Papers by Keyword: Thermosensitive Hydrogel

Abstract: A local drug delivery system constituted by hybrid microsphere/thermosensitive hydrogel was fabricated for Osteoarthritis (OA) therapy in the research. The hydrogel were synthesized by ring-opening copolymerization. Microsphere was fabricated by O/W emulsion and solution evaporation method. The properties of the products were characterized by ¹HNMR, FTIR and phase transition diagram. The microsphere/hydrogel was prepared for in vitro drug release research. The results showed microsphere/hydrogel hybrid system can alleviate initial burst release. After 650 hours, only 60 percent of the drugs were released. Kinetics research implied the drug release is controlled by diffusion/erosion mechanism.

Abstract: Long-term drug delivery based on the injectable thermosensitive hydrogel is of great advantage to the administration of naltrexone, but the constant release is hard to reach due to the sol-gel transition and the high water content of the hydrogel. The aim of the present study is to develop an injectable implant delivery system by the incorporation of microspheres into thermosensitive hydrogel for the long-term constant release of naltrexone. Naltrexone was loaded in PLGA microsphere dispersed in the methylcellulose based thermosensitive sol, which formed the hydrogel containing the naltrexone-loaded microspheres at the body temperature. The presence of microsphere in the hydrogel delayed the sol-gel transition slightly but enhanced the mechanical strength of the hydrogel significantly. The microspheres degradation in water diffusion dominated phase was decelerated when they were embed in the hydrogel. The in vitro naltrexone release from the microsphere/hydrogel system showed an over 60 days constant release with no significant burst release, and the drug release rate was in proportion to the microsphere concentration in the hydrogel.

Abstract: The composite of methoxy polyethylene glycol (mPEG) and poly(lactic-co- glycolic acid) (PLGA) thermosensitive hydrogel mixed with different mass raio of hydroxyapatite and β-tricalcium phosphate (β-TCP) were used as bone graft substitutes. The physical properties of a series of composite gels, including the critical micelle concentration (CMC), particle sizes, zeta potential, rheological behavior, morphology of composite gels, and sol–gel transition, were characterized in vitro. These composite gels could form a gel at body temperature and could be controlled easily at room temperature. During the in vitro degradation process, composite gels demonstrated a slight decrease in pH value, a slower degradation rate, less toxicity, and a higher cell survival rate. The biocompatibility of the composite gels was validated by hemolysis test. In vivo animal studies demonstrated both radiographic and gross bone union when the ratio of HAP/ β-TCP was 7:3.

Abstract: Huperzine A loaded microspheres are prepared using a W/O solvent evaporation method. The fixed speed release system is that microspheres composed with thermosensitive methylcellulose based hydrogel. SEM is used to analysis the surface morphology of Huperzine A loaded microspheres, which is shown that the difference of the size of microspheres. The size less than 200µm can be used as injection. Gelation experiment shows that the methylcellulose based solution can be transformed into in-situ hydrogel in 15 minutes at body temperature. The result of in vitro release shows that Huperzine A released in a nearly fixed speed. All the meterials of experiment can be biodegrated completely without operating to remove the gel. This is a promising long-term injection system, which is security and controlable for clinic.

Abstract: In the article, a new thermosensitive 5-Fu-ACS hydrogel was prepared as control release drug carrier, and its in vitro release capability in phosphate buffer solution (PBS) were determined by UV spectrum

Abstract: A new thermosensitive hydrogel had been prepared that could be transformed into gel at 37 °C from chitosan and a mixture of α- and β-glycerophosphate (αβ-GP). The appearance of hydrogel was compact and corrugated. There was little granule in the appearance of gel loaded with adriamycin and the granules might be crystals of the added model drug. In vitro cytotoxicity of the hydrogel was tested by the MTT method using mouse embryonic fibroblasts (MEF). MEF cultured with leachates of CS-αβ-GP were investigated and the relative growth rate (RGR) was calculated and the cytotoxicity was graded by generally accepted standard. The study of in vitro degradation of CS-αβ-GP hydrogels included hydrolysis and degradation by lysozyme. The CS-αβ-GP thermosensitive hydrogel was degradable in vitro and the degradation rate was faster in lysozyme solution than that in the medium of PBS. So the CS-αβ-GP system had good cell biocompatibility and biodegradability which provided possibilities and foundations for the further research.

Abstract: We have developed a new injectable bone substitute combining specific granules of BCP with or without radiopaque elements with a reversible thermo sensitive resorbable carrier such as Pluronic F-127. The composite is liquid at ambient temperature and set as hydrogel at 37°C. Rabbit experiment demonstrates high biocompatibility and bone ingrowth at the expense of the injectable bioceramic composite.