Chitosan-dextran sulfate nanoparticles for delivery of an anti-angiogenesis peptide

A novel nanoparticle delivery system has been developed by employing the oppositely charged polymers chitosan (CS) and dextran sulfate (DS), and a simple coacervation process. Under the conditions investigated, the weight ratio of the two polymers is identified as a determining factor controlling particle size, surface charge, entrapment efficiency and release characteristics of the nanoparticles produced. Particles of 223 nm mean diameter were produced under optimal conditions with a zeta potential of approximately -32.6 mV. A maximum of 75% anti-angiogenesis peptide entrapment efficiency was achieved with a CS:DS weight ratio of 0.59:1. The same nanoparticle formulation also showed slow and sustained peptide release over a period of 6 days. In contrast, the formulation containing a lower ratio of CS:DS (0.5:1) was found to have reduced entrapment efficiency and more rapid peptide release characteristics. The results of this study suggest that physicochemical and release characteristics of the CS-DS nanoparticles can be modulated by changing ratios of two ionic polymers. The novel CS-DS nanoparticles. prepared by the coacervation process have potential as a carrier for small peptides.