High-performance liquid chromatographic method for the simultaneous determination of monoethylglycinexylidide and lignocaine.

An accurate and sensitive high-performance liquid chromatographic method with UV detection was developed for the simultaneous measurement of monoethylglycinexylidide (MEGX) and lignocaine in human plasma and serum, using organic solvent extraction and trimethoprim (TMP) as an internal standard. The mean recoveries for MEGX, TMP and lignocaine were 86.1 +/- 3.7, 98.3 +/- 1.8 and 77.0 +/- 4.7%, respectively (n = 6). The relative standard deviations for MEGX concentrations of 10 and 200 ng/ml were less than 4% and for lignocaine concentrations of 200 and 1200 ng/ml they were less than 8%.