Present work concerned with development and evaluation of an innovative drug carrier, as smart drug delivery system for highly acid labile drug. Free radical polymerization technique was employed to develop pH sensitive drug delivery system by using carboxymethyl cellulose (polymer), methacrylic acid (monomer), potassium persulfate (initiator) and N,N methylene bisacrylamide (crosslinker). Prepared crosslinked polymer was characterized by swelling analysis at acidic and basic pH to evaluate pH responsive swelling, instrumental analysis (SEM, FIIR and thermal analysis) and pH responsive release of model drug rabeprazole sodium. Characterization of smart drug delivery concluded that pH responsive swelling and drug release parameters were directly related with methacrylic acid concentration in the crosslinked polymer. It was observed that by raising methacrylic acid contents swelling at basic pH enhanced and crosslinker contents increment reduce swelling. Among nine formulations with varying formulation contents, CMA2 exhibited more pH sensitive swelling and cumulative drug release at alkaline pH. Results of investigation recommended that CMA2 can be a best crosslinked polymer as smart drug carrier.