Structural, thermal, mechanical, swelling, drug release, antibacterial and cytotoxic properties of P(HEA/IA)/PVP semi-IPN hydrogels

The aim of this work was to synthesize a series of semi-interpenetrating polymer networks (semi-IPNs) of 2-hydroxyethyl acrylate and itaconic acid, in the presence of poly(N-vinylpyrrolidone). Samples were synthesized by free radical copolymerization with constant PVP and variable IA content and characterized for structural, morphological, thermal, swelling, drug release, antibacterial and cytotoxic properties. The chemical structure of samples was confirmed by Fourier-transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to examine morphology of samples and glass transition temperatures were determined by differential scanning calorimetry (DCS). The pH and temperature sensitivity was confirmed by measuring the dependence of the degree of swelling on pH and temperature. All samples show volume phase transition temperature (VPTT) around 47 °C. Drug release profiles were investigated using vitamin B3 as a model drug. The vitamin B3 transport mechanism was studied by fitting experimental data to five different model equations and calculating the corresponding parameters. It was also observed that IA content has a marked influence on the release profiles of vitamin B3, so the rate of drug release can be designed by changing the HEA/IA ratio. Cell viability, performed using MTT test, was high for all samples and all concentration of extract used. The antibacterial activity of hydrogels was determined against Pseudomonas aeruginosa. It turns out that IA content and time of exposure have an influence on the antibacterial potential. All samples showed satisfied cell viability. Due to these characteristics, P(HEA/IA)/PVP semi-IPNs represent interesting biomaterials for biomedical applications.