DETERMINATION OF AMANTADINE IN HUMAN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION

A simple and highly sensitive fluorimetric high-performance liquid chr omatographic (HPLC) method was developed for the determination of aman tadine in plasma. After a single-step extraction from plasma (50 mu l) with toluene, the drug and 1-(1-adamantyl)ethylamine (internal standa rd) were converted into the corresponding fluorescent derivatives by r eaction with ,7-dimethoxy-4-methyl-3-oxo-quinoxaline-2-carbonyl chlori de, a fluorescence derivatization reagent for amines, in the presence of triethylamine. The derivatives were separated within 20 min on a re versed-phase column (YMC-Pack C-8) using isocratic elution with methan ol-acetonitrile-water (35:35:30, v/v) and detected spectrofluorimetric ally at 500 nm with excitation at 400 nm. The detection limit for aman tadine added to plasma was 360 fmol (54 pg) ml(-1) plasma (18 fmol on column) at a signal-to-noise ratio of three.