Physically crosslinked salicylate-based poly (N-isopropylacrylamide-co-acrylic acid) hydrogels for protein delivery

Physically crosslinked hydrogels were developed via solvent casting methods using a temperature-sensitive polymer, poly( N-isopropylacrylamide- co-acrylic acid), and a therapeutic polymer, salicylate-based poly(anhydride-esters), to concurrently release salicylic acid and bovine serum albumin in a sustained manner. The physical interactions between the two polymer systems were confirmed using Fourier transform infrared spectroscopy. The crosslinked polymers were porous, thus able to encapsulate bovine serum albumin (23 wt%) and then released the protein in a sustained fashion over 96 h. Concurrently, the hydrogel releases salicylic acid in a sustained manner up to 120 h. Hydrogel systems were cytocompatible at relevant therapeutic concentrations. These hydrogel systems can be used for simultaneous delivery of salicylic acid and protein to achieve synergic effects.