Qualitative Analysis of Different Formulations of Losartan Potassium Using Raman Spectroscopy

Raman spectroscopy has demonstrated great potential as an alternative technique for drug analysis due to its molecular specificity, speed and simplicity of analysis. In this study, the potential of Raman spectroscopy for qualitative analysis of losartan potassium in 50 mg tablets in different commercially available pharmaceutical formulations (reference, similar and generic) was evaluated. The spectra were obtained from a dispersive Raman spectrometer (830 nm and 300 mW excitation) coupled to a fiber optic probe (Raman probe). Spectra with integration time of 30 s were collected in triplicate. The average spectra of the triplicates from each sample were examined. Comparing the Raman spectra obtained by the literature, it was observed that all have peaks in height and width similar to losartan. Some peaks presented “blue shift”, suggesting hydrolysis of the losartan. Small differences in peak intensities were observed at locations where the spectrum of the losartan molecule does not show peaks, suggesting that they are related to the different excipients used in the production of the drug in the different formulations. It was concluded that the six commercial presentations contain the active ingredient losartan potassium, with very similar Raman spectra.