Temperature-responsiveness and sustained delivery properties of macroporous PEG-co-PNIPAAm-co-PCL hydrogels

A series of novel thermosensitive macroporous poly (ethylene glycol) (PEG)- co -poly( N -isopropylacrylamide) (PNIPAAm)- co -poly (ε-caprolactone) (PCL) hydrogels were synthesized via in situ free radical polymerization. Poly(ethylene glycol diacrylate) (PEGDAc) and poly(ε-caprolactone diacrylate) (PCLDAc) were prepared as macrocrosslinkers. All compounds were investigated by Nuclear Magnetic Resonance (NMR) and Fourier transform-infrared spectroscopy (FT-IR). Differential Scanning Calorimetry (DSC) results showed the lower critical solution temperatures (LCSTs) of the gels were at around 31°C. The macroporous gels not only had considerable swelling ratios, but also exhibited rapid swelling kinetics and response sensitivity. Above mentioned hydrogels showed a remarkable oscillatory swelling–deswelling transition, making them have potential application in long-term drug delivery. POLYM. ENG. SCI., 55:223–230, 2015. © 2014 Society of Plastics Engineers