Absorption of bacterially-synthesized folate across the large intestine pre-trial i and ii: in-vivo behaviour of placebo caplets with ph-sensitive coatings designed for colon targeting

Abstract

The purpose of this study was to design and test the effectiveness of two pH- dependent coatings in delivering intact barium sulfate caplets to the large intestine. In the future, this work will enable us to non-invasively assess the absorption of folate across the human colon. Barium sulphate caplet cores were coated with Eudragit L100 and S100, in either a 1:0 or 3:1 ratio. Each formulation was administered to ten volunteers, and monitored in-vivo via fluoroscopy. Test caplets with 3:1 coating formulations had 40% higher colon-targeting specificity compared to 1:0 caplets, and tended to begin dissolving at a later time after administration (p=0.09). The total time from administration to complete dissolution was also significantly longer for 3:1 coated caplets (p=0.003). These results suggest that barium sulphate caplets with a 3:1 (Eudragit L100:S100) coating formulation ratio would be a suitable delivery system for investigating the absorption of folate across the large intestine.