Smart biomaterials composed of pH responsive polymers, poly((meth)acrylic acid), were synthesized using a precipitation polymerization technique. The microparticles were graftecl with poly(ethylene glycol) (PEG) chains that are capable of complexing with the hydroxyl groups of the polyacid and interpenetrating into the mucus gel layer upon entry into the small intestine. Upon introduction of an alkaline solution, these materials imbibe a significant amount of water and create a highly viscous suspension. These materials have the necessary physicochernical properties to serve as mucoadhesive controlled release drug carriers for the oral delivery of drugs. (c) 2007 Elsevier Ltd. All rights reserved.