A sustainable approach for the determination of pacritinib in biological samples with dispersive liquid-liquid microextraction and using hydrophobic natural deep eutectic solvents

The work demonstrates the viability of using hydrophobic natural deep eutectic solvents (NADES) as extraction solvents in dispersive liquid-liquid microextraction (DLLME). To this aim, a menthol-thymol mixture is employed to develop, for the first time, a hydrophobic NADES-based DLLME method for determining novel anticancer drug, pacritinib (PAC), in serum samples prior to LC-UV analysis. In addition, critical aspects of the sample preparation protocol are optimized, including the molar ratio of the hydrogen bond donor and acceptor in the hydrophobic NADES, the amount of extraction solvent, the dispersion method, the pH, the salting-out effect, and the extraction time. The interactions between the hydrophobic NADES components were investigated via FT-IR analysis, with the validation parameter results confirming the assay's acceptable performance. The proposed method's linearity ranged between 0.1 and 3.5 μg mL⁻¹ (R² = 0.9936), with an LOD and LOQ of 0.025 μg mL⁻¹ and 0.1 μg mL⁻¹, respectively. Furthermore, the method's precision and accuracy ranged between 3.45-10.98% and 100.88–111.01%, respectively. Significantly, all values obtained using the hydrophobic NADES-DLLME-LC-UV method complied with ICH requirements for bioanalytical methods. Moreover, the proposed method's greenness and practicality were also assessed using the sample-preparation metric of sustainability (SPMS) and Blue Applicability Grade Index (BAGI). The resultant SPMS score of 8.21 confirmed the method's excellent greenness, and the total BAGI score of 62.5 confirmed the method's practicality.