Tioconazole(TCZ), a broad-spectrum antifungal agent, has significant activity against Candida albicans and other Candida species, and therefore, it is indicated for the topical treatment of superficial mycoses.The mai...Tioconazole(TCZ), a broad-spectrum antifungal agent, has significant activity against Candida albicans and other Candida species, and therefore, it is indicated for the topical treatment of superficial mycoses.The main goal of this work is to report an exhaustive identification and characterization procedure to improve and facilitate the online quality control and continuous process monitoring of TCZ in bulk material and loaded in two different dosage forms: ovules and nail lacquer. The methodologies were based on thermal(differential scanning calorimetry(DSC), melting point, and thermogravimetry(TG)),spectroscopic(ultraviolet(UV), Raman, near infrared(NIR), infrared spectroscopy coupled to attenuated total reflectance(FTIR-ATR), and nuclear magnetic resonance(NMR)), microscopic and X-ray diffraction(XRD). The TCZ bulk powder showed a high crystallinity, as observed by XRD, with a particles size distribution(3–95 mm) resolved by microscopic measurements. TCZ melting point(82.8 °C) and a degradation peak centered at 297.8 °C were obtained by DSC and DTG, respectively. An unambiguous structure elucidation of TCZ was obtained by mono-and two-dimensional1 H and13 C NMR spectral data analysis. The FTIR-ATR, Raman and NIR spectra of both the raw material and the commercial products were analyzed and their characteristic bands were tabulated. The best methods for TCZ identification in ovules were DSC, TG, XRD, NIR and Raman, while NIR and FTIR-ATR were the most appropriate techniques to analyze it in the nail lacquer. DSC, TG, DRX, Raman, FTIR-ATR and NIR spectroscopy are effective techniques to be used in online process analysis, because they do not require sample preparation, and they are considerably sensitive to analyze complex samples.展开更多
Calcium exchanged A type zeolite is extensively used as an adsorbent in petroleum and gas purification application. The precursor of calcium and silver-exchanged zeolite was prepared in a hydrothermal process, followe...Calcium exchanged A type zeolite is extensively used as an adsorbent in petroleum and gas purification application. The precursor of calcium and silver-exchanged zeolite was prepared in a hydrothermal process, followed by an exchange process. In this study, LTA zeolite was synthesized. Calcium-ex- changed and silver-exchanged molecular sieves were prepared and characterized by a series of techniques, such as scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, etc. Physical properties of Ca- and Ag-exchanged zeolite A, such as surface structure, crystal structure, cation exchange capacity, and the ion-exchange properties were measured. Water adsorption studies using thermogravimetric method indicated that water molecules are more strongly bound in the Ca-A zeolite compared to Ag-A zeolite. XPS studies confirmed the presence of highly dispersed cationic silver species at exchange sites. The results of this study indicated that sodium was successfully exchanged with the calcium and silver in both Ca- and Ag-ex- changed zeolite frameworks. High cation exchange capacity, tailored aperture size, high porosity and specific surface area, as well as high thermal stability make cation-exchanged A type zeolite a successful candidate for adsorption, ion exchange, and catalysis applications.展开更多
This paper aims to briefly summarize the major differences in form, techniques and characterization between modern fiction and conventional realistic novels by comparatively analyzing the typical masterpiece in the tw...This paper aims to briefly summarize the major differences in form, techniques and characterization between modern fiction and conventional realistic novels by comparatively analyzing the typical masterpiece in the two fields: Kew Gardens and Pride and Prejudice.展开更多
Incremental forming is a novel die-less sheet forming process. There is a need for special means to retain lubricant at the tool/sheet interface during forming. To fulfillthe stated aim, a porous ceramic film was deve...Incremental forming is a novel die-less sheet forming process. There is a need for special means to retain lubricant at the tool/sheet interface during forming. To fulfillthe stated aim, a porous ceramic film was developed on pure Ti substrate, and it was done through an electrochemical depsition process known as plasma electrolytic oxidation. The film with preferred pore size could be realized after several attempts by varying the processing parameters. In order to characterize the film, a variety of tests including rnicrostructure, film-substrate bond strength and tribological properties tests were conducted. On-job performance of the film was also examined by forming Ti components employing a range of forming conditions. It was found that the proposed method of lubrication was effective, and the plasma eletrolytic oxidation process can be employed to fabricate films on pure Ti sheet to provide means of lubrication during incremental forming.展开更多
Irbesartan (IBS) is a tetrazole derivative and antihypertensive drug that has two interconvertible structures, 1H- and 2H-tautomers. The difference between them lies in the protonation of the tetrazole ring. In the so...Irbesartan (IBS) is a tetrazole derivative and antihypertensive drug that has two interconvertible structures, 1H- and 2H-tautomers. The difference between them lies in the protonation of the tetrazole ring. In the solid-state, both tautomers can be isolated as crystal forms A (1H-tautomer) and B (2H-tautomer). Studies have reported that IBS is a polymorphic system and its forms A and B are related monotropically. These reports indicate form B as the most stable and less soluble form. Therefore, the goal of this contribution is to demonstrate through a complete solid-state characterization, thermodynamic study and dissolution properties that the IBS forms are desmotropes that are not related monotropically. However, the intention is also to call attention to the importance of conducting strict chemical and in solid-state quality controls on the IBS raw materials. Hence, powder X-ray diffraction (PXRD) and Raman spectroscopy (RS) at ambient and non-ambient conditions, differential scanning calorimetry (DSC), hot stage microscopy (HSM), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) techniques were applied. Furthermore, intrinsic dissolution rate (IDR) and structural stability studies at 98% relative humidity (RH), 25℃ and 40 ℃ were conducted as well. The results show that in fact, form A is approximately four-fold more soluble than form B. In addition, both IBS forms are stable at ambient conditions. Nevertheless, structural and/or chemical instability was observed in form B at 40℃ and 98% RH. IBS has been confirmed as a desmotropic system rather than a polymorphic one. Consequently, forms A and B are not related monotropically.展开更多
基金Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)Agencia Nacional de Promoción de Ciencia y Tecnología (ANPCyT )Universidad Nacional de Rosario (UNR) for financial support
文摘Tioconazole(TCZ), a broad-spectrum antifungal agent, has significant activity against Candida albicans and other Candida species, and therefore, it is indicated for the topical treatment of superficial mycoses.The main goal of this work is to report an exhaustive identification and characterization procedure to improve and facilitate the online quality control and continuous process monitoring of TCZ in bulk material and loaded in two different dosage forms: ovules and nail lacquer. The methodologies were based on thermal(differential scanning calorimetry(DSC), melting point, and thermogravimetry(TG)),spectroscopic(ultraviolet(UV), Raman, near infrared(NIR), infrared spectroscopy coupled to attenuated total reflectance(FTIR-ATR), and nuclear magnetic resonance(NMR)), microscopic and X-ray diffraction(XRD). The TCZ bulk powder showed a high crystallinity, as observed by XRD, with a particles size distribution(3–95 mm) resolved by microscopic measurements. TCZ melting point(82.8 °C) and a degradation peak centered at 297.8 °C were obtained by DSC and DTG, respectively. An unambiguous structure elucidation of TCZ was obtained by mono-and two-dimensional1 H and13 C NMR spectral data analysis. The FTIR-ATR, Raman and NIR spectra of both the raw material and the commercial products were analyzed and their characteristic bands were tabulated. The best methods for TCZ identification in ovules were DSC, TG, XRD, NIR and Raman, while NIR and FTIR-ATR were the most appropriate techniques to analyze it in the nail lacquer. DSC, TG, DRX, Raman, FTIR-ATR and NIR spectroscopy are effective techniques to be used in online process analysis, because they do not require sample preparation, and they are considerably sensitive to analyze complex samples.
文摘Calcium exchanged A type zeolite is extensively used as an adsorbent in petroleum and gas purification application. The precursor of calcium and silver-exchanged zeolite was prepared in a hydrothermal process, followed by an exchange process. In this study, LTA zeolite was synthesized. Calcium-ex- changed and silver-exchanged molecular sieves were prepared and characterized by a series of techniques, such as scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, etc. Physical properties of Ca- and Ag-exchanged zeolite A, such as surface structure, crystal structure, cation exchange capacity, and the ion-exchange properties were measured. Water adsorption studies using thermogravimetric method indicated that water molecules are more strongly bound in the Ca-A zeolite compared to Ag-A zeolite. XPS studies confirmed the presence of highly dispersed cationic silver species at exchange sites. The results of this study indicated that sodium was successfully exchanged with the calcium and silver in both Ca- and Ag-ex- changed zeolite frameworks. High cation exchange capacity, tailored aperture size, high porosity and specific surface area, as well as high thermal stability make cation-exchanged A type zeolite a successful candidate for adsorption, ion exchange, and catalysis applications.
文摘This paper aims to briefly summarize the major differences in form, techniques and characterization between modern fiction and conventional realistic novels by comparatively analyzing the typical masterpiece in the two fields: Kew Gardens and Pride and Prejudice.
文摘Incremental forming is a novel die-less sheet forming process. There is a need for special means to retain lubricant at the tool/sheet interface during forming. To fulfillthe stated aim, a porous ceramic film was developed on pure Ti substrate, and it was done through an electrochemical depsition process known as plasma electrolytic oxidation. The film with preferred pore size could be realized after several attempts by varying the processing parameters. In order to characterize the film, a variety of tests including rnicrostructure, film-substrate bond strength and tribological properties tests were conducted. On-job performance of the film was also examined by forming Ti components employing a range of forming conditions. It was found that the proposed method of lubrication was effective, and the plasma eletrolytic oxidation process can be employed to fabricate films on pure Ti sheet to provide means of lubrication during incremental forming.
基金financial support of FEES-CONARE (Ref 115B5662)the University of Costa Rica (UCR)+1 种基金the Costa Rica Institute of Technology (TEC)the National Laboratory of Nanotechnology (LANOTEC)
文摘Irbesartan (IBS) is a tetrazole derivative and antihypertensive drug that has two interconvertible structures, 1H- and 2H-tautomers. The difference between them lies in the protonation of the tetrazole ring. In the solid-state, both tautomers can be isolated as crystal forms A (1H-tautomer) and B (2H-tautomer). Studies have reported that IBS is a polymorphic system and its forms A and B are related monotropically. These reports indicate form B as the most stable and less soluble form. Therefore, the goal of this contribution is to demonstrate through a complete solid-state characterization, thermodynamic study and dissolution properties that the IBS forms are desmotropes that are not related monotropically. However, the intention is also to call attention to the importance of conducting strict chemical and in solid-state quality controls on the IBS raw materials. Hence, powder X-ray diffraction (PXRD) and Raman spectroscopy (RS) at ambient and non-ambient conditions, differential scanning calorimetry (DSC), hot stage microscopy (HSM), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) techniques were applied. Furthermore, intrinsic dissolution rate (IDR) and structural stability studies at 98% relative humidity (RH), 25℃ and 40 ℃ were conducted as well. The results show that in fact, form A is approximately four-fold more soluble than form B. In addition, both IBS forms are stable at ambient conditions. Nevertheless, structural and/or chemical instability was observed in form B at 40℃ and 98% RH. IBS has been confirmed as a desmotropic system rather than a polymorphic one. Consequently, forms A and B are not related monotropically.
