Pseudopolymorphs in Industrial Use

Bechtloff, B.; Nordhoff, Sonja; Ulrich, Joachim

doi:10.1002/1521-4079(200112)36:12<1315::aid-crat1315>3.0.co;2-r

Cited by 88 publications

(75 citation statements)

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“…The thermodynamic stability of true polymorphs does not depend on the solvent, but of course the situation is different for solvates 3 . Hence, in a water solution the hydrate could be more stable than the anhydrate, but when exposed to the atmospheric environment it might rapidly lose the hydrate water.…”

Section: Discussionmentioning

confidence: 99%

“…In a survey from 1997 it is reported that more than half of the active pharmaceutical ingredients in use can crystallize in more than one polymorphic form 1 . Regarding pseudo-polymorphism, in 1980 it was estimated that approximately one third of all pharmaceutical ingredients were reported to have the capability to form crystalline hydrates 2 , while 57% of the pharmaceuticals in the 1991 European Pharmacopoeia have reported hydrate forms 3 . If other solvents are considered, these numbers rise further.…”

Section: Introductionmentioning

confidence: 99%

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Oiling out or molten hydrate—liquid–liquid phase separation in the system vanillin–water

Svärd

Gracin

Rasmuson

2007

Journal of Pharmaceutical Sciences

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PostprintThis is the accepted version of a paper published in Journal of Pharmaceutical Sciences. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.Citation for the original published paper (version of record):Svärd, M., Gracin, S., Rasmuson, Å C. (2007) Oiling out or molten hydrate-liquid-liquid phase separation in the system vanillin-water. Journal of Pharmaceutical ABSTRACTVanillin crystals in a saturated aqueous solution disappear and a second liquid phase emerges when the temperature is raised above 51°C. The phenomenon has been investigated with crystallization and equilibration experiments, using DSC, TGA, XRD and hot-stage microscopy for analysis. The new liquid solidifies on cooling, appears to melt at 51°C, and has a composition corresponding to a dihydrate. However, no solid hydrate can be detected by XRD, and it is shown that the true explanation is that a liquid-liquid phase separation occurs above 51°C where the vanillin-rich phase has a composition close to a dihydrate. To our knowledge, liquid-liquid phase separation has not previously been reported for the system vanillin-water, even though thousands of tonnes of vanillin are produced globally every year.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oiling out or molten hydrate—liquid–liquid phase separation in the system vanillin–water

Svärd

Gracin

Rasmuson

2007

Journal of Pharmaceutical Sciences

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“…Pseudopolymorphs, also termed solvates or hydrates, generally show different solubility, dissolution rate, mechanical behavior, stability and bioavailability from their unsolvated counterparts (Bechtloff et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Characterization and pseudopolymorphism of l-phenylalanine anhydrous and monohydrate forms

Lü¹,

Wang²,

Li³

et al. 2012

Afr. J. Pharm. Pharmacol.

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In this work, the preformulation study on the solid state characterization for the anhydrous form and the monohydrate form of L-phenylalanine has been initially conducted by the use of powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and microscopy. Meanwhile, the solubility of both forms and the transformation kinetics from anhydrous form to monohydrate form in different water/acetone mixtures were studied as well. The transformation rate can be prohibited by increasing temperature and reducing water content in the solvent mixtures. These results will contribute to a better understanding of drugs' pseudopolymorphism for pharmaceutical industry.

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“…25) These differences can inf luence formulation, processing, and stability under various storage conditions of the drug compound, as well as in the pharmaceutical product.…”

Section: Types Of Pharmaceutical Cr Ystalsmentioning

confidence: 99%

Relationship between the Structure and Properties of Pharmaceutical Crystals

Sheth

Grant

2005

KONA

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The majority of drug products are solid dosage forms, most of which contain the drug substance in the crystalline state. This review considers the forces responsible for crystal packing, the various types of pharmaceutical crystals, and the methods used to determine the structure of pharmaceutical crystals. These topics provide background for the main thrust, which focuses on the importance of studying the structure of pharmaceutical crystals with particular stress on phase changes of crystal forms of drugs during pharmaceutical processing and implications of different solid forms of drugs on its mechanical properties. The present review does not consider pharmaceutical co-crystals, which could be the subject of another review.

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Pseudopolymorphs in Industrial Use

Cited by 88 publications

References 0 publications

Oiling out or molten hydrate—liquid–liquid phase separation in the system vanillin–water

Oiling out or molten hydrate—liquid–liquid phase separation in the system vanillin–water

Characterization and pseudopolymorphism of l-phenylalanine anhydrous and monohydrate forms

Relationship between the Structure and Properties of Pharmaceutical Crystals

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