Functionalization of Cationic Polymers for Drug Delivery Applications

Cationic polymers have attracted tremendous attention in recent years as non-viral vectors in gene delivery, owing to their high cellular uptake efficiency, good water solubility, excellent transfection efficiencies and facile synthesis. These polymers also show great potential for drug delivery applications, as their structure can be easily tailored to meet our growing understanding of the biological processes that govern biodistribution and biocompatibility of the carrier molecules. The incorporation of peptides, dyes or drug molecules into polymeric macromolecules has led to a synergistic combination of properties, improving the effectiveness of cationic polymers in biological applications even further. The numerous functionalization strategies, which have been developed in order to achieve this goal, are the centre of attention of this chapter. We focus on the most prominent cationic polymers and types of modification that have found applications in drug delivery, rather than trying to include all existing examples. We also describe the intrinsic functional groups of cationic polymers, which are available for further derivatization, as well as the conjugation chemistry that can be applied for the attachment of therapeutic molecules.