A study of variable hydration states in topotecan hydrochloride

Vogt, Frederick G.; Dell`Orco, P.C.; Diederich, Ann M.; Su, Qiaogong; Wood, J. L.; Zuber, Gary E.; Katrincic, Lee M.; Mueller, Ronald L.; Busby, David J.; DeBrosse, Charles W.

doi:10.1016/j.jpba.2005.08.032

Cited by 49 publications

(29 citation statements)

References 21 publications

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“…The alcohol molecules are strongly hydrogen-bonded with the droperidol O1 atom, thus affecting the strength of the intermolecular hydrogen bond between droperidol molecules N2-H···O1 and the calculated chemical shift difference for N2 is significantly higher in S Me and S Et , 1.6 and 3.2 ppm respectively. In contrast to S ACN , only one, somewhat broader, line is observed in the 15 N spectrum for the alcohol solvates (45-50 Hz for N2 compared to [35][36][37][38][39][40] Hz for other nitrogen resonances). This strongly suggests that the alcohol molecules in S Me and S Et are dynamically disordered, resulting in a single resonance.…”

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confidence: 76%

Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol

Be̅rziņš

Hodgkinson

2015

Solid State Nuclear Magnetic Resonance

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Citation for published item:frzi § sD eF nd rodgkinsonD F @PHISA 9olidEstte xw nd omputtionl investigtion of solvent moleule rrngement nd dynmis in isostruturl solvtes of droperidolF9D olid stte nuler mgneti resonneFD TS F ppF IPEPHF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHITGjFssnmrFPHIRFHWFHHI Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in Solid State Nuclear Magnetic Resonance. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reected in this document. Changes may have been made to this work since it was submitted for publication. A denitive version was subsequently published in Solid State Nuclear Magnetic Resonance, 65, February 2015, 10.1016/j.ssnmr.2014.001. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. 2 H NMR spectra of deuterium-labelled samples allowed the characterization of the solvent molecule dynamics in the alcohol solvates and the non-stoichiometric hydrate. The likely motion of the alcohol molecules is rapid libration within a site, plus occasional exchange into an equivalent site related by the inversion symmetry, while the water molecules are more strongly disordered. DFT calculations strongly suggest that the differences in dynamics between the solvates are related to differences in the energetic penalty for reversing the orientation of a solvent molecule.Keywords: droperidol; solid-state NMR; hydrates/solvates; isostructural solvates; solvent dynamics; spin-lattice relaxation; motional broadening; ab initio calculations Graphical abstract Highlights 15 N CP/MAS NMR clearly distinguishes ordered and dynamically disordered systems.  Spectral quality is strongly correlated to ABMS broadenings.  2 H MAS NMR provides direct insight into the nature of the solvent motion.  DFT calculations help to rationalise the differences in experimental observations.

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confidence: 76%

Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol

Be̅rziņš

Hodgkinson

2015

Solid State Nuclear Magnetic Resonance

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“…Finer crystallites are prone to react faster (or to react better as catalysts). Assessment of crystallite shape (in case of anisotropic peak size broadening) Lattice parameters and hence metallic contents can be accurately determined [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…The purity of a sample can be accessed by diffraction pattern (Figure 1) by taking into consideration the proportion and composition of impurities present. PXRD is the prime requisite for differentiating the crystalline sample ( Figure 2) from semi-crystalline like in polymer like cotton and amorphous materials like phenol-formaldehyde complex resin ( Figure 3) [1][2][3][4][5][6][7][8].XRD is helpful in qualitative and quantitative phase abundance analysis. It can identify the polymorph and determine the phase abundance to classify the cement and correlating the performance with composition [9][10][11][12][13][14][15].…”

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confidence: 99%

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Usage of Powder XRD Technique for Material Characterization and Analysis of Portland Cement

Chauhan¹,

Chauhan²

2015

J Anal Bioanal Tech

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PXRD technique has non-destructive nature, marked sensitivity, reliability, simple and fast sample preparation, user friendly, convenient, fast speed, high resolution, minimum maintenance cost, proper automation, easy interpretation of the information that could be utilized for both qualitative and quantitative aspects of analysis. It is the primary tool for solid state characterization. Material characterization provides the information about the particle size, crystallite size, phase transitions, texture, strain broadening, crystal structure and lattice parameters. It can be used to study the crystallinity, crystalline index, identify the crystalline phases, spacing between lattice planes, scales of existence, preferential order and epitaxial growth of crystallites. Every material or compound has its unique diffraction patterns so materials and compounds can be identified by comparing a database of diffraction patterns. The purity of a sample can be accessed by diffraction pattern (Figure 1) by taking into consideration the proportion and composition of impurities present. PXRD is the prime requisite for differentiating the crystalline sample ( Figure 2) from semi-crystalline like in polymer like cotton and amorphous materials like phenol-formaldehyde complex resin ( Figure 3) [1][2][3][4][5][6][7][8].XRD is helpful in qualitative and quantitative phase abundance analysis. It can identify the polymorph and determine the phase abundance to classify the cement and correlating the performance with composition [9][10][11][12][13][14][15]. Material CharacterizationX-rays were discovered by German Scientist Röntgen in 1868. Von Laue in 1912 discovered X-ray diffraction by crystals. The wavelength of X-rays is similar to the distance between atoms. Atoms in a crystal form a periodic array of coherent scatters. When each object in a periodic array scatters radiation coherently the diffraction occurs that leads to constructive interference at each specific angle. Diffraction from different planes of atom produces a diffraction pattern (diffractogram) that contains information about the atomic arrangement in the crystal (Figure 1). We get information like d-value and peak position at 2-theta scale.The peak position at 2 theta scale depends on instrumental characteristics such as wavelength. The peak position as d hkl is an intrinsic, instrument-independent, material property. XRD diffraction intensity depends upon polarization factor, structure factor (F 2 ), multiplicity factor, Lorentz factor, absorption factor and temperature factor. The diffraction pattern for every phase is as unique as fingerprint. Phases with the same chemical composition can have drastically different diffraction patterns. Peak areas are much more reliable than peak heights as a measure of intensity. Crystallites smaller than 120 nm create broadening of diffraction peaks. Micro strain may also create peak broadening. Presence of coarse particles and bad loading cause several negative effects such as preferred orientation, pattern shifts, poor re...

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“…Many experimental techniques permit to characterize these influences [9]. Among them, the association of techniques controlling the Relative Humidity (hereafter RH), like the Dynamic Vapour Sorption (hereafter DVS), with the static vapour sorption [10], the Infrared Spectroscopy [11] [12] [13] or classical analyses as X-Ray Powder Diffraction (XRPD hereafter), Thermogravimetric analyses associated to Differential Scanning Calorimetry (TG-DSC hereafter) [13], [14] are very helpful to understand solid-vapour equilibria. The present study aims at describing these equilibria through some examples treated in our laboratory.…”

Section: Introductionmentioning

confidence: 99%

Influence of solid/vapour equilibria on the stability of organic solids

Couvrat

Cartigny

2009

XXXV JEEP – 35th Conference on Phase Equilibria

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The influence of water (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of solid/vapour equilibria, several behaviours were highlighted (stoichiometric or non stoichiometric hydrates, hydration/dehydration mechanisms, stability domains of multi-hydrates as a function of relative humidity). Phase diagrams (as a function of partial water pressure) and stability diagrams have been proposed for each example. This study illustrates that solid/vapour equilibrium knowledge is a crucial step during the complete characterization of solid organic compounds.

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A study of variable hydration states in topotecan hydrochloride

Cited by 49 publications

References 21 publications

Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol

Solid-state NMR and computational investigation of solvent molecule arrangement and dynamics in isostructural solvates of droperidol

Usage of Powder XRD Technique for Material Characterization and Analysis of Portland Cement

Influence of solid/vapour equilibria on the stability of organic solids

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