Determination of antihyperglycemic drugs in nanomolar concentration levels by micellar electrokinetic chromatography with non-ionic surfactant

A method for the separation of six selected antihyperglycemic (antidiabetic) drugs (tolbutamide, gliclazide, glimepiride, glibenclamide, repaglinide, and glipizide) was developed with use of micellar electrokinetic chromatography. Two non-ionic poly(ethylene glycol)-based surfactants Genapol X-080 and Triton X-114 (reduced) were studied as neutral pseudostationary phases. High alkaline pH 10.0 was used to obtain negative charges of separated antidiabetic drugs and non-ionic surfactants were employed for selectivity alteration. Both non-ionic surfactants provided good selectivity at concentration 0.2% (v/v) in sodium borate buffer and the separation of six drugs was obtained within 5 min. An on-line preconcentration method based on reversed electrode polarity switching was employed for the determination of antihyperglycemic drugs in blood serum after acetonitrile protein precipitation. The limits of detection ranged from 20.8 nmol L−1 for tolbutamide to 6.5 nmol L−1 for glibenclamide, respectively.