Hydrophilic Polyacrylamide Gels Modified with Poly-N-vinylpyrrolidone

In modern medicine, there is a need to create biologically active polymer materials for the controlled release of drugs with improved characteristics compared to existing materials. Hydrogels are an ideal basis for creating such materials due to their high water content, excellent biocompatibility, and soft consistency, which is similar to that of body tissues. Therefore, this study aimed to develop and investigate hydrogels modified with poly-N-vinylpyrrolidone (PVP) for their potential use as drug carriers. A series of polyacrylamide gels (PAAGs) were synthesized, modified with PVP at concentrations of 0.3 wt.%, 0.5 wt.% and 1.0 wt.% relative to the weight of acrylamide. The synthesis was performed through free radical polymerization of acrylamide, N,N'-methylene-bis-acrylamide, and PVP in a sodium phosphate buffer solution (pH 8.0–8.5) in the presence of an oxidation-reduction initiation system (ammonium persulfate and N,N,N′,N′-tetramethylethylenediamine). The structural characteristics, water absorption, rheological, and sorption properties of these hydrogels were analyzed. IR spectroscopic analysis revealed that the incorporation of PVP into the PAAG structure leads to alterations in the hydrogen bonding of NH groups within the polymer matrix and changes in the skeletal chain, associated with varying contents of CH, CH<sub>2</sub>, CH<sub>3</sub> groups. Rheological studies demonstrated that PVP-modified hydrogels exhibit a reduction in viscosity by 22.4-35.3% compared to unmodified PAAGs, depending on the PVP content. Despite this decrease in viscosity, the structural stability remained sufficient for the hydrophilic matrix to function effectively in drug immobilization. The water absorption studies indicated absorption values ranging from 761.9 to 1059.8%. Sorption properties were assessed using the drug dacarbazine, revealing that increasing the PVP content in the hydrogel to 0.5 wt.% and 1.0 wt.% enhanced the sorption capacity of PAAGs by 21.1% and 27.1%, respectively. Thus, the synthesized hydrogel materials exhibit sorption capacity for dacarbazine and demonstrate high water absorption values, indicating that they are promising materials for use as drug carriers in medical practice; thus, they require further medical and biological research.