Facile Spectrophotometric Determination of Metronidazole and Secnidazole in Pharmaceutical Preparations Based on the Formation of Dyes

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 λmax = 510 nm or coupling with 2,5dihydroxy benzoic acid at λmax = 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. INTRODUCTION: Nitroimidazoles are a class of veterinary drugs used for the treatment and prevention of certain bacterial and protozoal diseases in poultry as well as for swine dysentery. Their main compounds include metronidazole (MNZ), ornidazole (ONZ) and secnidazole (SNZ) 1 . Metronidazole (2-methyl-5nitroimidazole – 1 ethanol) and secnidazolel (2-mehyl 5 nitroimidazole – 1 yl propan – 2 ol) are used as antiprotozoal, antiamebic and antibacterial drugs 2 . Excellent reviews have been published on the activity and pharmacokinetics of these drugs. QUICK RESPONSE CODE DOI: 10.13040/IJPSR.0975-8232.6(1).103-10 Article can be accessed online on: www.ijpsr.com DOI link: http://dx.doi.org/10.13040/IJPSR.0975-8232.6(1).103-10 Recently, spectrophotometric methods have been widely used in pharmaceutical analysis successfully 3 . Several methods have been reported for determination of both Metronidazole and Secnidazole which includes potentiometric 4, 5 , polarographic 6, 7 , CPG 8 , supercritical Fluid Chromatography 9 , TLC 10 , HPLC 11-14 , Voltammetric 15 , derivative spectrophotometry 16-18 , flow injection analysis 19 and Spectrophotometry 20-