Determination of nateglinide in animal plasma by micellar electrokinetic chromatography and on-line sweeping technique.

A micellar electrokinetic chromatography (MEKC) method was developed for the determination of nateglinide in animal plasma by on-line sweeping technique, in which plasma samples were simply deproteinized with acetonitrile, and analyzed with 16 mmol/L NaH2PO4 + 6 mmol/L Na2B4O7 + 60 mmol/L sodium dodecyl sulfate (SDS) (pH 7.14) as the running buffer, a fused-silica capillary as the separation tube, 21 kV as the running voltage and UV detection at 214 nm. Under these conditions, more than 100-fold enrichment of nateglinide was obtained with the good linear relation in the range of nateglinide plasma concentration 0.2-7 mg/L (R = 0.998). The method could be applied successfully to determine trace drugs in clinical analysis.