The purpose of this study is to determine the efficacious dose range when used as a bowel preparation before colonoscopy.

Inclusion Criteria:

• Men and nonpregnant women who are scheduled for an elective colonoscopy and who are at least 50 years of age.
• Are able to communicate with study personnel and comply with study requirements.
• Are able and willing to follow study-specified testing, diet, and hydration regimen.
• Have been informed of the nature and risks of the study and have given written informed consent.

Exclusion Criteria:

• Have known or suspected liver disease or any history of abnormal liver function tests.
• Have clinically active cardiovascular disease within the past 6 months.
• Have blood pressure greater than 150/90 mm Hg.
• Have known or suspected renal insufficiency.
• Have known or suspected electrolyte abnormalities, gastrointestinal obstruction, gastric retention, bowel perforation, toxic colitis, toxic megacolon, or ileus.
• Have a history of prior bowel surgery within 2 years before enrollment, or active inflammatory bowel disease.
• Have diabetes or a history of diabetes.
• Have clinical evidence of dehydration.
• Are pregnant or breast-feeding.
• Are unwilling to abstain from alcohol consumption from one day before colonoscopy until discharged from the study.
• Use prohibited medications of the study in the defined timeframes.
• Have received any investigational agent within 30 days before dosing.
• Have any known contraindications to the study treatment.
• Have any known or suspected allergies to the components of the study medication.
• Have any other condition which would make the subject unsuitable for inclusion in the study.