In this case study, we will focus on the identification of particulate contamination in pharmaceutical products. This is an example where several batches of pharmaceutical raw materials passed the USP compendial tests but received numerous customer complaints due to particulate contamination. The particulate was first isolated from the raw material by dissolution of the product followed by filtration. After the initial documentation and examination of the filters by light microscopy, we begin to isolate representative particulate for identification. Black particles were prevalent on the filters, so we isolated a couple and analyzed them by Raman spectroscopy. Raman spectroscopy is great for analyzing small particles (down to one micrometer). The technique is also non-destructive if you don't burn the sample by ramping up the laser power. Analysis of the contaminants in the raw materials by SEM, light microscopy, FTIR and Raman showed a large variety of materials including several different polymers, metals and metal corrosions, inorganic salts, combustion products, charcoal, textile fibers and hair. The investigation revealed that the particles originated from multiple sources.
