The simultaneous determination of lidocaine and procainamide in serum by use of high pressure liquid chromatography.

This report describes an accurate, sensitive rapid procedure for the determination of lidocaine and procainamide at therapeutic concentrations in serum. The drugs and an added internal standard (procaine) are extracted from serum using charcoal adsorption. The analysis is carried out by high pressure liquid chromatography on a reverse-phase column using buffered aqueous acetonitrile as the mobile phase. Chromatography is complete in 10 min. C.V. values of 10% and 6% for concentrations of 1 mg/l and 20 mg/l, respectively, are attainable routinely. Total analysis time is 15 min.