By Robert L. Green, Robert Brush, Wayne Jalenak, and Christopher D. Brown
Pharmaceutical manufacturers are seeking ways to maintain and improve product quality while reducing manufacturing costs, including in the analytical testing of raw materials. Movement toward 100% inspection of raw materials as well as increased production volumes and the desire for lean manufacturing are additional motivations to find more cost-effective testing technologies.
Raman spectroscopy's inherent selectivity makes it an effective option for qualitative verification of pharmaceutical raw materials . Until recently, Raman spectroscopy was difficult to implement because of the technical challenge of detecting the relatively weak but highly selective Raman scattering effect. During the past 10 years, improvements in the sensitivity of charge-coupled device (CCD) detectors, the increased availability of longer-wavelength diode lasers, and developments in Rayleigh rejection filters have made Raman spectroscopy suitable for routine applications. Moreover, miniaturization of optical components has enabled the development of portable, handheld Raman spectrometers capable of robust material verification through transparent packaging materials such as glass and plastic.