LAP-Floating Drug Delivery Systems

2011

Gastric emptying is a complex process and makes in vivo performance of the drug delivery systems uncertain. Floating drug delivery systems (FDDS) can remain in the gastric region for several hours and hence significantly prolong the gastric residence time of drugs, thereby improving bioavailability, reduced drug waste and improved solubility for drugs that are less soluble at a higher pH environment. In order to understand the various physiological barriers to achieve gastric retention, a thorough understanding of the important factors controlling gastric retention is essential.

2011

Controlled release (CR) dosage forms have been extensively used to improve therapy with many important drugs. Several approaches are currently utilized in prolongation of gastric residence time, including floating drug delivery system, swelling and expanding system, polymeric bioadhesive system, modified shape system, high density system and other delayed gastric emptying devices. However, the development processes are faced with several physiological difficulties such as the inability to restrain and localize the system within the desired region of the gastrointestinal tract and the highly variable nature of the gastric emptying process. On the other hand, incorporation of the drug in a controlled release gastroretentive dosage forms (CR-GRDF) which can remain in the gastric region for several hours would significantly prolong the gastric residence time of drugs and improve bioavailability, reduce drug waste, and enhance the solubility of drugs that are less soluble in high pH environment. Gastroretention would also facilitate local drug delivery to the stomach and proximal small intestine. Thus, gastroretention could help to provide greater availability of new products and consequently improved therapeutic activity and substantial benefits to patients. The purpose of this paper is to review the recent literature and current technology used in the development of gastroretentive dosage forms.

The promise of gastric retentive drug delivery systems has propagated numerous inventions. The therapeutic window of many drugs is limited by their short circulating half-life and absorption via a defined segment of the GI tract. Four technologies have involved a substantial number of human clinical trials: floating, mucoadhesion, density modification, and expansion. The floating drug delivery system can remain in the gastric region for several hours via float on the gastric contents and hence significantly prolong the gastric residence time of drugs. Here the stomach may be used as a 'depot' for sustained release (SR) dosage forms which can be affected by gastric emptying time. Region-specific and narrow absorption and poor bioavailability of drug promoted the invention of floating drug delivery system. Although the goal remains valuable, the promise of gastric retentive drug delivery systems can be fulfilled in near future. INTRODUCTION Oral ingestion has long been the mos...

Asian Journal of Pharmaceutical and Clinical Research, 2013

The purpose of writing this review was to compile recent literature on pharmaceutical approaches used in enhancing the Gastric residence time (GRT). Enhancing the GRT may explore new potentials of stomach as drug-absorbing organ. Several approaches are currently used including Floating Drug Delivery System (FDDS), swelling and expanding system, polymeric bioadhesive systems, modified-shape systems, high density system and other delayed gastric emptying devices. The drugs having absorption window in the upper part of Gastro Intestinal Tract (GIT) have enhanced bioavailability when formulated through these techniques. The recent technological development for enhancing GRT including the physiological and formulation variables affecting gastric retention, patented delivery systems, approaches to design single-unit and multiple-unit floating systems, and their classification and formulation aspects are covered in detail. In addition this review also summarizes the in vitro and in vivo st...

The gastro retentive drug delivery system is a novel approach for the drugs having narrow absorption window in the gastrointestinal tract and has poor absorption. Gastro retentive drug delivery system mainly prolongs the gastric emptying time, thereby targeting site-specific drug release. Several approaches had been developed such as floating drug delivery system, low density system, raft system, mucoadhesive system, high density system, super porous hydro gel and magnetic system for effecient drug delivery. The physiological problems like short gastric residence time and unpredictable gastric emptying time were overcome with the use of floating dosage forms which provide opportunity for both local and systemic effect. Floating drug delivery system enable prolonged and continuous input of the drug to the upper part of the gastro retentional tract and improve the bioavailability of medication that is characterized by a narrow absorption window.

Controlled release (CR) dosage forms have been extensively used to improve therapy with several important drugs. However, the development processes are faced with several physiological difficulties. Such as the inability to restrain and localize the system within the desired region of the gastrointestinal tract and the highly variable nature of the gastric emptying process. This variability may lead to unpredictable bioavailability and times to achieve peak plasma levels. On the other hand, incorporation of the drug in a controlled release gastroretentive dosage forms (CR-GRDF) which can remain in the gastric region for several hours would significantly prolong the gastric residence time of drugs and improve bioavailability, reduce drug waste, and enhance the solubility of drugs that are less soluble in high pH environment. Gastroretention would also facilitate local drug delivery to the stomach and proximal small intestine. Thus, gastro retention could help to provide greater availability of new products and consequently improved therapeutic activity and substantial benefits to patients. Controlled gastric retention of solid dosage form may be achieved by the mechanisms of floatation, mucoadhesion, sedimentation, expansion or by a modified shaped system. The purpose of this paper is to review the recent literature and current technology used in the development of gastroretentive dosage forms.

Journal of Drug Delivery and Therapeutics, 2014

The purpose of writing this review on gastro retentive drug delivery systems was to compile the recent literature with special focus on floating drug delivery systems (FDDS) to achieve gastric retention. FDDS are of particular interest for drugs that are locally active and have narrow absorption window in stomach or upper small intestine, unstable in the intestinal or colonic environment, and exhibit low solubility at high pH value. It is known that differences in gastric physiology (such as, gastric pH, motility) exhibit both intra as well as inter subject variability demonstrating significant impact on gastric retention time and drug delivery behaviour.Thus, gastroretention helps to increase the gastric residence time and improve absorption of drugs with narrow absorption window. The recent developments of FDDS including the pharmacokinetic and pharmacodynamic aspects affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, advantages and limitations over the conventional drug delivery systems, and their classification and formulation aspects are covered in detail. This review also summarizes the studies to evaluate the performance and application of floating systems, and applications of these systems.

Gastro retentive systems can remain in the gastric region for several hours and hence significantly prolong the gastric residence time of drugs. Prolonged gastric retention improves bioavailability, reduces drug waste, and improves solubility for drugs that are less soluble in a high pH environment. Gastro retentive systems (GRDDS) are designed on the basis of delayed gastric emptying and CR principles, and are intended to restrain and localize the drug delivery device in the stomach or within the upper parts of the small intestine until all the drug is released. Various mechanisms (approaches) of achieving gastric retention include floatation or buoyancy, mucoadhesion, sedimentation, expansion, and geometry. Other approaches include co administration of drugs or fatty acid salts, or sham feeding of indigestible or enzyme-digestible hydrogels that convert the motility pattern of the stomach to a fed state. GRDDS have great potential in improving the bioavailability of drugs that exh...

The purpose of writing the article on gastroretentive drug delivery systems was to compile the recent literature with special focus on various gastroretentive approaches that have recently become leading methodologies in the field of site-specific orally administered controlled release drug delivery. In order to understand various physiological difficulties to achieve gastric retention,In this article we have summarized important factors controlling gastric retention. Gastroretention would also facilitate local drug delivery to the stomach and proximal small intestine. So, gastroretention could help to provide greater availability of new products and consequently improved therapeutic activity and required benefits to patients. Controlled gastric retention of solid dosage form may be achieved by the mechanisms of floatation, mucoadhesion, sedimentation, expansion or by a modified shaped system.