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(epsilon-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.

Automated summary

The semi-interpenetrating polymer network (semi-IPN) hydrogel synthesized through free radical UV-photopolymerization technique showed increased elasticity and water absorption capacity, while being non-cytotoxic. Efficient encapsulation of the model drug CIP was achieved, with drug loading capacity enhanced by increasing PCL diol and CIP content. Drug release profiles were influenced by the ratios of Na-AMPS to PCL diol and CIP content, showing diffusion and swelling-controlled release mechanisms. The P(Na-AMPS)/PCL diol semi-IPN hydrogels are promising candidates for drug delivery and controlled release applications in biomedicine.