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International audience; A new absorption spectroscopy method which enables rapid measurement of the diffusion coefficient of Fe3+ in gelatin gel used in dosimetry was investigated. The physical approach, the preparation and the experimental application of this new method were tested on the EasyDosit dosimetry gel and the results were validated by MRI measurement. The diffusion coefficients measured on this gel were then compared with those of the other gels presented in the literature. This gel, which is considered stable, has a small post-irradiation ion diffusion, despite the absence of a complexing or crosslinking agent. The diffusion coefficients of a range of dosimetry gels containing different proportions of gelatin were also measured and the results show diffusion coefficients D from 3.21.10(-10) m(2).s(-1) to 2.41.10(-10) m(2).s(-1).

International audience; A new range of equivalent tissue materials has been formulated starting from proprietary gelatin-based gels. Depending on the formulation and the experimental conditions these materials have radiological properties close to breast tissue, compact bone or lung tissue with respect to photon, electron, and neutron interactions and they have also morphology and mechanical properties close to the biological specimen. These new equivalent-tissues materials contain paramagnetic elements and can be used for MRI dosimetry. This paper describes the preparation and the physical properties of these tissue-inspired formulations.

In this study the spectrophotometric behaviour of gelatin-based hydrogels, in the presence and absence of dyes, was studied. The aim was to formulate equivalent-tissue phantoms to be used as 3D-dosimeter, suitable for Optical Computed Tomography (OCT). The hydrogels show good transparency and good stability of baseline optical density and, in the presence of dye, the response of optical density as a function of concentration was higher than in aqueous solution. The hydrogels were formulated in order to reduce the diffusion of the image of the irradiated field over time and to have stable fantoms as a function of time. To this purpose, the diffusion coefficients of two dyes, Bromophenol Blue (BPB) and Bromocresol Green (BCG), were determined as a function of the hydrogel chemical composition. As comparison, in some experiments Xylenol Orange (XO) was used. In particular, the presence of sucrose, as thickener, can reduce to almost half BPB mobility. In conclusion, it was shown that optical properties and controlled dye diffusion in gelatin-based hydrogels could allow using them as 3D-dosimeter for optical detection.

Reactions of Co(II) and Ni(II) salts with the monosodium salt of 3-hydroxy-4-nitrobenzoic acid (3) in aqueous solution resulted in isomorphous covalent complexes 3C and 3D, of centrosymmetric geometries. In similar conditions, 2-hydroxy-4-methoxybenzoic acid (5) led to the covalent Zn(II) complex 5A, exhibiting a marked dissymmetric geometry. The present crystallographic data with structural data for a series of closely related metal complexes previously reported allow a tentative rationalization of the solid-state architecture of such complexes. The dissymmetry in 5A was interpreted on the basis of a mixed (monodentate and bidentate) metal-ligation mode and a pyramidal coordination at the metal.

The purpose of this study was to investigate the complexes formed by copper(II) with potential non-steroidal anti-inflammatory agents (NSAIDs) under physiological conditions. A former study suggested that 2-benzylaminomethylpyrrolidine ligands could be good candidates as potential OIL ( OH-inactivating ligand) when complexed to copper(II). In order to assess the chemical behavior as OIL, [S]-2-[N-(2′-hydroxybenzyl)aminomethyl]pyrrolidine (OHbamp) was synthesized and bound to copper(II). Physico-chemical properties were determined at 37 °C in 0.15 M NaCl using glass electrode potentiometry, UV–Vis and circular dichroism spectroscopies, before and after copper(II) complexation. [Cu(OHbamp)(H2O)3]+ was the main complex found at both physiological and inflammatory pH values, showing appreciable stability at pathological pH compared to copper(II) complexes of histidine, the predominant low-molar-mass ligand of copper(II) in blood plasma. However, neutral species such as [Cu(OHbamp)2(H2O)2] and [Cu(OHbamp)(OH)(H2O)3] are predominant only above pH 8, preventing a significant amount of drug from diffusing through membranes at inflammatory pH. In conclusion, copper(II)-OHbamp system does not meet all the requirements to be an OIL. Nevertheless, these results allow us to better identify the chemical features needed for a good OIL candidate.

The crystal structures of two Mg(II) complexes of 3-hydroxy-4-nitrobenzoic acid have been reported. The first complex, 2 (C14H20N2O16Mg), consists of ionic entities comprising one hexaaquamagnesium cation and two organic carboxylate anions. The second complex, 3 (C7H15NO11Mg) consists of zwitterionic entities comprising one organic ligand per Mg atom. In both cases, the complexes are linked through an extensive hydrogen bonding network. The 3D supramolecular architectures of these complexes are also stabilized by two types of stacking interactions. An interesting interconversion between the two complexes was observed in aqueous solution.

International audience; Monocalcium phosphate monohydrate (MCPM) was obtained by water extraction of triple superphosphate. The solubility of MCPM is 783.1 g/L, and is entirely soluble. Saturated MCPM solution dissociates into free phosphoric acid and monetite (CaHPO4), but evaporation to dryness by spray drying forms MCPM during crystallization. Complete characterization by infrared, X-ray diffraction, and scanning electron microscopies and NMR is reported for MCPM and the derived pyrophosphates.