Drug tablets are occasionally tainted or stained with contaminants that can come from various sources. Some common sources are lubricants from manufacturing equipment and residues from packaging material. The contamination could happen during manufacturing or after the tablet has been sent to packaging.
In this example, a pharmaceutical tablet displaying a yellowish stain had been returned to a major pharmaceutical manufacturer. The contamination raised concerns regarding product purity, manufacturing problems and/or product tampering. Examination and identification of the yellow stain was needed to address these concerns and provide information to determine the origin of the contaminant.
Upon receiving the stained drug tablet, we carefully documented it by taking notes and photos. Figure 1 shows the contamination was a yellow smear with heavy spotty stains. We used micro tools to isolate the stains for Fourier transform infrared spectroscopy (FTIR) analysis.
FTIR (Figure 2) is a great instrument for identifying organic materials. It is non-destructive and gives molecular information to help quickly identify unknown materials. In this case, the FTIR analysis indicated that the yellow stain contaminant is another pharmaceutical product not associated with the manufacturer.
The interior of the tablet was also examined for contamination, which showed that the yellow stain contamination was confined to the surface of the tablet. With this information, the pharmaceutical manufacturer was able to conclude that the staining occurred after manufacturing and packaging.