Publications by authors named "Philippe Espeau"

Three-dimensional printing (3DP) technology in pharmaceutical areas is leading to a significant change in controlled drug delivery and pharmaceutical product development. Pharmaceutical industries and academics are becoming increasingly interested in this innovative technology due to its inherent inexpensiveness and rapid prototyping. The 3DP process could be established in the pharmaceutical industry to replace conventional large-scale manufacturing processes, particularly useful for personalizing pediatric drugs.

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Studies of the interactions between paracetamol, chosen as model active ingredient, and PEG 1500, a pharmaceutical carrier, are conducted in the solid state. Solid dispersions of PEG 1500 and paracetamol were prepared in different mass ratios. Two temperature cycles are then applied and the characterization is carried out by DSC and X-ray powder diffraction.

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Lung cancer is a highly vascularized tumor for which a combination between an antitumor agent, cisplatin, and an antiangiogenic molecule, fisetin, appears a promising therapeutic approach. In order to deliver both chemotherapies within the tumor, to enhance fisetin solubility and decrease cisplatin toxicity, an encapsulation of both drugs into liposomes was developed. Purification and freeze-drying protocols were optimized to improve both the encapsulation and liposome storage.

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The dehydration of prednisolone sesquihydrate is studied and characterized by different physico-chemical analysis methods. The meticulous study of this dehydration led to the highlighting of a new solid form (form 3), metastable, never identified before. In a second step, the rehydration of anhydrous forms 1 and 2 of prednisolone is studied, in particular by Dynamic Vapor Sorption.

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This study describes the preparation, characterization, and influence of the enantiopure vs. racemic coformer on the physico-chemical properties of a pharmaceutical cocrystal. For that purpose, two new 1:1 cocrystals, namely lidocaine:dl-menthol and lidocaine:d-menthol, were prepared.

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The stable and metastable phase diagrams between the sinister and the rectus ibuprofen enantiomers were established by means of thermal analysis and X-ray powder diffraction experiments as a function of temperature. The results obtained allow proving for the first time the existence, for the stable system, of a solid solution by mixing the racemic ibuprofen with one of its enantiomers for low concentration of the enantiomer. Since the rectus ibuprofen is a non-active pharmaceutical agent which can be partially bio-converted into the sinister enantiomer, the present work offers a new approach for scalemic mixtures preparation in order to improve the benefit/risk ratio related to ibuprofen solid dosage form administration.

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(1) Background: Glioblastoma (GBM) is the most frequent cerebral tumor. It almost always relapses and there is no validated treatment for second-line GBM. We proposed the coencapsulation of fisetin and cisplatin into liposomes, aiming to (i) obtain a synergistic effect by combining the anti-angiogenic effect of fisetin with the cytotoxic effect of cisplatin, and (ii) administrate fisetin, highly insoluble in water.

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The solid-form screening of active principal ingredients is a challenge for pharmaceutical drug development, as more than 80 % of marketed drugs are formulated in the solid form. A broad and comprehensive study of the various solid forms of drugs is needed to enhance their translation into the clinic. Therefore, the most suitable solid form must be taken into consideration regarding ex vivo and in vivo stability, targeting, solubility, dissolution rate, and bioavailability.

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Amphiphilic triblock (Atri) copolymers made of perfluorinated alkyl chain linked to hydrocarbon chain and methoxy-poly(ethylene glycol) of three different molecular weights were synthesized. In vitro evaluation demonstrated that these new compounds were noncytotoxic. Characterization and interaction of each triblock copolymer with a branched polyamine myristoyl lipid (2-{3[bis-(3-amino-propyl)-amino]-propylamino}- N-ditetradecyl carbamoyl methyl-acetamide, DMAPAP) were studied by the Langmuir film method and thermal analysis.

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Prednisolone is known to exist in two anhydrous solid polymorphic forms. The substance is known to degrade upon melting, resulting in erroneous melting data, as shown by the widely scattered results reported in the literature. In this article, thermal analyses carried out at different scan rates show that the onset temperature and the enthalpy value of the signal increase with the scan rate and reach plateau values for high scan rates.

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Cell penetrating peptides are promising vectors for molecular drug delivery in eukaryotic cells. Despite of their discovery 20years ago, the mechanisms of peptide membrane crossing are still controversial. The different suggested penetration mechanisms reflect the high sequence and structural diversity of cell penetrating peptides.

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Fast scanning calorimetry, a technique mainly devoted to polymer characterization, is applied here for the first time to low molecular mass organic compounds that degrade upon melting, such as ascorbic acid and prednisolone. Due to the fast scan rates upon heating and cooling, the substances can be obtained in the molten state without degradation and then quenched into the glassy state. The hydrated form and the polymorphic Form 1 of prednisolone were investigated.

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Purpose: The objective was to develop, characterize and assess the potentiality of W1/O/W2 self-emulsifying multiple nanoemulsions to enhance signal/noise ratio for Magnetic Resonance Imaging (MRI).

Methods: For this purpose, a new formulation, was designed for encapsulation efficiency and stability. Various methods were used to characterize encapsulation efficiency ,in particular calorimetric methods (Differential Scanning Calorimetry (DSC), thermogravimetry analysis) and ultrafiltration.

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The three known polymorphs of malonamide have been characterized by thermal analysis and X-ray powder diffraction. The melting thermodynamic characteristics of the three forms are thus proposed in the present paper. From these data, the relative thermodynamic stability of these three solid forms has been determined.

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The aim of this study was to investigate the solid dispersion phase behavior of s- or rs-ibuprofen in stearic acid. By means of thermal analysis, we have demonstrated the total immiscibility, in solid state, of the corresponding binary mixtures. This indicates that no specific interactions exist between the chosen excipient and active pharmaceutical ingredient (API) that lead to eutectic systems.

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Although quinacrine dihydrochloride dihydrate is a widely used drug substance, a comprehensive determination of its stability profile is lacking. In this work, an integrative approach is implemented to determine the drug stability both in the solid state and aqueous solutions, identify the impurities that can be found in the active pharmaceutical ingredient, and evaluate the associated toxicity risks. Thermal analyses pointed out a two-step dehydration of the solid state.

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In 1981, Jacques, Collet, and Wilen already put forward the idea to use pressure to influence equilibria in binary enantiomer systems in analogy with temperature (Jacques et al. Enantiomers, Racemates and Resolutions; John Wiley & Sons: New York, 1981). Whereas temperature is used routinely to study phase equilibria, pressure is an all but forgotten parameter.

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We present the synthesis, structure determination, and thermodynamic properties of a never reported cocrystal prepared with lidocaine and L-menthol. The temperature-composition phase diagram of the lidocaine/L-menthol binary system was achieved using differential scanning calorimetry and X-ray diffraction experiments. The present study demonstrates that the only way to perform a phase equilibrium survey of the lidocaine/L-menthol system is to prepare the binary mixtures from the cocrystal, an equimolar stoichiometric compound of L-menthol and lidocaine.

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The pressure-temperature (P-T) melting curve of lidocaine was determined (dP/dT = 3.56 MPa K(-1)), and the lidocaine-water system was investigated as a function of temperature and pressure. The lidocaine-water system exhibits a monotectic equilibrium at 321 K (ordinary pressure) whose temperature increases as the pressure increases until the two liquids become miscible.

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Temperatures and melting enthalpies of orthorhombic Phases I and II of natural progesterone, together with the temperature dependence of their lattice parameters and the specific volume of the melt at ordinary pressure, have been determined. With these results, a topological pressure-temperature (P-T) phase diagram accounting for the thermodynamic relationships between these phases has been constructed by way of the Clapeyron equation. The dependence of the melting temperature on the pressure has also been determined for each phase by high-pressure differential thermal analysis.

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The phase relationships involving the metastable orthorhombic (R(I)) phase and the stable triclinic (T) phase were established for even-numbered carbon atom n-alkanes in the range of 8-20 carbon atoms. It is shown that the R(I) phase behaves monotropically whatever the pressure and temperature (i.e.

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The thermodynamic relationships between the two known polymorphs of paracetamol have been investigated, and the subsequent pressure-temperature and temperature-volume phase diagrams were constructed using data from crystallographic and calorimetric measurements as a function of the temperature. Irrespective of temperature, monoclinic Form I and orthorhombic Form II are stable phases at ordinary and high pressures, respectively. The I and II phase regions in the pressure-temperature diagram are bordered by the I-II equilibrium curve, for which a negative slope (dp/dT approximately -0.

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