Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam

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Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam. / Upadhyay, Pratik Pankaj; Bond, Andrew.

In: CrystEngComm, Vol. 17, 05.03.2015, p. 5266-5272.

Research output: Contribution to journal › Journal article › Research › peer-review

Harvard

Upadhyay, PP & Bond, A 2015, 'Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam', CrystEngComm, vol. 17, pp. 5266-5272. https://doi.org/10.1039/C5CE00050E

APA

Upadhyay, P. P., & Bond, A. (2015). Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam. CrystEngComm, 17, 5266-5272. https://doi.org/10.1039/C5CE00050E

Vancouver

Upadhyay PP, Bond A. Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam. CrystEngComm. 2015 Mar 5;17:5266-5272. https://doi.org/10.1039/C5CE00050E

Author

Upadhyay, Pratik Pankaj ; Bond, Andrew. / Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam. In: CrystEngComm. 2015 ; Vol. 17. pp. 5266-5272.

Bibtex

@article{fd81e874ac514fb38e0f78320da7b9d9,
title = "Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam",
abstract = "Polymorphism of the active pharmaceutical ingredient piroxicam, C15H13N3O4S, is investigated with an aim to clarify the identity and crystallization conditions of the α1 and α2 polymorphs. The structures are polytypic, containing identical 2-dimensional layers, with different symmetry relationships between the layers. The α1 structure is orthorhombic and non-centrosymmetric (space group type Pca21), while the α2 structure is monoclinic and centrosymmetric (space group type P21/c). α2 can be crystallized by evaporation from ethanol at 25 °C, while α1 is obtained by crystallization from the same solvent at 4 °C. The polytypic relationship provides a suitable condition for order–disorder phenomena to be observed in single crystals. Intermolecular interaction energies calculated using the PIXEL method suggest that the centrosymmetric interlayer regions in α2 involving the pyridyl groups are more stabilising than the corresponding non-centrosymmetric interlayer regions in α1. This is consistent with observations of inversion twinning in non-centrosymmetric α1 crystals. The interlayer regions involving the benzothiazine groups have very similar interaction energies in the two structures.",
author = "Upadhyay, {Pratik Pankaj} and Andrew Bond",
year = "2015",
month = mar,
day = "5",
doi = "10.1039/C5CE00050E",
language = "English",
volume = "17",
pages = "5266--5272",
journal = "CrystEngComm",
issn = "1466-8033",
publisher = "Royal Society of Chemistry",

}

RIS

TY - JOUR

T1 - Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam

AU - Upadhyay, Pratik Pankaj

AU - Bond, Andrew

PY - 2015/3/5

Y1 - 2015/3/5

N2 - Polymorphism of the active pharmaceutical ingredient piroxicam, C15H13N3O4S, is investigated with an aim to clarify the identity and crystallization conditions of the α1 and α2 polymorphs. The structures are polytypic, containing identical 2-dimensional layers, with different symmetry relationships between the layers. The α1 structure is orthorhombic and non-centrosymmetric (space group type Pca21), while the α2 structure is monoclinic and centrosymmetric (space group type P21/c). α2 can be crystallized by evaporation from ethanol at 25 °C, while α1 is obtained by crystallization from the same solvent at 4 °C. The polytypic relationship provides a suitable condition for order–disorder phenomena to be observed in single crystals. Intermolecular interaction energies calculated using the PIXEL method suggest that the centrosymmetric interlayer regions in α2 involving the pyridyl groups are more stabilising than the corresponding non-centrosymmetric interlayer regions in α1. This is consistent with observations of inversion twinning in non-centrosymmetric α1 crystals. The interlayer regions involving the benzothiazine groups have very similar interaction energies in the two structures.

AB - Polymorphism of the active pharmaceutical ingredient piroxicam, C15H13N3O4S, is investigated with an aim to clarify the identity and crystallization conditions of the α1 and α2 polymorphs. The structures are polytypic, containing identical 2-dimensional layers, with different symmetry relationships between the layers. The α1 structure is orthorhombic and non-centrosymmetric (space group type Pca21), while the α2 structure is monoclinic and centrosymmetric (space group type P21/c). α2 can be crystallized by evaporation from ethanol at 25 °C, while α1 is obtained by crystallization from the same solvent at 4 °C. The polytypic relationship provides a suitable condition for order–disorder phenomena to be observed in single crystals. Intermolecular interaction energies calculated using the PIXEL method suggest that the centrosymmetric interlayer regions in α2 involving the pyridyl groups are more stabilising than the corresponding non-centrosymmetric interlayer regions in α1. This is consistent with observations of inversion twinning in non-centrosymmetric α1 crystals. The interlayer regions involving the benzothiazine groups have very similar interaction energies in the two structures.

U2 - 10.1039/C5CE00050E

DO - 10.1039/C5CE00050E

M3 - Journal article

VL - 17

SP - 5266

EP - 5272

JO - CrystEngComm

JF - CrystEngComm

SN - 1466-8033

ER -

ID: 139904464