pH-responsive hyaluronic acid-co-poly(acrylic acid) hydrogel scaffolds for modified release of mesalamine; characterization and biosafety evaluation.

The current study focuses on the development of pH-sensitive hydrogels for the controlled release of mesalamine at a specific pH. A free radical polymerization technique was used, and the formulated hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, scanning electron microscopy, swelling and drug release studies. FTIR confirmed the successful formation of a polymeric network with efficient incorporation of the drug. TGA revealed that the hydrogel demonstrated significantly improved thermal stability compared to the unmodified polymer, with SEM images showing a rough surface with a notable porous structure. Swelling and drug release behaviors were assessed at 37 °C in buffer solutions simulating gastric (pH 1.2) and intestinal (pH 7.4) conditions. The results demonstrated significantly higher swelling ratios and drug release rates at pH 7.4, indicating pH-responsive characteristics of the formulation, favoring enhanced drug release in the intestinal conditions. Increasing the concentrations of hyaluronic acid and acrylic acid led to enhanced porosity, improved swelling behavior, increased drug loading capacity, faster release rates, and a higher gel fraction, while simultaneously reducing the sol fraction. These observations suggested that the developed pH-sensitive hydrogel holds considerable potential as an effective carrier for pH-responsive, site-specific drug delivery systems. This study highlights the significant advancements in the design of hydrogels with tailored properties for controlled drug release, offering new opportunities for precision medicine.