Iodine-responsive poly (HEMA-PVP) hydrogel for self-regulating burst-free extended release

New Materials Based on Polyvinylpyrrolidone-Containing Copolymers with Ferromagnetic Fillers

The article investigates the peculiarities of the effect of ferromagnetic fillers (FMFs) of various natures (Ni, Co, Fe, FeCo, SmCo₅) on the formation of the structure and properties of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP) copolymers. The composites were characterized using FTIR-spectroscopy, SEM, DMTA, magnetometry of vibrating samples, specific electrical resistivity studies, and mechanical and thermophysical studies. The formation of a grafted spatially crosslinked copolymer (pHEMA-gr-PVP) was confirmed and it was established that the FMF introduction of only 10 wt.% into the copolymer formulation increased the degree of crosslinking of the polymer network by three times. The surface hardness of composites increased by 20–25%. However, the water content decreased by 16–18% and lay within 42–43 wt.%, which is a relatively high number. The heat resistance of dry composites was characterized by Vicat softening temperature, which was 39–42 °C higher compared to the unfilled material. It was established that the obtained composites were characterized by a coercive force of 200 kA × m⁻¹ and induction of a magnetic field at the poles of 4–5 mT and 10–15 mT, respectively. The introduction of FMF particles into pHEMA-gr-PVP copolymers, which, in the dry state, are dielectrics, provides them with electrical conductivity, which was evaluated by the specific volume resistance. Depending on the FMF nature and content, as well as their orientation in the magnetic field, the resistance of filled materials could be regulated within 10²–10⁶ Ohm·m. Therefore, the modification of HEMA with PVP copolymers by ferromagnetic fillers of various natures provides the possibility of obtaining materials with unique predicted properties and expands the fields of their use, for instance as magnetic sorbents for various applications, as well as the possibilities associated with their being electrically conductive materials that can respond by changing of electrical conductivity, depending on various factors.

Agar-Iodine Transdermal Patches for Infected Diabetic Wounds

In the present work, we have tested the potency of iodine-loaded agar transdermal patches (5 mg/cm²) for the treatment of infected diabetic wounds in the Wistar rat model. The rats were treated with the newly developed agar-iodine-potassium iodide (KI)-glycerol (AKIG) patch along with two other commercial dressings Iodoflex and Tegaderm as controls. Animals that received treatment with AKIG patches and Iodoflex showed better infection containment as compared to that with Tegaderm-covered control and exhibited complete healing. The antimicrobial property of all the patches was tested on three bacterial species-Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa-found in infected wounds. P. aeruginosa exhibited the highest minimum inhibitory concentration and minimum bactericidal concentration values among the three bacterial species for all the patches. The patch showed values of tensile strength, elongation, water vapor transmission rate, and swelling in the range of 34 ± 5 MPa, 51% ± 5, 2700 ± 110 g/m²/day, and 250% ± 25, respectively, for the agar-KI-iodine patch. The release kinetics of iodine through the agar matrix was found to follow the first-order drug release kinetics.