Hydrogen-bonded polymer gel and its application as a temperature-sensitive drug delivery system.

The mixture of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (F-68) and poly vinyl alcohol (PVA) forms a polymer complex gel by intra/intermolecular interaction via hydrogen bonding in water, which is verified by differential scanning calorimetry. With 30 wt% F-68 aqueous solution and 15 wt% PVA aqueous solution, F-68/PVA complex gel was prepared and its swelling transition was observed at approximately 37 degrees C. Based on the temperature-sensitivity of hydrogen bondings in F-68/PVA complex gel, temperature sensitive drug delivery system has been designed and characterized. For the stability in the aqueous media, F-68/PVA complex gel was prepared with a form of polymeric bead, followed by the encapsulation with poly(lactide-co-glycolide) membrane. With changing the ratio of F-68/PVA, the swelling transition of polymer complex gel was manipulated and pulsatile release of acetoaminophen, used as a model drug, was demonstrated in response to pulsatile change of temperature between 35 degrees C and 40 degrees C.