ABSTRACT
OBJECTIVE:To investigate the characteristics of cecum and colon-specific drug delivery system of 4-aminosalicyl-ic acid-maltoside (4-ASA-Mal) in vitro. METHODS:With the cumulative release rate of 4-ASA as the index,HPLC was em-ployed to observe the delivery of 4-ASA-Mal (equivalent to 250 μg/ml 4-ASA) in the buffer solutions of different pH (1.2,6.8 and 7.4)and in the aqueous contents in different parts(stomach,small intestine,cecum and colon)of normal rats and the rat mod-els of ulcerative colitis. RESULTS:4-ASA-Mal was hardly released in the buffer solutions of different pH. 12 h cumulative release rates were less than 8% in the aqueous contents in the stomachs and small intestines of normal rats and rat models,and were 55%and 81% in the aqueous contents in the cecum and colons of normal rats,and 55% and 74% in the aqueous contents in the cecum and colons of model rats with ulcerative colitis. CONCLUSIONS:4-ASA-Mal can release a lot of 4-ASA in aqueous contents in ce-cum and colon,targeting cecum and colon in vitro.