Putting pressure on elusive polymorphs and solvates

Oswald, Iain D. H.; Chataigner, Isabelle; Elphick, Stephen C.; Fabbiani, Francesca P. A.; Lennie, Alistair R.; Maddaluno, Jacques; Marshall, William G.; Prior, Timothy J.; Pulham, Colin R.; Smith, Ronald I.

doi:10.1039/b814471k

Cited by 60 publications

(60 citation statements)

References 73 publications

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“…Such examples, when a stable high-pressure phase cannot be obtained on compression via a solid-state transformation, but is formed via recrystallization, often on decompression from a higher pressure, have been documented for other compounds: paracetamol, 8,26,77 β-alanine, 10 imidazole, 72 4,4′bipyridine hydrobromide monohydrate, 75 3-hydroxy-4,5dimethyl-1-phenylpyridazin-6-one, 27 and bromochlorofluoroacetic acid. 78 In the latter case, in particular, the preference for dimeric over catemeric polymorphs was impossible to detect without completely dissolving or melting the compound.…”

Section: Resultsmentioning

confidence: 99%

Effect of pressure on two polymorphs of tolazamide: why no interconversion?

et al. 2017

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Two polymorphs of tolazamide, N-[(azepan-1-ylamino)carbonyl]-4-methylbenzenesulfonamide, a sulfonylurea anti-diabetic drug, have different densities and molecular packings. Polymorph II converts into polymorph I in the solid state on heating or via recrystallization if solvent-assisted. The effect of pressure on the two forms and the possibility of a transformation to a denser form on compression have been studied.No phase transitions have been observed in either of the forms in a pentane-isopentane mixture (when no recrystallization is possible). Polymorph II recrystallized partly into a denser polymorph I in methanol at 0.1 GPa, but the transformation stopped at an early stage. Solid state DFT calculations of the two forms as well as conformational landscape investigation in the gas phase were used to rationalize this result. The anisotropic pressure-induced strain of the two polymorphs has been compared in relation to changes in the hydrogen bond geometry and the behavior of stacking interactions. † Electronic supplementary information (ESI) available: Information on tolazamide crystallization in methanol, low-temperature experiments, details of computational techniques and other data for tolazamide polymorphs: summary of the structural data at multiple pressures and temperatures; data on H-bonds and stacking interactions under pressure, parameters of the equations of state, and information on the strain ellipsoids; figures presenting the tolazamide molecule conformational landscape, conformational disorder in form II and pressure dependencies of tolazamide polymorphs' enthalpies. CCDC 1495203-1495210 and 1493069-1493078. For ESI and crystallographic data in CIF or other electronic format see

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Section: Resultsmentioning

confidence: 99%

Effect of pressure on two polymorphs of tolazamide: why no interconversion?

et al. 2017

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“…1 Polymorphism is also an important issue for the protection of intellectual property, 2,3 and so for all of these reasons a complete description of all possible polymorphs is now recommended by Federal Food and Drug Administration (FDA) regulations. [9][10][11] Two additional polymorphs were recently reported to form reversibly at very high (above 8 GPa) pressures. Three polymorphs of this compound have been obtained at ambient pressure, and all have different physical properties that are related to the differences in crystal structures.…”

Section: Introductionmentioning

confidence: 99%

A new polymorph of metacetamol

et al. 2015

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Metacetamol is a structural isomer of the widely used drug paracetamol and is being considered as a promising alternative to the latter because of its lower toxicity. Due to the importance of the well-known polymorphism of paracetamol, an investigation of the polymorphism of metacetamol was successfully undertaken. A new polymorph of metacetamol has been discovered and extensively characterised using a variety of analytical techniques (IR-and Raman spectroscopy, UV-visible optical spectroscopy, X-ray powder and single-crystal diffraction, TGA and DSC). A procedure for the reliable and reproducible preparation of the new polymorph is described. Its properties and crystal structure are compared with those of the previously known polymorph, as well as with those of paracetamol. CrystEngComm This journal isScheme 1 Molecular structures of metacetamol (left) and paracetamol (right) containing the same characteristic functional groups.

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“…This is reflected in phenomena which were term-coined as "concomitant polymorphism" (several phases co-existing at the same conditions, often in the same batch) [12] , "disappearing polymorphs" (a fast-growing metastable polymorph obtained once can no longer be crystallised after a seed of the stable form has been obtained) [13,14] , "pre-nucleation" (molecular clusters in solution predetermine the structure of a crystalline nucleus formed at later stages) [15] , "seeding-triggered crystallization" (a seed of a phase triggers crystallization of the same phase) [16] , "template crystallization" (molecules or molecular clusters in solution direct crystallization of a certain crystalline form, even if not included in the final crystal structure themselves) [17,18] . Highpressure has been recently proposed as a tool to obtain new polymorphs of pharmaceuticals, which, if preserved on flashdecompression, can be used as seeds for mass-crystallization at ambient conditions [19][20][21][22][23] . However, the control of highpressure polymorphism is not a trivial task [19,[24][25][26][27][28] .…”

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confidence: 99%

Unusual seeding effect in the liquid-assisted high-pressure polymorphism of chlorpropamide

2016

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When crystals of four polymorphsa stable α-form and three metastable ones (β-, γ-, δ-forms)are simultaneously present in a pressure cell, immersed in a 1 : 1 pentane-isopentane mixture, the least stable β-form recrystallises exclusively into the γ-form (if no δ-form seed is present) or concomitantly into the γand δ-forms (if a seed of the δ-form is present). However, the β-form never recrystallises to the stable α-form, even if the latter is also present as a potential seed.

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Putting pressure on elusive polymorphs and solvates

Cited by 60 publications

References 73 publications

Effect of pressure on two polymorphs of tolazamide: why no interconversion?

Effect of pressure on two polymorphs of tolazamide: why no interconversion?

A new polymorph of metacetamol

Unusual seeding effect in the liquid-assisted high-pressure polymorphism of chlorpropamide

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