title: Literature Review of Gastrointestinal Physiology in the Elderly, in Pediatric Patients, and in Patients with Gastrointestinal Diseases.
abstract: Oral bioavailability studies during the development of new medical entities or generic drugs are typically performed in healthy volunteers. Approved drug products are, however, used by patients with diverse disease backgrounds, and by pediatric and elderly patients. To provide the knowledge base for assessing the potential effects of age or co-morbidity on the in vivo performance of an orally absorbed, systemically active drug product, the literature regarding the gastrointestinal (GI) physiological characteristics (pH, permeability, and transit time) in children, in the elderly, and in patients with GI diseases (irritable bowel syndrome, ulcerative colitis, and Crohn's disease) is reviewed herein, with the knowledge gaps highlighted.
authors.affiliation: Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland 20993. Electronic address: jane.bai@fda.hhs.gov.
authors.forename: Jane P F
authors.initials: JPF
authors.lastname: Bai
authors.affiliation: Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland 20993.
authors.forename: Gilbert J
authors.initials: GJ
authors.lastname: Burckart
authors.affiliation: Division of Gastroenterology and Inborn Error Products, Office of Drug Evaluation III, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland 20993.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Mulberg
mesh_terms: D000367:Age Factors; D000368:Aged; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002648:Child; D005765:Gastrointestinal Agents / Q000008:administration & dosage / Q000378:metabolism*; D005767:Gastrointestinal Diseases / Q000188:drug therapy* / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000378:metabolism*; D005772:Gastrointestinal Transit / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology*; D010372:Pediatrics
chemical_list: D005765:Gastrointestinal Agents
keywords: CYP enzymes; elderly; gastrointestinal transit; metabolism; paracellular transport; passive transport disease effects; pediatric; permeabiltiy; solubility; transporters