Separation and determination of Alprazolam and Chlordiazepoxide by counter current salting–out homogenous liquid–liquid extraction joined with the dispersive liquid–liquid microextraction (DLLME) coupled with HPLC

Benzodiazepines are a type of drug that acts on the neurotransmitter gammaaminobutyric acid (GABA) receptors, resulting in sedative, hypnotic, and anxiolytic properties [1]. These drugs are commonly misused because of their sedative and hypnotic effects and their use have rapidly expanded in recent years [2]. Thus the analytical information derived from the analysis of these illicit drugs is important for legal purposes. Alprazolam and Chlordiazepoxide are two important drugs from this class. The amount of these drugs in the biological samples are low and on the other hand, the matrix of these samples are complex. So, application of a preconcentration method before their analysis is needed. In this work, an efficient method entitled counter current salting–out homogenous liquid–liquid extraction joined with the dispersive liquid–liquid microextraction (DLLME) coupled with HPLC was performed for extraction and determination of these drugs. To obtain the optimum conditions, we used from a chemometrics method by Box–Behnken methodology. Also, the significant parameters were selected by using by the Plackett-Burman (PB) factorial design. Under the optimal extraction conditions calibration curves are linear in the range of 4–5600 µg L−1 for Chlordiazepoxide and 5-6100 µg L−1 for alperazolam and limit of detections (LODs) are in the range of 1–1.7 µg L−1. The proposed method was successfully applied to the determination of these drugs in their tablets and biological samples.