Evaluate the percentage of subjects in remission at the end of an 8-week treatment period for three dose groups (SPD476 1.2 g/day, 2.4 g/day or 4.8 g/day, administered once daily).

Inclusion Criteria:

• male & female subjects greater than or equal to 18 years of age with newly diagnosed or relapsing mild to moderate ulcerative colitis
• general medical assessment satisfactory and no clinically significant and relevant abnormalities

Exclusion Criteria:

• severe ulcerative colitis
• subject in relapse for > 6 weeks
• use of systemic or rectal steroids within last 4 weeks prior to baseline
• subjects with proctitis, previous colonic surgery, Crohn's disease, bleeding disorders, active ulcer disease
• subjects hypersensitive to salicylates/aspirin
• subjects with moderate or severe renal impairment