Drug targeting to specific organs and tissues is one of the crucial endeavors of modern pharmacotherapy. Controlled targeting at the site of action and reduced time of exposure of nontargeted tissues increase the efficacy of the treatment and reduce toxicity and side effects, improving compliance and convenience. Nanocarriers based on the branched copolymers dextran-graft-polyacrylamide were synthesized and characterized and were tested on phagocytic cells. It was shown that these nanoparticles are actively captured by phagocytic cells and that they are not cytotoxic. The polymer nanoparticles loaded with cisplatin at different concentrations from 0.1 to 10 μg/mL yielded dose-dependent decrease in viability of chronic myelogenous leukemia and histiocytic lymphoma cells. The lowest percentage of viable cells was observed for lymphoma cells (22%). Taking into account the fact that our nanoparticles will act mainly on malignant phagocytic cells and do not affect healthy cells, they can thus potentially be used for the therapeutic treatment of tumor cells having phagocytic activity. The effect of nanosilver on cell viability was lower than the one of polymer/cisplatin composite. The data from the cytotoxic studies indicate that nanosilver induces toxicity in cells. However, when the copolymers were conjugated to both nanosilver and cisplatin, such a nanosystem displayed less cytotoxic effect compared to the conjugates of dextran-polyacrylamide and cisplatin.
Thermal behavior of poly(vinyl alcohol)‐graft‐polyacrylamide copolymers (PVA‐g‐PAA), so‐called intramolecular polymer‐polymer complexes (intraPC), with variable M̄ vPAA and constant average number N of grafts is considered in this report. Complete compatibility of PVA and PAA through hydrogen bonding is realized in the range of the graft lengths not exceeding some critical value. The content of adsorbed and trapped water in graft copolymers reflects some features of PVA‐g‐PAAN structure depending on the graft lengths. The first thermal decomposition region in air for copolymers begins at higher temperatures with growing M̄ vPAA, but the total destruction interval reduces. Formal kinetic decomposition parameters of the first decomposition stage appear to be the largest for the PVA‐g‐PAA with the largest quantity of H‐bonds between the main and graft chains. Chemical transformations in graft copolymers, PVA and PAA during thermal decomposition are discussed.
Structure and properties of polyacrylamide‐grafted silica have been investigated with the help of thermal analysis methods, NMR spectroscopy and by measuring the ability solubilization in benzene when compared with homopolymer polyacrylamide (PAA). More homogeneous structure, low rigidity and density of packing have been revealed for the polymer shell. PAA form a dense polymer shell, which interact with silica surface through H‐bonds. 1H NMR spectroscopy suggests no influence of silica particles on PAA stereoregularity. PAA‐grafted silica considered as a special type of polymer‐colloid complex where polymer chains are covalently bound to silica with one end and polymer segments along the chain are hydrogen bound to the particle surface.
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