Spectrophotometric and High Performance Liquid Chromatographic Determination of Ofloxacin and Azithromycin in Pharmaceutical Tablets

Abstract

Absorbance ratio spectrophotometric method and high performance liquid chromatographic method were developed for the determination of the Ofloxacin and Azithromycin in tablet dosage form. In UV-Spectrophotometric method, estimation of Ofloxacin and Azithromycin was carried out at 230.60 nm (isoabsorptive point) and 288.60 nm (λ max of Ofloxacin) for absorbance ratio method. Calibration curves were linear in the range of 4–20 μg/ml for Ofloxacin and 5-25 μg/ml Azithromycin for absorbance ratio method. Correlation coefficient found to be close to 0.9995 for both the drugs. Accuracy for both the drugs was in the range of 98-101%. A simple liquid chromatographic assay has been developed for the determination of Ofloxacin and Azithromycin. A C 18 (250 mm × 4.6 mm, 5 μ) column was used with a mobile phase consisting of Phosphate buffer: Methanol ( pH adjusted to 5.0 with ortho phosphoric acid) at a flow rate of 1.0 ml min -1 . Quantitation was achieved with UV detection at 215 nm based on the peak height ratios. Beer’s law was obeyed in a concentration range of 12-28 μg ml -1 for Ofloxacin and 15-35 μg ml -1 for Azithromycin and the regression line equation was derived with a correlation coefficient of 0.9970 and 0.9980 for Ofloxacin and Azithromycin respectively. The validity of the methods was further confirmed using the standard addition method. The proposed procedures were successfully applied to the determination of Ofloxacin and Azithromycin in bulk and tablet form, with high percentage of recovery, good accuracy and precision. Key words: Absorbance ratio method, Azithromycin, HPLC, Ofloxacin, Tablets.