Tautomeric transformations of piroxicam in solution: a combined experimental and theoretical study

D Ivanova, V Deneva, D Nedeltcheva, Fadhil S. Kamounah, G Gergov, Poul Erik Hansen, S Kawauchi, L Antonov

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review


Piroxicam tautomerism was studied in solution by using UV-Vis spectroscopy, NMR measurements and advanced chemometrics. It has been found that in ethanol and DMSO the enol-amide tautomer is present mainly as a sandwich type dimer. The addition of water leads to distortion of the aggregate and to gradual shift of the equilibrium towards the zwitterionic tautomer. Quantitative data for the aggregation and the tautomeric equilibria are presented. Quantum chemical calculations (M06-2X/TZVP) have been used to explain stability of the tautomers as a function of the solvent and concentration.
TidsskriftRSC Advances
Udgave nummer40
Sider (fra-til)31852-31860
Antal sider9
StatusUdgivet - 2015


  • piroxicam

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