Liquid-chromatographic analysis for common tricyclic antidepressant drugs and their metabolites in serum or plasma with the technicon "FAST-LC" system.

We describe a single procedure for assay of seven tricyclic antidepressant drugs and metabolites in serum or plasma: protriptyline, nortriptyline, amitriptyline, desmethyldoxepin, doxepin, desipramine, and imipramine. With the Technicon "FAST-LC" system, samples are aspirated directly into the unit and pretreated via double extraction; the concentration of each drug is then determined by "high-performance" liquid chromatography. Final chromatograms are monitored at 205 nm, at analysis rates of 7.5 samples/h. Concentration and absorbance are linearly related for each drug from 0 to 1400 micrograms/L. Day-to-day CVs averaged 5 to 6% for each drug, and there is good correlation of FAST-LC values with those obtained by gas-chromatographic methods. Total sample volume is 750 microliters.