In vivo investigation of an intragastric floating multi-unit system

Oral floating devices are made to be retained in the stomach for a long time assuring a slow delivery of the drug above its absorption site providing increased and more reproducible bioavailability.An air compartment multiple-unit system able to float immediately on being placed into artificial gastric fluid and obtainable by a simple technological approach was developed. The designed units are constituted by coated beads composed of a calcium alginate core separated by an air compartment from a calcium alginate/polyvinylalcohol membrane .The “in vivo” assay demonstrated the actual floatability of the units on the gastric content and a prolongation of the gastric residence time (GRT) in comparison with non floating units in different feeding conditions .In the present study, the floating system was loaded with riboflavin-5’-phosphate having absorption sites which are mainly limited to the upper region of the small intestine.The “in vivo” study was carried out by administering to healthy subjects floating and control systems according to a randomized crossover design on different separate sessions.Riboflavin urinary excretion values among subjects alternatively fed after a light meal or after a heavy meal were measured for 24 h.Riboflavin cumulative urinary excretion data, indicative of bioavailability values, were statistically analized by the one-way ANOVA method. The values estimated for the floating system resulted higher than those for the control system, with a more significant difference if formulations with similar “in vitro” release patterns were considered.This finding may suggest the possibility to achieve increased bioavailability by dosing riboflavin through a floating system.