Development and Application of Kinetic Spectrophotometric Method for the Determination of Metronidazole

Purpose: To develop an improved kinetic-spectrophotometric procedure for the determination of metronidazole (MNZ) in pharmaceutical formulations.
Methods: The method is based on oxidation reaction of MNZ by hydrogen peroxide in the presence of Fe(II) ions at pH 4.5 (acetate buffer). The reaction was monitored spectrophotometrically by measuring the rate of change of absorbance at 317nm.
Results: The optimum operating conditions for reagent concentrations and temperature were established. Linear calibration curve was obtained in the range of 85.77 – 513.45ng mL^-1 with standard deviation from 1.77 to 4.55 %-. The optimized conditions yielded a theoretical detection limit of 15.20 ng mL^-1 based on 3.3S_ocriterion. Commonly used excipients and other additives such as talc, glucose, fructose, lactose, starch, magnesium stearate, microcrystalline cellulose and several ions were found not to have interference.
Conclusion: The developed method is sensitive, accurate and reproducible and could be used for routine analysis of metronidazole in pharmaceutical preparations.

Keywords
Metronidazole; Kinetic spectrometry; Validation; Pharmaceutical preparation