Preparation And Release Performances Of The Chitosan/NaCS/TPP Protein Drug Microcapsule

In order to develop a novel kind of carrier for the oral colon-specific drug delivery system, the microcapsule, which was composed of chitosan, sodium cellulose sulfate (NaCS) and sodium tripolyphosphate(TPP), was prepared by reaction in aqueous phase. Two kinds of applied widely proteins, BSA and LF were chosen as model drugs.Firstly, the microcapsule"s physical personalities were measured. The microscope and SEM observation results showed that the microcapsules were in the same size and in spherical form, and reaction time was30min. the diameter of microcapsule drying by critical point method was about1mm and the freeze drying one was about2mm. FTIR results showed the reaction mechanism. The drug loading capacity (DLC) and encapsulation efficiency (EE) was determined by UV spectrophotometer method. The molecular weight cut-off (MwCO) of the microcapsules was determined by exposing the microcapsules to the cell lysate. The microcapsule in nanometer size was prepared, and the mean diameter was about550nm.Secondly, 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 of drying methods and protein kinds. The results indicated that the microcapsule carrying lactoferrin (LF) dried by critical point drying method showed the best release performance and critical point drying was a better choice. At25℃, Mw31.9kDa NaCS and Mwll8kDa chitosan were conducive to the release of BSA. And improving the ratio of chitosan and TPP would help avoid acidic corrosion.The experiments results suggested that chitosan/NaCS/TPP microcapsule was a promising system for protein drug colon-specific delivery.