The purpose of this study is to investigate a novel thermosensitive topical gel formulation for the treatment of inflammatory bowel disease (IBD), specifically ulcerative colitis.

Inclusion Criteria:

• Voluntarily sign written informed consent.
• Male or non-pregnant and non-lactating females at least 8 years of age.
• Confirmed diagnosis of active, mild to moderate ulcerative proctitis or proctosigmoiditis extending no further than 40cm from the anal verge. Typically, baseline Mayo Disease Activity Index (MMDAI) score between 5 and 10 (indicating mild to moderate disease).

Exclusion Criteria:

• Known infection with Clostridium difficile (C. difficile) and/or other enteric pathogens
• 5-aminosalicylic acid (5-ASA) intolerance
• Current or recent (3 weeks) oral or rectal steroids
• History of thiopurine or Anti-tumor necrosis factor (Anti-TNF) alpha treatment for colitis
• Abnormal creatinine
• Previous small bowel or colonic resection,
• Anal sphincter incompetence,
• Current smokers.
• History or current diagnosis of Crohn's disease or indeterminate colitis.
• History of diverticulitis, collagenous colitis, celiac disease, recurrent pancreatic or known gallbladder disease.
• Unstable significant cardiovascular, endocrine, neurologic or pulmonary disease.
• Hemoglobin levels < 7.5 g/dL.
• History of sclerosing cholangitis, cirrhosis, or hepatic impairment
• Pregnant or at risk of pregnancy.
• Some medications to treat UC are prohibited during participation in the study, including laxatives and anti-diarrhea medications; oral 5-ASA agents and daily fiber supplements are allowed.