Solid form, polymorphism and phase purity
Many solid materials, such as pharmaceutical intermediates, APIs and final products, can exhibit polymorphism – the ability of a solid to express more than one crystalline form – and different polymorphs of the same material can exhibit startlingly different properties, from melting point and hydration state, to dissolution performance, long term physical stability and bioavailability. Hence, understanding the polymorphic behavior of your product is of key importance – and a regulatory expectation.
XRPD can be used to understand this behavior, as each polymorph – or pseudo-polymorph, solvate, co-crystal, or salt form – will demonstrate a unique diffraction pattern. This facilitates the monitoring of any polymorphic or solid form changes that may occur during development, scale up, manufacturing or on storage, and also enables optimization of solid form, by allowing for a close understanding of the form being expressed.
Moreover, XRPD is the key technique utilized to carry out polymorphic risk assessments, polymorph and salt screening studies, phase purity assessments, and batch release testing for solid form.
Methodologies can be qualitative (pattern matching), function as limit tests or quantitative.
Our service offering includes XRPD method development, pre-validation, validation and method transfers, plus storage stability studies.
Crystallinity and amorphicity
XRPD analysis enables the qualitative and quantitative assessment of the degree of crystallinity of a powder sample. By utilizing the relationship between crystallinity and pattern intensity, and controlling for factors such as particle size and morphology, indicative comparisons may be made between samples of the same type. Quantitative methodologies require the preparation of calibration standards; our micronizing, milling and blending capability enable the preparation of reference materials and calibration blends.
XRPD is a key companion technique to isothermal calorimetry by perfusion (ITC) and dynamic vapor sorption (DVS) for amorphous content determination.
Rietveld analysis and crystal structure database
The Malvern Panalytical HighScore Plus software allows for complex pattern deconvolution via the Rietveld refinement approach. This enables phase quantification of complex samples via a whole pattern matching approach; additionally, Rietveld refinement can be used for analysis of crystallite size based on the change in profile parameters, compared with those of a standard sample.
HighScore Plus also includes access to International Centre for Diffraction Data (ICDD) databases, enabling comparison of your sample patterns with premium quality reference patterns.
- Malvern Panalytical Empyrean Series 3 X-Ray diffractometer with PIXcel3D detector, in situ non-ambient analysis and high-throughput measurements on multi well-plates
- HighScore Plus data processing include Rietveld
- Bruker D8 Advance X-Ray diffractometer with LynxEye™ detector