A Stability-Indicating RP-HPLC Method for Simultaneous Determination of Triclabendazole and Levamisole in Oral Suspension Formulation.

A fast, simple, and precise stability-indicating high-performance liquid chromatographic (HPLC) method was developed for analysis of triclabendazole (TBZ) and levamisole (LEV) in oral suspension. Using a mobile phase composed of acetonitrile, methanol, and water (50:40:10, v/v/v), with the pH adjusted to 4.6 with 0.1 M phosphoric acid. The mobile phase was filtered, degassed, and pumped at a flow rate of 1.0 mL/min. Detection was performed at 245 nm. The proposed method was validated with respect to specificity, linearity, limit of detection (LOD) and limit of quantification (LOQ), interday and intraday precision, robustness, and accuracy. The retention times for TBZ and LEV were found to be about 3.116 and 1.385 min, respectively. Calibration plots were linear with correlation coefficient of 0.9999 in the concentration range of 200-800 and 150-600 μg/mL for TBZ and LEV, respectively. The method was verified to be stability indicating by separating the active ingredients from their stressed testing degradation products. The procedure proved acceptable robustness to variations in flow rate, wavelength, and column temperature. The method was conveniently used for the analysis of TBZ and LEV in oral suspension.