Near-infrared spectroscopy for non-destructive coating analysis calibrated by Terahertz Pulsed Imaging

Near-infrared (NIR) spectroscopy is a versatile technique for non-destructive analysis of pharmaceutical tablet coating thickness; however, it needs a calibration model and thus the prior knowledge about the coating thickness of each tablet is required. In this work, we demonstrate that Terahertz Pulsed Imaging (TPI) can provide, in a nondestructive fashion, such coating thickness information for building the calibration model needed by the NIR technique.