Water dynamics in channel hydrates investigated using H/D exchange

Ahlqvist, Marie; Taylor, Lynne S.

doi:10.1016/s0378-5173(02)00242-9

Cited by 36 publications

(48 citation statements)

References 10 publications

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“…Caffeine 0.8 hydrate [35][36][37] and theophylline monohydrate [38,39] form channels in their structure as well. Both materials are isostructural and stoichiometric, while the water release behaviour from the channels differs significantly [40][41][42]. Another example of a channel hydrate is given in the co-crystal of pamoic acid and piperazine, which forms a trihydrate [32].…”

Section: Single Crystal X-ray Structures Of Hydratesmentioning

confidence: 99%

X-ray and Neutron Diffraction in the Study of Organic Crystalline Hydrates

Fucke

Steed

2010

Water

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A review. Diffraction methods are a powerful tool to investigate the crystal structure of organic compounds in general and their hydrates in particular. The laboratory standard technique of single crystal X-ray diffraction gives information about the molecular conformation, packing and hydrogen bonding in the crystal structure, while powder X-ray diffraction on bulk material can trace hydration/dehydration processes and phase transitions under non-ambient conditions. Neutron diffraction is a valuable complementary technique to X-ray diffraction and gives highly accurate hydrogen atom positions due to the interaction of the radiation with the atomic nuclei.Although not yet often applied to organic hydrates, neutron single crystal and neutron powder diffraction give precise structural data on hydrogen bonding networks which will help explain why hydrates form in the first place.

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Section: Single Crystal X-ray Structures Of Hydratesmentioning

confidence: 99%

X-ray and Neutron Diffraction in the Study of Organic Crystalline Hydrates

Fucke

Steed

2010

Water

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“…Thus, Raman spectroscopy has been successfully used for monitoring the hydration and dehydration processes of different sugars, such as glucose and cyclodextrins, [18][19][20][21][22][23][24] and pharmaceutical drugs. 7,[25][26][27][28] Theophylline [1,3-dimethyl-xanthine, hereafter named by TP ( Fig. 1)] is a natural derivative of xanthine found mainly in tea, which presents several pharmaceutical and medical applications, [29][30][31] and is included in the core essential medicines list of the World Health Organization (WHO).…”

Section: Introductionmentioning

confidence: 99%

Probing Pseudopolymorphic Transitions in Pharmaceutical Solids using Raman Spectroscopy: Hydration and Dehydration of Theophylline

Amado

Nolasco

Ribeiro‐Claro

2007

Journal of Pharmaceutical Sciences

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Theophylline is known to undergo vapor phase induced hydrate-anhydrate pseudopolymorphic transformations, which can affect its bioavailability. In this work, the kinetics of the pseudopolymorphic transitions of theophylline crystals in different storage conditions is studied using a vibrational spectroscopic technique. While the hydration is a single-step process with a half-life time of ca. 5 h, the dehydration occurs through a two-step mechanism. In addition, the phase stability of hydrate-anhydrate systems in different relative humidity (RH) conditions was probed. The critical RH for anhydrous teophylline was found to be at ca. 79%, while the critical RH for dehydration is ca. 30%. ß

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“…Of particular relevance to this paper are the investigations using deuterium exchange to probe water diffusion in sugars (22) and water dynamics in channel hydrates (23). To the best of our knowledge there have been no other examples where this approach has been applied to pharmaceutically relevant compounds.…”

Section: Introductionmentioning

confidence: 99%