An amidic derivative of carboxymethylcellulose was synthesized (CMCA). The new polysaccharide was obtained by converting a large percentage of carboxylic groups (*50%) of carboxymethylcellulose into amidic groups rendering the macromolecule quite similar to hyaluronan. Then, the polysaccharide (CMCA) was crosslinked. The behavior of CMCA hydrogel towards normal human articular chondrocytes (NHAC) was in vitro studied monitoring the cell proliferation and synthesis of extra cellular matrix (ECM) components and compared with a hyaluronan based hydrogel (Hyal). An extracellular matrix rich in cartilage- specific collagen and proteoglycans was secreted in the presence of hydrogels. The injectability of the new hydrogels was also analysed. An ex...