Effect of proteolytic enzymes in gastrointestinal fluids on drug release from polyelectrolyte complex microspheres based on partially phosphorylated chitosan

This study investigated the effect of proteolytic enzymes on in vitro release of ibuprofen from phosphorylated chitosan (PCS) microspheres in simulated gastric fluid (SGF) (pH 1.4) and simulated intestinal fluid (SIF) (pH 7.4). To reduce the enzymatic degradability and to enhance the sustained release property, polyelectrolyte complex microspheres based on PCS were developed and characterized. The ibuprofen release from PCS microspheres was found to be sustained more effectively than that from CS microspheres in the medium containing proteolytic enzymes. It was concluded that the PCS microspheres can be used more successfully as sustained oral drug-delivery vehicles than CS microspheres due to their lesser enzymatic degradability. (C) 2004 Society of Chemical Industry.