MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffra...MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffraction（XRD）,Brunauer-Emmett-Teller（BET）,X-ray photoelectron spectroscopy（XPS）,Raman,O2 temperature-programmed desorption（O2-TPD）,H2 temperature-programmed reduction（H2-TPR） and NO temperature-programmed oxidation（NO-TPO）.The MnOx-CeO2 solid solutions did not form without any calcination process.The oxidation state of manganese tended to increase while the ionic valence of cerium decreased in the mixed oxides,accompanied with the formation of oxygen vacancies.This long-ranged electronic interaction occured more significantly in the tight-contact mixture of MnO and CeO2.The formation of more Mn4＋and oxygen vacancies promoted the catalytic oxidation of NO in an oxygen-rich atmosphere.展开更多
The purpose of this study was to improve the dissolution rate and anti-inflammatory effect of ibuprofen by a solid dispersion(SD)method.Initial screening was developed based on drug solubility in carriers in the liqui...The purpose of this study was to improve the dissolution rate and anti-inflammatory effect of ibuprofen by a solid dispersion(SD)method.Initial screening was developed based on drug solubility in carriers in the liquid state to select a suitable water-soluble carrier system for the preparation of SDs.The dissolution of ibuprofen in urea was higher than in PEG4000 or mannitol.Thus,urea was selected as the carrier for the preparation of SDs.SDs were characterized in terms of dissolution,differential scanning calorimetry(DSC),X-ray diffraction(XRD),scanning electron microscopy(SEM),and Fourier transform infrared(FTIR)spectroscopy.Solid dispersionbased(SDBT)and conventional(CT)tablets were prepared by the wet granulation method.The antiinflammatory effect of SDBT was evaluated using the mouse ear edema test with xylene.In vitro release results indicated that the ibuprofen dissolution rate was improved by the SD.SD characterization results suggested that ibuprofen partly precipitates in crystalline and amorphous forms after SD preparation and that ibuprofen and urea do not interact.SDBT displayed more significant anti-inflammatory effects than CT.The dissolution rate and anti-inflammatory effect of ibuprofen were significantly enhanced by the ibuprofen-urea SD.展开更多
基金supported by National Natural Science Foundation of China(51072096)National Basic Research Program of China(2010CB732304)National High-Tech Research and Development Program of China(2013AA065302)
文摘MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffraction（XRD）,Brunauer-Emmett-Teller（BET）,X-ray photoelectron spectroscopy（XPS）,Raman,O2 temperature-programmed desorption（O2-TPD）,H2 temperature-programmed reduction（H2-TPR） and NO temperature-programmed oxidation（NO-TPO）.The MnOx-CeO2 solid solutions did not form without any calcination process.The oxidation state of manganese tended to increase while the ionic valence of cerium decreased in the mixed oxides,accompanied with the formation of oxygen vacancies.This long-ranged electronic interaction occured more significantly in the tight-contact mixture of MnO and CeO2.The formation of more Mn4＋and oxygen vacancies promoted the catalytic oxidation of NO in an oxygen-rich atmosphere.
基金International S&T Cooperation Program of China(ISTCP,No.2011DFA31270)National Natural Science Foundation of China&Korea Science and Engineering Foundation(NSFC-KOSEF,No.40911140282)the Fundamental Research Funds for the Central Universities(Nos.841111042 and 201213006)for their financial support.
文摘The purpose of this study was to improve the dissolution rate and anti-inflammatory effect of ibuprofen by a solid dispersion(SD)method.Initial screening was developed based on drug solubility in carriers in the liquid state to select a suitable water-soluble carrier system for the preparation of SDs.The dissolution of ibuprofen in urea was higher than in PEG4000 or mannitol.Thus,urea was selected as the carrier for the preparation of SDs.SDs were characterized in terms of dissolution,differential scanning calorimetry(DSC),X-ray diffraction(XRD),scanning electron microscopy(SEM),and Fourier transform infrared(FTIR)spectroscopy.Solid dispersionbased(SDBT)and conventional(CT)tablets were prepared by the wet granulation method.The antiinflammatory effect of SDBT was evaluated using the mouse ear edema test with xylene.In vitro release results indicated that the ibuprofen dissolution rate was improved by the SD.SD characterization results suggested that ibuprofen partly precipitates in crystalline and amorphous forms after SD preparation and that ibuprofen and urea do not interact.SDBT displayed more significant anti-inflammatory effects than CT.The dissolution rate and anti-inflammatory effect of ibuprofen were significantly enhanced by the ibuprofen-urea SD.
