Rapid, Simultaneous Determination of Levamisole and Abamectin in Liquid Formulations Using HPLC

Abstract

The aim of the study was to develop a high performance liquid chromatography (HPLC) assay for the rapid, simultaneous determination of levamisole phosphate and abamectin in liquid formulations containing mixtures of solvents and medium chain mono‐ and diglycerides and triglycerides. The experimental procedure involved reversed‐phase‐HPLC with a Zorbax ODS column (7 µm particle size, 4.6 ID × 250 mm), acetonitrile‐water‐ and ammonia 1.0N volumetric solution (80:20:0.1, v/v/v) mobile phase, UV detection at 253 nm for both levamisole phosphate and abamectin. The flow rate of the mobile phase was 2 mL/min. The retention times of levamisole phosphate and abamectin varied from 2.45–2.46 min and 5.78–5.82 min, respectively. Formulation components did not give rise to any interfering peaks. Calibration curves were linear over the range 13.5–270 µg/mL for levamisole phosphate and 0.5–10 µg/mL for abamectin. The maximum intraday and interday coefficients of variation were 0.7% and 1% at 13.5 µg/mL for levamisole phosphate, and 2.2% and 5.8% at 0.5 µg/mL for abamectin, respectively. Accuracies were 98.9 ± 5.2% and 96.2 ± 3.1% (Mean ± SD, n = 14) for levamisole phosphate and abamectin, respectively, at concentrations of 27.3 µg/mL of levamisole phosphate and 1 µg/mL of abamectin. The assay was used to evaluate the stability of these drugs in the liquid formulations. A simple and accurate liquid chromatographic method was developed and validated for simultaneous determination of levamisole and abamectin in liquid formulations. Due to its simplicity and accuracy, the assay method is suitable for routine analysis of both drugs in liquid formulations.