5.2.1. Minor component detection
Many new drugs contain small concentrations of potent
APIs delivered by complex delivery systems. It is imperative
that content uniformity can be maintained in such systems.
Sˇ
asˇic [52] published a study on Raman Chemical
Imaging of low content API pharmaceutical formulations
in which Raman maps were obtained from the flattened
surfaces of 6 tablets using a pushbroom Raman Imaging
system. Univariate images, produced from the intensity
recorded at each pixel at individual wavelengths, were difficult
to interpret, and the author reported that reliable API
Raman signal was only detected upon applying Principal
Component Analysis (PCA) to the data.