Gellan for the formulation of sustained delivery beads

Gellan beads containing a model molecule, clay, and in most cases oil and a surfactant were prepared. The release from the obtained beads was studied in vitro with different techniques and the effects of the presence of varying amounts of oil in the formulation was investigated. The behaviour of gellan was compared with that of alginate in the same experimental conditions. The results indicate that gellan is suitable for the formulation of sustained release beads and that, for the tested preparations, the presence of oil results in a marked reduction in delivery rate. From release experiments, carried out with the various formulations and with different concentrations of the substances used as models, it can be suggested that the swelling of the matrix seems to be the most likely factor responsible for the overall rate of delivery.