Ultrasound-assisted dispersive liquid-liquid microextraction for determination of three gliflozins in human plasma by...

A novel, highly sensitive ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) high performance liquid chromatography with diode-array detection (HPLC/DAD) method was developed for the determination of empagliflozin, dapagliflozin and canagliflozin in human plasma using methanol as protein precipitating agent/disperser and 1-dodecanol as extracting solvent. The analytes were eluted with an isocratic mobile phase consisting of acetonitrile:aqueous 0.1% trifluoroacetic acid pH 2.5, (40:60, v/v), at a flow rate of 1 mL/min and UV detection at 210 nm. The microextraction conditions were optimized regarding type and volume of extractant, type of disperser, sample pH, extraction time and centrifugation time. Under the optimal conditions, the enrichment factors were 19 for empagliflozin, 27 for dapagliflozin and 50 for canagliflozin. Linearity ranges were 2-2500 ng/mL, 3.5-2500 ng/mL and 1.1-2500 ng/mL for empagliflozin, dapagliflozin and canagliflozin, respectively. The developed method employs very small volumes of organic solvents in sample extraction and allows determination of small concetrations of gliflozins in human plasma.