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Quantitative analysis of pharmaceutical polymorphic forms via the DD Method

AppNote B-XRD1120: Quantitative analysis of pharmaceutical polymorphic forms via the DD Method

Background

Organic compounds represented by drug substances sometimes have crystal structures with a low symmetry in molecular arrangement, and dozens of peaks are observed in the X-ray diffraction profile. With a mixture of compounds exhibiting such a complex profile, peak separation is difficult. For this reason, it was also difficult to obtain an accurate value in quantitative analysis that calculates the weight fraction from the integrated intensity of the separated peak. The new quantitative analysis method developed by Rigaku; Direct Derivation method (DD method) calculates the quantitative value based on the single-phase diffraction profile. This improves the peak separation accuracy of mixtures that shows complex profiles and makes quantification straightforward. In this application, quantitative analysis of trace amounts of pharmaceutical polymorphic forms was conducted as an example.

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