Poly(ethylene glycol) Composite Hydrogels with Natural Zeolite as Filler for Controlled Delivery Applications

In this study, composite hydrogels based on crosslinked polyethylene glycol diacrylate (PEGDA) and natural zeolite, with potential applications for the controlled release of phytoextracts, were synthesized by radical polymerization and characterized herein for the first time. The influence of various synthesis parameters, such as the use of distilled water or rose hip extract as reaction medium, or the percentage of the zeolite in the composite hydrogel upon the morphology, swelling kinetics and the rheological properties was investigated. By conducting polymerization of PEGDA in the rose hip extract, the crosslinking reaction yield was almost 100%, because of the chain transfer reactions of the polyphenols from the rose hip extract. Rose hip release tests were used to evaluate the release profiles of the natural bioactive substances from phytoextracts. The results showed that the hydrogel loaded with 3% zeolite displayed the lowest burst release and the slowest release rates of the extract.