Dose-response effect of a β3-adrenergic receptor agonist, solabegron, on gastrointestinal transit, bowel function, and somatostatin levels in health

April B.M. Grudell, Michael Camilleri, Kim L. Jensen, Amy E. Foxx-Orenstein, Duane D. Burton, Michael D. Ryks, Kari L. Baxter, Donna S. Cox, George E. Dukes, Dennis L. Kelleher, Alan R. Zinsmeister

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


β3-Adrenoceptors (β3-AR) are expressed by cholinergic myenteric neurons and β3-AR agonists are effective in experimental models of diarrhea. Our aim was to explore the effects of a β3-AR agonist, solabegron, on gastrointestinal transit, safety, bowel function, plasma somatostatin, and solabegron pharmacokinetics (PK) following single and multiple doses. In a single-center, double-blind, parallel-group trial, 36 healthy volunteers were randomized to oral solabegron (50 or 200 mg twice daily) or placebo. Transit was measured by a validated method (99mTc-labeled egg meal and 111In charcoal delivered to the colon via delayed-release capsule). Stool frequency, form, and ease of passage were measured on a validated daily diary; plasma somatostatin by radioimmunoassay and plasma solabegron and its active metabolite by validated liquid chromatography-tandem mass spectroscopy analysis followed by PK analysis using noncompartmental methods. There were no overall or dose-related effects of solabegron on gastric, small bowel, or colonic transit, plasma somatostatin levels, stool frequency, form, or ease of passage in healthy volunteers. Solabegron and active metabolite exposures (area under the curve and maximum serum concentration) at both dose levels were consistent with PK at similar doses in previous phase I studies. We concluded that 7 days of the β3-AR agonist, solabegron, 50 or 200 mg twice daily, did not significantly alter gastrointestinal or colonic transit or bowel function. In this study, medication was generally well tolerated with few adverse events reported and no clinically significant changes in vital signs observed. Further studies on clinical efficacy, visceral sensitivity, and gastrointestinal transit are required in irritable bowel syndrome patients.

Original languageEnglish (US)
Pages (from-to)G1114-G1119
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Issue number5
StatePublished - May 2008


  • Colon
  • Motility
  • Pharmacokinetics

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)


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