A novel technique combining high resolution synchrotron X-ray Micro-Tomography and X-ray Diffraction for characterisation of micro particulates

Wesley Armour2, Danny Axford2, Mark Basham2, Thomas Connolley2, Gwyndaf Evans2, Katherine E McAuley2, David R Merrifield1, Robin L Owen2, Vasuki Ramachandran1, Kevin J Roberts1, James Sandy2

1Institute of Particle Science & Engineering, School of Process, Environmental & Materials Engineering, University of Leeds, Leeds LS2 9JT. UK, k.j.roberts@leeds.ac.uk

2Diamond Light Source Ltd., Diamond House, Harwell Science & Innovation Campus, Didcot, Oxfordshire, OX11 0DE. UK, gwyndaf.evans@diamond.ac.uk

ABSTRACT

Processing of solids such as crystalline material is strongly influenced by the nature of surface structures. In recent years the pharmaceutical industry has shown a great interest in identifying, or chemically speciating, the molecular components of crystal faces. Formerly the molecular identity of particular faces was restricted to the study of large single crystals. This would have been primarily for structure determination as part of the drug registration process. The Diamond Light Source in Oxfordshire is a new synchrotron facility in the UK, having 15 beamlines. Each beamline has a specific beam size and energy, and thus lends itself to different types of application and experiment. This high energy light source enables the study of sub-micron objects in great detail. It has been well-known that X-ray microtomography (XMT) can be used to investigate the external morphology of a crystal whereas X-ray diffraction (XRD) is used to study the molecular orientation, structure and packing within the crystal. The objective of this research is to assess the feasibility of, and thereby develop a new methodology for, characterizing the molecular identity of a particular face of a crystalline particle at a scale of scrutiny of 20-50 µm. This work demonstrates combining measurements of XMT and XRD to investigate respectively the shape and crystalline phase/orientation of the same particle. This research has applications in pharmaceutical industry in that when the exact molecular nature of a particular face is known, the important physico-pharmaceutical properties stemming from that can be better understood. Some of the initial data are presented and discussed here.