title: Pharmacokinetic and pharmacodynamic aspects of gastroretentive dosage forms.
abstract: Controlled release gastroretentive dosage forms (CR-GRDF) enable prolonged and continuous input of the drug to the upper parts of the gastrointestinal (GI) tract and improve the bioavailability of medications that are characterized by a narrow absorption window. CR-GRDF provide a means to utilize all the pharmacokinetic (PK) and pharmacodynamic (PD) advantages of controlled release dosage forms for such drugs. Thus, CR-GRDF may improve therapy with clinically used medications, as well as enable oral administration of drugs, or drug candidates, that hitherto had to be infused parenterally. This manuscript discusses the complexity of the PK and PD factors that influence the treatment benefits of CR-GRDF and summarizes the results of our recent in vivo investigations in animal models (rats and dogs) and in human subjects. We found that a CR-GRDF formulation was superior to the other modes of administration for levodopa and riboflavin, but not for metformin. The PK and PD rationales of GRDFs for the studied drugs are presented and discussed. We conclude that due to the complexity of the PK and PD factors for a certain drug, the rationale for continuous administration obtained by CR-GRDF should be assessed and established in vivo.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, PO Box 12065, Jerusalem 91120, Israel. ahoffman@cc.huji.ac.il
authors.forename: Amnon
authors.initials: A
authors.lastname: Hoffman
authors.forename: David
authors.initials: D
authors.lastname: Stepensky
authors.forename: Eran
authors.initials: E
authors.lastname: Lavy
authors.forename: Sara
authors.initials: S
authors.lastname: Eyal
authors.forename: Eytan
authors.initials: E
authors.lastname: Klausner
authors.forename: Michael
authors.initials: M
authors.lastname: Friedman
mesh_terms: D000818:Animals; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000493:pharmacokinetics* / Q000494:pharmacology; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000378:metabolism*; D006801:Humans
chemical_list: D003692:Delayed-Action Preparations