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International Centre for Diffraction Data round robin on quantitative Rietveld phase analysis of pharmaceuticals

  • T. G. Fawcett (a1), F. Needham (a1), J. Faber (a1) and C. E. Crowder (a1)

Abstract

The ICDD sponsored a round robin on the quantitative Rietveld phase analysis of pharmaceuticals. 11 participating laboratories from the pharmaceutical community submitted both raw data and processed quantitative results. The purpose of the round robin was to evaluate current practices in laboratories, so procedures and methods were not specified, but they were recorded. Cluster analysis tools were applied to all the data sets and their use helped identify the root causes of several types of errors in specimen preparation, data treatment, and Rietveld analysis. The authors considered this round robin to be difficult. Sample homogeneity was an issue and molecular orientation was observed in many data sets. Each material studied has structural polymorphs so the selection of starting parameters and their refinement was nontrivial. Similar to prior round robins on inorganic materials and minerals, this round robin identified operator errors as the major contributor to poor results. Four laboratories achieved excellent results on all phases in all three samples, with accuracy within relative errors of 5% to 10%.

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Corresponding author

a)Author to whom correspondence should be addressed. Electronic mail: fawcett@icdd.com

References

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Faber, J. (2007). “An invitation to participate in an XRD round robin,” PPXRD-7 Symposium, Barcelona, Spain.
Faber, J. and Needham, F. (2008). “Pharmaceutical round robin for quantitative phase analysis,” Book of Abstracts, PPXRD-8 Symposium, Orlando, Florida, pp. 3637.
Gonzalez, R. M., Edwards, T. E., Lorbiecke, T. D., Winburn, R. S., and Webster, J. R. (2003). “Analysis of geologic materials using Rietveld quantitative X-ray diffraction,” Adv. X-Ray Anal. AXRAAA 46, 204209.
Gonzalez, R. M., Lorbiecke, T. D., McIntyre, B. W., Cathcart, J. D., Brownfield, M., and Winburn, R. S. (2002). “Factors influencing quantitative results for coal combustion by-products using the Rietveld method,” Adv. X-Ray Anal. AXRAAA 45, 188193.
Hubbard, C. R., Evans, E. H., and Smith, D. K. (1976). “The reference intensity ratio, I/Ic, for computer simulated patterns,” J. Appl. Crystallogr. JACGAR 9, 169174 .10.1107/S0021889876010807
Jenkins, R. and Snyder, R. L. (1996). X-ray Powder Diffractometry (Wiley, New York).
Madsen, I. C., Scarlett, N. V. Y., Cranswick, L. M. D., and Lwin, T. (2001). “Outcomes of the International Union of Crystallography Commission on powder diffraction round robin on quantitative phase analysis, samples 1a to 1h,” J. Appl. Crystallogr. JACGAR 34, 409426 .10.1107/S0021889801007476
Needham, F., Crowder, C. E., and Fawcett, T. G. (2009). “Round robin for pharmaceutical compounds: Results from PPXRD-7,” Book of Abstracts, PPXRD-8, Glasgow, Scotland, p. 52.
O’Connor, B. H. and Li, D. Y. (1998). “Influence of refinement strategies on Rietveld phase composition determinations,” Adv. X-Ray Anal. AXRAAA 42, 204211.
O’Connor, B. H. and Li, D. Y. (2000). “Attaining 1% accuracy in absolute phase composition levels by Rietveld analysis,” Adv. X-Ray Anal. AXRAAA 43, 305312 (and references therein).
Rietveld, H. M. (1990). The Rietveld Method, Report No. ECN-RX-90-035, Energy Research Foundation, Petten, The Netherlands.
Scarlett, N. V. Y. and Madsen, I. C. (2001). “Accuracy in X-ray powder diffraction: A comparison of quantitative methods,” CPD Newsletter 26, 2123.
Scarlett, N. V. Y., Madsen, I. C., Cranswick, L. M. D., Lwin, T., Grouleau, E., Stephenson, G., Aylmore, M., and Agron-Olshina, N. (2002). “Outcomes of the International Union of Crystallography Commission on powder diffraction round robin on quantitative phase analysis, samples 2,3,4, synthetic bauxite, natural granodiorite and pharmaceuticals,” J. Appl. Crystallogr. JACGAR 35, 383400 .10.1107/S0021889802008798
Webster, J. R., Kight, R. P., Winburn, R. S., and Cool, C. A. (2003). “Heavy mineral analysis of sandstones by Rietveld analysis,” Adv. X-Ray Anal. AXRAAA 46, 198203.
Winburn, R. S. (2003). “Rietveld analysis of complex mixtures: What can we do?Adv. X-Ray Anal. AXRAAA 46, 210219.
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Powder Diffraction
  • ISSN: 0885-7156
  • EISSN: 1945-7413
  • URL: /core/journals/powder-diffraction
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