Phase transition system: novel oral in-situ gel.
Inspite of the various impediments in the bioavailability of orally delivered drugs, oral dosage forms, both solid and liquid, occupy a center stage in the therapeutic regimen of diseases. However, liquid dosage forms are more prone to low bioavailability because of their quick transit from the stomach/ duodenum. This could be a serious problem for drugs, which are absorbed from these sites of the GIT. The gastric retention of an oral liquid formulation could be successfully augmented substantially through a strategy of liquid in-situ gelling system. Natural polymers like alginate, gellan and chitosan can undergo sol to gel transformation in the presence of either divalent cations or due to a change in pH. The gel so formed, being lighter than gastric fluids, floats over the stomach contents and is retained there in for periods upto 24 hours. The in-situ gel formation enhances the local or systemic bioavailability of the administered drug. This concept is a redesign of liquid oral dosage form, which fulfills the requirement for a sustained release liquid preparation. This review discusses the various aspects associated with the in-situ gelling systems and their therapeutic applications.
Nagarwal
Ramesh C
RC
Department of Pharmaceutics, Institute of Technology, Banaras Hindu University Varanasi-221005, India. ramesh_itbhu79@yahoo.co.in
Pandit
J K
JK
D000284:Administration, Oral; D000464:Alginates / Q000008:administration & dosage / Q000737:chemistry; D048271:Chitosan / Q000008:administration & dosage / Q000737:chemistry; D003692:Delayed-Action Preparations; D004058:Diffusion; D005782:Gels; D020723:Glucuronic Acid / Q000008:administration & dosage / Q000737:chemistry; D006603:Hexuronic Acids / Q000008:administration & dosage / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D044367:Phase Transition; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage / Q000737:chemistry; D012995:Solubility; D013696:Temperature; D014783:Viscosity
D000464:Alginates; D003692:Delayed-Action Preparations; D005782:Gels; D006603:Hexuronic Acids; D011135:Polysaccharides, Bacterial; C048288:gellan gum; D020723:Glucuronic Acid; D048271:Chitosan