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This Article Full Text Full Text (PDF) All Versions of this Article: 294/5/G1114    most recent 00051.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Grudell, A. B. M. Articles by Zinsmeister, A. R. PubMed PubMed Citation Articles by Grudell, A. B. M. Articles by Zinsmeister, A. R.

NEUROREGULATION AND MOTILITY

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

¹Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER) and ²Department of Health Sciences Research, Division of Biostatistics, College of Medicine, Mayo Clinic, Rochester, Minnesota; and ³GlaxoSmithKline, Research Triangle Park, North Carolina and King of Prussia, Pennsylvania

Submitted 31 January 2008 ; accepted in final form 24 March 2008

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.

colon; motility; pharmacokinetics