Abstract

MOYA-HERNANDEZ, Rosario; GOMEZ-BALDERAS, Rodolfo  and  ROJAS-HERNANDEZ, Alberto. Chemical Speciation of the Fe(III)-piroxicam and Fe(III)-tenoxicam Systems in Aqueous Solution. J. Mex. Chem. Soc [online]. 2011, vol.55, n.2, pp.94-100. ISSN 1870-249X.

A chemical speciation study of the antiinflamatory drugs piroxicam and tenoxicam was carried out with the Fe(III) ion, under pseudophysiological conditions (T = 37°C and I = 0.15 M). The equilibrium constants for the formation of the Fe(III)-oxicam species were obtained from UV/VIS spectrophotometric data assisted by SQUAD program. The hydrolysis constants of Fe(III) were also refined under the same experimental conditions. For tenoxicam, the constants refined correspond to the species Fe(H₂tenox)₂⁵⁺, Fe(Htenox)₂³⁺, Fe(OH)₂(Htenox)₂⁺, Fe(OH)₂(tenox)₂-, FeH₂tenox⁴⁺, FeHtenox³⁺, Fe(OH)₂Htenox⁺ and Fe(OH)₂tenox, an analogous model was established to refine the piroxicam constants. The molar absorptivity coefficients for all the species were also calculated.

Keywords : Fe(III); tenoxicam; piroxicam; SQUAD; chemical speciation.

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