Hybrid drug delivery systems(DDS) have been prepared by grafting poly(NIPAM-co-MPS) chains on multimodal porous silica nanoparticles having an inner mesoporous structure and an outer thin layer of micropores. The hybr...Hybrid drug delivery systems(DDS) have been prepared by grafting poly(NIPAM-co-MPS) chains on multimodal porous silica nanoparticles having an inner mesoporous structure and an outer thin layer of micropores. The hybrid thermoresponsive DDS were fully characterized and loaded with a model drug. The in vitro drug release tests are carried out at below and above the lower critical solution temperature(LCST) of the copolymer. The results have revealed that due to the presence of small diameter(~1.3 nm) micropores at the periphery of the particles, the collapsed globules of the thermoresponsive copolymer above its LCST hinders the complete release of the drug which resulted in a reverse thermoresponsive drug release profile by the hybrid DDS.展开更多
The medical grade poly(vinylmethyl siloxane)(PVMS) and silica filled PVMS were crosslinked with benzoyl peroxide(BPO). The glass transition of the crosslinked silicone rubber was evaluated by measurment of thermally s...The medical grade poly(vinylmethyl siloxane)(PVMS) and silica filled PVMS were crosslinked with benzoyl peroxide(BPO). The glass transition of the crosslinked silicone rubber was evaluated by measurment of thermally stimulated current(TSC). The releasing rate of 1 norgestrel(LNG) through the membrane of the vulcanized silicone rubber in saturated physiological salt solution and that from the intrauterine device(IUD) were determined. The results showed that the drug deli very behavour was influenced by the structure of PVMS molecules which were controlled by the content of BPO and silica used in vulcanization of PVMS. The burst effect at first stage of drug delivery was observed probably due to the interaction between LNG and macromolecules. The releasing curve of LNG from IUD could be kept constant for period of half a year.展开更多
文摘Hybrid drug delivery systems(DDS) have been prepared by grafting poly(NIPAM-co-MPS) chains on multimodal porous silica nanoparticles having an inner mesoporous structure and an outer thin layer of micropores. The hybrid thermoresponsive DDS were fully characterized and loaded with a model drug. The in vitro drug release tests are carried out at below and above the lower critical solution temperature(LCST) of the copolymer. The results have revealed that due to the presence of small diameter(~1.3 nm) micropores at the periphery of the particles, the collapsed globules of the thermoresponsive copolymer above its LCST hinders the complete release of the drug which resulted in a reverse thermoresponsive drug release profile by the hybrid DDS.
文摘The medical grade poly(vinylmethyl siloxane)(PVMS) and silica filled PVMS were crosslinked with benzoyl peroxide(BPO). The glass transition of the crosslinked silicone rubber was evaluated by measurment of thermally stimulated current(TSC). The releasing rate of 1 norgestrel(LNG) through the membrane of the vulcanized silicone rubber in saturated physiological salt solution and that from the intrauterine device(IUD) were determined. The results showed that the drug deli very behavour was influenced by the structure of PVMS molecules which were controlled by the content of BPO and silica used in vulcanization of PVMS. The burst effect at first stage of drug delivery was observed probably due to the interaction between LNG and macromolecules. The releasing curve of LNG from IUD could be kept constant for period of half a year.
