Magnetic dual-responsive semi-IPN nanogels based on chitosan/PNVCL and study on BSA release behavior

Magnetic thermoresponsive nanogels present a promising new approach for targeted drug delivery. In the present study, bovine serum albumin (BSA) loaded thermo-responsive magnetic semi-IPN nanogels (MTRSI-NGs) were developed. At first poly(N-vinyl caprolactam) (PNVCL) was synthesized by free radical polymerization and then MTRSI-NGs were prepared by crosslinking chitosan in presence of chitosan and Fe₃O₄. The formation of MTRSI-NGs has been confirmed by FTIR, and the average molecular weight of PNVCL was determined by GPC analysis. Rheological and turbidimetry analysis were used to determine lower critical solution temperature (LCST) of PNVCL and magnetic thermo-responsive nanogels (MTRSI-NGs) around 32 and 37 °C, respectively. FE-SEM analysis showed particle size at less than 20 nm in the dried state. Dynamic light scattering determined particle size at about 30 nm in a swelling state. The analysis of release behavior showed that the BSA release ratio at 40 °C was faster than 25 °C. The pH release behavior was evaluated at pH 5.5 and 7.4 and showed that the drug release rate at pH 5.5 was more rapid than pH 7.4. The results show MTRSI-NGs are applicable to protein targeted delivery by thermosensitive targeted drug delivery systems.