The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereeva...The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.展开更多
The influence of solvent and the rate of addition of water on the characteristics of alumina-zirconia powders obtained by sol-gel method were investigated. The Al2O3-ZrO2 powders (1:1 molar ratio) were prepared using ...The influence of solvent and the rate of addition of water on the characteristics of alumina-zirconia powders obtained by sol-gel method were investigated. The Al2O3-ZrO2 powders (1:1 molar ratio) were prepared using aluminum tri-sec-butoxide and zirconium n-propoxide as precursors. Ethanol (EtOH), isopropanol (iPrOH) and isobutanol (iBuOH) were used as solvents. The Al2O3-ZrO2 powders were characterized by nitrogen physisorption (SBET), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Prepared oxides calcined at 700℃ showed high specific surface area (200 - 240 m2/g). Obtained results suggest that the homogeneity of the mixed oxides is favored by using a water addition rate of 0.06 and 0.10 mL/min with ethanol as solvent.展开更多
Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres befor...Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres before and after high temperature treatment(HTT) were characterized by X-ray diffractometry(XRD) ,scanning electronic microscopy(SEM) ,energy diffraction spectroscopy(EDS) ,and transmission electron microscopy(TEM) .The formation mechanism of carbon spheres was discussed.The results indicate that the carbon spheres convert to hollow polyhedron through HTT.Carbon spheres are composed of entangled and curve graphitic layers with short range order similar to cotton structure,and carbon polyhedron with dimension of 50-250 nm and shell thickness of 15-30 nm.The change of solid spheres to hollow polyhedron with branches gives a new evidence for formation mechanism of hollow carbon spheres.展开更多
An O / W emulsion non-solvent addition method was used to prepare ethyleellulose (EC) microcapsules of water soluble pharmaceutical (theophylline). The solvent and non-solvent reagents used in this work were toluene a...An O / W emulsion non-solvent addition method was used to prepare ethyleellulose (EC) microcapsules of water soluble pharmaceutical (theophylline). The solvent and non-solvent reagents used in this work were toluene and cyclohexane. The effects of polymer concentration, core wall ratio and particle size on the kinetics as well as the dissolution rate of the drug were investigated. The results show that the dissolution rate increases with the increasing of polymer concentration and core wall ratio. The release of microcapsules prepared with different procedures can be selectively profiled with first order and Higuchi matrix kinetic models.展开更多
[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behn...[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.展开更多
基金Project ( 2001AA218011) supported by the National High Technology Development "863" Program of China
文摘The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.
文摘The influence of solvent and the rate of addition of water on the characteristics of alumina-zirconia powders obtained by sol-gel method were investigated. The Al2O3-ZrO2 powders (1:1 molar ratio) were prepared using aluminum tri-sec-butoxide and zirconium n-propoxide as precursors. Ethanol (EtOH), isopropanol (iPrOH) and isobutanol (iBuOH) were used as solvents. The Al2O3-ZrO2 powders were characterized by nitrogen physisorption (SBET), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Prepared oxides calcined at 700℃ showed high specific surface area (200 - 240 m2/g). Obtained results suggest that the homogeneity of the mixed oxides is favored by using a water addition rate of 0.06 and 0.10 mL/min with ethanol as solvent.
基金Project(2006CB600901) supported by the National Basic Research Program of ChinaProject(0991015) supported by Guangxi Natural Science Foundation,ChinaProject(200808MS083) supported by Guangxi Education Department Foundation,China
文摘Carbon spheres with size of 50-300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave.The morphologies and microstructures of carbon spheres before and after high temperature treatment(HTT) were characterized by X-ray diffractometry(XRD) ,scanning electronic microscopy(SEM) ,energy diffraction spectroscopy(EDS) ,and transmission electron microscopy(TEM) .The formation mechanism of carbon spheres was discussed.The results indicate that the carbon spheres convert to hollow polyhedron through HTT.Carbon spheres are composed of entangled and curve graphitic layers with short range order similar to cotton structure,and carbon polyhedron with dimension of 50-250 nm and shell thickness of 15-30 nm.The change of solid spheres to hollow polyhedron with branches gives a new evidence for formation mechanism of hollow carbon spheres.
文摘An O / W emulsion non-solvent addition method was used to prepare ethyleellulose (EC) microcapsules of water soluble pharmaceutical (theophylline). The solvent and non-solvent reagents used in this work were toluene and cyclohexane. The effects of polymer concentration, core wall ratio and particle size on the kinetics as well as the dissolution rate of the drug were investigated. The results show that the dissolution rate increases with the increasing of polymer concentration and core wall ratio. The release of microcapsules prepared with different procedures can be selectively profiled with first order and Higuchi matrix kinetic models.
文摘[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.
