Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/53897
Type: Artigo de periódico
Title: A theoretical and spectroscopic study of conformational structures of piroxicam
Author: de Souza, KF
Martins, JA
Pessine, FBT
Custodio, R
Abstract: Piroxicam (PRX) has been widely studied in an attempt to elucidate the causes and mechanisms of its side effects, mainly the photo-toxicity. In this paper fluorescence spectra in non-protic solvents and different polarities were carried out along with theoretical calculations. Preliminary potential surfaces of the keto and enol forms were obtained at AM1 level of theory providing the most stable conformers, which had their structure re-optimized through the B3LYP/CEP-31G(d,p) method. From the optimized structures, the electronic spectra were calculated using the TD-DFT method in vacuum and including the solvent effect through the PCM method and a single water molecule near PRX A new potential surface was constructed to the enol tautomer at DFT level and the most stable conformers were submitted to the QST2 calculations. The experimental data showed that in apolar media, the solution fluorescence is raised. Based on conformational analysis for the two tautomers, keto and enol, the results indicated that the PRX-enol is the main tautomer related to the drug fluorescence, which is reinforced by the spectra results, as well as the interconvertion barrier obtained from the QST2 calculations. The results suggest that the PRX one of the enol conformers presents great possibility of involvement in the photo-toxicity mechanisms. (C) 2009 Elsevier B.V. All rights reserved.
Subject: Piroxicam
Total fluorescence
Conformational analysis
Density functional theory
Electronic spectra
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Rights: fechado
Identifier DOI: 10.1016/j.saa.2009.12.031
Date Issue: 2010
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File Description SizeFormat 
WOS000274591200063.pdf645.67 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.