High-performance liquid chromatographic method for the determination of amineptine and its main metabolite in human plasma.

An isocratic reversed-phase ion-pair liquid chromatographic method for the determination of amineptine and its main metabolite in plasma using an internal standard, is reported. The effects of stationary phase alkyl chain length and the concentration of alkyl sulfonate in the mobile phase were investigated. The drugs were extracted as ion pairs and the influence of various parameters on the extraction efficiency are discussed. Using a heptane-octanol-tetraheptylammonium bromide mixture (98:2:0.5, v/v/w) as extraction solvent, more than 60% of each drug was recovered with a very good selectivity. UV detection at 220 nm allowed drug determination down to 0.010 microgram/ml. Linear standard curves up to 1.00 microgram/ml were observed.