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Reports - Spring Meeting, Loughborough 12th to 14th April 2005
In Situ: Processing in Industry.This session aimed to present some applications of diffraction to the study of real industrial processing systems where the in-situ approach has given an essential insight for understanding and development. "Surfactant Formulation" "Processing block co-polymers for nano-pores" "In Situ Crystallisation Studies of Pharmaceutical Materials" Mary Vickers 
Crystallography in Industry 1 & 2Fist published in Crystallography News - June 2005 Wednesday's afternoon session "Crystallography in industry" was chaired by Judith Shackleton and opened with Michael Preuss (University of Manchester) lecturing on 'Residual stresses in friction welded aeroengine components'. He talked about the types of friction welding: friction welding has the advantage over fusion processes which cannot reliably weld many of the high temperature alloys now found in aero engine components: the inertia friction method is used to join discs/shafts and the linear friction method for joining blades onto discs. A consideration during friction welding however is the generation of residual stress, during joining, and stress relief during post weld heat treatment. Industry has turned to synchrotron high energy dispersive X-ray scattering to enable researchers to undertake systematic studies of the residual stress profiles in welds and improve the understanding of how welding parameters and post weld heat treatments affect the residual stress fields and the performance of the welded component. The talk was concluded with the fact that higher temperatures for annealing brings down stresses to acceptable levels. Tony Fry (National Physical Laboratory) followed with his lecture on 'Residual stress measurements at NPL. Increasing confidence and development best practice' in which he talked about the parameter study to find how robust the x-ray diffraction method is. He went through two projects undertaken at the NPL and ended with mention of the Good Practice Guide authored with the Projects Industrial Advisory Group. The talk ended with a good discussion from delegates in the room. Martijn Fransen (PANalytical) ended this first session with an enthusiastic lecture on 'The problem of sample fluorescence when dealing with transition metals in industrial samples'. The talk covered 1 -D and 2-D detection systems and posed the question "Can you get good peak/ background ratio?" He went through the best choices of the practical aspects from the monchromator to the detector as a function of the elemental composition of the sample. The second part of the session, chaired by Richard Morris, opened with Peter Laggner (Graz, Austria) on Bridging the nano-gap: simultaneous SAXS and XPD on nanomaterials. He covered a lot in his talk giving a range of examples such as synthesis of mesoporous materials and dissolution of drug-delivery C/R microspheres. He focused on the design of the HECUS-System3 SWAXS (small and wide angle x-ray scattering) and its use in different applications. The need for SAX for determining domain size and surface roughness and XPD for crystal structure and amorphous content was explained. The session was brought to an end with a interesting lecture from lan Cope (Imperial College), lan explained his PhD research: Using XRD to support the study of an iron oxide deposit, called the Pic de Fon deposit. This deposit is a potential new source of iron ore located in the Eastern Republic of Guinea, West Africa. The aim is to combine XRD and geochemical analysis to constrain the process by which banded iron formation is converted to iron ore. It was good because as a field geologist he knew little about XRD, but was interested in how it could help in his research. XRD results indicate that distinct crystallographic signature may exist for the different ore grade material types. Each ore-grade material type exhibits different physical properties, hard, biscuit and powder, which in turn will control the metallurgical performance of the final delivered product. All the presentations gave a useful insight into where and how crystallography is used in industry and the different type of demands industry places on crystallographic hardware compared to academia. Robert Davies (University of Oxford)
Non-ambient Pharmaceutical Studies 1 & 2Jonathan Burley opened this session, chaired by Anne Kavanagh with Crystal structure and intermolecular forces from variable temperature PXRD. The structure was that of Glipizide, a major drug for treating diabetes. Variable temperature data were used to confirm the index of the cell, and Jonathan recommended this as a facile method of ensuring crystals are correctly indexed when using powder diffraction. Since structure-property relationships are of interest, he investigated intermolecular forces quantitatively by working out the Debye temperatures along the cell axes. This temperature is a measure of the lattice stiffness, i.e. bond strength. The anisotropic lattice expansion was fitted to the sum of phonon modes. Jonathan showed that glipizide has single phonon modes along the a and c axes, which he attributed to π-π interactions and hydrogen bonding respectively, and the b axis is characterised by two phonon modes, which correspond to van der Waals interactions and steric interlock. For a patent, every pharmaceutical requires characterization; this is often achieved, at least in part, by powder diffraction. One of the questions Jeremy Cockcroft considered in his talk Obtaining accurate non-ambient laboratory PXRD data for pharmaceutical studies was whether the powder diffraction patterns always represent a polymorph of the material. In order to answer this, accurate data are required, ideally without preferred orientation. To get good data, the diffractometer configuration has to be considered and the calibration of the equipment checked. Low temperature diffraction is often a useful tool, providing turbulence, draughts and icing problems can be dealt with. LT work requires capillary geometry, which has the advantage of reducing or removing preferred orientation. Several case studies were presented Steve Cosgrove finished the first session with Probing (De)Hydration Behaviour by High Resolution X-ray Powder Diffraction. He described studies of a candidate drug, as its sodium salt, which was known to crystallise as four polymorphs, three hydrates and a number of other solvates. Steve discussed DSC and derivative TGA for probing dehydration and hydration of the compound. Mass spectrometry is also used, with monitoring of the m/z = 18 peak indicating the loss of water from the compound. Dynamic vapour sorption is also used to cycle the compound within various humidity environments to monitor moisture sorption and dehydration. This method can highlight stable higher hydrates, which would be more appropriate for manufacture as the risk of water sorption by a lower hydrate would cause problems during weighing stages. After the coffee break, Roy Copley took the chair, and Francesca Fabbiani spoke on Probing Polymorphism with High Pressure based on a search for high pressure polymorphs of piracetam. Varying of pressure adds an additional dimension to the search for polymorphs of pharmaceuticals. Three approaches are available - direct compression (best for very small molecules), growth of crystals from the melt and recrystallisation from solution under pressure. Three new polymorphs of piracetam have been structurally characterised. Francesca used graph set analysis to demonstrate the differences in the hydrogen bonding patterns within the polymorphs, and also introduced the concept of Hirschfeld surfaces to differentiate between the polymorphs. Emphasising the importance, and often difficulty, of understanding polymorphs and hydrates of pharmaceuticals, Angus Foster discussed The Use of X-ray Diffraction in the Pharmaceutical Development of a Dihydrate API, a compound with complex hydration behaviour, which readily loses water under typical manufacturing conditions. Many techniques, including single crystal and VT powder XRD, VT-FTIR and isothermal-TGA to investigate under which conditions the compound could be dried and still remain crystalline. Peter Laggner finished the session by discussing Monitoring non-ambient nanophase processes by TR-SWAXS. He gave a description of the equipment used, and then went on to discuss lipid polymorphism. By using temperature jump and pressure studies on membranes he could show that cholesterol induces softening when present in low concentration, but at high concentrations caused hardening of the membrane. Sophie Dale (University of Newcastle)
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Industrial Group of the BCA