Four novel cyclic phosphates of the anti-inflammatory agent 5-aminosalicylic acid (5-ASA) were designed and synthesized as cytochrome P450 (CYP)-activated prodrugs. These prodrugs can be used for targeting into gut wall, since these types of cyclic phosphates are known to be activated mainly by CYP3A forms, which are expressed not only in the liver but also in the small intestine and to a lesser extent in the colon. The present study shows that ...