Biocompatible Gel-like Forms of Drugs on the Basis of Solutions of Polysaccharide Chitosan with Alcohols

We propose an approach to the preparation of viscoelastic systems based on chitosan without crosslinking agents. It is the formation of an additional network of physical links by introducing a low molecular weight modifier – ethanol or glycerol. It turns out that gelation of chitosan in the solution is accompanied by the formation of additional meshes of physical links, nodes or aggregates of chitosan macromolecules formed in a mixed solvent of acetic acid-water-glycerol or acetic acid-water-ethanol. It promotes an earlier formation of viscoelastic properties, which eventually leads to gelation at lower polymer concentrations than in the case of chitosan solutions without alcohol additives. The resulted gelled systems are characterized by good biocompatibility, and therefore can be used as polymeric forms of drugs.