Deducing high pressure behavior for chemically fragile systems: the polymorphism of spironolactone

International audienc

La crénothérapie (relations entre la composition chimique des eaux thermales et leurs indications thérapeutiques)

PARIS-BIUP (751062107) / SudocSudocFranceF

Contribution de la thermodynamique classique à l'établissement de la hiérarchie de stabilité des variétés cristallines d'un matériau moléculaire à usage thérapeutique

En pharmacie industrielle, le choix raisonné de la variété cristalline d une substance active est une étape essentielle du développement d un nouveau médicament. La réponse à cet impératif actuel passe par la re-découverte de la thermodynamique classique des états d équilibre. A l aide de l interprétation géométrique de la thermodynamique inventée par Gibbs mais totalement oubliée aujourd hui- appliquée à des données cristallographiques et calorimé-triques spécifiques du composé étudié, la hiérarchie de stabilité des polymorphes d une substance active donnée peut être établie avec certitude au travers de la construction topologique du diagramme de phases pression-température . Alternative rigoureuse à l approche règles de Burger et diagrammes énergie-température hégémoni-quement employée aujourd hui dans les laboratoires académiques et industriels malgré des fondements erronés, cette méthodologie originale est exposée au travers d aspects historiques, théoriques et appliquésPARIS-BIUP (751062107) / SudocSudocFranceF

On the Dimorphism and the Pressure-Temperature State Diagram of Gestodene, a Steroidal Progestogen Contraceptive

International audienc

Solid-State Characterization of Enantiomeric and Racemic Hydrated and Anhydrous Zinc-Pidolate Complexes

Zn(II) L- and DL-pidolates diaqua complexes dehydrate at around 407 K, leading to amorphous anhydrous complexes. Only amorphous anhydrous Zn(II) L-pidolate was found to crystallize on heating into a crystalline anhydrous phase whose crystal structure was solved from a high-resolution X-ray powder diffraction pattern. Orthorhombic anhydrous Zn(II) L-pidolate exhibits a structure in which (4 + 2)-coordinated Zn atoms (with four usual and two additional Zn-O distances of 2.53 and 2.69 Å) and L-pidolate ligands alternate so as to form a three-dimensional polymerized network. Room-temperature rehydration processes under saturating water vapor for amorphous and crystalline anhydrous complexes were found to be different from each other, although they all led back to crystalline diaqua complexes whose relative stabilities were inferred from measurements of their solubilities in water

The surprising case of spironolactone polymorphism: enantiotropy in a system with a large difference in melting points

International audienc

Deducing high pressure behavior for chemically fragile systems: the polymorphism of spironolactone

International audienc

Polymorphism of benzylthiouracil, an active pharmaceutical ingredient against hyperthyroidism

International audienceThe crystal structures of dimorphic benzylthiouracil, a drug against hyperthyroidism, have been redetermined and the atom coordinates of the two independent molecules of form I have been obtained for the first time. The dimorphism convincingly demonstrates the conformational versatility of the benzylthiouracil molecule. It has been established through calorimetric studies that the low-temperature form II transforms endothermically (ΔII→IH = 5.6(1.5) J g− 1) into form I at 405.4(1.0) K. The high-temperature form I melts at 496.8(1.0) K (ΔI→LH = 152.6(4.0) J g− 1). Crystallographic and thermal expansion studies show that form II is denser than form I, leading to the conclusion that the slope of the II-I equilibrium curve in the pressure-temperature phase diagram is positive. It follows that this dimorphism corresponds to a case of overall enantiotropic behaviour, which implies that both solid phases possess their own stable phase region irrespective of the pressure. Moreover, form II is clearly the stable polymorph under ambient conditions

The surprising case of spironolactone polymorphism: enantiotropy in a system with a large difference in melting points

International audienc

The surprising case of spironolactone polymorphism: enantiotropy in a system with a large difference in melting points

International audienc