Oral absorption of riboflavin dosed by a floating multiple-unit system in different feeding conditions

An air compartment multiple-unit system composed of a calcium alginate core separated by an air compartment from a calcium alginate/PVA membrane has shown excellent in vivo buoyancy ability and prolonged gastric residence time (GRT) in previous published works. In the present investigation, the floating system was loaded with riboflavin-5'-phosphate (FMN), mainly absorbed in the upper region of the small intestine, assayed in humans for riboflavin pharmacokinetics under different feeding conditions and compared with a non-floating system. The cumulative urinary excretion within 24 h resulted in generally higher by dosing FMN through the floating system under all feeding protocols. The highest values were observed when meals followed dosing (succession of meals protocol), though there was a certain variability between the subjects; the highest reproducibility among the subjects was achieved with dosing of the drug after a substantial meal (lunch protocol).