Development and Validation of a Novel Stability-Indicating Reversed-Phase Ion-Pair Chromatographic Method for the Quantitation of Impurities in Marbofloxacin Tablets.

A stability-indicating isocratic reversed-phase ion-pair chromatographic method was designed for the separation of impurities in the presence of degradation products. Marbofloxacin tablets and a placebo were exposed to the stress conditions of oxidative, acid, base, humidity, thermal, and photolytic degradation. Significant and moderate degradation was observed in acidic and oxidative stress conditions, respectively. The degradation products were well resolved from the main peak and its impurities, thus proving the stability-indicating analytical method. The method was developed by using an XTerra RP18 3.5 μm (150 × 4.6 mm) column, with the mobile phase containing a mixture of buffer (pH 2.5)-methanol-glacial acetic acid (77 + 23 + 0.5, v/v). The flow rate of the mobile phase was 1.2 mL/min, with a column oven temperature of 40°C and a detection wavelength of 315 nm. The proposed method met Veterinary International Conference on Harmonization requirements and was successfully used for impurity quantitation in marbofloxacin tablets.