Synthesis and properties of polyvinylpyrrolidone films containing iron nitrosyl complexes as nitric oxide (NO) donors with antitumor and antiseptic activities

New homogeneous water-soluble polyvinylpyrrolidone composites containing iron sulfur nitrosyl complexes as nitric oxide donors with antitumor and antiseptic activities were synthesized. The morphology of the composites in the solid state was examined by X-ray diffraction and scanning electron microscopy. The study by small-angle X-ray scattering showed that samples of the composites do not contain 10–100-nm aggregates and that iron sulfur nitrosyl complexes are uniformly distributed in polymer matrices. The percentage of NO-releasing iron sulfur nitrosyl complexes in the composites was determined by ESR spectroscopy. An amperometric analysis demonstrated that the polymer composites decompose to yield NO within a few seconds after the dissolution in water without additional thermal and photoactivation. The dependences of the amount of NO and the maximum level of NO release on the duration of the storage of aqueous solutions for all of the synthesized films were determined at pH 7.0. Some of the synthesized polymer composites retain NO-donor activity of the starting pharmacologically active iron nitrosyl complexes and can be recommended to be used as targeted delivery systems of this class of compounds to biological targets.