Paired-ion chromatographic analysis of tamoxifen and two major metabolites in plasma.

A method is described for the clinical analysis of the non-steroidal anti-estrogenic, antineoplastic agent, tamoxifen and its 4-hydroxy and N-desmethyl metabolites in human plasma. The analytes are extracted from biological fluid with diethyl ether and subsequently converted to fluorescent phenanthrene derivatives by irradiation with UV light. The fluorophores are separated by paired-ion chromatography on a reversed-phase (C18) column. Spectrofluorometric monitoring of the column eluent allows quantitation of analytes as their phenanthrene derivatives to levels of 100 pg/ml of plasma.