Chitosan is α (1 → 4) 2-amino 2-deoxy β-D-glucan, having structural characteristics similar to glycosaminoglycans (Figure 1-1). This polycationic biopolymer is generally obtained by alkaline deacetylation at 120°C for 1-3h from chitin, which is the main component of the exoskeleton of crustaceans, such as shrimps [1]. The physicochemical and biological properties of chitosan led to the recognition of this polymer as a promising material for drug delivery applications. It is extremely important that chitosan be hydrosoluble and positively charged. This property enables it to interact with negatively charged polymers, macromolecules and polyanions on contact in an aqueous environment. It has...