Behavior of a Chitosan–Drug System during Diffusion Processes

The process of water vapor sorption by medical chitosan films and the release of nonelectrolyte drugs from these films are investigated. It is shown that the nonelectrolyte drugs are unable to modify the chitosan matrix and cannot provide a prolonged drug release. The modification of chitosan–drug films, for example, by isothermal annealing or transition from the salt form of chitosan to the base one, is required to decelerate the release of drugs from the films.