Thermoresponsive PNIPAAm Hybrid Hydrogels With Physical and Chemical Cross‐Links for Controlled Release of Sulfacetamide Sodium

ABSTRACT Thermoresponsive hybrid poly(N‐isopropylacrylamide) (PNIPAAm) hydrogels physically cross‐linked with Laponite RD (Lap) platelets and chemically cross‐linked PNIPAAm hydrogels formed within polyvinyl formal (PVF) sponges were synthesized. The hydrogel systems were loaded with the bacteriostatic agent sulfacetamide sodium (SAS). Their swelling behavior and SAS sorption and release were investigated at 22°C and 45°C. All formulations exhibited temperature‐responsive swelling, with reduced swelling above the PNIPAAm volume phase transition temperature. SAS sorption was higher at 22°C than at 45°C. The release profiles depended on hydrogel architecture and temperature and exhibited a multistep pattern consisting of an initial burst followed by a slower release phase over several hours. The results demonstrate that the cross‐linking mode, Lap content, and PVF scaffold architecture influence SAS uptake and release from PNIPAAm‐based hybrid hydrogels.