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°) 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.