In vitro release studies of furosemide reference tablets: influence of agitation rate, USP apparatus and dissolution media

Furosemide is a diuretic drug widely used in chronic renal failure. The drug has low solubility and permeability, which cause clinical problems. Studying the in vitro release performance elucidates the rate and extent of drug dissolved from dosage forms under different conditions. Furosemide reference tablets were tested using USP Apparatuses 1 and 2 as well as the flow-through cell method (USP Apparatus 4), a dissolution apparatus that simulates the human gastrointestinal tract better than the other methods. Dissolution profiles were created with USP Apparatuses 1 and 2 at 25, 50, and 75 rpm and 900 mL of 0.1 M hydrochloric acid, acetate buffer (pH 4.5), and phosphate buffer (pH 6.8). USP Apparatus 4 with a laminar flow of 16 mL/min and 22.6 mm cells was used. Drug dissolution was quantified at 274 nm for 60 min. Mean dissolution time, dissolution efficiency, time to 50 % dissolution, and time to 80 % dissolution data were used to compare dissolution profiles. Additionally, zero-order, first-order, Higuchi, Hixson-Crowell, Makoid-Banakar, and Weibull models were used to adjust furosemide dissolution data. Between USP Apparatus 1 and 2, significant differences were observed in almost all parameters at 50 and 75 rpm (p 50) with a pharmacopoeial dissolution method (USP Apparatus 2 at 50 rpm and 900 mL of phosphate buffer pH 5.8) and USP Apparatus 4 (laminar flow of 16 mL/min, 22.6 mm cells, and pH 6.8) was observed. The Weibull function was the best mathematical model to describe the in vitro release performance of furosemide in the three USP dissolution apparatuses. These results could be used to manufacture better furosemide dosage forms and decrease the negative clinical impact of current furosemide formulations.</p

Active oxygen by Ce–Pr mixed oxide nanoparticles outperform diesel soot combustion Pt catalysts

A Ce0.5Pr0.5O2 mixed oxide has been prepared with the highest surface area and smallest particle size ever reported (125 m2/g and 7 nm, respectively), also being the most active diesel soot combustion catalyst ever tested under realistic conditions if catalysts forming highly volatile species are ruled out. This Ce–Pr mixed oxide is even more active than a reference platinum-based commercial catalyst. This study provides an example of the efficient participation of oxygen species released by a ceria catalyst in a heterogeneous catalysis reaction where both the catalyst and one of the reactants (soot) are solids. It has been concluded that both the ceria-based catalyst composition (nature and amount of dopant) and the particle size play key roles in the combustion of soot through the active oxygen-based mechanism. The composition determines the production of active oxygen and the particle size the transfer of such active oxygen species from catalyst to soot.The authors thank the financial support of Generalitat Valenciana (Project PROMETEOII/2014/010), the Spanish Ministry of Economy and Competitiveness (Project CTQ2012-30703), and the UE (FEDER funding)

Behavior of different soot combustion catalysts under NOx/O2. Importance of the catalyst–soot contact

Four different catalysts (Pt/Al2O3, Ce0.8Zr0.2O2, PrO2−x and SrTiCuO3) have been investigated on a laboratory scale to evaluate their potential as diesel soot combustion catalysts under different experimental conditions, which simulate the situation found in a continuous regeneration technology trap (dual-bed configuration of catalyst and soot) or a catalyst-coated filter system (single-bed configuration, both catalyst and soot particles mixed under loose-contact mode). Under dual-bed configuration, the behavior of the catalysts towards soot combustion are very similar, despite the differences observed in the NO2 production profiles. However, under single-bed configuration, there are important differences in the soot combustion activities and in the NO2 slip profiles. The configurations chosen have an enormous impact on CO/(CO + CO2) ratios of combustion products as well. The most active catalyst under NOx + O2 is PrO2−x combining a high contribution of active oxygen-assisted soot combustion as well as high NO2 production activity along the catalytic bed.Financial support of Generalitat Valenciana (Prometeo/2009/047 project) and the Spanish Ministry of Science and Innovation (project CTQ2012-30703, which is co-funded by FEDER resources). N. G. H. wishes to thank Generalitat Valenciana her Ph.D. grant within VAL i+d Program

Efficience des missions sociales d’education en utilisant la logique floue.

This research had as objective to determine a mathematical model of efficiency of the social missions directed to the education in the Metropolitan Area of Mérida through the fuzzy logic method for the measurement of the phenomenon under study, achieving to explain the efficiency of the educational missions from a multidimensional approach. The research carried out presents a descriptive-exploratory methodology, which allowed describing and explaining variables not included in the traditional methods of measuring social policy efficiency. In the research, the units of observation were the beneficiaries or participants of each of the social educational missions (Robinson, Ribas, Sucre), through a sample of 330 people. It was concluded that educational missions obtained an efficiency threshold described by: [0.263, 0.329], [0.291, 0.355], [0.254, 0.324] respectively, representing a classification of almost inefficient to close to inefficient.Esta investigación tuvo como objetivo determinar un modelo matemático de eficiencia de las misiones sociales dirigidas a la educación en el Área Metropolitana del Estado de Mérida mediante la aplicación de lógica difusa para la medición integral del fenómeno en estudio, lográndose explicar la eficiencia de las misiones educativas desde un enfoque multidimensional. La metodología de tipo descriptivo-exploratorio, permitió describir y explicar variables no contempladas en métodos tradicionales de medición de eficiencia de políticas sociales. En la investigación, las unidades de objeto de observación y estudio fueron los beneficiarios o participantes de cada una de las misiones sociales educativas (Robinson, Ribas, y Sucre), mediante una muestra de 330 personas, significativa de la población. Se concluyó que durante el periodo de estudio (2013-2015), las misiones educativas obtuvieron un umbral de eficiencia descrito por: [0.263, 0.329], [0.291, 0.355], [0.254, 0.324] respectivamente, que representa una clasificación de casi ineficiente a cercana a ineficiente.L’objectif de cette recherche était de déterminer un modèle mathématique de l’efficacité des missions sociales visant l’éducation dans la région métropolitaine de l’État de Mérida, au moyen d’une logique floue. L’application de la logique floue a permis l’utilisation de variables objectives et subjectives pour la mesure intégrale du phénomène à l’étude, en permettant d’expliquer l’efficacité des missions éducatives à partir d’une approche multidimensionnelle. La recherche effectuée présente une méthodologie de type descriptive-exploratoire, qui a permis de décrire et d’expliquer des variables ignorées dans les méthodes traditionnelles de mesure de l’efficacité des politiques sociales. Dans l’enquête, les unités d’observation et d’étude étaient les bénéficiaires ou les participants de chacune des missions sociales éducatives (Robinson, Ribas et Sucre). Nous avons travaillé sur un échantillon de 330 personnes, ce qui représente un nombre important de la population pour élaborer les résultats. Il a été conclu qu’au cours de la période étudiée 2013-2015, les missions éducatives avaient atteint un seuil d’efficacité décrit par: [0.263, 0.329], [0.291, 0.355], [0.254, 0.324] respectivement, ce qui correspond à une classification presque inefficace presque inefficace

Study of Ce/Pr ratio in ceria-praseodymia catalysts for soot combustion under different atmospheres

The effect of Ce/Pr ratio on ceria-praseodymia on structural and surface properties is studied. The catalytic activity towards soot combustion under NOx/O2 and O2/N2 atmospheres is also evaluated, together with the NO oxidation activity to NO2. CexPr1-xO2-δ compositions (x = 0.8, 0.5 and 0.2) have been prepared along with ceria and praseodymia. Catalysts were prepared by co-precipitation. The Ce0.5Pr0.5O2-δ composition, was also prepared by nitrate calcination. Ceria-praseodymia mixed oxides yield reduction profiles shifted to lower temperatures, higher NO oxidation activities to NO2 and improved catalytic activities for soot combustion with respect to pure ceria. Ce0.5Pr0.5O2-δ was the most active one. Under NOx/O2, it has greater soot combustion activity if it is prepared by nitrate calcination. However, under O2/N2, the co-precipitation method is more favorable because of the better dopant insertion achieved in the ceria lattice, which seems to lead better oxygen mobility on the surface and in the bulk oxide.The authors gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEO/2018/076 project) and the Spanish Ministry of Economy and Competitiveness (CTQ2015-64801-R project) and the UE-FEDER funding. J.C.M.M. also acknowledges Spanish Ministry of Science, Innovation and Universities for the financial support through a FPU grant (FPU17/00603)

Ceria-Praseodymia Mixed Oxides: Relationships Between Redox Properties and Catalytic Activities Towards NO Oxidation to NO2 and CO-PROX Reactions

A series of CexPr1−xO2−δ catalysts was prepared by co-precipitation method in alkali media. These catalysts were characterized by N2 adsorption–desorption isotherms at −196 °C, X-ray diffraction, thermogravimetry combined with mass spectrometry (TG-MS), and temperature-programmed reduction with H2 and CO (H2-TPR and CO-TPR, respectively). Catalytic tests were performed for temperature programmed NO oxidation to NO2 (from 25 to 750 °C) and for the preferential oxidation of CO in H2 rich stream (CO-PROX reaction) in the range of 150–500 °C. The trends in the order of catalytic activities towards NO oxidation and CO-PROX are correlated with the redox properties of the catalysts and their composition. CexPr1−xO2−δ mixed oxides present very different catalytic behaviours towards NO oxidation and CO-PROX reactions. These experimental trends might be explained by the balance of several factors: the acid character of the NO and CO molecules, the different lattice oxygen mobility of the catalysts, the presence of surface carbonates species in the samples, and the catalysts’ reducibility under H2 and CO. The understanding of the features that govern the activity towards these environmentally relevant oxidation reactions is important in the designing of effective catalysts.The authors gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEOII/2014/010), MINECO (CTQ2015-64801-R, MAT2013-40823-R, CSD2009-00013) and the UE (FEDER funding). X. Chen thanks the program of “Ramón y Cajal” from Ministry of Science and Innovation of Spain

Strong dispersion effect of cobalt spinel active phase spread over ceria for catalytic N2O decomposition: The role of the interface periphery

A series of Co3O4/CeO2 catalysts with increasing cobalt spinel loading in the range of 1–20 wt.% was prepared by incipient wetness impregnation of CeO2. The obtained catalysts were thoroughly examined by XRD, XPS, XRF, RS, TEM/EDX/EELS, TPR and BET techniques. The catalytic tests in deN2O reaction revealed that the 10 wt.% of cobalt spinel in supported system is able to reproduce the activity of bare Co3O4 catalyst. However, it was found that the catalyst with the lowest content of Co3O4 equal to 1 wt.% exhibits the highest apparent reaction rate per mass of the spinel active phase. The observed activity was explained basing on the transmission electron microscopy analysis in terms of the dispersion of spinel phase over ceria support. A simple model that accounts for the observed strong dispersion effect is proposed. It consists in a two-step mechanism, where N2O is dissociated on the spinel nanograins and the resultant oxygen species are preferentially recombined at the Co3O4/CeO2 interface periphery.The authors would like to acknowledge the Polish National Centre for Research and Development funding awarded by the decision number PBS2/A5/38/2013. On the Polish part the research was partially carried out with the equipment purchased thanks to the financial support of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (contract no.POIG.02.01.00-12-023/08)

Moxifloxacin versus Clindamycin/Ceftriaxone in the management of odontogenic maxillofacial infectious processes: a preliminary, intrahospital, controlled clinical trial

Background: The aim of this study was to compare the days of hospitalization length between patients treated with Moxifloxacin with that of patients treated with a Clindamycin/Ceftriaxone combination and additionally, to isolate and identify the oral pathogens involved in orofacial odontogenic infections. Material and Methods: A pilot-controlled-clinical-trial was carried out on hospitalized patients with cervicofacial odontogenic abscesses or cellulitis, who were randomly asigned to two study groups: 1) patients who received Moxifloxacin, and 2) patients receiving Clindamycin/Ceftriaxone combination. Infiltrate samples were collected through transdermic or transmucosal punction and later cultured on a media specific for aerobic and anaerobic microorganisms. Mean hospitalization duration in days until hospital discharge and susceptibility assessment in rates were established. Results: Mean hospitalization time in days of patients treated with Moxifloxacin was 7.0 ± 1.6 days, while in the Clindamycin/Ceftriaxone group, this was 8.4 ± 1.8 days, although significant difference could not be demonstrated ( p =0.074). A total of 43 strains were isolated, all of these Gram-positive. These strains appeared to be highly sen - sitive to Moxifloxacin (97.5%) and Ceftriaxone (92.5%). Conclusions: Moxifloxacin and Ceftriaxone appear to be potential convenient and rational alternatives to traditional antibiotics, for treating severe odontogenic infections, in conjunction with surgical extraoral incision, debridement, and drainage

Catalytic Soot Oxidation Activity of NiO–CeO2 Catalysts Prepared by a Coprecipitation Method: Influence of the Preparation pH on the Catalytic Performance

A series of NiO–CeO2 mixed oxide catalysts have been synthesized by a modified coprecipitation method at three di erent pH values (pH = 8, 9, and 10). The NiO–CeO2 mixed oxide samples were characterized by TGA, XRD, inductively coupled plasma atomic emission spectroscopy (ICP-AES), FTIR, Brunauer–Emmett–Teller (BET) surface area, H2 temperature-programmed reduction (H2-TPR), and electron microscopy (high-angle annular dark-field transmission electron microscopy/energy-dispersive X-ray spectroscopy (HAADF-TEM/EDS)). The catalytic activities of the samples for soot oxidation were investigated under loose and tight contact conditions. The catalysts exhibited a high BET surface area with average crystal sizes that varied with the pH values. Electron microscopy results showed the formation of small crystallites (~5 nm) of CeO2 supported on large plate-shaped particles of NiO (~20 nm thick). XRD showed that a proportion of the Ni2+ was incorporated into the ceria network, and it appeared that the amount on Ni2+ that replaced Ce4+ was higher when the synthesis of the mixed oxides was carried out at a lower pH. Among the synthesized catalysts, Ni-Ce-8 (pH = 8) exhibited the best catalytic performance

Evidences of the Cerium Oxide-Catalysed DPF Regeneration in a Real Diesel Engine Exhaust

The active phase Ce0.5Pr0.5O2 has been loaded on commercial substrates (SiC DPF and cordierite honeycomb monolith) to perform DPF regeneration experiments in the exhaust of a diesel engine. Also, a powder sample has been prepared to carry out soot combustion experiments at laboratory. Experiments performed in the real diesel exhaust demonstrated the catalytic activity of the Ce–Pr mixed oxide for the combustion of soot, lowering the DPF regeneration temperature with regard to a counterpart catalyst-free DPF. The temperature for active regeneration of the Ce0.5Pr0.5O2-containing DPF when the soot content is low is in the range of 500–550 °C. When the Ce0.5Pr0.5O2-containing DPF is saturated with a high amount of soot, pressure drop and soot load at the filter reach equilibrium at around 360 °C under steady state engine operation due to passive regeneration. The uncoated DPF reached this equilibrium at around 440 °C. Comparing results at real exhaust with those at laboratory allow concluding that the Ce0.5Pr0.5O2-catalysed soot combustion in the real exhaust is not based on the NO2-assisted mechanism but is most likely occurring by the active oxygen-based mechanism.The authors thank the financial support of Generalitat Valenciana (Project Prometeo 2009/047), Spanish Ministry of Science and Innovation (project CIT-420000-2009-48) and EU (FEDER funding)