Skip to main content

Quantitative analysis of pharmaceutical polymorphic forms via the DD Method

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


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.

XRD products from Rigaku

Advanced state-of-the-art high-resolution XRD system powered by Guidance expert system software

Highly versatile multipurpose X-ray diffractometer with built-in intelligent guidance

New 6th-generation general purpose benchtop XRD system for phase i.d and phase quantification

Compact X-ray diffractometer for quality control of materials that is easy to use and is ideal for routine work

Laboratory micro-spot XRD residual stress analysis with both iso- and side-inclination methods

Windows®-based software suite for Rigaku's X-ray diffractometers

high energy resolution pixel detector capable of 0, 1, and 2D measurements

2D X-ray detector with latest semiconductor technology designed for home lab diffractometers