Floating Drug Delivery System: An Overview

In recent years scientific and technological advancements have been made in the research and development of rate-controlled oral drug delivery systems by overcoming physiological adversities, such as short gastric residence times (GRT) and unpredictable gastric emptying times (GET). Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems (FDDS), also known as hydrodynamically balanced systems (HBS), swelling and expanding systems, polymeric bioadhesive systems, modified-shape systems, high-density systems, and other delayed gastric emptying devices. The different strategies used in the development of FDDS by constructing the effervescent and noneffervescent type of floating tablets basis of which is buoyancy mechanism. FDDS is a method to deliver the drugs that are active locally with a narrow absorption window in the upper gastrointestinal tract, unstable in the lower intestinal environment, and possess low solubility with higher pH values. The recent developments in floating drug delivery systems are containing the physiological and formulation variables impacting on gastric retention time, approaches to formulating of single-unit and multiple-unit floating systems, and their classification and formulation aspects are discussed in detail. This review also summarizes evaluation parameters and application of floating drug delivery systems.

Comprehensive review on characterizations and application of gastro-retentive floating drug delivery system

Current pharmaceutical situation focuses on the preparation of gastro-retentive floating drug delivery system (GRFDDS). This systems has gained noteworthy interest in the past decades. These are the low density systems that float over the gastric contents and remain buoyant in the stomach for a prolonged period of time without affecting the gastric emptying rate. GRFDDS is used to delay the residence time of delivery in stomach. The controlled gastric retention of solid dosage forms may be achieved by the mechanism of mucoadhesion, floatation, sedimentation, expansion, modified shape systems or by the administration of pharmacological agents that delaying gastric emptying. This results in targeting of release of drug at a specific site for the systemic or local effects. GRDDS is used to overcome challenges associated with conventional oral dosage forms and to release the drug at a specific absorption site to improve bioavailability of particular drug substance. Some floating drug delivery systems have shown the capability to accommodate these variations without affecting drug release. This review mainly focuses characterizations and application of gastro-retentive floating drug delivery systems.

A Recent Update on Formulation and Development of Gastro-Retentive Drug Delivery Systems

Oral route has been the most convenient and accepted route of drug delivery. Owing to tremendous curative benefits of the oral controlled release dosage forms are being preferred as the interesting topic in pharmaceutical field to achieved improved therapeutics advantages. Gastro retentive drug delivery system is novel drug delivery systems which has an upper hand owing to its ability of prolonged retaining ability in the stomach and thereby increase gastric residence time of drugs and also improves bioavailability of drugs. Concept of novel drug delivery system arose to overcome the certain aspect related to physicochemical properties of drug molecule and the related formulations. In this context, various gastro retentive drug delivery systems have been used to improve the therapeutic efficacy of drugs that have a narrow absorption window, are unstable at alkaline pH, are soluble in acidic conditions, and are active locally in the stomach. Concept of novel drug delivery system arose to overcome the certain aspect related to physicochemical properties of drug molecule and the related formulations. Various approaches are currently used including gastro retentive floating drug delivery systems, swelling and expanding system, polymeric bio adhesive systems, modified shape systems, high density system and other delayed gastric emptying devices. Moreover, future perspectives on this technology are discussed to minimize the gastric emptying rate in both the fasted and fed states. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres. Attempt has been made to summarize important factors controlling gastro retentive drug delivery systems. Overall, this review may inform and guide formulation scientists in designing the gastro retentive drug delivery system.

FLOATING DRUG DELIVERY SYSTEM: A REVIEW

In recent years scientific and technological advancements have been made in the research and development of rate-controlled oral drug delivery systems by overcoming physiological adversities, such as short gastric residence times (GRT) and unpredictable gastric emptying times (GET). Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems (FDDS), also known as hydrodynamically balanced systems (HBS), swelling and expanding systems, polymeric bioadhesive systems, modified-shape systems, high-density systems, and other delayed gastric emptying devices. The different strategies used in the development of FDDS by constructing the effervescent and noneffervescent type of floating tablets basis of which is buoyancy mechanism. FDDS is a method to deliver the drugs that are active locally with a narrow absorption window in the upper gastrointestinal tract, unstable in the lower intestinal environment, and possess low solubility with higher pH values. The recent developments in floating drug delivery systems are containing the physiological and formulation variables impacting on gastric retention time, approaches to formulating of single-unit and multiple-unit floating systems, and their classification and formulation aspects are discussed in detail. This review also summarizes evaluation parameters and application of floating drug delivery systems. Keywords: Floating drug delivery systems (FDDS), Gastric residence time, Swelling index, Buoyancy.

FLOATING TABLETS AND ITS POLYMERS

Oral drug delivery system is the most preferred route of administration for drug delivery. In the development of the drug delivery system many components play important role. Polymers are amongst those components which have evolved with the drug delivery system. Polymers are the macromolecule compound containing many monomer units joined to each other by bonds. The floating drug delivery systems (FDDS) become an additional advantage for drugs that are absorbed primarily in the upper segments of gastrointestinal (GI) tract, i.e., the stomach, duodenum and jejunum. The purpose of writing this review on floating drug delivery systems (FDDS) was to focus on the types of floating drug delivery systems, principal and mechanism of floatation to achieve gastric retention and polymers used in floating Drug delivery systems. Polymers used in the drug delivery system are of two types Natural and Synthetic based on their origin. Both types of the polymers have some advantages and disadvantages. This particular article gives information about the different types of natural and synthetic polymer used in the drug delivery system. Natural polymers like guar gum, chitosan, xanthan gum, Gellan gum and sodium alginate are mentioned in the article. Synthetic polymers mentioned are HPMC, Eudragit, and Ethylcellulose. Keywords: Floating Drug Delivery System, Polymers, Natural gums, HPMC.