Air compartment multiple-unit system for prolonged gastric residence. Part II. In vivo evaluation

The intragastric behaviour of a floating multiple-unit system was assayed in humans. The floating units used in this study, composed of a calcium alginate core separated by an air compartment from a calcium alginate/polyvinylalcohol membrane, had shown an excellent buoyancy ability in the previous in vitro investigation. The present in vivo study was conducted in three different sessions (fasted state, fed state after a meal and fed state after a succession of meals) by administering to each subject at the same time both floating and control systems, loaded with barium sulfate, and monitoring them in the gastric region at determined time intervals using X-ray apparatus. Unlike the control, the floating system remained buoyant on the gastric content under both fasted and fed stales. In the fasted state, the intragastric buoyancy of the system did not influence its gastric residence time (GRT). In the fed state after a meal, all the floating units showed a floating time (FT) of about 5 h and a GRT prolonged by about 2 h over the control. In the fed state after a succession of meals, most of the floating units showed a FT of about 6 h and a GRT prolonged by about 9 h over the control, though a certain variability of the data owing to mixing with heavy solid food ingested after the dosing was observed. (C) 1998 Elsevier Science B.V. All rights reserved.