OPTIMIZATION OF PLASTICIZERS IN FREE COATING MEMBRANES OF OSMOTIC ACRYLIC RESIN EUDRAGIT RS100

AIM To screen plasticizers type in free controlled release coating membranes of osmotic acrylic resin Eudragit RS100. METHODS The efficiency of plasticizations was evaluated with respect to different types and levels of plasticizers by measuring glass transition temperature and mechanical properties of membranes in the dry and wet state. The leaching of plasticizers in simulated intestinal fluid was investigated by a dissolution method and a horizontal diffusion cell method. The loss of plasticizers was determined by using accelerated tests method. RESULTS The glass transition temperatures of plasticized Eudragit RS100 membranes suggest that Eudragit RS100 has good compatible with plasticizers and that triacetin and dibutyl phthalate have stronger plasticizers efficiency. The mechanical properties of the polymeric membranes before and after hydrated vary markedly. The water-soluble plasticizers leached from the membranes during exposure to the aqueous medium, while the water-insoluble plasticizers were almost completely retained within the wet membranes. The plasticizers amounts in the membranes demonstrated a triacetin loss of 6.46% and a dibutyl phthalate loss of 0.29% from the initial amount added after 40 days in (40±1)℃ and 75% RH conditions. CONCLUSION The water insoluble plasticizers such as dibutyl phthalate are more suitable to Eudragit RS100 controlled released coating membranes.