Voltammetric determination of coenzyme Q 10 in pharmaceutical dosage forms

Abstract

A simple and rapid voltammetric method has been developed for the quantitative determination of coenzyme Q 10 (CoQ 10) in pharmaceutical preparations. Studies with differential pulse voltammetry (DPV) were carried out using a glassy carbon electrode (GCE) in a mixed solvent containing 80 vol.% acetic acid and 20 vol.% acetonitrile. A well-defined reduction peak of CoQ 10 was obtained at − 20 mV vs. Ag/AgCl. The voltammetric technique applied provides a precise determination of CoQ 10 using the multiple standard addition method. The statistical parameters and the recovery study data clearly indicate good reproducibility and accuracy of the method. The accuracy of the results assessed by recovery trials was observed to be within the range of 101.1% to 102.5%. The detection and quantification limits were found to be 0.014 mM (12 mg L − 1 ) and 0.046 mM (40 mg L − 1 ), respectively. An analysis of real samples containing CoQ 10 showed no interferences with common additives and excipients, such as unsaturated fatty acids and soya lecitine. The method proposed does not require any pretreatment of the pharmaceutical dosage forms. A spectrophotometric determination of CoQ 10 in real samples diluted in mixtures containing ethanol and n-hexane was also performed for comparison.