Voltammetric behaviour of bromhexine and its determination in pharmaceuticals

M. Turchán, P. Jara-Ulloa, S. Bollo, L. J. Nuñez-Vergara, J. A. Squella, A. Álvarez-Lueje

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

A complete electrochemical study and a novel electroanalytical procedure for bromhexine quantitation are described. Bromhexine in methanol/0.1 mol L-1 Britton-Robinson buffer solution (2.5/97.5) shows an anodic response on glassy carbon electrode between pH 2 and 7.5. By DPV and CV, both peak potential and current peak values were pH-dependent in all the pH range studied. A break at pH 5.5 in EP versus pH plot revealing a protonation-deprotonation (pKa) equilibrium of bromhexine was observed. Spectrophotometrically, an apparent pKa value of 4.3 was also determined. An electrodic mechanism involving the oxidation of bromhexine via two-electrons and two-protons was proposed. Controlled potential electrolysis followed by HPLC-UV and GC-MS permitted the identification of three oxidation products: N-methylcyclohexanamine, 2-amino-3,5-dibromobenzaldehyde and 2,4,8,10-tetrabromo dibenzo[b,f][1,5] diazocine. DPV at pH 2 was selected as optimal pH for analytical purposes. Repeatability, reproducibility and selectivity parameters were adequate to quantify bromhexine in pharmaceutical forms. The recovery was 94.50 ± 2.03% and the detection and quantitation limits were 1.4 × 10-5 and 1.6 × 10-5 mol L-1, respectively. Furthermore, the DPV method was applied successfully to individual tablet assay in order to verify the uniformity content of bromhexine. No special treatment of sample were required due to excipients do not interfered with the analytical signal. Finally the method was not time-consuming and less expensive than the HPLC one.

Original languageEnglish
Pages (from-to)913-919
Number of pages7
JournalTalanta
Volume73
Issue number5
DOIs
Publication statusPublished - 31 Oct 2007

Keywords

  • Bromhexine
  • Differential pulse voltammetry
  • Oxidation mechanism
  • Tablets

ASJC Scopus subject areas

  • Analytical Chemistry

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