Thermo-responsive shear-induced structural transitions in Poloxamer-Based Carriers for Anti-Inflammatory Drugs

Poloxamer-based drug delivery systems, particularly those employing P407 (Pluronic® F-127), are extensively utilized in pharmaceutical formulations due to their thermoresponsive behavior, biocompatibility, and capacity for controlled drug release. At concentrations above the critical micelle concentration (CMC), P407 forms micelles that transition into a gel phase at physiological temperatures (37 °C), reverting to a liquid state below ~15 °C or above ~75 °C. This reversible sol-gel transition makes P407 highly suitable for applications including oral, injectable, and topical drug delivery. However, the effect of mechanical stress on its nanostructure, particularly under physiological conditions and in the presence of encapsulated drugs, remains insufficiently explored. This study proposes a structural investigation using Rheo-SANS to analyze the behavior of P407 systems under shear at 10, 25, 37 and 50 °C. The samples will include pure P407 and drug-loaded hydrogels containing 0.2% ketoprofen, ibuprofen, or diclofenac, across concentrations of 20%, and 25%. By correlating the applied strain with structural responses at the nanoscale, we aim to investigate how formulation and mechanical conditions affect micellar organization and stability. These insights will be critical for optimizing poloxamer-based drug delivery systems for real-world physiological and mechanical environments.