Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5611_Библиотеки_им_академика_М_И_Перельмана

data were validated with the conventional reference destructive, expensive and time- consuming HPLC assay for quinine dihydrochloride. The spectroscopy results indicated that it was possible to use PCA as a discriminating method to rapidly detect substandard samples and a successful study outcome was that the NIR spectroscopy qualitative model was to be implemented for routine analysis and replace the existing HPLC method in a national quality control laboratory of drugs (Mbinze et al., 2015). The feasibility of NIR and Raman spectroscopy to discriminate between genuine and counterfeits tablets of a cholesterol- lowering medicine, Lipitor was also investigated. Classication based on PLS- DA models was successful for both vibrational spectroscopic methods, irrespective of whether atorvastatin or lovastatin was used as the API. This study concluded that the discriminative power of the NIR spectroscopy model relies mainly on the spectral differences of the tablet matrix, which is due to the relatively large sample volume being probed with NIR radiation and the excipient’s strong spectroscopic activity. It was further postulated that since Raman spectroscopy is primarily a surface technique, it poses a disadvantage for this type of analysis as the spectra for the tablet coating and core might differ and that the Raman spectra may change with the position of the laser for a non- homogenous sample (de Peinder et al., 2008). Sacre and co- workers aimed to compare and combine FTIR, NIR, and Raman spectroscopy for the detection of counterfeit Viagra and Cialis tablets. PLS analysis results revealed that for Viagra, the best results were provided by a combination of FTIR and NIR, while for Cialis the best results were provided by the combination of NIR and Raman spectroscopy (Sacre et al., 2010). Classication and regression tree algorithms were evaluated for modeling FTIR, NIR, and Raman spectroscopic data in order to discriminate between genuine and counterfeit tablet samples of Viagra and Cialis. k- NN was also applied to the same data sets. The results obtained with this tree- based method were easily interpretable and better than the more traditional k- NN discriminating method, although the CART models are limited by the nature of the data set and they should be adapted and updated each time new samples or classes are encountered (Deconinck et al., 2012). Rebiere and co- workers employed a two- step analytical approach to the rapid NIR and Raman spectroscopy non- destructive screening of anabolic tablets. Here the fast analysis of tablets using NIR spectroscopy to assess sample homogeneity based on their global composition, followed by Raman chemical imaging to obtain information on sample formulation was conducted. NIR spectroscopy assisted by PCA enabled fast discrimination of different proles based on the excipient formulation and Raman imaging provided chemical images of the distribution of the active compound and excipients within tablets and facilitated identication of the active compounds (Rebiere et al., 2016). Another study evaluated the performances of various NIR and Raman spectroscopy handheld instruments in specic brand identication of tablet and capsule medicines through their primary packaging. The overall results showed good detection abilities for NIR instruments compared to Raman instruments, which are less sensitive to the physical state of the samples than the NIR systems (Ciza et al., 2019).