DETERMINATION OF KETAMINE AND NORKETAMINE ENANTIOMERS IN PLASMA BY SOLID-PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A high-performance liquid chromatographic method is described for dete rmination of sub-anaesthetic concentrations of the enantiomers of keta mine and its metabolite norketamine in plasma. The samples are purifie d by reversed-phase solid-phase extraction. The enantiomers are separa ted on a Chiral AGP column with a mobile phase containing 16% methanol and a 10 mM phosphate buffer at pH 7.0, and measured by W-detection a t a wavelength of 220 nm. Linear calibration curves with correlation c oefficients better than 0.995 have been obtained in the range 10-320 n g/ml. Minimum detectable concentrations were about 2 ng/ml.