Synthesis and Characterization of Chemically Modified Hyaluronan and Chondroitin Sulfate

Glycosaminoglycans (GAGs) occur in many tissues. There is increasing evidence that the sulfation of GAGs does not occur at random, but a “sulfation code” exists that mediates the physiological functions of GAGs. Therefore, certain GAGs might also have interesting pharmacological properties. We will give here an overview on chemical functionalization strategies of hyaluronan (HA) and chondroitin/ dermatan sulfate (CS/DS). This is a challenging task from the synthetic as well as analytical viewpoint because both, regioselective GAG modifications with defined molecular weights and methods to unequivocally characterize the structures of the modified GAGs must be adapted and/or developed. Consequently, in the last part of this review, methods of GAG characterization will be introduced and their capabilities and limitations discussed. Keywords: Glycosaminoglycans, chondroitin sulfate, dermatan sulfate, hyaluronan, chemical functionalization, mass spectrometry, NMR spectroscopy, chromatography