Synthesis of Ca+2-Al+3-xanthan biopolymer particles and evaluation of in vitro protein release behaviors

In this work, a hydrogelation method was used for the development of protein-loaded xanthan biopolymer particles. The gelation of the aqueous polymer droplets was accomplished in a mixture of calcium chloride and aluminium chloride solution. The particles were less than 900 μm in diameter and appeared spherical under scanning electron microscope. The particles retained a maximum of 90% of its initial load and released the protein molecules over an extended period in phosphate buffer saline solution (pH 7.4). The protein release was <13% in acidic medium (pH 1.2). The protein release was interrelated with pH-dependent swelling of the particles. The polymer relaxation phenomenon predominated over simple diffusion mechanism in anomalous protein release process as the ratio of di- and trivalent metal ions was decreased. No protein-biopolymer interaction was evident by FTIR spectroscopy. The divalent and trivalent metal ion cross-linked xanthan particles showed immense potential in controlled oral delivery of macromolecules.