This project concerns fundamental and strategically important research underlying the development of new drug delivery vehicles. We propose to sample phase diagram of polyelectrolyte polysaccharides, positively charged chitosan and negatively charged heparin, in aqueous solution, with and without added salt. Both bio-macromolecules are promising candidates for delivery of drug molecules to the cell. The long term objective is to study the structural aspects of interaction of supramolecular complexes with model membranes; the present pilot study aims to determine the behaviour of polysaccharides prior to interaction with membranes. The shape of molecules inside supramolecular complexes in dilute solutions will be retrieved using RMC programs, and relevant parameters such as Rg and the correlation length will be interpreted in terms of scaling theory of polyelectrolytes.