An overview on various types of gastroretentive drug delivery system

Polymeric Excipients in the Technology of Floating Drug Delivery Systems

“…NA is a heteropolymer formed by polyuronic acid residues of G-fragments (α-l-guluronic acid residue) and M-fragments (β-d-mannuronic acid residue) [13,19,20]. This polysaccharide slowly dissolves in water with the formation of a viscous colloidal solution (viscosity of a 1% solution is 20-400 cP at 20 • C), is practically insoluble in solutions with a pH below 3, and has bioadhesive properties [1][2][3]19,21]. In FDF technology, it can be used as a matrix-forming substance; in addition, NA reacts with salts of Ca 2+ and other metals, forming water-insoluble gels with a network structure, capable of adsorption and delayed release of API [13].…”

“…This galactomannan is soluble in water; when it enters cold or hot water, it immediately swells, forming a highly viscous, thixotropic sol; a 1% solution has a pH of the medium of 5.0-7.0 and a dynamic viscosity of 4860 cP; the dry substance has a density of 1.492 g/cm 3 [19]. In the technology for the production of FDF, guar gum is used as a matrix-forming agent and retardant, as well as to provide mucoadhesion, moreover, due to significant swelling in water, the polymer can both reduce the density of the DF and provide an increase in its size to prevent removal from the stomach [13,19,21].…”

“…In the FDF application technology, it is used as a matrix-forming agent, as well as an agent providing mucoadhesion [2,3,19]. A matrix based on high-viscosity hypromellose grades is able to retain CO 2 released during the reaction of a gas-forming mixture, and also swells significantly upon contact with a liquid, which is used in the production of non-gas-forming FDFs and gastroretentive delivery systems that increase in size [1][2][3]21].…”

“…NaCMC is the sodium salt of polycarboxymethyl cellulose ether [19]. Carmellose sodium is a water-soluble polymer capable of absorbing significant amounts of water and acting as a gelling agent with a high swelling index, the viscosity of 1% aqueous solutions varies from 5 to 20,000 cP depending on the brand, the bulk density, and after compaction is 0.52 and 0.78 g/cm 3 [19,21]. In the technology of gastroretentive systems, this explosive is used in the composition of matrices and ensures the rapid formation of a gel layer on the surface of the system and a significant increase in DF in size.…”

“…These polymers swell significantly in water and glycerin, but do not dissolve, since they are three-dimensionally cross-linked microgels, in addition, they have low bulk density and density after compaction: 0.2-0.4 g/cm 3 and 0.3-0.4 g/cm 3 , respectively [19]. In the technology of obtaining floating delivery systems, they are used as matrix formers and low-density Es, and are also used to impart mucoadhesive properties to DF and a significant increase in size [1][2][3]21,75,76].…”