NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate

Apperley, D.C.; Markwell, A.F.; Frantsuzov, I.; Ilott, A.J.; Harris, R.K.; Hodgkinson, P.

Abstract

Solid-state NMR is used to characterise dynamics in the ethanol solvate of the pharmaceutical material formoterol fumarate and its associated desolvate. Jump rates and activation barriers for dynamic processes such as phenyl ring rotation and methyl group rotational diffusion are derived from 1D-EXSY and 13C spin–lattice relaxation times respectively. 2H and 13C spin–lattice relaxation times measured under magic-angle spinning conditions are used to show that the fumarate ion in the desolvate is undergoing small-amplitude motion on a frequency scale of 100s of MHz at ambient temperature with an activation parameter of about 32 kJ mol−1. Exact calculations of relaxation times under MAS provide a simple and robust means to test motional models in cases where relaxation rate maxima are observed, including for systems where the crystal structure of the material is unknown.

Citation

Apperley, D., Markwell, A., Frantsuzov, I., Ilott, A., Harris, R., & Hodgkinson, P. (2013). NMR characterisation of dynamics in solvates and desolvates of formoterol fumarate. Physical Chemistry Chemical Physics, 15(17), 6422-6430. https://doi.org/10.1039/c3cp50180a

• Journal Article Type: Article
• Acceptance Date: Mar 12, 2013
• Publication Date: May 7, 2013
• Deposit Date: Sep 15, 2013
• Publicly Available Date: Feb 15, 2016
• Journal: Physical Chemistry Chemical Physics
• Print ISSN: 1463-9076
• Electronic ISSN: 1463-9084
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 15
• Issue: 17
• Pages: 6422-6430
• DOI: https://doi.org/10.1039/c3cp50180a
• Public URL: https://durham-repository.worktribe.com/output/1447301