Dynamic release of riboflavin from ethyl cellulose coated barium alginate beads for gastrointestinal drug delivery:: An in vitro study

The present work describes the dynamic release of model drug riboflavin form uncoated and ethyl cellulose coated barium alginate beads in the media of continuous varying pH at the physiological temperature 37 degrees C The drug release behavior has been studied in the simulating gastric fluid (SGF, pH 1.2)for 0-2 h and then in the simulating intestinal fluid (SIF pH 6.8) for 2-48 h. In addition to the traditional dissolution test (TDT, the dynamic release has also been studied by a newly developed method, called flow through diffusion cell' (FTDC). The release profiles, obtained by using these two methods have been found to differ appreciably from each other. Moreover, the nature of the solid mass surrounding the beads in the FTDC method also influences the release behavior of beads. The uncoated beads demonstrated faster drug release of drug in the medium of lower pH (i.e., 1.2) as compared to that in the medium of pH 6.8 and the release process was found to be diffusion controlled.