Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via...Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.展开更多
Microspheres containing an antimetabolite drug 5-Fluorouracil were prepared from (poly(lactic) acide)(PLA) or poly(lactic acid)-polyethylene glycol(PLA-PEG) as the carrier by using a water-in-oil-in-water emulsion sol...Microspheres containing an antimetabolite drug 5-Fluorouracil were prepared from (poly(lactic) acide)(PLA) or poly(lactic acid)-polyethylene glycol(PLA-PEG) as the carrier by using a water-in-oil-in-water emulsion solvent evaporation technique. The conditions of the microspheres preparation such as polymer concentration in organic solvent, relative molecular weight of PLA-PEG and PLA/PEG mass ratio were discussed. The surface morphology and the size of the microspheres were observed by SEM. The drug content of microspheres was examined by TGA and the drug release in vitro was evaluated. According to the results, the drug content increased with the nano-silica used. The highest drug content in this study was 39.9%. The drug-release kinetics satisfied the requirements of controlled drug-release.展开更多
Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG an...Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG and PLA chain segments was made to be quite different. Nanoparticles were prepared by using the copolymer via a double emulsion-evaporation technique. The paticles tended to form the configuration like capsules, i.e., the nanocapsules, because of the great size difference in PEG and PLA segments of the copolymer. Insulin, chosen as a model drug, was encapsulated into nanocapsules. The effect of preparation conditions on the size, insulin encapsulation efficiency, and in vitro drug release behavour of the nanoparticles were investigated. The experimental results show that the nanocapsules had a smooth spherical surface and the mean diameter was in the range from 180 nm to 350 nm, and the entrapment of insulin achieved up to 78.4. The drug-loaded nanocapsules released their content continuously, remarkably different from the corresponding micelles which gave a significant initial burst release followed by a slow release.展开更多
文摘Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.
文摘Microspheres containing an antimetabolite drug 5-Fluorouracil were prepared from (poly(lactic) acide)(PLA) or poly(lactic acid)-polyethylene glycol(PLA-PEG) as the carrier by using a water-in-oil-in-water emulsion solvent evaporation technique. The conditions of the microspheres preparation such as polymer concentration in organic solvent, relative molecular weight of PLA-PEG and PLA/PEG mass ratio were discussed. The surface morphology and the size of the microspheres were observed by SEM. The drug content of microspheres was examined by TGA and the drug release in vitro was evaluated. According to the results, the drug content increased with the nano-silica used. The highest drug content in this study was 39.9%. The drug-release kinetics satisfied the requirements of controlled drug-release.
文摘Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG and PLA chain segments was made to be quite different. Nanoparticles were prepared by using the copolymer via a double emulsion-evaporation technique. The paticles tended to form the configuration like capsules, i.e., the nanocapsules, because of the great size difference in PEG and PLA segments of the copolymer. Insulin, chosen as a model drug, was encapsulated into nanocapsules. The effect of preparation conditions on the size, insulin encapsulation efficiency, and in vitro drug release behavour of the nanoparticles were investigated. The experimental results show that the nanocapsules had a smooth spherical surface and the mean diameter was in the range from 180 nm to 350 nm, and the entrapment of insulin achieved up to 78.4. The drug-loaded nanocapsules released their content continuously, remarkably different from the corresponding micelles which gave a significant initial burst release followed by a slow release.
