Tuning Pluronic Hydrogel Networks: Effects of Vancomycin Loading on Gelation, Rheological Properties, and Micellar Structures.

Thermoresponsive Pluronic hydrogels offer a promising platform for localised antibiotic delivery. However, how drug loading affects the structural integrity and gelation of these systems remains underexplored. This study evaluates the impact of vancomycin on the physicochemical and self-assembly behaviour of Pluronic F127, F108, and F68 hydrogels. Rheological analysis revealed that vancomycin altered the critical micellisation and gelation temperatures (CMT and CGT, respectively), accelerating gelation in weak gel systems but disrupting network formation in stronger gels. Small-angle X-ray scattering (SAXS) showed that vancomycin suppressed micellar ordering, particularly along FCC (111) planes in F127, without inducing a phase transition. Scanning electron microscopy (SEM) imaging confirmed reduced pore integrity in vancomycin-loaded F127 and F108 gels, while 35% F68 gels failed to form stable structures at the tested concentrations despite enhanced drug solubility. F127 (18%) and F108 (22-23%) maintained gelation at 37 °C with reasonable mechanical strength and partial cubic ordering, making them suitable candidates for drug-eluting gels. These findings inform the design of thermoresponsive hydrogels for localised, implant-associated antibiotic delivery.