Issue 16, 2017

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

Abstract

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.

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

Supplementary files

Article information

Article type
Paper
Submitted
08 Dec 2016
Accepted
27 Mar 2017
First published
06 Apr 2017
This article is Open Access
Creative Commons BY license

CrystEngComm, 2017,19, 2243-2252

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

A. Yu. Fedorov, D. A. Rychkov, E. A. Losev, B. A. Zakharov, J. Stare and E. V. Boldyreva, CrystEngComm, 2017, 19, 2243 DOI: 10.1039/C6CE02527G

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