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

Zakharov, Boris A.; Goryaĭnov, S. V.; Болдырева, Е. В.

doi:10.1039/c6ce00711b

Cited by 30 publications

(26 citation statements)

References 66 publications

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“…However, this new form is not necessarily the most thermodynamically stable polymorph under these conditions. Different poly-morphs can be formed, depending on the starting structure, [3][4][5][6][7] compression-decompression protocol, [8][9][10][11][12] in particular the rate of pressure increase, [12][13][14][15] the presence of nuclei of other phases, 16 or the nature of the pressuretransmitting fluid. 10,[17][18][19][20][21][22] Some polymorphic transformations are purely solid-state, whereas others are solvent-assisted and are related to complete or partial recrystallization.…”

Section: Introductionmentioning

confidence: 99%

“…10,[17][18][19][20][21][22] Some polymorphic transformations are purely solid-state, whereas others are solvent-assisted and are related to complete or partial recrystallization. 16,[21][22][23][24][25] It is also not uncommon that a polymorph does not undergo any transformations on variation of (P, T) conditions, even if it becomes thermodynamically unstable. [26][27][28] This is often due to kinetic restrictions on nucleation and/or nuclei growth of a new phase.…”

Section: Introductionmentioning

confidence: 99%

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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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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“…However, if seeds of δ-CPA are present, these seeds grow in size (although no new δ-CPA crystals nucleate), concomitantly with the fast nucleation and growth of new γ-CPA crystals. 45 This complex interplay of kinetics and thermodynamics is likely responsible for the drastically different results observed for the mechanochemistry of β-CPA. Dissolution and re-crystallisation play a critical role in the mechanically-induced polymorphism of CPA.…”

Section: Discussionmentioning

confidence: 99%

“…The formation of δ-CPA in the presence of heptane corresponds to the known crystallisation of the δ-form from heptane-ethyl acetate solution, 37 believed to be associated with interaction of the solvent alkyl chains with the CPA tail on recrystallisation. 45 This suggests that wet mechanochemical processing proceeds via solution-phase intermediates. Pure shear treatment under atmospheric conditions led to conversion of the ε-form towards the thermodynamic α-phase.…”

Section: Liquid-assisted Grinding (Lag) Of ε-Chlorpropamidementioning

confidence: 99%

“…Transitions between polymorphs of the CPA on hydrostatic compression have been shown to depend strongly on the presence of a pressure-transmitting fluid 43 and on its choice. [44][45][46] CPA thus provides an intriguing system for further analysis of the effects of different liquids on its polymorphism, including polymorphic transitions induced by mechanical treatment. The molecular structure of CPA contains three chemically unique segments, an aliphatic tail, a carbamide group, and a halogenated aromatic (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Polymorphism of chlorpropamide on liquid-assisted mechanical treatment: choice of liquid and type of mechanical treatment matter

et al. 2018

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Different types of mechanical treatment (tableting, grinding, milling, etc.) are important technological operations in the pharmaceutical industry. Solid materials are not merely comminuted during such treatment, but can undergo polymorphic transitions and amorphisation. A liquid is often added to the solid sample on purpose, e.g. in order to facilitate comminution. In many cases, liquid is present inadvertently, either as a result of trace solvent following up-stream operations, or sorbed from the atmosphere. This work explores the liquid-assisted mechanical treatment of two metastable forms of a model pharmaceutical compound chlorpropamide (CPA), namely the β-and ε-forms. We investigate the stability of these polymorphs to mechanical treatment in the presence of a series of fluids that have affinity for different fragments of the CPA molecule. In addition to variation in fluids, the effect of different mechanical treatment is explored, employing model shear and restricted impact devices, alongside grinding in a mortar. CPA offers a clear example of the drastically different results of shear and impact on mechanochemical polymorphism, on the importance of the careful selection of solvent for liquid-assisted treatment, and on the possible role of even trace quantities of solvent. Further, this work demonstrates the importance of the starting polymorph in determining the outcome of a mechanochemical process. All of these factors can have notable consequence on the outcome of technological operations that include mechanical treatment.

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Impact of the Polymorphic Form of Drugs/NCEs on Preformulation and Formulation Development

Alsirawan

Paradkar

2019

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

Cited by 30 publications

References 66 publications

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

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

Polymorphism of chlorpropamide on liquid-assisted mechanical treatment: choice of liquid and type of mechanical treatment matter

Impact of the Polymorphic Form of Drugs/NCEs on Preformulation and Formulation Development

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