Novel stability indicating RP-HPLC method for the simultaneous estimation of tobramycin and loteprednol in pharmaceutical dosage forms

A simple, accurate, rapid and precise isocratic stability indicating reversed-phase high-performance liquid chromatographic method has been developed and validated for simultaneous determination of Tobramycin and Loteprednol in combined tablet dosage form. The chromatographic separation was carried out on Zodiac C18 (150 x 4.6mm, 5µ) with a mixture of Phosphate buffer: acetonitrile (60:40%v/v) as a mobile phase at a flow rate of 1.0 mL/min. UV detection was performed at 243nm. The retention times were 2.442 and 3.269 min for Tobramycin and Loteprednol respectively. Calibration plots were linear (r2=0.999) over the concentration range of 3.75-22.5 µg/mL for Tobramycin 6.25-37.5µg/mL for Loteprednol. The method was validated for accuracy, precision, specificity, linearity, robustness, LOD and LOQ. The proposed method was successfully used for quantitative analysis of tablets. No interference from any component of pharmaceutical dosage form was observed. Validation studies revealed that developed method is specific, rapid, reliable, and reproducible. The high recovery and low relative standard deviation confirm the suitability of the method for routine determination of Tobramycin and Loteprednol in bulk and tablet dosage form.