Design and development of multi-component polymer materials for controlled drug release has become a subject of great interests [1].In this work,a new semi-IPN hydrogel composed of carboxymethyl cellulose-g-poly(acrylic acid)/polyvinylpyrrolidone (CMC-g-PAA/PVP) was synthesized by solution polymerization as a carrierfor diclofenac sodium (DS) [2].However,results showed burst DS release from CMC-g-PAA/PVP hydrogels at pH 6.8.It is known that sodium alginate (SA) can form a reticulated structure in the presence of Ca2+.