Voltammetric investigation of macrolides by an HPLC-coulometric assay

J Pharm Biomed Anal. 2005 Jul 1;38(3):390-6. doi: 10.1016/j.jpba.2005.01.028.

Abstract

Voltammograms of macrolides, including anhydroerythromycin A, azithromycin, erythromycin A, erythromycin A enol ether, pseudoerythromycin A enol ether, oleandomycin and tylosin have been investigated using a dual electrode cell in combination with a high-throughput LC method. The half-wave potentials (E(1/2)) of the seven macrolides investigated ranged from 0.734 to 0.866 V, and the current responses reached the maxima at over 1.0 V. The current response of the downstream electrode displayed a non-linear behavior at high potentials over +0.75 V, probably because of polarization of solvent components, e.g., water. The HPLC-coulometric assay was optimized with the potentials of the upstream and downstream electrodes at +0.65 and +0.85 V, respectively. This method is suitable for detection of 14- and 15-membered macrolides (sensitivity<0.05 microg ml(-1)), but not for a 16-membered macrolide, tylosin (sensitivity>0.1 microg ml(-1)). The assay shows interferences from biomatrices in rat's blood plasma and serum, and human urine, but they were effectively removed by a cold acetonitrile extraction method.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Chromatography, Liquid / methods*
  • Electrochemistry / instrumentation
  • Electrochemistry / methods*
  • Humans
  • Macrolides / blood*
  • Macrolides / chemistry
  • Macrolides / urine*
  • Molecular Structure
  • Rats
  • Rats, Inbred F344
  • Reproducibility of Results
  • Technology, Pharmaceutical / methods

Substances

  • Macrolides