title: Advances in gastro retentive drug-delivery systems.
abstract: BACKGROUND
  In recent years, various technological improvements have been achieved and new concepts have been developed, in the area of controlled release solid oral dosage forms, especially for products where an extended time of release is associated with an extended gastric retention time. These Gastro Retentive Systems have been quite investigated because they can improve the in-vivo performance of many drugs.
  
  
  METHODS
  This paper summarizes current approaches in the research and development of gastro retentive dosage forms from recent literature. Apart from the numerous mechanisms of action involved, a short review of different key parameters is proposed, taking into account the stomach physiology. Most of the current technologies published, patented or marketed are presented. Promising drugs to develop in the near future are mentioned, and the importance of such systems in fixed Dose Combinations is also discussed. The importance of food effect is mentioned, and the impact of the multiple unit systems versus monolithic approach is discussed, especially regarding the dose intake.
  
  
  CONCLUSIONS
  In conclusion, numerous mechanisms like floating, sinking, effervescence, swelling, bioadhesion, magnetic, etc. have been proposed over the years. While most of the proposed systems show promising dissolution profiles and in-vitro retention, only few of them have also shown success in-vivo. Currently, the polymeric swelling monolithic systems are the most prominent marketed forms. The possibility to combine different mechanisms in order to ensure true gastric retention even in the fasted state should be further investigated.
authors.affiliation: Universite de la Mediterranee, School of Pharmacy, Laboratoire de Pharmacie Galenique, Marseille Cedex, France. pprinderre@pharmacie.univ-mrs.fr
authors.forename: Pascal
authors.initials: P
authors.lastname: Prinderre
authors.forename: Christophe
authors.initials: C
authors.lastname: Sauzet
authors.forename: Claus
authors.initials: C
authors.lastname: Fuxen
mesh_terms: D000284:Administration, Oral; D000818:Animals; D003692:Delayed-Action Preparations / Q000493:pharmacokinetics; D004338:Drug Combinations; D016503:Drug Delivery Systems; D018565:Food-Drug Interactions; D005746:Gastric Emptying; D006801:Humans; D013270:Stomach / Q000502:physiology*; D013678:Technology, Pharmaceutical
chemical_list: D003692:Delayed-Action Preparations; D004338:Drug Combinations