Quantitation of crystallinity in substantially amorphous pharmaceuticals and study of crystallization kinetics by X-ray powder diffractometry

The first object was to develop an X-ray diffractometric method fur the det ection and quantification of crystalline sucrose when it occurs as a mixtur e with amorphous sucrose. Standards consisting of amorphous sucrose physica lly mixed with 1 to 5 weight percent crystalline sucrose were prepared. The sum of the background subtracted integrated intensities of the 12.7 degree s 2 theta 16.94 Angstrom) and 13.1 degrees 2 theta (6.73 Angstrom) sucrose diffraction peaks were linearly related to the weight percent crystalline s ucrose. The limits of detection and quantitation of crystalline sucrose wer e 0.9% and 1.8% w/w, respectively. The second object was to study the kinet ics of crystallization of sucrose as a function of temperature (at 102, 105 and 110 degrees C under a water vapor pressure of 0 Torr) and water vapor pressure (17.4, 19.8 and 21.4 Torr at 27 degrees C). In all cases, the crys tallization kinetics was best described by the Avrami-Erofe'ev model (three -dimensional nucleation). (C) 2000 International Centre for Diffraction Dat a. [S0885-7156(99)00204-3].