The objective of this study is to evaluate the relative bioavailability of the test formulation of mesalamine suspension rectal enema with the already marketed reference formulation Rowasa® in healthy, adult subjects.

Criteria for Evaluation: FDA Bioequivalence Criteria

Statistical Methods: FDA bioequivalence statistical methods

Inclusion Criteria:

• Males and females, 18 years or older, with a body mass index (BMI) of 30 or less.
• Good health as determined by lack of clinically significant abnormalities in health assessments performed at screening.
• Signed informed consent form, which meets all criteria of current FDA regulations.
• If female and of child bearing potential prepared to abstain from sexual intercourse or use a reliable method of contraception during the study (e.g. condom, IUD, hormonal contraceptives).

Exclusion Criteria:

• If female pregnant, lactating, or likely to become pregnant during the study.
• History of allergy or sensitivity to mesalamine or other salicylic drugs (e.g. aspirin, sulfasalazine) or history of any drug hypersensitivity or intolerance which, in the opinion of the Investigator, would compromise the safety of the subject or the study.
• Colitis, hemorrhoids, anal fissures, or other disease of the anus, rectum or colon.
• Significant history or current evidence of chronic infections disease, system disorder or organ disorder.
• History of psychiatric disorders occuring within the last two years that required hospitalization or medication.
• Presence of a medical condition requiring regular treatment with prescription drugs (other than contraceptives).
• Use of pharmacologic agents known to significantly induce or inhibit drug-metabolizing enzymes within 30 days prior to dosing.
• Receipt of any drug as part of a research study within 30 days prior to dosing.
• Drug or alcohol addiction requiring treatment in the past 12 months.
• Donation or significant loss of whole blood (480 mL or more) within 30 days or plasma within 14 days prior to dosing.
• Positive test for HIV, Hepatitis B surface antigen, or Hepatitis C antibody.
• Positive test results for drugs of abuse at screening.
• Positive serum pregnancy test at screening.
• Unable or unwilling to tolerate multiple venipunctures.