Effect of Sodium Alginate on the Properties of Thermosensitive Hydrogels

Sodium alginate (SA) was combined with poly( N -isopropylacrylamide) (PNIPAAm) to prepare thermosensitive hydrogels through semi-interpenetrating polymer network (semi-IPN) and fully interpenetrating polymer network (full-IPN). The thermosensitive, swelling, mechanical, and thermal properties of pure PNIPAAm, SA/PNIPAAm semi-IPN, and Ca-alginate/PNIPAAm full-IPN hydrogels were investigated. The formation of semi-IPN and full-IPN significantly improved the hydrogels’ swelling capability and mechanical properties without altering their thermosensitivity. 5-Fluorouracil (5-Fu) was selected as a model drug to study the release behaviors of the hydrogels. It was found that in vitro controlled drug release from semi-IPN hydrogels showed an initial release burst, followed by a slower and sustained release, before reaching equilibrium. Full-IPN hydrogels showed slow and sustained release during the whole process. Temperature and pH were found to affect the rate of drug release. Ca-alginate/PNIPAAm full-IPN hydrogels have potential application as drug delivery matrices in controlled drug release.