title: Overview on gastroretentive drug delivery systems for improving drug bioavailability.
abstract: In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems.
authors.affiliation: Fernando Pessoa Energy, Environment and Health Research Unit/Biomedical Research Center (FP-ENAS/CEBIMED), Faculty of Health Sciences, Fernando Pessoa University, Rua Carlos da Maia, 296 P-4200-150 Porto, Portugal. Electronic address: cmlopes@ufp.edu.pt.
authors.forename: Carla M
authors.initials: CM
authors.lastname: Lopes
authors.affiliation: Fernando Pessoa Energy, Environment and Health Research Unit/Biomedical Research Center (FP-ENAS/CEBIMED), Faculty of Health Sciences, Fernando Pessoa University, Rua Carlos da Maia, 296 P-4200-150 Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Bettencourt
authors.affiliation: Department of Pharmacy, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Rossi
authors.affiliation: Department of Pharmacy, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy; Institute of Pharmaceutical Science, King's College London, 150 Stamford Street, SE19NH London, UK.
authors.forename: Francesca
authors.initials: F
authors.lastname: Buttini
authors.affiliation: Fernando Pessoa Energy, Environment and Health Research Unit/Biomedical Research Center (FP-ENAS/CEBIMED), Faculty of Health Sciences, Fernando Pessoa University, Rua Carlos da Maia, 296 P-4200-150 Porto, Portugal. Electronic address: pbarata@ufp.edou.pt.
authors.forename: Pedro
authors.initials: P
authors.lastname: Barata
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D001682:Biological Availability; D016503:Drug Delivery Systems / Q000379:methods* / Q000639:trends; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology; D005753:Gastric Mucosa / Q000378:metabolism; D005765:Gastrointestinal Agents / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D013270:Stomach / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D005765:Gastrointestinal Agents
keywords: Controlled drug release; Gastric retention time; Gastroretentive system; Multiple unit dosage form; Narrow absorption window