The preparation and release performances of a novel colon-specific protein drug delivery system

In order to develop a novel carrier for the oral colon-specific drug delivery system, a microcapsule composed of chitosan, sodium cellulose sulfate (NaCS) and sodium tripolyphosphate(TPP) was prepared by reaction in aqueous phase. The microscope and SEM observation results show that the microcapsules are in the same size and in spherical form. In vitro protein drug release studies, three kinds of simulated fluids, i.e. simulated gastric fluid (SGF), simulated small intestinal fluid (SIF) and simulated colonic fluid (SCF), were used to evaluate the effects of preparation parameters and delivery conditions on the release performance, especially the effects of drying methods and protein kinds. The results indicate that the microcapsule carrying lactoferrin (LF) dried by critical point drying method shows the best release performance. Less than 20% of LF is released after staying in the SGF and SIF for 5 hours, and then more than 80% of LF is released in the SCF for next 4 hours. The experiments results suggest that chitosan/NaCS/TPP microcapsule is a promising system for protein drug colon-specific delivery.