D-INDOBUFEN EXTENDED-RELEASE PELLETS PREPARED BY COATING WITH AQUEOUS POLYMER DISPERSIONS

A multiple units dosage form has been prepared in order to control the release of d-Indobufen, a carboxylic acid used as an inhibitor of platelet aggregation. The system consists of cores containing the active substance coated with a diffusive film and represents a classic ''reservoir'' system. Extrusion-spheronization was used in order to prepare the active cores. The drug release control was obtained by modifying both the core composition and the film composition characteristics. Acid and basic compounds were incorporated in the core to influence the inside microenvironment pH. Polymers chosen for the film formulation were: ethylcellulose (Aquacoat) and copolymers of acrylic esters with differing permeability characteristics (Eudragit RL/RS 30D). Technological and physical characteristics of coated pellets proved the production feasibility of an extended release multiple unit dosage form of d-Indobufen. Preliminary data of accelerated stability indicated the important role played by the thermal treatment of polymer membrane after the coating process.