In vitro and In vivo Characterization of Pectin Based In situ Gelling System of Famotidine

In this study famotidine was used as a model drug to formulate and evaluate pH-induced in situ gelling system for oral sustained release drug delivery in stomach which has shorter biological half-life. To study the effect of independent variables 3 full factorial design was employed, concentration of pectin as pH dependant polymer and concentration of calcium chloride on dependent variables like viscosity, drug content, 50% and 80% drug release and similarity factor. It was found that both the concentration of pectin and concentration of calcium chloride had significant effect on viscosity, drug content, 50% and 80% drug release and similarity factor of the system. In vitro drug release study showed that drug released from the in situ gel followed non-Fickian diffusion. Mathematical modeling was employed for quantitative evaluation of the effect of formulation variables. Rat pylorus legation model was used for in vivo study of the selected formulation. Results shows gel formation in gastric juice and reduction in ulcer index. There were few or no major changes in the formulation during three months stability testing. The in situ gelling systems are useful for delivery of famotidine.