['chronic constipation']
['rm-131', 'placebo']

        Inclusion Criteria:

          1. Able to provide written informed consent prior to any study procedures, and be willing
             and able to comply with study procedures.

          2. Subjects with chronic IDIOPATHIC constipation, including experiencing constipation for
             12 or more weeks in the preceding 12 months. Chronic constipation is to be defined by
             the Rome III criteria for Functional Constipation

          3. Stable concomitant medications defined as no changes in regimen for at least 2 weeks
             prior to the study period.

          4. Body mass index of 18-40 kg/m2

          5. Female patients must have negative urine pregnancy tests and must not be lactating.
             For females able to bear children, a hormonal (i.e., oral, implantable, or injectable)
             and single-barrier method, or a double-barrier method of birth control must be used
             throughout the study. Female patients unable to bear children must have this
             documented in their medical history. (i.e., tubal ligation, hysterectomy, or
             post-menopausal [defined as a minimum of one year since the last menstrual period]).

        Exclusion Criteria:

          1. Unable or unwilling to provide informed consent or to comply with study procedures

          2. Diagnosis of secondary constipation e.g. underlying general neurological disease such
             as Parkinsonism, multiple sclerosis, diseases associated with peripheral neuropathy,
             iatrogenic constipation

          3. Structural or metabolic diseases that affect the GI system NOTE: Patients with
             clinical suspicion of upper or lower GI obstruction must have been evaluated per
             standard of care and obstruction ruled out before screening

          4. Unable to withdraw the following medications 48 hours prior to the colon study day and
             throughout the study:

               -  Medications that alter GI transit including laxatives, magnesium and aluminum
                  containing antacids, prokinetics, erythromycin, narcotics, aspirin,
                  anti-cholinergics, tricyclic antidepressants, SNRI and newer antidepressants.
                  With the exception of GoLYTELY which will be taken the evening prior to colon
                  study day. 4- Selective serotonin reuptake inhibitor (SSRI) antidepressants are
                  permissible at low, stable doses. All medications shall be reviewed and
                  dis/approved by the principal investigator on a case by case basis.

               -  Analgesic drugs including opiates, NSAIDs and COX-2 inhibitors

               -  GABAnergic agents

               -  Benzodiazepines NOTE: stable doses of thyroid replacement, estrogen replacement
                  and birth control (but with adequate backup contraception as drug-interactions
                  with birth control have not been conducted) are permissible.

               -  Drugs with a low therapeutic index, such as warfarin, digoxin, anti-seizure
                  medications

          5. History of recent surgery (within 60 days of screening)

          6. Acute or chronic illness or history of illness, which in the opinion of the
             Investigator, could pose a threat or harm to the patient or obscure interpretation of
             laboratory test results or interpretation of study data such as frequent angina, Class
             III or IV congestive heart failure, moderate impairment of renal or hepatic function,
             poorly controlled diabetes, etc.

          7. Any clinically significant abnormalities on physical examination or laboratory
             abnormalities identified in the medical record, as determined by the Investigator

          8. Acute GI illness within 48 hours of initiation of the colonic study day

          9. Females who are pregnant or breastfeeding

         10. History of alcohol or substance abuse; Alcohol use 2 days before colonic study day

         11. Participation in a clinical study involving an investigational medication within the
             30 days prior to dosing in the present study

         12. Any other reason, which in the opinion of the Investigator, would confound proper
             interpretation of the study
      