The Efficacy of AZD1722 in Constipation Predominant Irritable Bowel Syndrome (IBS-C)

Inclusion Criteria:

- Females and males must agree to use appropriate methods of contraception or be
sterile (with appropriate documentation)

- Subject is ambulatory

- Subject meets definition of IBS-C using Rome III Criteria for the Diagnosis of IBS
with a history of <5 SBMs per week

- Subject meets Screening eligibility criteria (see below)

- A colonoscopy based on AGA guidelines; every 10 years at ≥ 50 years old, or the
occurrence of any warning signs (i.e., unexplained weight loss, non-hemorrhoid blood
in stools)

- Ability to communicate well with the Investigator and to comply with the requirements
of the entire study, including an understanding of how to use the touch-tone
telephone electronic diary.

- Written informed consent and a willingness to participate in the study as it is
described.

- Daily access to a touch tone telephone.

Exclusion Criteria:

- Functional diarrhea as defined by Rome III criteria

- IBS with diarrhea (IBS-D), mixed IBS (IBS-M), or unsubtyped IBS as defined by Rome
III criteria

- Diagnosis or treatment of any clinically symptomatic biochemical or structural
abnormality of the GI tract within 6 months prior to screening, or active disease
within 6 months prior to screening. Including but not limited to cancer,
inflammatory bowel disease, diverticulitis, duodenal ulcer, erosive esophagitis,
gastric ulcer, pancreatitis (within 12 months of screening), cholelithiasis,
amyloidosis, ileus, non-controlled GERD, gastrointestinal obstruction or carcinoid
syndrome.

- Use of medications that are known to affect stool consistency (Prohibited
Medications), including fiber supplements, anti-diarrheals, cathartics, antacids,
opiates, prokinetic drugs, laxatives, enemas, antibiotics within 4 weeks of
enrollment, probiotics (including probiotic yogurt); or salt or electrolyte
supplements containing sodium, potassium, chloride, or bicarbonate formulations
during the seven days prior to treatment; unless specified as rescue medication, and
used accordingly.

- Clinical evidence of significant cardiovascular, respiratory, renal, hepatic,
gastrointestinal, hematologic, neurologic, psychiatric or any disease that may
interfere with the subject successfully completing the trial.

- The subject has a history or current evidence of laxative abuse (in the clinical
judgment of the physician).

- Hepatic dysfunction (ALT [SGPT] or AST [SGOT] >2.5 times the upper limit of normal)
or renal impairment (serum creatinine > 2mg/dL).

- Any evidence of or treatment of malignancy (other than localized basal cell, squamous
cell skin cancer or cancer in situ that has been resected) within the previous year.

- Any surgery on the stomach, small intestine or colon, excluding appendectomy.

- Pregnant or lactating women.

- A major psychiatric disorder (DSM-III-R or DSM-IV) including major depression or
other psychoses that has required hospitalization in the last 3 years. History of
attempted suicide or uncontrolled bipolar disorder. Alcohol or substance abuse in
the last year.

- Participation in other clinical trials within 1 month prior to Day -14 (beginning of
screening period).

- If, in the opinion of the Investigator the subject is unable or unwilling to fulfill
the requirements of the protocol or has a condition, which would render the results
uninterpretable.