Classification

Scientific and technological developments in the research and development of new drug delivery systems have been made in recent years by resolving physiological disorders, such as short gastric residence periods and unpredictable gastric emptying times. Dosage forms that can be hold within the stomach are called as Gastro-retentive Dosage Forms (GRDF). Multiple methods used in the prolongation of gastric residence time are floating drug delivery system, swelling and expanding system, polymeric bio-adhesive system, high density system and other delayed gastric emptying system. Medication-based disease treatment is entering a new era in which a increasing range of innovative drug delivery technologies are being used and are available for clinical use. Floating Drug Delivery Systems (FDDS) is one of the gastro-retentive dosage forms used to achieve extended duration of gastric residency. The aim of writing this review on floating drug delivery systems (FDDS) was to compile the recent literature with particular focus on the main floating mechanism to achieve gastric retention. Sustained oral release of gastrointestinal dosage types provides many benefits for drugs with absorption from the upper sections of the gastrointestinal tract and those that function locally throughout the stomach. This review includes the physiology, factors controlling gastric retention time, excipient variables influencing gastric retention, approaches to designing single-unit, hydro-dynamically balanced system and multi-unit floating structure, and aspects of their classification, formulation and evaluation are discussed in detail, and few applications of these systems.

Hydrogels are three-dimensional, hydrophilic & polymeric networks capable of absorbing large amounts of water or biological fluids. Due to their high water content, porosity & soft consistency, they closely simulate natural living tissues, more so than any other class of synthetic biomaterials. Hydrogels can be formulated in a variety of physical forms, including slabs, micro-particles, Nano-particles, coatings and films. As a result, hydrogels are commonly used in clinical practice & medicine for a wide range of applications, including Tissue engineering & Regenerative medicine, Diagnostics, Cellular immobilization, separation of biomolecules or cells, & barrier materials to regulate biological adhesions. Hydrogels are also relatively deformable & can conform to the shape of the surface to which they are applied. In the latter context, the bioadhesive properties of some hydrogels can be advantageous in immobilizing them at the site of application or in applying them on surfaces that aren’t horizontal. They have started to create a niche in several fields of medicine like in specific site drug delivery, tissue reconstruction & tissue engineering and even as biosensors. In this review article an attempt has been made to explain the properties of hydrogels, their methods of preparation & its applications.