title: Expandable gastroretentive dosage forms.
abstract: Expandable gastroretentive dosage forms (GRDFs) have been designed for the past 3 decades. They were originally created for possible veterinary use, but later the design was modified for enhanced drug therapy in humans. These GRDFs are easily swallowed and reach a significantly larger size in the stomach due to swelling or unfolding processes that prolong their gastric retention time (GRT). After drug release, their dimensions are minimized with subsequent evacuation from the stomach. Gastroretentivity is enhanced by the combination of substantial dimensions with high rigidity of the dosage form to withstand the peristalsis and mechanical contractility of the stomach. Positive results were obtained in preclinical and clinical studies evaluating GRT of expandable GRDFs. Narrow absorption window drugs compounded in such systems have improved in vivo absorption properties. These findings are an important step towards the implementation of expandable GRDFs in the clinical setting. The current review deals with expandable GRDFs reported in articles and patents, and describes the physiological basis of their design. Using the dog as a preclinical screening model prior to human studies, relevant imaging techniques and pharmacokinetic-pharmacodynamic aspects of such delivery systems are also discussed.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem POB 12065, Jerusalem 91120, Israel.
authors.forename: Eytan A
authors.initials: EA
authors.lastname: Klausner
authors.forename: Eran
authors.initials: E
authors.lastname: Lavy
authors.forename: Michael
authors.initials: M
authors.lastname: Friedman
authors.forename: Amnon
authors.initials: A
authors.lastname: Hoffman
mesh_terms: D000818:Animals; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000493:pharmacokinetics; D004064:Digestive System / Q000187:drug effects* / Q000378:metabolism; D004304:Dosage Forms; D016503:Drug Delivery Systems / Q000379:methods*; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology
chemical_list: D003692:Delayed-Action Preparations; D004304:Dosage Forms