The Synthesis, Property Of The Thermo-responsive Gel And Its Application In The Naproxen Drug Vitro Release

The thermo-responsive hydrogels are known to exhibit a unique phenomenon: as the temperature is raised through one temperature, the gel itself shrink and deswell in aquous solution, in other words, the swelling degree of the gel changed suddenly when the temperature just increased past a lower critical solution temperature(LCST).the phenomen is reversible and the gels expand and reswell upon cooling below the LCST.Poly N-isopropylacrylamide(NIPA) gels is one kind of this thermo-responsive gel. In this paper, 4 kinds of Poly(NIPA) based gels have been synthesized ,and their unque property have also been studied in the development of the intelligent drug delivery system.4 kinds of thermo-responsive hydro gels based on N-isopropylacrylamide(NIPA) crosslinked with methylene-bisacrylamide has been prepared in this paper, including the Poly N-isopropylacrylamide(NIPA) gels,the NIPA co polymerized with methacryl-amide(MAA) ,butyl methacrylate(BMA) and even theβ-cyclodetrin(β-CD).namely NIPA gels, NIPA-co-MAA gels, NIPA-co-BMA gels and the [NIPA-co--(β-CD)] gels respectively.Since the study on the effect of the condition on the synthesis reaction and the property of gels We get a clearer idea of the thermo-responsive phenomenon of different gels, the optimum condition process for the reaction is found. Based on the orthogonal design results, the NIPA gel with the best swelling degree is found. Furthermore, the ~1HNMR is a useful tool for determining not only the structure of the gels but also the thermo-sensitive property.It is revealed by the results that the swelling degree rises as the amount of cross-linker is raised. While increasing amount of methacrylamide results in the improved swelling behavior and the raising LCST.On the other hand, the increasing amount of the hydrophobic monomer BMA results in the falling LCST,the LCST of the NIPA-co-(β-CD) gels shows no significant change.Based on the research of the preparation and property of the gels, we choose a most suitable gel for drug delivery, and study the effect of different conditions on the loding and release . A newly intelligent drug delivery systems has been set up.Drug release is taken under a simulated condition of body environment. The result shows the tendency of naproxen and sodium naproxen release with different enviromrnt(including the simulated gastric juice and the simulated enterogastrone). We also compare the tendency of drug release between different temperature to find ou whether it has the practical value. It is identified that the drug in the hydrogel material could be delivered with fairly high release ratio and moderate rate in the 37℃.furthermore, the drug is released with a slower ratio in the simulated gastric juice.It is a good way to avoid the side effect caused by the drug absorbtion in the stomach.