Computational study and spectroscopic investigations of antihypertensive drugs

Sartans are orally active non-peptide molecules that competitively block the access of the AT1 receptor to angiotensin II used to treat hypertension and related pathologies. In particular, candesartan and valsartan are currently used in clinical therapy, and it is of interest to characterize them and their anionic forms under physiological conditions by means of their vibrational properties. The Fourier transform Raman (FT-Raman) and Fourier transform infrared (FTIR) spectra of candesartan, valsartan in their protonated and deprotonated forms were recorded in the solid phase. The vibrational wavenumbers, infrared intensities and Raman scattering activities were calculated by density functional B3LYP method with the 6-31+G(d,p) basis set, and theoretical spectrograms have been constructed. The scaled theoretical wavenumbers showed very good agreement with the experimental values. A detailed interpretations of the infrared and Raman spectra were performed for both the synthetic and the bioactive drugs. (C) 2012 Elsevier B.V. All rights reserved.