Materiales Compuestos Zeolita-Surfactante-Fármaco con Uso Potencial en la Industria Farmacéutica

Ce travail étudie les matériaux composites zéolithes surfactifs, principes actifs pour des applications pharmaceutiques. D'abord sont identifiées les principales propriétés physiques, chimiques et biologiques des matériaux, requises pour des applications en tant que supports médicamenteux ciblant certaines formes de cancer. Par la suite sont décrits les différentes étapes de formulation des supports médicamenteux à base des zéolithes naturelles, les caractéristiques des matériaux intermédiaires ainsi obtenus, ainsi que les mécanismes des phénomènes interfaciaux à l'origine de l'action de ces matériaux. La dernière partie est consacrée à l'étude d'un relargage contrôlé des principes actifs de l'interface jusque dans un milieu aqueux modèle.This work studies the composite zeolites surfactants, active principles for pharmaceutical applications. First identified the main physical, chemical and biological materials, required for applications as drug carriers targeting some cancers. Subsequently described the various stages of formulation of drug carriers based on natural zeolites, the characteristics of intermediate materials obtained, and the mechanisms of interfacial phenomena at the origin of the action of these materials. The last part is devoted to the study of controlled release of active ingredients of the interface into a model aqueous medium.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

NMR; 129Xe; alkali metals; Metal clusters; bimetallic; AlPO4-5; NaY

International audienceDehydrated NaY zeolite and AlPO4-5 molecular sieves have been reacted with sodium, rubidium and cesium metal vapor and sodium metal vapor, respectively. Using 129Xe, 23Na, 87Rb and 133Cs solid state NMR technique, we were able to characterize the sodium nanoparticles and Na-M bimetallic alloys (M=Rb, Cs) formed in the cavities of NaY zeolite and in the channels of AlPO4-5 molecular sieves

Application de La RMN a L'Etude De La Chimisorption de L'Hydrogene sur Platine Supporte

International audienceL'étude par RMN de l'adsorption de l'hydrogène sur platine supporté a permis de mettre en évidence par spectroscopie l'hydrogène fortement chimisorbé sur ce métal. Celui-ci peut se trouver sous deux formes. L'une, indépendante de la nature du support et de la taille des particules est liée au métal par liaison covalente ou métallique. La liaison Pt-H évolue avec le diamètre de la particule et le taux de recouvrement de la surface. La nature de la seconde forme, essentiellement détectée sur le platine supporté sur silice, n'a pas encore été déterminée

Removal of basic dyes from aqueous solutions with a treated spent bleaching earth

International audienceA spent bleaching earth from an edible oil refinery was treated by impregnation with a normal sodium hydroxide solution followed by mild thermal treatment (100 ◦C). The obtained material (TSBE) was washed, dried, and characterized by X-ray diffraction, FTIR, SEM, BET, and thermal analysis. The clay structure was not apparently affected by the treatment and the impregnated organic matter was quantitatively removed. We have investigated the comparative sorption of safranine and methylene blue on this material, the spent bleaching earth (SBE), and the virgin bleaching earth (VBE). The kinetic results fit the pseudo-second-order kinetic model and the Weber and Morris intraparticle diffusion model. The pH had no effect on the sorption efficiency. The sorption isotherms followed the Langmuir model for various sorbent concentrations with good values of the determination coefficient. A linear relationship was found between the calculated maximum removal capacity and the solid/solution ratio. A comparison between the results obtained with this material and those of the literature highlighted the low cost and the good removal capacity of treated spent bleaching earth

Nuclear magnetic resonance study of xenon adsorbed on metal-NaY: zeolites

The NMR spectrum of 129Xe adsorbed on a sample of platinum supported on NaY zeolite, at 25°C, consists usually of a single component whose chemical shift is : δ (Xe) = λ . δPt + μ . δs + δ(Xe–Xe). PXe where δPt, δS and δ(Xe–Xe) are the chemical shifts of Xe atoms colliding with the platinum particles, the wall S of the supercages or another Xe atom, respectively. pXe is the adsorbate density ; λ and μ are the Xe-Pt and Xe-S collision frequencies. We have shown that it is possible to calculate the shift δPt from the dependence of δ (Xe) on pXe. δPt varies with the number of Pt atoms per particle, x and with the coverage of the metal surface by prechemisorbed hydrogen. The high value of δPt is attributed to charge transfer from xenon to the metal (Pt–, Xe+)

Photocatalytic decolourization of indigo carmine on 1,10-phenanthrolinium intercalated bentonite under UV-B and solar irradiation

International audienceIn the present work, organophilic clay was prepared and characterized by XRD, FT-IR, TGA, 13C MAS NMR and UV-vis DRS. The obtained material was investigated as photocatalyst on photo-decolourization of indigo carmine under UV-B and solar irradiation. The decolourization capacity of the obtained material against indigo carmine was very low. Besides, the kinetic photo-decolourization data under UV-B and solar irradiation fitted well the pseudo-first order and Langmuir-Hinshelwood kinetic models. The photodecolourization rate was found better under solar than UV-B irradiation. A total colour removal was obtained at natural pH after 160 min of solar irradiation of a 10mg L−1 indigo carmine solution. The prepared material was used four times with practically the same decolourization efficiency

129Xe NMR Study of Small Sodium Particles in NaY Zeolite

International audienceThe distribution of sodium metal particles inside the cavities of a NaY zeolite has been investigated using 129Xe NMR spectroscopy. For a sample prepared by vapor-phase deposition at 520 K, the 129Xe NMR spectrum shows three lines which are interpreted in terms of domains of a nonuniformly distributed metal particles, oxidized particles, and empty cavities. After annealing the sample at 670 K, the lz9Xe spectrum collapses to one single line, characteristic of a narrow particle size distribution. Oxidation of the sample by oxygen decreases the chemical shift of the 129Xe NMR line, which is mainly due to a loss of paramagnetism and a volume contraction of the small sodium metal particles

Removal of Evans Blue and Yellow thiazole dyes from aqueous solution by Mg-Al-CO3 Layered Double Hydroxides as anion-exchanger

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Nuclear magnetic resonance study of xenon adsorbed on metal-NaY zeolites. A new method for the determination of the mean number of atoms in small metallic particles supported on Y zeolites

International audienceA nuclear magnetic resonance study of xenon adsorbed on Pt-NaY zeolites, with or without pre-chemisorbed hydrogen, has made it possible, first, to prove that chemisorption of hydrogen occurs homogeneously on all particles of similar size, and, secondly, to determine the number of platinum particules and therefore their mean size. This technique seems highly useful when particles contain very few atoms and cannot be detected by electron microscopy

Benzalkonium chloride and sulfamethoxazole adsorption onto natural clinoptilolite: Effect of time, ionic strength, pH and temperature

International audienceThe influence of different physical factors on the adsorption of the cationic surfactant benzalkoniumchloride (BC) and the model drug sulfamethoxazole by a purified natural clinoptilolite (NZ) has been studied in order to employ zeolite-surfactant-drug composites as drug deliverer. It has been demonstrated that the adsorption of BC and sulfamethoxazole onto NZ depends of the time, the temperature, the ionic strength and the pH of the aqueous medium. The optimal conditions for the preparation of the zeolite-surfactant and zeolite-surfactant-drug composite materials are established. The results of the composite characterization support the presence of BC and sulfamethoxazole, as well as the structural stability of NZ during the treatments performed. The release experiments in acid medium demonstrate that the adsorption of sulfamethoxazole is reversible. It is also confirmed that the drug release profile corresponds to a diffusion or zero-order mechanism as a function of the compression pressure