Determination of arbidol in rat plasma by HPLC–UV using cloud-point extraction

A method based on cloud-point extraction (CPE) was developed to determine arbidol in rat plasma by high performance liquid chromatography separation and ultraviolet detection (HPLC–UV). The non-ionic surfactant Triton X-114 was chosen as the extract solvent. Variable parameters affecting the CPE efficiency were evaluated and optimized. A Zorbax SB-C18 column (4.6 mm i.d. × 150 mm, 5 μm particle size) was used for isocratic elution separation at 40 °C with detection wavelength at 316 nm. Under the optimum conditions, the method was shown to be reproducible and reliable with intraday precision below 6.6%, interday precision below 8.8%, accuracy within ±5.0% and mean extraction recovery more than 89.7%, which were all calculated using a range of spiked samples at three concentrations of 0.2, 2 and 16 μg/ml for arbidol in plasma. The linear range was from 0.08 to 20 μg/ml. After strict validation, the method was successfully applied to the pharmacokinetic study of arbidol in rats after oral and intravenous administration, respectively.