ultrasound-assisted dispersive liquid–liquid microextraction and multivariate optimization for determination of sodium closantel in biological samples and pharmaceutical formula

A fast and simple ultrasound-assisted dispersive liquid–liquid microextraction method for determination of sodium closantel has been developed. high-performance liquid chromatography with ultraviolet detector has been used for the determination of sodium closantel. the effect of influencing parameters such as type and volume of extraction and disperser solvents, ph of sample solution, extraction time and amount of salt was also investigated. optimization of method was performed using plackett–burman experimental design and surface response methodology. under the optimal conditions, the linear dynamic range of sodium closantel was from 10 to 3000 µg l−1 with a correlation coefficient of 0.997 and a detection limit of 1.0 µg l−1. the relative standard deviation was less than 3.5% (n = 5). the method has been successfully applied for determination of sodium closantel in real samples. the enrichment factor was 48 under optimal conditions.