Flow Injection Spectrophotometric Determination of Dipyrone in Pharmaceutical Formulations Using Fe(III) as Reagent

Abstract

A flow injection spectrophotometric procedure with symmetric merging zones for dipyrone determination in pharmaceutical formulations is proposed. The determination is based on the formation of a blue complex (monitored at a wavelength of 642 nm) yield in the complexation reaction of dipyrone with Fe(III) in acid medium. Under optimum conditions, a calibration curve was obtained from 3.5 to 281 mg L⁻¹ with a detection limit of 2.8 mg L⁻¹ and the samples throughput was 80 h⁻¹. The analytical results obtained for commercial formulation samples by applying the proposed method were in good agreement with labeled values and those obtained by a comparative procedure at a 95% confidence level.

Keywords:

• Determination of dipyrone
• Fe(III)
• Flow injection spectrophotometry
• Pharmaceutical formulations

Acknowledgments

This paper was submitted as part of a Special Issue on Flow Injection Analysis.

The authors are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support.

Notes

*mg/mL; **mg/tablet n = 3, mean ± standard deviation, confidence level 95%. Er₁ = relative error flow procedure vs. labeled value and Er₂ = relative error flow procedure vs. comparative method.