title: Canine gastrointestinal physiology: Breeds variations that can influence drug absorption.
abstract: Although all dogs belong to Canis lupus familiaris, the physiological diversity resulting from selective breeding can lead to wide interbreed variability in drug pharmacokinetics (PK) or in oral drug product performance. It is important to understand this diversity in order to predict the impact of drug product formulation attributes on in vivo dissolution and absorption characteristics across the canine population when the dog represents the targeted patient population. Based upon published information, this review addresses breed differences in gastrointestinal (GI) physiology and discusses the in vivo implications of these differences. In addition to the importance of such information for understanding the variability that may exist in the performance of oral dosage forms in dogs for the purpose of developing canine therapeutics, an appreciation of breed differences in GI physiology can improve our prediction of oral drug formulation performance when we extrapolate bioavailability results from the dog to the humans, and vice versa. In this literature review, we examine reports of breed associated diversity in GI anatomy and morphology, gastric emptying time (GET), oro-cecal transit time (OCTT), small intestinal transit time (SITT), large intestinal transit time (LITT), intestinal permeability, sodium/potassium fecal concentrations, intestinal flora, and fecal moisture content.
authors.affiliation: US FDA Center for Veterinary Medicine, Rockville, MD 20852, United States.
authors.forename: Hayley
authors.initials: H
authors.lastname: Oswald
authors.affiliation: US FDA Center for Veterinary Medicine, Rockville, MD 20852, United States.
authors.forename: Michele
authors.initials: M
authors.lastname: Sharkey
authors.affiliation: Simcyp Blades Enterprise Centre, John Street, Sheffield, S2 4SU, UK.
authors.forename: Devendra
authors.initials: D
authors.lastname: Pade
authors.affiliation: US FDA Center for Veterinary Medicine, Rockville, MD 20852, United States. Electronic address: marilyn.martinez@fda.hhs.gov.
authors.forename: Marilyn N
authors.initials: MN
authors.lastname: Martinez
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D004285:Dogs / Q000502:physiology*; D005772:Gastrointestinal Transit / Q000502:physiology; D007408:Intestinal Absorption / Q000502:physiology*; D010539:Permeability; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000378:metabolism; D010599:Pharmacokinetics; D000068618:Selective Breeding; D012995:Solubility
chemical_list: D004364:Pharmaceutical Preparations
keywords: Absorption; Dog; GI transit time; Gastrointestinal physiology; Permeability