RAMAN SUPPLEMENT


legislation exists, the globalised complexity of the market and the high profits generated4


. It is a


relatively low risk business with high returns for organised crime and policies have to be developed by governments. Given the devastating health repercussions involved, drastic measures are immediately required5


. The


main economic victims, the pharmaceutical companies, have developed measures to protect their products6


. They also have a variety


of techniques at their disposal for differentiating between counterfeits and their own medicines, essentially chromatography7,8


and spectro - scopy9,10. Screening usually begins with rapid


visual inspection. Then the packaging can be studied in detail and the content of the suspect product analysed. Time is a crucial factor for the detection of counterfeits and vibrational spectroscopy offers this capability. In this paper, the potential of Raman spectroscopy for the detection, the analysis of the composition and the profiling of medicine counterfeits is presented. Quick and efficient methods of identification are indeed still required. If a counterfeit is detected, the study of the chemical content is moreover necessary in order to evaluate the risk the patients can be exposed


Raman spectroscopy: basic principles and advantages for the analysis of counterfeits The Raman Effect is the result of a change in the polarisability of molecular bonds. It is generated by a laser that enables reaching an energy state higher than the initial one. The radiations are


“Since repeatable spectral profiles are generated, Raman spectra can be compared with database


references or computed with chemometric methods for the analysis of counterfeits ”


then scattered in an inelastic way. One in 106 to 108


to. In addition, the chemical profiling in a forensic intelligence perspective can then give useful information for investigation needs. The applications of Raman spectroscopy for counterfeit analyses are summarised in Figure 1 on page 4.


energy. The spectra range from 100 to 3000 cm-1 .


They can be interpreted like infrared spectra given that the position of the peaks in wavelength is identical to the position of the infrared bands11


. Both methods are comp -


lementary since the intensity of the peaks is inversely proportional most of the time. The main advantage of Raman


spectroscopy is its chemical selectivity that allows many applications in the pharmaceutical field, such as the study of polymorphs, the chemical analysis of solids or the quantification of API in a medicine. Since repeatable spectral profiles are generated, Raman spectra can be compared with database references or computed with chemometric methods for the analysis of counterfeits. Raman handheld spectrometers are thus increasingly used in the field for the detection of medicine counterfeits12-14


. Some products are nevertheless photons undergoes Raman scattering.


A Raman spectrum is referred as the number of Raman photons plotted against the shifted


hard to measure by Raman spectroscopy, such as low concentrated liquid medicines. The phenomenon of fluorescence might be observed for several compounds. This can be diminished by changing the laser wavelength or using methods like Spatially Offset Raman Spectroscopy15


.


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