Ca-alginate microparticles prepared by spray-drying

5-ASA is widely used for its local effects in the treatment of inflammatory bowel diseases (Loftus, 2004). Because of the 4-aminophenol structure and antioxidative properties it is considered as a light, temperature and oxygen sensitive drug and its major degradation products are well established (Jensen, 1992). As a zwitter ion, dominantly anionic, 5-ASA has low aqueous solubility and it is poorly absorbed and inactivated before reaching the lower intestine. The optimum oral 5-ASA delivery system requires technologies that protect the drug during microencapsulation and during the distribution in the stomach and small intestine. For these requirements, new chitosan-alginate microparticluated colon drug delivery system was prepared and characterized. Stability of 5-ASA in solutions at various pH intended for spray-drying to obtain 5-ASA loaded chitosan-Ca-alginate microparticles and in microparticles was studied.