The use of delivery systems to deliver therapeutic agents is a strategy used to enhance drug stability, reduce side effects, and target specific sites. The work presented will focus on the use of chitosan nanoparticles for cancer therapy and tissue regeneration. Optimised pegylation and the incorporation of a targeting ligand allows formation of nano-sized particles with a near-neutral charge. In vitro evaluation demonstrates the therapeutic capacity of these passive and active targeting particles. Challenges and pitfalls in characterisation of the delivery systems; the effect of the release media; and the method of evaluating release of therapeutic agents will also be highlighted.