Development and validation of a high-performance liquid chromatography method for the determination of cocaine, its metabolites and ketamine.

Cocaine abuse is an extensive problem in the USA. During the past decade, ketamine abuse also has emerged as a public health concern and is now considered a controlled substance. The prevalence of the simultaneous use of cocaine and ketamine has been shown to be high. Previous research indicates that ketamine affects the enzymes that metabolize cocaine. In order to investigate this pharmacokinetic interaction, it was necessary to identify and quantitate each compound. The aim of this study is to develop a method of detecting and resolving cocaine, its metabolites and ketamine. A new precise, accurate and sensitive reversed-phase high-performance liquid chromatography method has been developed and validated. This assay employed a phosphate-buffered aqueous mobile phase (pH 6.9) with an organic component consisting of acetonitrile and methanol and a C-18 column as stationary phase at 225 nm wavelength. Minimum detection limits were 5 ng ml(-1) for cocaine and 10 ng ml(-1) for benzoylecgonine, norcocaine and ketamine. Linearity was demonstrated over a broad range of concentration in plasma, with good sensitivity for ketamine, cocaine and cocaine metabolites. Copyright 2002 John Wiley & Sons, Ltd.