[Biospecific properties of lysine-contained polyelectrolyte coatings for devices contacting blood].

Biospecific properties of thromboresistant bilayer and multilayer coatings based on polyelectrolyte complexes of modified copolymer of N-vinylpyrrolidone and maleic acid (VPMA) with chitosan, amphiphilic chitosan or albumin were investigated. VPMA contained affinity ligand towards plasminogen--alpha-amino coupled lysine residues. Polyethylene and polystyrene surfaces were investigated before and after their covering by protective polyelectrolyte coatings. The specific adsorption of plasminogen (precursor of the fibrinolytic enzyme plasmin) from its solutions and from human plasma was investigated using these model systems. It was found that all coatings with the outer contact lay of lysine-contained affinity polymer had affinity to plasminogen. But multilayer polyelectrolyte coatings were more efficient than bilayer coatings with single application of layers and the affinity polymer coatings without interlayer. The decrease in trombogenicity degree of the materials modified by polyelectrolyte coatings was shown in vitro and ex vivo. Emplyment of proposed modification of surfaces will improve hemocompatibility of medical devices.

[New liposomal forms of antifungal antibiotics, modified by amphiphilic polymers].

A method has been developed, for incorporating macrocyclic polyene antibiotics nistatin and amphotericin B into liposomes containing phosphatidylcholine and cholesterol (7:3) or phosphatidylcholine, cholesterol, and cardiolipin (7:3:1), the membranes of which were modified with an amphiphilic polymer of N-vinylpyrrolidone, carrying one terminal n-octadecyl group and having a molecular weight of 4000 Da. The amount of antibiotics within such liposomal nanocarriers may be as high as 17-22%. It was demonstrated that the modified liposomes have sizes in the range 150-200 nm and exhibit increased long-term storage stability and increased resistance to disrupting agents (Triton X-100 or ethanol) and ultrasound. The antifungal activity of the liposomal preparations obtained exceeded that of the antibiotics not subjected to immobilization.

[Sorption of wheat seed lectin by polyelectrolyte complexes of chitosan]. / Sorbtsiia lektina zarodyshei pshenitsy poliélektrolitnymi kompleksami khitozana.

The possible application of polyelectrolyte complexes (PEC) of chitosan and copolymers of maleic acid with N-vinylpyrrolidone, styrene, and ethylene and/or chitin cross-linked sorbents (CCLS) synthesized on the basis of PEC for sorption of wheat germ agglutinin (WGA) was studied. The synthesis of spherically granulated sorbents was shown. Compared to unmodified chitosan, there was a significant increase in sorption of WGA by the PEC: PEC, 2.5-fold, and CCLS, from 3.5-fold to 7-fold.