Relationship between particle size and dissolution rate of bulk powders and sieving characterized fractions of two qualities of orthoboric acid

Drug Dev. Ind. Pharm. ISI Document Delivery No.: VN279 Times Cited: 1 Cited Reference Count: 22 Tromelin, A Habillon, S Andres, C Pourcelot, Y Chaillot, BInternational audienceWe have carried out a study of the particle size distribution and aqueous dissolution rate of two commercially available qualities of orthoboric acid, labeled ''crystal'' (ABC) and ''powder'' (ABP). In a previous work, we have shown that the two commercial qualities of orthoboric acid chosen as model compound (''powder'' and ''crystal'') are related to the same crystal network in spite of their different names. However, these two qualities have very different size particle distributions, as previously determined by sieving and confirmed by the present laser light scattering study. Dissolution testing is performed under sink conditions and show that the bulk ABC quality dissolves far move rapidly that the bulk ABP quality. For each quality, dissolution rates of four sieved particle size fractions (0-90 mu m; 90-125 mu m; 125-180 mu m; 180-250 mu m) were compared. Concerning the ABC quality, comparisons were also done with three other particles size fractions: 250-355 mu m, 355-500 mu m, and 500-710 mu m, This study used the dQ/dt versus t profile. Dissolution profiles of the fractions enclosing particles with a size superior to 125 mu m are very close. On the other hand, fractions enclosing particles with a size smaller than 90 mu m present a different profile and a slower rate of dissolution

Formation des agrégats à partir d'une phase cristalline d'acide orthoborique. Intérêt pour la technologie des poudres pharmaceutiques

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MgAl Hydrotalcite-derived Mixed Oxides for CO2 Adsorption

SSCI-VIDE+ATARI+VFO:AAUInternational audienceLayered Double Hydroxides (LDHs) and LDH-derived materials are potentially good adsorbents for CO2. Moreover, they are relatively cheap, they are easy to synthesize, they present high sorption capacity, and surface basicity. They have been intensively studied in CO2 capture at high temperature, presenting variable sorption capacities for MgAl LDHs with the same composition, but prepared under different synthesis conditions. The sol-gel synthesis method is an attractive one-step procedure to synthesize LDHs under mild conditions, with low energy consumption and short synthesis time. The present study is based on the synthesis of hydrotalcites (HTs) by sol-gel process for CO2 adsorption. The structural and physico-chemical properties of the as-synthesized and calcined HTs have been deeply characterized. Moreover, the effect of the surface basicity and the CO2 sorption capacity have been investigated.Adsorption calorimetry was applied for determining the concentration (from the adsorption volumetric isotherms), strength and strength distribution (using the differential heat of adsorption as a function of coverage) of the basic sites involved in CO2 adsorption. The hydrotalcite-derived mixed oxides surface basicity was probed by adsorption calorimetry of SO2.Two population of basic sites were identified, at low energy (heat of adsorption below 60 kJ/mol) and high energy (heat of adsorption higher than 150 kJ/mol). The sol-gel method led to the formation of hydrotalcites with similar (sometimes higher) performances than conventional LDHs prepared by time and energy consuming methods (like coprecipitation). The calcined hydrotalcites exhibit CO2 adsorption capacities of around 0.5 mmol/g, a value similar to those reported in the literature for sample generally synthesized by coprecipitation (see figure).A linear correlation between the surface basicity (concentration of low and high energy sites) and the adsorption capacity was found. The possibility to tune the Mg/Al molar ratio is a promising feature to obtain a wide range of LDHs (with various surface basicity) with a higher efficiency in CO2 adsorption.Acknowledgments: This work was supported by Université de Haute Alsace and École Doctorale Physique et Chimie- Physique (ED 182). XRD, NMR, XRF, BET, TGA, were performed on the technical platforms of IS2M

MgAl Hydrotalcite-derived Mixed Oxides for CO2 Adsorption

SSCI-VIDE+ATARI+VFO:AAUInternational audienceLayered Double Hydroxides (LDHs) and LDH-derived materials are potentially good adsorbents for CO2. Moreover, they are relatively cheap, they are easy to synthesize, they present high sorption capacity, and surface basicity. They have been intensively studied in CO2 capture at high temperature, presenting variable sorption capacities for MgAl LDHs with the same composition, but prepared under different synthesis conditions. The sol-gel synthesis method is an attractive one-step procedure to synthesize LDHs under mild conditions, with low energy consumption and short synthesis time. The present study is based on the synthesis of hydrotalcites (HTs) by sol-gel process for CO2 adsorption. The structural and physico-chemical properties of the as-synthesized and calcined HTs have been deeply characterized. Moreover, the effect of the surface basicity and the CO2 sorption capacity have been investigated.Adsorption calorimetry was applied for determining the concentration (from the adsorption volumetric isotherms), strength and strength distribution (using the differential heat of adsorption as a function of coverage) of the basic sites involved in CO2 adsorption. The hydrotalcite-derived mixed oxides surface basicity was probed by adsorption calorimetry of SO2.Two population of basic sites were identified, at low energy (heat of adsorption below 60 kJ/mol) and high energy (heat of adsorption higher than 150 kJ/mol). The sol-gel method led to the formation of hydrotalcites with similar (sometimes higher) performances than conventional LDHs prepared by time and energy consuming methods (like coprecipitation). The calcined hydrotalcites exhibit CO2 adsorption capacities of around 0.5 mmol/g, a value similar to those reported in the literature for sample generally synthesized by coprecipitation (see figure).A linear correlation between the surface basicity (concentration of low and high energy sites) and the adsorption capacity was found. The possibility to tune the Mg/Al molar ratio is a promising feature to obtain a wide range of LDHs (with various surface basicity) with a higher efficiency in CO2 adsorption.Acknowledgments: This work was supported by Université de Haute Alsace and École Doctorale Physique et Chimie- Physique (ED 182). XRD, NMR, XRF, BET, TGA, were performed on the technical platforms of IS2M

ECOVIR : mise en place d’une cohorte en soins primaires, un exemple de coopération pluri-professionnelle ville-hôpital

Acute Respiratory Infections (ARI) need be better understood and more effectively treated, especially insofar as they are of pivotal importance in public health, particularly during a crisis such as the SARS-CoV2 pandemic. The prospective, multicentric cohort study of viral codetections in respiratory samples study known as ECOVIR was conducted in Normandy, France during two winters (2018-2019, 2019-2020). The objective of the project was to create a biobank of respiratory tract samples from patients consulting their general practitioner (GP) for ARI symptoms. ECOVIR involved 36 GP investigators (GPI), from 8 health care centers throughout Normandy. Six hundred and eighty-five patients with ARI symptoms were included; naso-pharyngeal samples were taken by the GPIs and subsequently analyzed in virology laboratories for the purposes of viral codetection. The median of inclusions was 16 patients for each of the 31 actively participating GPIs over the two winters (CI25-75% [4.75; 27]). By D7, 92% of the patients contacted had responded to our call for participation, enabling us to obtain clinical, environmental and socio-demographic data. Through this study, we created an original functional network, thereby establishing a viable link between research and primary care, which is generally underrepresented in research protocols, even though it constitutes the cornerstone of the French health care system, especially during this prolonged period of sanitary crisis.Comprendre et traiter les infections respiratoires aiguës (IRA) sont un enjeu majeur de santé publique, particulièrement en cette période de pandémie à SARS-CoV2. ECOVIR (Étude des co-détections virales dans les prélèvements respiratoires), est une étude prospective, multicentrique, en Normandie, sur deux saisons hivernales (2018–2019 et 2019–2020). L’objectif de ce projet était de créer une biothèque de prélèvements respiratoires à partir d’une cohorte de patients consultant leur médecin traitant pour des symptômes d’IRA, permettant d’étudier les co-détections virales. Trente-six médecins généralistes investigateurs (MGI), dans 8 maisons de santé normandes, ont participé à l’étude. Au total, 685 patients ont été inclus, présentant des symptômes d’IRA, et ont bénéficié d’un prélèvement nasopharyngé au cabinet médical par les MGI pour analyse virologique. Trente et un MGI/36 ont inclus des patients. La médiane d’inclusion était de 16 patients par MGI sur les 2 saisons (IC25–75 % [4,75 ; 27]). De plus, 92 % des patients ont répondu à l’appel à j7, recueillant des données cliniques, environnementales, et sociodémographiques. Nous avons donc créé un vrai réseau, original, permettant d’assurer un lien entre la recherche et les soins primaires, peu représentés dans les protocoles de recherche mais qui sont la pierre angulaire de notre système de santé en France, comme nous le constatons actuellement avec la crise sanitaire