Simultaneous analysis of ketamine and bupivacaine in plasma by high-performance liquid chromatography.

A reversed-phase HPLC technique for the simultaneous measurement of both bupivacaine and ketamine in plasma is described. Plasma samples (0.5 ml) were prepared using a rapid and simple back-extraction technique. Resolution of both analytes and the internal standard, desipramine, from medicines coadministered to surgical paediatric patients was obtained using a 5 microm cyano (CN) (250x4.6 mm) column and a mobile phase comprising methanol-acetonitrile-orthophosphoric acid-0.01 M sodium dihydrogenphosphate (200:80:2:718). Good sensitivity for both analytes was observed using UV detection at a wavelength of 215 nm. The method has been validated according to the criteria established by the Journal of Chromatography B.