Biocidal coatings are of great interest to the healthcare system. In this work, the biocidal activity of coatings based on a complex biocide containing polymer and inorganic active antibacterial c omponents was studied. Silver oxide was distributed in a matrix of a positively charged interpolyelectrolyte complex (IPEC) of polydiallyldimethylammonium chloride (PDADMAC) and sodium polystyrene sulfonate (PSS) using ultrasonic dispersion, forming nanoparticles with an average size of 5-6 nm. The formed nanoparticles in the matrix are not subject to agglomeration and changes in morphology during storage. It was found that the inclusion of silver oxide in a positively charged IPEC allows a 4-fold increase in the effectiveness of the complex biocide against E. coli K12 in comparison with the biocidal effect of PDADMAC and IPEC. Polycation, IPEC and the IPEC/Ag2O ternary complex form coatings on the glass surface due to electrostatic adsorption. Adhesive and cohesive forces in the resulting coatings were studied on micron-scale coatings using dynamometry. It was found that the stability of the coating is determined primarily by adhesive interactions. At the macro level, it is not possible to reliably identify the role of IPEC formation on adhesion. On the other hand, the use of the optical tweezers method makes it possible to analyze macromolecules in submicron scale and to evaluate the multiple increase in adhesive forces when forming a coating from IPEC compared to coatings from PDADMAC. Thus, the application of ternary IPEC/Ag2O complexes makes it possible to obtain coatings with increased antibacterial action and improved adhesive characteristics.

Interpolyelectrolyte complexes Eudragit® EPO/L100 received in different pH were characterized by different degree of swelling in mimicking fasted stomach medium (0.1 M HCl) and saved their shape during 6 hours of the experiment. The microenvironmental changes in IPECs structure during swelling testing were inves-tigated using FT-IR spectroscopy, thermal and elemental analysis. Both samples of IPECs during swelling were transformed to a similar structure with approximately the same composition. IPEC samples showed bioadhesive properties that was not significantly different from the positive control (Carbopol) in the test with the mucin compacts. The release rate of metronidazole (class I BCS) from IPEC matrices increased with the increasing degree of swelling. IPEC 1 provided 49.62 ± 6.20% and IPEC 2 – 87.69 ± 5.15 % of metronidazole release after 6 hours in mimicking fasted stomach medium (0.1 M HCl). Total amount of released acyclovir (class III BCS) from IPEC 1 was 25.76 ± 5.67 % and from IPEC 2 was 21.48 ± 5.00 %. Release of both drugs was controlled by relaxation of polymeric chains in matrices according to the Peppas-Sahlin model. According to the received results, investigated interpolymer complexes are perspective for further evalua-tion as carriers for gastroretentive bioadhesive systems.

Many studies have been conducted using pectin for modified drug delivery. In this regard, the goal of the work was to obtain interpolyelectrolyte complexes based on citrus or apple pectin and the Eudragit® EPO and study properties from the standpoint of using these carriers for oral drug delivery. Turbidity, gravimetry, viscosity, elementary analysis and FTIR spectroscopy, DSC analysis were used for physicochemical characterization. Diffusion-transport characteristics were studied to assess the swelling ability of the matrices and the release of diclofenac sodium. Mathematical modeling of the release parameters was carried out using the Krosmayer-Peppas equation. During the turbidity study, stoichiometry compositions were selected for the studied IPECs EPO/PeсA and EPO/PeсC at pH values = 4.0, 5.0, 6.0, 7.0. FTIR spectra of the complexes are characterized by an increase in the intensity of the bands at 1610 cm-1 and 1400 cm-1. According to the DSC analysis IPEC has a certain Tg = 57.3°C. The highest release rates are shown by IPEC EPO/PecC_1 and EPO/PecC_4. The mechanism of drug transport from the matrices IPEC EPO/PecC, IPEC EPO/PecA_3 and EPO/PecA_4 can be characterized as Super Case II. Anomalous (non-Fickian release) is typical for IPEC EPO/PecA_1 and EPO/PecA_2. Thus, the resulting systems are suitable for colon-specific drug delivery systems.