New method for high-performance liquid chromatographic determination of amantadine and its analogues in rat plasma

A novel precolumn derivatization method is described for the quantitative determination of amantadine, rimantadine and memantine in biological samples by HPLC with UV detection. The derivatization was performed at room temperature using anthraquinone-2-sulfonyl chloride (ASC) as reagent for only 10 min and without postderivatization treatment to inactivate excess reagent. The derivatives were analyzed by isocratic HPLC with a UV detector at 256 nm on a Lichrosper C18 column. The linear range for the determination of three drugs spiked in plasma (0.2 ml) was 0.05–5.0 μg/ml for amantadine and rimantadine, 0.05–2.0 μg/ml for memantine, respectively. The limits of detection and quantification were 20 and 50 ng/ml for the analytes, respectively. Application of the method to the analysis of amantadine, rimantadine and memantine in rat plasma and pharmacokinetic studies are demonstrated and proved feasible.