High-performance liquid chromatographic method for an automated determination of local anaesthetics in human plasma.

A method is described that allows the rapid and precise determination of the local anaesthetics bupivacaine and etidocaine from biological fluids. This method uses a fully automated system with solid-phase extraction in combination with a column-switching technique. Both sample extraction on a LiChrocart pre-column and elution onto the analytical LiChrospher column, were performed automatically and concomitantly using conventional HPLC equipment in conjunction with an OSP-2 on-line sample preparator from Merck combined with UV detection. Recoveries were found to be 96.7 and 96.4% for 2 micrograms/ml bupivacaine and etidocaine, respectively. Lower limits of quantification were found to be 0.05 microgram/ml plasma for both of the compounds.