Effect of surfactant on voltammetric behaviour of ornidazole

The objective of the present work is to develop a voltammetric method for the determination of ornidazole in pharmaceutical formulations and it also deals with the beneficial use of surfactants in the catalysis of electrode reactions. The proposed method is rapid and sensitive for the qualitative and quantitative analysis of ornidazole in solubilized systems. The voltammetric behaviour of ornidazole has been studied in different surfactant media viz., anionic, cationic, non-ionic surfactants over the pH range 2.5 to 12.0 in phosphate buffer (0.2 M). Addition of non-ionic surfactant (Tween 20) to the ornidazole containing electrolyte enhanced the reduction current signal while the anionic surfactant sodium lauryl sulphate and cationic surfactant cetyltrimethylammonium bromide showed a small enhancement in peak current. The mechanism of reduction has been postulated on the basis of controlled potential electrolysis, coulometry and spectral analysis. The reduction process is irreversible and was diffusion controlled. Analytical method with adequate precise and accuracy was developed for the determination of ornidazole with linear concentration range 4.0 × 10−3 to 4.0 × 10−6 mol L−1. The lower limit of quantification (LOQ) and the lower limit of detection (LOD) were found to be 1.2 × 10−6 and 3.6 × 10−7 mol L−1 respectively. The analysis of ornidazole in its pharmaceutical formulation exhibited the mean recovery of 98% for the reduction peak.