SUSTAINED-RELEASE OF FERROUS SULFATE FROM POLYMER-COATED GUM ARABICA PELLETS

Sustained release of ferrous sulfate (FeSO4) from gum arabica pellets has been achieved for 7 h. Release is further sustained for 12 to 600 h by coating the pellets with polyvinyl acetate and ethylene vinyl ace tate, respectively. An increase in the amount of gum arabica in the pe llets decreases the rate of release due to the gelling property of gum arabica. The gel layer acts as a barrier and retards the rate of diff usin of FeSO4 through the pellet. In coated pellets, an increase in th ickness of membrane helps to sustain the release of FeSO4 for a longer duration. Thus, the release of FeSO4 can be sustained for the require d duration by adjusting the amount of gum arabica in the pellet and th e composition and thickness of polymeric coat. The mechanism of releas e accordingly varies from Fickian to zero-order and super case II tran sport.