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

Published online by Cambridge University Press:  10 January 2013

Rahul Surana
Affiliation:
College of Pharmacy, 308 Harvard Street SE, University of Minnesota, Minneapolis, Minnesota 55455
Raj Suryanarayanan*
Affiliation:
College of Pharmacy, 308 Harvard Street SE, University of Minnesota, Minneapolis, Minnesota 55455
*
a)Corresponding author. Telephone: 612 624 9626; Fax: 612 626 2125; E-mail: [email protected]

Abstract

The first object was to develop an X-ray diffractometric method for the detection and quantification of crystalline sucrose when it occurs as a mixture with amorphous sucrose. Standards consisting of amorphous sucrose physically mixed with 1 to 5 weight percent crystalline sucrose were prepared. The sum of the background subtracted integrated intensities of the 12.7°2θ (6.94 Å) and 13.1°2θ (6.73 Å) sucrose diffraction peaks were linearly related to the weight percent crystalline sucrose. The limits of detection and quantitation of crystalline sucrose were 0.9% and 1.8% w/w, respectively. The second object was to study the kinetics of crystallization of sucrose as a function of temperature (at 102, 105 and 110 °C under a water vapor pressure of 0 Torr) and water vapor pressure (17.4, 19.8 and 21.4 Torr at 27 °C). In all cases, the crystallization kinetics was best described by the Avrami-Erofe’ev model (three-dimensional nucleation).

Type
Technical Articles
Copyright
Copyright © Cambridge University Press 2000

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