These experiments are part of a much broader programme at the University of Reading. focused on the use of water-soluble half-acetylated chitosan as a mucoadhesive polymer, excipient for tableting and vector for gene delivery. The neutron scattering experiments are focused on the study of gels formed in water containing a systematic series of partially-acetylated chitosan. We will use deuterated water as the swellant. The level of deacetylation determines the solubility of the polymer and the level of crystallinity present. The latter drops quickley with increasing levels of deacetylation. The availability of different levels of deacetylation will allow the structure of the gels to be studied in some detail. The results will enable systems most suited for use as pharmaceutical media to be identified.