Pressure-induced formation of a solvate of paracetamol.
Recrystallisation of paracetamol from a solution in methanol at a pressure of 0.62 GPa gives a new 1:1 solvate that has been characterised by single crystal X-ray diffraction.
Acetaminophen↗
Biomedical subjects
William I F David
Publications and source records attributed to William I F David.
Indexing powder patterns in physical form screening: instrumentation and data quality.
Two multisample laboratory powder diffractometers have been evaluated for the purpose of pattern indexing in the context of physical form screening. Both diffractometers utilise foil transmission geometry, primary monochromated radiation, and a position-sensitive detector. Data collected from six compounds (sotalol hydrochloride, hydroflumethiazide, verapamil hydrochloride, captopril, clomipramine hydrochloride, and famotidine) showed good angular resolution (FWHM as small as ca. 0.06 degrees ) and lattice parameters were easily obtained using the indexing program DICVOL-91. The extent of preferred orientation in each pattern was estimated using the DASH implementation of the March-Dollase function and is most evident with clomipramine hydrochloride and famotidine. Otherwise, the data compare favorably with reference capillary data sets. In conclusion, where there is a requirement to analyze 20-30 samples per day, with an emphasis on obtaining the high-quality data that are important in pattern recognition and imperative in indexing, the combination of foil transmission geometry, primary monochromated radiation, plus a position-sensitive detector is highly effective. The data also afford opportunities for crystal structure determination.
Chemical Phenomena↗
Conformational analysis by solid-state NMR and its application to restrained structure determination from powder diffraction data.
Solid-state NMR is used to dramatically improve the efficiency and reliability of molecular crystal structure determination from X-ray powder diffraction data.
Journal Article↗
A hybrid Monte Carlo method for crystal structure determination from powder diffraction data.
A hybrid Monte Carlo algorithm for crystal structure determination from powder diffraction data is presented. The algorithm combines the key components of molecular dynamics and Monte Carlo simulations to achieve efficient sampling of phase space, allowing the crystal structure of capsaicin to be determined from powder diffraction data more effectively than by a simulated-annealing approach. The implementation of the algorithm, the choice of the simulation parameters and the performance of the algorithm are discussed.
Journal Article↗
A maximum-likelihood method for global-optimization-based structure determination from powder diffraction data.
A maximum-likelihood algorithm has been incorporated into a crystal structure determination from a powder diffraction data framework that uses an integrated-intensity-based global optimization technique. The algorithm is appropriate when the structural model being optimized is not a complete description of the crystal structure under study.
Journal Article↗