The transmittance spectra of powders and tablets are very similar; the most remarkable difference is the change in baseline due to the scattering of radiation by the particles in the blend and the minimum baseline differences in tablet spectra.
The calibration models developed for transmittance in powders present a good predictive capacity, especially the calibration models developed with spectra of resolution 64 and 16 cm−1. The promising results obtained in this study indicate that a real time method could be developed for powders in the future. However, sample deposition for transmittance measurements would have to be improved or a more suitable design developed.