Spectrophotometric determination of erythromycin using charge transfer complexation

Abstract

A simple and sensitive spectrophotometric method is described for the quantitative determination of erythromycin. The method is based on charge transfer complexation reaction of, erythromycin as n-electron donor with 2, 3 dichloro-5,6-dicyano-1,4- benzoquinone (DDQ) as -acceptor to give highly coloured complex with 1:1 stoichiometric ratio. The coloured products were quantified at 464nm under the optimized experimental conditions. Beer’s law is obeyed over the concentration ranges of 5-150μg/ml. The apparent molar absorptivity was calculated to be 1.27 x 103 Lmol-1cm-1 and corresponding Sandell sensitivity of 1.56. The limit of detection and quantification were 2.1and 6.4 respectively. The proposed methods were applied successfully to the determination of erythromycin in pure and commercial forms with good average recovery of 105.4 %. Statistical comparison of the result was performed with regards to accuracy and precision using student’s t-test and f-test at 95% confidence level.