Synthesis and characterization of semi-IPN hydrogels composed of sodium 2-acrylamido-2-methylpropanesulfonate and poly(ε-caprolactone) diol for controlled drug delivery

Semi-interpenetrating polymer network (semi-IPN) hydrogel of sodium 2-acrylamido-2-methylpropane sulfonate (Na-AMPS) and poly(ε-caprolactone) (PCL) diol for drug delivery applications was synthesized via free radical UV-photopolymerization technique using 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone as an initiator and poly(ethylene glycol) diacrylate (PEGDA) as a crosslinker. The hydrogels' chemical structure and internal morphology have been explored using Fourier-transform infrared spectroscopy and scanning electron microscopy. The influence of PCL diol and PEGDA concentrations on the synthesized semi-IPN hydrogel properties was investigated. The semi-IPN hydrogel can increase the elasticity of the hydrogel while simultaneously providing enough water uptake and water retention. Furthermore, the semi-IPN hydrogel was non-cytotoxic to mouse fibroblasts L929 cells. Finally, ciprofloxacin (CIP) was used as a model drug and was efficiently encapsulated into the semi-IPN hydrogels. Drug loading capacity was enhanced with increasing PCL diol and CIP content. It was also observed that the PCL diol and CIP contents had a marked influence on the release profiles. Thus, the rate of release could be designed by changing the Na-AMPS to PCL diol ratio and CIP content. Drug release was found to be both diffusion and swelling-controlled in accordance with the Fickian and non-Fickian transport mechanisms. In the light of the results obtained, their easy formability, their appropriate mechanical and physical properties make P(Na-AMPS)/PCL diol semi-IPN hydrogels are the potential candidates for use as drug carrier and controlled drug release materials in the biomedical field.