Preparation, optimization and in vitro activity analysis of PVA/gelatin/sodium alginate-based (PGS) hydrogels loaded with Gardeniae Fructus Preparatus (JZZ) extract

In this study, polyvinyl alcohol (PVA) was introduced into the traditional gelatin (Gel)/sodium alginate (SA) system, and PVA/Gel/SA hydrogels (PGS) were prepared by freeze-thaw cycling and Cu²⁺ crosslinking. After screening, proper PVA/Gel ratios were found to significantly improve mechanical strength and flexibility, with all formulations showing high water content and swelling ratios. Among them, PGS4 (5% Gel, 3% PVA, 2% SA) and PGS6 (5% Gel, 7% PVA, 2% SA) showed optimal mechanical performance (321.65 and 428.80 kPa) and proper swelling behavior (swelling ratios of 13.80 and 12.65 at 24 h). After loading the extract of Gardeniae Fructus Preparatus (JZZ), the water content of JZZ-PGS4 and JZZ-PGS6 decreased slightly, while swelling behavior was basically unchanged. JZZ-PGS4 had favorable stability (37.21% degradation at 14 days), high encapsulation efficiency (82.73%) and effective drug release behavior. Both JZZ-PGS4 and JZZ-PGS6 exhibited strong antioxidant activity. PGS4 and PGS6 showed moderate antibacterial activity and good cytocompatibility, which were enhanced by JZZ extract. In conclusion, JZZ-PGS4, possessing balanced comprehensive properties, could serve as a drug-loaded hydrogel platform based on the PVA/Gel/SA system for chronic diabetic wounds.