The Pharmacopeial Forum (PF) from January/February 2012 contains a publication entitled "Stimuli to the Revision Process" article about the verification of wavelengths for near-infrared diffuse reflection spectrometry (NIRS) by calibration standards.
In order to get accurate and right results for NIRS determinations, the spectra of the instruments used for the measurement must closely match the spectrum of the spectrometer used to acquire the calibration spectra.
There are at least two standards available for NIR wavelength uncertainty determination: one from the National Institute of Standards and Technology (NIST) and one from USP itself. The USP NIR System Suitability RS Standard was introduced in 2004 when the revision of General Chapter <1119> about near-infrared spectrometry was made.
In this article of the PF, the authors give reasons for their recommendation for the continued use of the USP NIR System Suitability Reference Standard. In future, the new lot G will provide more information about the absorption maxima as yet. (Note: in the meantime, the new lot G (GOK 264) has become the valid lot for this standard and replaced lot F (FOG 007)). A list of 36 positions regarding absorption maxima can be found in the current lot documentation for Lot GOK264.
The USP Standard is a mixture of rare earth oxides (REOs), Dy2O3, Er2O3, Ho2O3 and talc (in a 1:1:1:1 ratio).
Regulatory requirements regarding near-infrared spectrometry as well as practical examples from the pharmaceutical industry will be key topics at the QbD/PAT Conference organised by the University of Heidelberg on 26/27 September 2012 in the Marriott Hotel in Heidelberg, Germany. Case Studies from the pharmaceutical industry will address the use of NIRS for "Real Time Release Testing" and NIRS for continuous manufacturing processes.
Please use the free access to the Pharmacopeial Forum where you will find the article about "Wavelengths of Calibration Standards for Near-infrared Diffuse Reflection Spectrometry".
CONCEPT HEIDELBERG (a service provider entrusted by the ECA Foundation)