Platinum Nanoparticles in Aqueous Solutions of a Chitosan–Vinylpyrrolidone Copolymer: Synthesis and Biological Activity

Grafted copolymers of chitosan–vinylpyrrolidone, water-soluble at a pH of 6.8–7.5, were obtained. A technique has been developed for obtaining an aggregatively stable system of platinum nanoparticles in copolymer solutions with an average size of ~4 nm. The thermophysical and structural characteristics of the powdered composition of a platinum nanoparticle-copolymer are investigated. An in vitro comparison of the antitumor activity of solutions of the developed composition and cisplatin at the same platinum concentration was performed. It was found that with respect to the culture of HeLa Kyoto and A431 cancer cells, the composition is five and two times less effective than cisplatin, respectively. Along with this, the biocompatibility of the composition is 17 times higher than that of cisplatin, which allows its use at elevated concentrations and the development of an antitumor agent with platinum nanoparticles commensurate in effectiveness with cisplatin.