In vitro clot formation on the polyelectrolyte complexes of sodium dextran sulfate with chitosan

The solution of charged sodium dextran sulfate (molecular weight 6000) co‐reacted with that of oppositely charged chitosan to form a water‐insoluble hydrous complex, whose clot‐inhibiting property was sensitive to such reaction conditions as the order of mixing, the kind of acid species used for the adjustment of pH, and the concentration of hydrogen ion at which the preparation of polyelectrolyte complex was carried out, although all the polyelectrolyte complexes were prepared from the same starting materials. In order to clarify the relationship between the molecular conformation of the polyelectrolyte complex and its clot‐inhibiting property, ir spectroscopic studies, in vitro blood‐clotting tests, color reaction with toluidine blue, elemental analyses, and so on, were performed. Consequently, it was suggested that the polyelectrolyte complexes consisting of sodium dextran sulfate of lower molecular weight are more clot‐inhibiting than those with higher molecular weight. It was also found that polyelectrolyte complexes prepared under the mixing order of sodium dextran sulfate solution added to chitosan solution are also more clot‐inhibiting than those prepared under the reverse mixing order, chitosan solution added to sodium dextran sulfate solution. Furthermore, it has become apparent that the anticlotting polyelectrolyte complexes have some characteristic ir absorption bands, and that they displayed color reaction with toluidine blue. A new possibility may be anticipated from our experimental results, providing important information relating to realizing a functional polymer, antithrombogenic material, whose property may be ordered.