Spectrophotometric determination of ornidazole, secnidazole and tinidazole in pharmaceutical preparations based on formation of dyes

Abstract

SIMPLE and accurate spectrophotometric method was developed for the assay of omidazole (I), secnidazole (II) and tinidazole (III) in tablet dosage form. The method depends on the reduction of the drugs with zinc dust and hydrochloric acid followed by condensation with p-hydroxy benzaldehyede at 50°C to produce colored chromogens having absorbance at 402 nm for drugs I, II and III. The optimum experimental conditions for the proposed method were optimized and Beer's law was obeyed in the concentration ranges of 20-300 μg ml -1 for drugs I and II 20-250 Mg ml -1 for drug III. The apparent molar absorptivities of the resulting colored products were found to be 1.00x10 2, 1.24x10 2 and 1.70x10 2L mol -1 cm -1, whereas Sandell sensitivities are 4.5x10 -6, 3.9x10 -6 and 6.7x10 -6 μg cm -2 for I, II and III, respectively. The proposed method was applied successfully for the analysis of the investigated drugs in tablet form. The results obtained were statistically compared with a reported method using the student's t -test and F-variance ratio tests. Omidazole, Secnidazole, Tinidazole and P- hydroxybenzaldehyde.