The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface are...The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface area and XRD analysis. The studies indicate that the separation of the microemulsion phase during the preparation procedure can decrease the specific surface area of sample, adding hydrogen peroxide in the matrix solution can increase the specific surface area and stability of sample. The surface area of sample calcined at 550 ℃ for 5 h is 149 m^2·g^(-1), and that calcined at 900 ℃ for 6 h is 88 m^2·g^(-1). The sample with tetragonal symmetry Ce_(0.5)Zr_(0.5)O_2 phase has a higher stability.展开更多
Structural information on the crystalline forms of mebendazole, an anti-parasitic drug, is limited, although three polymorphic forms of this drug have been reported. The present work investigates the structures and pr...Structural information on the crystalline forms of mebendazole, an anti-parasitic drug, is limited, although three polymorphic forms of this drug have been reported. The present work investigates the structures and properties of different crystalline forms of mebendazole with a series of n-alkyl carboxylic acids, including trifluroacetic acid （1）, formic acid （2）, acetic acid （3）, propanoic acid （4）, butanoic acid （5）, valeric acid （6） and hexanoic acid （7）. These compounds were characterized by thermogravimetric analysis, IR spectra, as well as powder and single-crystal X-ray diffraction analysis. The R22（8） structural motif was detected in all the seven products, which was formed by a pair of N--H…O/O--H…N hydrogen bonds between mebendazole and carboxylic acid. Forms 3--7 were found to be neutral solvate, while in forms 1 and 2, proton transfer was observed from carboxylic acid to mebendazole.展开更多
The fast mixing of aqueous solutions of calcium chloride and sodium carbonate resulted in crystalline forms of vaterite and calcite under vigorous stirring. Then, the vaterite was transformed to pure calcite within ab...The fast mixing of aqueous solutions of calcium chloride and sodium carbonate resulted in crystalline forms of vaterite and calcite under vigorous stirring. Then, the vaterite was transformed to pure calcite within about 180 rain. The crystalline forms all grew with experimental time increase. Scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FT-IR）, and X-ray diffraction spectroscopy （XRD） techniques were employed to characterize the as-prepared samples. The heat capacity of the stable as-synthesized calcite was determined by means of an adiabatic calorimeter from 80 to 390 K. The thermodynamic functions of the calcite were derived based on the relationships among the thermodynamic functions and the function of the measured heat capacity with respect to temperature.展开更多
The solid forms of drugs play a central role in controlling their physicochemical properties and consequently the bioavailability. Multiple types of drug solid forms have been developed to achieve the desirable pharma...The solid forms of drugs play a central role in controlling their physicochemical properties and consequently the bioavailability. Multiple types of drug solid forms have been developed to achieve the desirable pharmaceutical profiles, but new solid forms will provide more options for the solid-state property optimization and hence are highly desirable. This review focuses on a new pharmaceutical solid form, drug-polymer inclusion complexes （ICs）, and summarizes their structural features, structure- property relationships, as well as potential pharmaceutical applications展开更多
文摘The CeO_2-ZrO_2 solid solutions were prepared by a reverse microemulsion method. The effect of preparation parameters on the surface area and crystalline form of the solid solutions were studied by the BET surface area and XRD analysis. The studies indicate that the separation of the microemulsion phase during the preparation procedure can decrease the specific surface area of sample, adding hydrogen peroxide in the matrix solution can increase the specific surface area and stability of sample. The surface area of sample calcined at 550 ℃ for 5 h is 149 m^2·g^(-1), and that calcined at 900 ℃ for 6 h is 88 m^2·g^(-1). The sample with tetragonal symmetry Ce_(0.5)Zr_(0.5)O_2 phase has a higher stability.
文摘Structural information on the crystalline forms of mebendazole, an anti-parasitic drug, is limited, although three polymorphic forms of this drug have been reported. The present work investigates the structures and properties of different crystalline forms of mebendazole with a series of n-alkyl carboxylic acids, including trifluroacetic acid （1）, formic acid （2）, acetic acid （3）, propanoic acid （4）, butanoic acid （5）, valeric acid （6） and hexanoic acid （7）. These compounds were characterized by thermogravimetric analysis, IR spectra, as well as powder and single-crystal X-ray diffraction analysis. The R22（8） structural motif was detected in all the seven products, which was formed by a pair of N--H…O/O--H…N hydrogen bonds between mebendazole and carboxylic acid. Forms 3--7 were found to be neutral solvate, while in forms 1 and 2, proton transfer was observed from carboxylic acid to mebendazole.
基金Project supported by the National Natural Science Foundation of China （No. 20073047） and Doctor Foundation of Shandong Province （No. 2004BS04021）.
文摘The fast mixing of aqueous solutions of calcium chloride and sodium carbonate resulted in crystalline forms of vaterite and calcite under vigorous stirring. Then, the vaterite was transformed to pure calcite within about 180 rain. The crystalline forms all grew with experimental time increase. Scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FT-IR）, and X-ray diffraction spectroscopy （XRD） techniques were employed to characterize the as-prepared samples. The heat capacity of the stable as-synthesized calcite was determined by means of an adiabatic calorimeter from 80 to 390 K. The thermodynamic functions of the calcite were derived based on the relationships among the thermodynamic functions and the function of the measured heat capacity with respect to temperature.
基金supported by the National Natural Science Foundation of China (No. 21434008)
文摘The solid forms of drugs play a central role in controlling their physicochemical properties and consequently the bioavailability. Multiple types of drug solid forms have been developed to achieve the desirable pharmaceutical profiles, but new solid forms will provide more options for the solid-state property optimization and hence are highly desirable. This review focuses on a new pharmaceutical solid form, drug-polymer inclusion complexes （ICs）, and summarizes their structural features, structure- property relationships, as well as potential pharmaceutical applications
