ERODIBLE PERFORATED COATED MATRIX FOR EXTENDED RELEASE OF DRUGS

A new oral modified release system exibiting an in vitro constant rele ase rate has been designed and prepared. The system consists of an ero dible matrix core with a central hole and is partially covered with an impermeable polymeric film. The perforated core is made of a low visc osity hydroxypropylmethylcellulose (HPMC); metoprolol tartrate and ben fluorex were used as model drugs. The inner hole surface is the only r eleasing surface of the system. This system can be prepared by using b oth conventional tabletting and film coating processes.