Sensitive and selective liquid chromatographic assay of memantine in plasma with fluorescence detection after pre-column derivatization

A procedure was developed for the determination of memantine in plasma usin g liquid chromatography with fluorescence detection. Following a liquid-liq uid extraction from 1 ml of plasma containing the internal standard amantad ine, the extract was derivatized at room temperature with dansyl chloride, and the highly fluorescent derivatives were chromatographed with a reversed -phase C-18 column and a mobile phase of phosphate buffer and acetonitrile. Dansylated memantine and amantadine were eluted in less than 13 min with n o interference from endogenous material. The calibration curve was Linear o ver the concentration range of 3-400 ng/ml with inter- and intra-assay impr ecision (C.V.) of less than 10%. The limit of quantitation was 3 ng/ml, and no major antidepressant, neuroleptic or their respective metabolites inter fered with the quantitation of memantine. This method could also be applied to the quantitation of amantadine. (C) 1999 Elsevier Science B.V. All righ ts reserved.