Polymorphism of chloroquine diphosphate

Bjåen, Anne-Kristin Bjerga; Nord, Karin; Furuseth, Sigrid; Ågren, Tove; Tønnesen, Hanne; Karlsen, Jan

doi:10.1016/0378-5173(93)90278-n

Cited by 7 publications

(3 citation statements)

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“…The anhydrous phase is reported 6,8 to be stable in a dry atmosphere, but in humid atmospheres at ambient temperature the anhydrous phase takes up water to form the hydrate phase. On rapid heating, the hydrate phase melts in the same temperature region as dehydration, whereas slow heating gives an essentially complete transformation to the anhydrous phase without melting (the melting points of the hydrate and anhydrous phases are reported 6 to be ca.…”

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

“…The hydrate phase of CQ(DHP) 2 is known to undergo a solid-state dehydration process at elevated temperature, although the crystal structure of the resultant anhydrous phase of CQ(DHP) 2 has not been reported previously. The anhydrous phase is reported , to be stable in a dry atmosphere, but in humid atmospheres at ambient temperature the anhydrous phase takes up water to form the hydrate phase. On rapid heating, the hydrate phase melts in the same temperature region as dehydration, whereas slow heating gives an essentially complete transformation to the anhydrous phase without melting (the melting points of the hydrate and anhydrous phases are reported to be ca.…”

Section: Introductionmentioning

confidence: 99%

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A Solid-State Dehydration Process Associated with a Significant Change in the Topology of Dihydrogen Phosphate Chains, Established from Powder X-ray Diffraction

Albesa‐Jové

Pan

Harris

et al. 2008

Crystal Growth & Design

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The anhydrous crystalline phase of chloroquine bis-(dihydrogen phosphate) is obtained by dehydration of the corresponding hydrate phase, but in common with many solid-state dehydration processes, the product is obtained as a polycrystalline powder, thus limiting the opportunity to carry out structural characterization using single crystal X-ray diffraction techniques. Instead, structure determination of the anhydrous phase has exploited the capabilities of modern powder X-ray diffraction techniques, employing the direct-space Genetic Algorithm technique for structure solution followed by Rietveld refinement. The results reveal that the dehydration process is associated with a significant change in the topology of hydrogen bonded chains of dihydrogen phosphate anions, arising from a change in the hydrogen bonding arrangement within the chains, together with a significant change in the conformation of the chloroquine cation.

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Section: Introductionmentioning

confidence: 97%