Study on drug loading and release from thermo-sensitive poly(N-isopropylacrylamide)

Used acetaminophen(APAP) as model drug and thermo-sensitive gel poly(N-isopropylacrylamide)(PNIP-AAm) as carrier,the drug loading and release behavior was investigated in phosphate buffer solution(pH 7.4) at different temperatures(25 and 37 ℃).It was found that the loading amount of APAP was about 35 wt% and interacted with PNIPAAm by intermolecular hydrogen bond.The results of drug release showed that APAP released slower at 37 ℃(above LCST) than that at 25 ℃(bellow LCST) in PBS.Therefore,the release of APAP from the thermo-sensitive PNIPAAm hydrogel could be controlled by changing the temperature around LCST.