Monoethylglycinexylidide and lidocaine determination in porcine microsomal preparations

A simple, accurate, and sensitive HPLC analysis of monoethylglycinexylidide (MEGX) and lidocaine in porcine microsome samples is described. Lidocaine and MEGX were measured by direct injection after the addition of the internal standard. Chromatography was performed on a μBondapak C18 column using an isocratic mobile phase of 0.03 M potassium dihydrogen phosphate:acetonitrile (87:13), pH 5.9. UV absorbance was measured at 205 nm. The procedure produced linear curves for the concentration range 50-1000 ng/mL with a limit of detection of 10 ng/mL. Recoveries for both compounds were greater than 90%. This assay produced accurate and repeatable results.