8 Weeks Treatment With DDP225 in Patients With Diarrhea Predominant IBS

This is a randomized, double-blind, placebo controlled, multicenter study designed to assess the safety and efficacy of DDP225 in patients with IBS-d. Female patients from 18 to 65 years of age with a history of IBS-d for at least 6 months are potentially eligible for entry into the study. A total of 88 eligible patients with IBS-d will be studied. The total duration of study participation for an individual patient is approximately 10 weeks (74 days) from the initial screening visit to final study evaluations. The total duration of dosing with study medication (either DDP225 or placebo) is 8 weeks. Patients who satisfy all of the inclusion criteria and none of the exclusion criteria are eligible to enter the Treatment Period and will be randomly assigned to one of four treatment groups. After a patient is randomized and enters the Treatment Period, she will take the appropriate study medication once a day for 56 days and return to the clinic at two week intervals for a total of four visits during the Treatment Period. During the Treatment Period, patients will maintain a daily diary and complete questionnaires. One week after completing the 56-day Treatment Period, patients return to the clinic for final safety evaluations which include a physical examination, electrocardiogram, and clinical laboratory testing.