Development and application of spectrophotometric method for quantitative determination of Metronidazole in pure and tablet formulations

A rapid, simple and sensitive spectrophotometric method has been developed for the determination of metronidazole in pharmaceutical pure and dosage forms. The method depends on alkaline hydrolysis of metronidazole releases the nitro group as nitrite ion and yielded nitrite ions can be used to give a colored complex that absorbs maximally at 505 nm. Beer's law is obeyed in the concentration ranges 9-100 g/ml with molar absorptivity of 1.14 ×103 L mole-1 cm-1. The proposed method is precise, accurate and specific for the quantitative determination of drug in bulk and dosage forms. The results of analysis of commercial formulations and the recovery study of metronidazole suggested that there is no interference from any excipients, which are present in pharmaceutical formulations of metronidazole. Statistical comparison of the results was performed with regard to accuracy and precision using student's t-test and F-ratio at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.