FACILE SPECTROPHOTOMETRIC DETERMINATION OF METRONIDAZOLE AND SECNIDAZOLE IN PHARMACEUTICAL PREPARATIONS BASED ON THE FORMATION OF DYES

摘要

A rapid and sensitive spectrophotometric method is proposed for the determination of Metronidazole and Secnidazole drugs. The method depends on the reduction of Metronidazole and Secnidazole molecules with zinc dust and hydrochloric acid followed by diazotization and coupling with α-naphthylamine to give red colored chromogens easily measured spectrophotometrically at λ_max = 510 nm or coupling with 2,5- dihydroxy benzoic acid at λ_max = 518nm. The Sandell’s sensitivity, the molar absorptivity, correlation coefficient and the regression equation were calculated. Under optimized experimental conditions Beer’s law is obeyed in the concentration range 3-30 and 2-12 μg/ml for Secnidazole and Metronidazole; respectively with α-naphthyl amine as a coupling agent. Also, by using 2, 5-dihydroxybenzoic acid as a coupling agent, the concentrations obtained were 5-50 μg/ml for both Secnidazole and Metronidazole. Both techniques were applied successfully for the analysis of Metronidazole and Secnidazole in tablets form. These methods are recommended for quality control and routine analysis where time, cost effectiveness and high specificity of analytical techniques are of great importance.