Calcium alginate microparticles alone are not suitable for sustained oral drug delivery applications. They rapidly disintegrate in weakly alkaline conditions of intestinal fluid and liberate their content. Herein, sodium alginate was chemically modified to circumvent this problem. The oxidation of the polymer was controlled such that oxidized alginate could form microparticles by ionic gelation with divalent Ca+2 ions. Oxidized polymer was characterized by measuring the aldehyde content, degree of oxidation and by FTIR spectroscopy. Spherical oxidized alginate particles were able to control...