Potential of low molecular weight natural polysaccharides for colon targeted formulation and its evaluation in human by Gamma Scintigraphy

Abstract

Colonic drug targeting is an elusive goal, implicated for localized drug and systemic delivery of proteins which otherwise cannot be delivered by oral route. The purpose of the present work was to evaluate the suitability of formulation design of compression coating and potential of low molecular weight natural polysaccharides for colonic drug targeting using Gamma Scintigraphy in human subjects and to establish platform technology. Before commencing with in vivo imaging studies in human by Gamma Scintigraphy, we performed in vitro release studies and scanning electron microscopy for surface topography of tablet formulations subjected to in vitro dissolution study. We investigated the applicability of low molecular weight and low viscosity grade Guar gum ULV 1000 and Pectin with low degree of methoxylation 9% as for site specific delivery. Gamma Scintigraphy imaging of formulation with biopolymer in human subject showed the transit of tablet intact in colon with average arrival time being 5.75 h and the activity was released continuously for 30 h. Scanning electron microscopy for surface topography of tablets subjected to simulated colonic fluid showed erosion caused by microbial flora of the colon. Taken together, compression coating design with low molecular weight biopolymer can serve as a platform technology to deliver other potential molecules to the colonic region for local and/or systemic effects in other therapeutic areas.