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Simultaneous administration of a copolymer of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine and cytostatic agents to mice with a variety of implanted tumors was found to increase treatment efficacy, promoting increases in survival time. This effect is of interest for further studies of the possible use of copolymer as an immunomodulator in chemotherapy.

Aseries of N-oxides of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers with various degrees of oxidation were prepared via oxidation of the copolymers by peracetic acid. The N-oxidation kinetic rate constants were calculated using UV spectrophotometry. The temperature dependence of the limiting N-oxidation was determined. The molecular-weight characteristics of the N-oxidized copolymers were established using 13C NMR methods. An approach based on direct UV spectrophotometry was proposed for practical monitoring of the reaction completion (degree of conversion).

Aqueous solutions of three samples of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers with different ratios of monomer units were studied by spectrophotometry. Concentration dependences of the solution optical density at 269 nm were obtained. Specific absorption coefficients of these solutions were calculated. Regions of pH and temperature with the most consistent determinations were found. The results could provide a basis for developing a quantitative determination method for N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers in aqueous solutions.

Techniques for quantitative determination of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers in aqueous solutions were developed. The spectrophotometric technique allowed the copolymer concentration in dilute solutions (0.8 – 1.2 mg/mL) to be determined even in the presence of the interfering additive merthiolate. The refractometric technique was simpler and allowed the copolymer concentration in concentrated solutions (> 1 mass%) to be determined.

The water solubility of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers with various monomer ratios was investigated. Aqueous solutions of the copolymers had low critical mixing temperatures. The water solubility of the copolymers decreased with increasing pH and concentration of 2-methyl-2-vinylpyridine monomers. Correlation dependences for predicting the concentration and pH range of the homogeneous solution at a given mixing temperature were determined. The results were useful for creating injection-ready drug forms based on N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers.

A copolymer of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine was shown to increase the phagocytic activity of macrophages. A tendency of the fraction of phagocytic cells, the phagocytic index, and the index of phagocytosis completeness to increase was observed after its administration.