Studies Demonstrate the Value of XRPD for Determining Process-Induced Phase Transformations in Pharmaceutical Solids

Studies undertaken at the Department of Pharmaceutical Technology at the University of Bonn, using PANalytical's X'Pert PRO MPD system, have demonstrated the value of X-ray powder diffraction (XRPD) for detecting process-induced crystallinity changes in pharmaceutical solids.

For samples with a low crystalline content, detection limits were down to around 0.5%, while for samples with a low amorphous content detection limits were less than 1%. Results were comparable with those using near infrared spectroscopy (NIRS) and significantly more accurate and reliable than those using differential scanning calorimetry.

Crystallinity changes are typically associated with a number of processing steps in the pharmaceutical industry. Milling, granulation, compression, spray-drying or lyophilization can all cause disruption of the crystalline structure, leading to the formation of amorphous regions. The detection of such regions is an important factor in process control because their presence, in either excipients or active ingredients, can have a profound influence on processing behavior and the bioavailability of the active ingredient in the finished product.

This study found both XRPD and NIRS to be precise and accurate methods, each characterized by low detection limits, non-destructive analysis and rapid production of results.

XRPD proved more precise than NIRS for samples with a low crystalline content. In addition, its high sensitivity for these samples makes it the preferred technique for monitoring crystallization processes, offering detection of crystallization at extremely low limits and direct determination of the crystallization products.

Source: PANalytical BV