Newsletter Archive >> Winter 2014 >> X-Ray Powder Diffraction

X-Ray Powder Diffraction: a crystalline fingerprint for identification

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Eurofins Lancaster Laboratories offers new technology for material ID & characterization

Jon C. Wenger, Principal Chemist, Pharmaceutical Raw Materials

A fingerprint is the residue pattern produced by epidermal ridges of fingertips. Since each person’s fingerprint is unique, it is excellent evidence for the identification of one’s presence. Crystalline materials, such as APIs, powder formulations, intermediates and excipients, also have unique structural patterns that distinguish one from another. Unlike a fingerprint, this pattern is consistent, repeating throughout the structure. When physically crushed or ground into smaller particles the matrix pattern remains intact in the fragments, yet the human eye cannot discern the structural pattern of the individual cells.

To address identification and characterization challenges of crystalline materials, Eurofins Lancaster Laboratories has turned to an innovative and precise X-Ray technology for identification confirmation as an incorrect or de-natured crystalline structure can affect a drug product’s efficacy. Responding to an increasing demand from clients who need this technology as part of characterization testing for API, reference standards, intermediates, as well as a tool for stability monitoring of these materials, Eurofins Lancaster Laboratories has invested in X-Ray Diffraction (XRD) instrumentation.

XRD offers a crystalline fingerprint for material identification and characterization as it studies the pattern produced by the interaction of monochromatic X-radiation precisely directed onto the sample target. This reflected (diffracted) energy is captured by a precisely positioned detector and thus is a critical measurement tool. XRD can also rapidly predict the percentage of crystallinity of a structure.

The basis of this technique is known as Bragg diffraction. X-ray wavelengths are of comparable scale with the inter-atomic distances. As Xradiation is focused on a surface at an angle Theta (θ) some “waves” will interact with (strike) two atoms specifically located on the atomic lattice but on separate planes – as radiation reflects from these atoms some waves interact. They could be in synchronization producing a constructive signal (a Bragg peak) or out of synchronization and cancel out (no signal). The reflected angle measured from the original beam path is Two Theta (2θ). A full peak profile scan characterizes a material.

For precision ID & characterization, XRD analysis can:

  • Fingerprint an unknown crystalline compound
  • Confirm material identity
  • Detect foreign contamination/other substances present
  • Discern material phases
  • Estimate percent crystallinity

For maximum testing flexibility and endless adaptability, Eurofins Lancaster Laboratories utilizes the state-of-the-art Bruker D8 ADVANCE with DAVINCI design currently centered in Bragg-Brentano Geometry with a LYNXEYE linear detector to broaden clients’ XRD service options, which include ID of excipients and API materials, identity confirmations, stability pull evaluations and method development for characterizing new and previously unknown compounds, transfer of client developed methods for routine testing, phase identification for polymorphic materials as well as maintain a library database for known material XRD scans.

Please contact BioPharm Business Development to discuss how we can solve your ID & characterization challenges at pha@eurofinsUS.com.