The hollow core-shell ferric oxide entrapped chitosan microcapsules as phosphate binders for phosphorus removal in vitro

Patients in hyperphosphatemia are orally prescribed with phosphate binders to excrete the non-metabolic phosphorus. Aiming for the bio-compatibility and binding efficacy, the Fe-based phosphate binders of low toxicity have been explored and improved. Herein, the hollow core-shell microcapsules as [email protected] (nano ferric oxide entrapped in the polymerized chitosan) were constructed via emulsion interface polymerization, to enhance the phosphate binding from -NH2 group and iron complex, and limit iron leakage significantly. Via the double emulsion polymerization based on the primary Pickering emulsion stabilized by oleic acid-modified ferric oxide, [email protected] performed as the rough polymerized-chitosan microcapsules entrapping well-distributed ferric oxide for the phosphate adsorption in vitro. At pH 3 and pH 5, [email protected] bound phosphorus efficiently, with the capacity of 55 mg/g and 65 mg/g respectively, along with the excellent shell isolation from iron leakage and remarkable safety. Prospectively, the [email protected] micro-sorbent is the proper candidate as the phosphate binder for hyperphosphatemia.