A sensitive method for the determination of amitriptyline and nortriptyline in human plasma.

A highly sensitive and reproducible GLC technique for the quantitation of amitriptyline and nortriptyline is described. The lower limit of detection is less than 1 ng/ml. 5 ng/ml samples (3 ml aliquots) can be accurately quantified (C of V less than 5%). Steady state data are reported together with data on amitriptyline and nortriptyline levels obtained in a volunteer who ingested a single oral dose (25 mg) of amitriptyline (Elavil).