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Analyses of Multi- Phase Pharmaceuticals Using SImultaneous Differential Scanning Calorimetry and X-Ray Diffraction

Published online by Cambridge University Press:  06 March 2019

T. G. Fawcett
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
E. J. Martin
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
C. E. Crowder
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
P. J. Kincaid
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
A. J. Strandjord
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
J. A. Blazy
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
D. N. Armentrout
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
R. A. Newman
Affiliation:
Michigan Applied Science and Technology Laboratories the Dow Chemical Company Midland, Michigan
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Extract

The analysis of multi-phase pharmaceuticals, particularly when similar structures are involved (i.e. polymorphs, salts or hydrates), can often be a difficult task. Historically, x-ray powder diffraction (XRD) and differential scanning calorimetry (DSC) have been utilized to study pharmaceutical samples. Relative to other materials, diffraction data for pharmaceuticals are often complex due to the large number of diffraction maxima caused by the size of the molecule and/or the molecular symmetry. Multi-phase mixtures tend to have a large number of overlapping peaks which can hinder the difftactionist's ability to identify phases and interpret the data. When similar structures are analyzed calorimetrically, their thermal events may severely overlap (as will be shown), preventing accurate interpretation of the data. In addition there are several types of thermal events which may not be related to structural transitions. A common one in pharmaceuticals is the loss of solvent or absorbed (versus molecular) water.

Type
Research Article
Copyright
Copyright © International Centre for Diffraction Data 1985

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References

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