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Acta Crystallographica. Section C,... Feb 2022In a detailed powder diffraction study of the structural forms of psilocybin, Sherwood [ C, 36–55] cast doubt that any other anhydrous polymorphs could exist.
In a detailed powder diffraction study of the structural forms of psilocybin, Sherwood [ C, 36–55] cast doubt that any other anhydrous polymorphs could exist.
Topics: Crystallography, X-Ray; Hallucinations; Humans; Hydrogen Bonding
PubMed: 35119383
DOI: 10.1107/S2053229622000511 -
Profiles of Drug Substances,... 2022A comprehensive profile of danazol describing the nomenclatures, formulae, elemental composition, appearance, uses and applications is presented. The profile contains...
A comprehensive profile of danazol describing the nomenclatures, formulae, elemental composition, appearance, uses and applications is presented. The profile contains the method which was utilized for the preparation of the drug substance and its respective scheme is outlined. The physical characteristics of the drug including the solubility, X-ray powder diffraction pattern, differential scanning calorimetry, thermal behavior and spectroscopic studies are described. The methods which were used for the analysis of the drug substance in bulk drug and/or in pharmaceutical formulations including the compendial, spectrophotometric, electrochemical and the chromatographic methods are reported. The stability, toxicity, pharmacokinetics, bioavailability, drug evaluation and monitoring, comparisons, pharmacology, in addition to several compiled reviews on the drug substance which were involved. Finally, two hundred and seventy-nine references are listed at the end of this profile.
Topics: Biological Availability; Danazol; Drug Compounding; Drug Stability; Solubility; X-Ray Diffraction
PubMed: 35396014
DOI: 10.1016/bs.podrm.2021.10.005 -
Profiles of Drug Substances,... 2020A comprehensive profile of piroxicam including the nomenclatures, formulae, elemental composition, appearance, uses and applications. The methods which were utilized for...
A comprehensive profile of piroxicam including the nomenclatures, formulae, elemental composition, appearance, uses and applications. The methods which were utilized for the preparation of the drug substance and their respective schemes are outlined. The physical characteristics of the drug including the ionization constant, solubility, x-ray powder diffraction pattern, differential scanning calorimetry, thermal behavior and spectroscopic studies are described. The methods which were used for the analysis of the drug substance in bulk drug and/or in pharmaceutical formulations including the compendial, spectrophotometric, electrochemical and the chromatographic methods are reported. The stability, toxicity, pharmacokinetics, bioavailability, drug evaluation, comparison, in addition to compiled reviews on the drug substance are involved. Finally, more than four hundred and fifty references are listed at the end of this profile.
Topics: Biological Availability; Drug Compounding; Drug Stability; Piroxicam; Solubility; X-Ray Diffraction
PubMed: 32164968
DOI: 10.1016/bs.podrm.2019.10.007 -
Molecules (Basel, Switzerland) Aug 2021The solvatomorphism of the anthelmintic drug moxidectin is investigated, and a new solvatomorph with nitromethane is reported. Moreover, the hitherto unknown crystal...
The solvatomorphism of the anthelmintic drug moxidectin is investigated, and a new solvatomorph with nitromethane is reported. Moreover, the hitherto unknown crystal structures of the solvatomorphs with ethanol and 2-propanol are reported and discussed. The thermal characterization of these solvatomorphs through variable-temperature powder X-ray diffraction analysis (VT-PXRD) is also described, providing new insights into the crystallochemistry of this active pharmaceutical ingredient.
Topics: Crystallography, X-Ray; Hydrogen Bonding; Macrolides; Molecular Conformation; Powder Diffraction; Solvents; Temperature
PubMed: 34443452
DOI: 10.3390/molecules26164869 -
Journal of Applied Crystallography Jun 2023The high-intensity time-of-flight (TOF) neutron diffractometer POWTEX for powder and texture analysis is currently being built prior to operation in the eastern guide...
The high-intensity time-of-flight (TOF) neutron diffractometer POWTEX for powder and texture analysis is currently being built prior to operation in the eastern guide hall of the research reactor FRM II at Garching close to Munich, Germany. Because of the world-wide He crisis in 2009, the authors promptly initiated the development of He-free detector alternatives that are tailor-made for the requirements of large-area diffractometers. Herein is reported the 2017 enterprise to operate one mounting unit of the final POWTEX detector on the neutron powder diffractometer POWGEN at the Spallation Neutron Source located at Oak Ridge National Laboratory, USA. As a result, presented here are the first angular- and wavelength-dependent data from the POWTEX detector, unfortunately damaged by a 50 shock but still operating, as well as the efforts made both to characterize the transport damage and to successfully recalibrate the voxel positions in order to yield nonetheless reliable measurements. Also described is the current data reduction process using the algorithm implemented in [Arnold (2014). , , 156-166]. The final part of the data treatment chain, namely a novel multi-dimensional refinement using a modified version of the software suite [Toby & Von Dreele (2013). , 544-549], is compared with a standard data treatment of the same event data conventionally reduced as TOF diffraction patterns and refined with the unmodified version of . This involves both determining the instrumental resolution parameters using POWGEN's powdered diamond standard sample and the refinement of a friendly-user sample, BaZn(NCN). Although each structural parameter on its own looks similar upon comparing the conventional (1D) and multi-dimensional (2D) treatments, also in terms of precision, a closer view shows small but possibly significant differences. For example, the somewhat suspicious proximity of the and lattice parameters of BaZn(NCN) crystallizing in as resulting from the 1D refinement (0.008 Å) is five times less pronounced in the 2D refinement (0.038 Å). Similar features are found when comparing bond lengths and bond angles, the two N-C-N units are less differently bent in the 1D results (173 and 175°) than in the 2D results (167 and 173°). The results are of importance not only for POWTEX but also for other neutron TOF diffractometers with large-area detectors, like POWGEN at the SNS or the future DREAM beamline at the European Spallation Source.
PubMed: 37284252
DOI: 10.1107/S1600576723002819 -
Acta Crystallographica. Section C,... Aug 2019
PubMed: 31380782
DOI: 10.1107/S2053229619010520 -
Current Opinion in Chemical Biology Oct 2022Polysaccharides are the most abundant class of biopolymers, holding an important place in biological systems and sustainable material development. Their spatial... (Review)
Review
Polysaccharides are the most abundant class of biopolymers, holding an important place in biological systems and sustainable material development. Their spatial organization and intra- and intermolecular interactions are thus of great interest. However, conventional single crystal crystallography is not applicable since polysaccharides crystallize only into tiny crystals. Several crystallographic methods have been developed to extract atomic-resolution structural information from polysaccharide crystals. Small-probe single crystal diffractometry, high-resolution fiber diffraction and powder diffraction combined with molecular modeling brought new insights from various types of polysaccharide crystals, and led to many high-resolution crystal structures over the past two decades. Current challenges lie in the analysis of disorder and defects by further integrating molecular modeling methods for low-resolution diffraction data.
Topics: Crystallography; Crystallography, X-Ray; Models, Molecular; Polysaccharides
PubMed: 35803025
DOI: 10.1016/j.cbpa.2022.102183 -
Physical Review Letters Apr 2024A new perovskite KOsO_{3} has been stabilized under high-pressure and high-temperature conditions. It is cubic at 500 K (Pm-3m) and undergoes subsequent phase...
A new perovskite KOsO_{3} has been stabilized under high-pressure and high-temperature conditions. It is cubic at 500 K (Pm-3m) and undergoes subsequent phase transitions to tetragonal at 320 K (P4/mmm) and rhombohedral (R-3m) at 230 K as shown from refining synchrotron x-ray powder diffraction (SXRD) data. The larger orbital overlap integral and the extended wave function of 5d electrons in the perovskite KOsO_{3} allow to explore physics from the regime where Mott and Hund's rule couplings dominate to the state where the multiple interactions are on equal footing. We demonstrate an exotic magnetic ordering phase found by neutron powder diffraction along with physical properties via a suite of measurements including magnetic and transport properties, differential scanning calorimetry, and specific heat, which provide comprehensive information for a system at the crossover from localized to itinerant electronic behavior.
PubMed: 38682975
DOI: 10.1103/PhysRevLett.132.156701 -
Molecules (Basel, Switzerland) Nov 2021Warfarin sodium is a low-dose pharmaceutical blood thinner that exists in two forms: the clathrate form and the amorphous form. In commercially available warfarin sodium...
Warfarin sodium is a low-dose pharmaceutical blood thinner that exists in two forms: the clathrate form and the amorphous form. In commercially available warfarin sodium oral suspension, the active pharmaceutical ingredient (API) is added in the amorphous state. This study investigates the apparent instability of the commercially available warfarin liquid oral formulation using Raman and IR spectroscopy, X-ray diffraction, differential scanning calorimetry, UV spectroscopy, and optical microscopy. Warfarin, not its sodium salt, was identified as the undissolved solid existing in the suspension. This was found to be due to the dissociation of sodium salt and the protonation of the warfarin ion in the liquid phase, which triggered the crystallization of the sparingly soluble unsalted form. The coexistence of protonated and unprotonated warfarin ions in the supernatant, as detected by Raman and UV spectroscopy, confirmed this assumption. Study of the dissolution of warfarin sodium amorphous salt and crystalline sodium clathrate in the placebo and pure water verified the results. The effect of pH and temperature on warfarin precipitation was also explored.
Topics: Administration, Oral; Drug Compounding; Drug Stability; Molecular Structure; Particle Size; Warfarin
PubMed: 34771040
DOI: 10.3390/molecules26216631 -
Microscopy Research and Technique Mar 2021To investigate intrinsic physicochemical properties and interactions of three different calcium hydroxide-based medications via means of different analytical methods....
To investigate intrinsic physicochemical properties and interactions of three different calcium hydroxide-based medications via means of different analytical methods. Two-commercial premixed medications: TempCanal(TCmx) and ProCalR(PCmx) and powder-form ProCal(PCpw) with glycerin were used. Vibrational modes were analyzed using Raman spectroscopy. Spectral mapping of samples was carried out using characteristic vibrational modes of calcium hydroxide and barium sulfate. Crystalline and amorphous phases were studied with X-rays powder diffraction analysis. Topographic features were examined by scanning electron microscope examination and quantitative analysis was determined using energy-dispersive X-ray spectroscopy analysis. Strong OH stretch of in Raman spectra were observed at 3,697 and 3,615 cm for TCmx and reference, respectively. However, OH mode was not observed for PCmx and PCpw. Moreover, some peaks in the fingerprint areas of TCmx and PCpw overlapped with each other. The characteristic vibration bands of barium sulfate and calcium hydroxide were observed in all samples, and no new peak was observed in the Raman spectra of samples. Calcium hydroxide-based medications were seen as differed in their chemical composition. No new crystalline or amorphous phase peak was observed. Only calcium hydroxide and barium sulfate were matched in X-rays powder-diffraction analysis. Energy-dispersive X-ray spectroscopy analysis showed that amount of Ba and S elements in the PCpw were lower than TCmx and PCmx whereas, for Ca in the PCpw was higher than TCmx and PCmx. The present study revealed the structural difference among different forms of calcium hydroxide-based medications. The vehicle and substrates of the tested medications altered the physicochemical properties of the compound via electrostatic interactions.
PubMed: 32959430
DOI: 10.1002/jemt.23600