Pharmaceutical Research

, Volume 28, Issue 5, pp 1041–1048 | Cite as

Data Requirements for the Reliable Use of Atomic Pair Distribution Functions in Amorphous Pharmaceutical Fingerprinting

  • Timur DykhneEmail author
  • Ryan Taylor
  • Alastair Florence
  • Simon J. L. Billinge
Research Paper



To determine the optimal measurement strategy for fingerprinting condensed phases of pharmaceutical systems using atomic pair distribution functions (PDFs) obtained from data collected using several types of x-ray diffraction instruments.


PDFs of crystalline and amorphous-phase molecular systems derived from data accessible to copper-, molybdenum-, and silver-anode laboratory sources were compared to one another and synchrotron data using qualitative and quantitative methods.


We find that reliable fingerprinting is still possible using silver and molybdenum laboratory sources, but data from copper anode laboratory sources are unreliable for fingerprinting, yielding ambiguous and potentially incorrect results.


The ambiguities make data measured using low energy x-rays unsuitable for fingerprinting active pharmaceutical ingredients and small molecule systems, and, in general, copper anode diffractometers are undesirable for this purpose; however, laboratory x-ray sources with either Mo or Ag anodes are well suited for this application.


amorphous fingerprinting nanocrystalline pair distribution function (PDF) x-ray diffraction (XRD) 



active pharmaceutical ingredient


pair distribution function


x-ray diffraction


total scattering pair distribution function


copper-anode laboratory source


molybdenum-anode laboratory source


silver-anode laboratory source



We would like to thank Pavol Juhás, Emil Božin, and Christopher Farrow for their help in collecting and analyzing the data. This work is supported through the US National Science Foundation through Grant DMR-0702940. The Advanced Photon Source is supported by the U.S. DOE, Office of Science, Office of Basic Energy Sciences, under contract No. W-31-109-Eng-38.


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Timur Dykhne
    • 1
    Email author
  • Ryan Taylor
    • 2
  • Alastair Florence
    • 2
  • Simon J. L. Billinge
    • 1
    • 3
  1. 1.Department of Applied Physics and Applied MathematicsColumbia UniversityNew YorkUSA
  2. 2.Solid-State Research Group, Strathclyde Institute of Pharmacy and Biomedical SciencesUniversity of StrathclydeGlasgowUK
  3. 3.Condensed Matter Physics and Materials Science DepartmentBrookhaven National LaboratoryUptonUSA

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