Effect of biopolymers composition on release profile of iron(II) fumarate from chitosan-alginate microparticles

Microencapsulation using biopolymers is considered as a proper method for protecting the iron from oxidation reaction, inhibitors (fitat, tannin) and competitors (divalent metal). Chitosan and alginate are carbohydrate biopolymers commonly used in food and drug application. In order to have a carrier that can send iron to the small intestine which has a high pH, but previously had to survive through the stomach which has gastric acid, the composition of chitosan-alginate as a carrier must be investigated. The objectives in this work were to investigate the effect of both chitosan and alginate concentrations on release profile of iron(II) fumarate in simulated gastric acid and intestinal fluids and its physicochemical property. The microparticles were prepared by dropping chitosan-iron solution into sodium tripolyphosphate solution as crosslinking agent. The electrostatic complexation was formed when the chitosan microparticles were mixed with alginate solution and followed with calcium chloride solution for ionotropic gelation to form chitosan-alginate-iron microparticles. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to describe polyelectrolyte properties of microparticles. The results showed that suitable compositions of chitosan-alginate have successfully improved the pH-sensitivity of the microparticles, thus the iron release was sustained in simulated gastric fluid (pH 1.2), while the release in simulated intestinal fluid (pH 7.4) extended. The release profile of iron from the chitosan-alginate microparticle indicated the effect of alginate on the release of iron. The existence of the polyelectrolyte complex of chitosan-alginate was proven by the appearance of certain functional groups at FTIR spectrum and surface images of iron loaded microparticles from SEM.