Crystal structure and hydration/dehydration behavior of Na2Mg(SO4)2{middle dot}16H2O: A new hydrate phase observed under Mars-relevant conditions

2013 ◽  
Vol 98 (10) ◽  
pp. 1772-1778 ◽  
Author(s):  
K. Leftwich ◽  
D. L. Bish ◽  
C. H. Chen
Keyword(s):  
Crystal Structure ◽  
Hydrate Phase ◽  
Dehydration Behavior

Crystal Structure of RbD2PO4.D2O: A new Hydrate Phase of KDP-type Compounds

2000 ◽  
Vol 35 (4) ◽  
pp. 501-509 ◽  
Author(s):  
S. Mattauch ◽  
W. Paulus ◽  
J. Glinnemann ◽  
G. Roth ◽  
G. Heger
Keyword(s):  
Crystal Structure ◽  
Hydrate Phase

scholarly journals Elucidation of the Crystal Structures and Dehydration Behaviors of Ondansetron Salts

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 180 ◽  
Author(s):  
Ryo Mizoguchi ◽  
Hidehiro Uekusa
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Hydrogen Bonding Networks ◽  
Dehydration Behavior ◽  
Crystal Lattice Parameters ◽  
Single Crystal Structure Analysis

In drug development, it is extremely important to evaluate the solubility and stability of solid states and to immediately determine the potential for development. Salt screening is a standard and useful method for obtaining drug candidates with good solid state properties. Ondansetron is marketed as a hydrochloride dihydrate, and its dehydration behavior was previously reported to transition to an anhydrate via a hemihydrate as an intermediate by heating. Here, we synthesized ondansetron hydrobromide and hydroiodide and examined their dehydration behaviors. Single-crystal structure analysis confirmed that like ondansetron hydrochloride, ondansetron hydrobromide formed a dihydrate. Moreover, the crystal lattice parameters and hydrogen bonding networks were similar and isomorphic. While single-crystal structure analysis showed that ondansetron hydroiodide also formed a dihydrate, the crystal lattice parameters and hydrogen bonding networks were different to those of ondansetron hydrobromide and hydrochloride. Additionally, the dehydration behavior of ondansetron hydrobromide differed from that of the hydrochloride, with no hemihydrate intermediate forming from the hydrobromide, despite similar anhydrate structures. Given that it is difficult to predict how a crystal structure will form and the resulting physical properties, a large amount of data is needed for the rational design of salt optimization.

scholarly journals Reversible De-/Rehydration Process in Paroxetine Hydrobromide

2014 ◽  
Vol 70 (a1) ◽  
pp. C999-C999
Author(s):  
Paulo Carvalho-Jr ◽  
Javier Ellena ◽  
Alejandro Ayala
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Pharmaceutical Formulations ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Stability ◽  
Dehydration Behavior ◽  
Rehydration Process

Paroxetine (PRX) is an antidepressant widely used in depression treatment for decades. The anhydrous and hemidrate chloride forms have been used in pharmaceutical formulations. During their developing a discussion associated with its physical forms and the complex hydration/dehydration behavior involving these phases were established. To improve our understanding of this issue we investigate the crystal structure of paroxetine bromide hemidrate, (PRX+.Br-).H2O, as a model for understanding the stability anhydrous/hemihydrate paroxetine arrangements and the nature of the intermolecular interaction of water within the crystal lattice by single crystal X-ray diffraction experiments. A combination of complementary characterization techniques were also used including Differential Scanning Calorimetry (DSC), thermogravimetric analysis (TGA), Hot Stage microscopy and solubility measurements. As expected the paroxetine bromide hemidrate, (PRX+.Br-).H2O, is isostructural with the paroxetine chloride hemidrate, (PRX+.Cl-).H2O. As in that case, the crystal packing of (PRX+.Br-).H2O is stabilized by strong NH2+...O and NH2+...Br hydrogen bonds which forms infinite channels along the b axis. The water and bromide anions are located along these channels. The DSC/TGA analysis for (PRX+.Br-).H2O show an endothermic desolvation process with an onset temperature of 77.09 °C, that is not present in the paroxetine chloride hemidrate DSC curve. This process leaves to a paroxetine anhydrous bromide crystal structure that is isomorphic to the anhydrous chloride one. However, this structure is spontaneously rehydrated at ambient atmosphere. This rehydration phenomenon probe the stability of paroxetine hemihydrate arrangement, since (PRX+.Br-) is slightly more soluble that its hydrate form. As opposed to chloride hemidrate, the rehydration of paroxetine bromide only involves a rearrangement of the water molecule within the cavities.

ChemInform Abstract: Crystal Structure of RbD2PO4×D2O: A New Hydrate Phase of KDP-Type Compounds.

ChemInform ◽  
2001 ◽  
Vol 32 (2) ◽  
pp. no-no
Author(s):  
S. Mattauch ◽  
W. Paulus ◽  
J. Glinnemann ◽  
G. Roth ◽  
G. Heger
Keyword(s):  
Crystal Structure ◽  
Hydrate Phase

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

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