Limitations of NIR Spectroscopy as a PAT-Tool in Pharmaceutical Manufacturing

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The Food and Drug Administration (FDA) strongly endorses the development and application of effective process analytical technology (PAT) tools in the pharmaceutical industry . Among these tools, near-infrared (NIR) spectroscopy has shown potential for monitoring in-situ powder processes such as mixing, granulation and tableting. Nonetheless, the limitations of this technology require to be well understood; in specific, the penetration depth of NIR in free flowing and/or compressed powders. Indeed, the penetration depth of NIR varies according to the properties of the powders analyzed, the density of the powders, and thickness of the sample. These characteristics can lead to incorrect measurements, where only the surface is analyzed, and therefore not necessarily representing the features of the sample examined.
This work shows the penetration depth of NIR for three excipients (MCC 102, lactose and DCP) mixed with lubricants (MgSt) and gliders (SiO2). A conventional manual tablet press with a die diameter of 10 mm was used to create thin films of 500 µm with different densities. The particle size of the powders was analysed using a Microtrac S3500 Particle Size Analyser. NIR spectra and film density was calibrated with a GeoPyc 1360 envelope density analyser. The NIR penetration depth of single and mixed powders/films was obtained by limiting the beam extent of penetration. This effect was achieved by measuring a reference compound and stacking films with defined thicknesses on top until the spectra of the reference compound was no longer detected. Indeed, the analysis provides guidelines for the application of NIR spectroscopy in as a PAT tool
Original languageEnglish
Publication statusPublished - 1 Oct 2017
Event10th World Congress of Chemical Engineering - Barcelona, Spain
Duration: 1 Oct 20175 Oct 2017


Conference10th World Congress of Chemical Engineering
Internet address


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