Investigations on drug release systems using CMC crosslinked with ferric ions

A drug delivery system with controlled release capability was developed by crosslinking carboxymethylcellulose with ferric ions. Erythromycin was used as model drug throughout the research. It was aimed to transport model drug through gastro intestinal track with minimal release up to intestines. Different techniques were applied to obtain a suitable delivery system and finally minimal release (10% of the total) in stomach (simulated by pH 2.0) and a high release (90% of the total) in intestinal systems (simulated by pH 7.5) was obtained by applying a combination of wet and dry coating, drying and secondary crosslinking.