High-performance liquid chromatographic analysis of emetine after oxidative activation to a fluorescent product

A clinically useful analytical method is described for monitoring plasma levels of emetine. The drug is initially extracted from plasma with dichloromethane (0.3 volumes). The extract can be analyzed directly by paired-ion reversed-phase high-performance liquid chromatography to levels of 500 ng/ml of plasma by spectrophotometric monitoring of column effluent. For analysis of emetine at lower concentrations, the dichloromethane extracts are subjected to mild mercuric acetate oxidation prior to separation, thereby converting emetine to a fluorescent product. Spectrofluorometric monitoring of the column effluent readily extends the sensitivity of the assay to 10 ng of emetine/ml of plasma. At these levels measurements can be made with a precision of +/- 4%.