Quantitative high-performance liquid chromatographic assay for the determination of maprotiline and oxaprotiline in human plasma.

A procedure is described which permits the determination of maprotiline and oxaprotiline in human blood or plasma at therapeutic concentrations. The biological fluids are extracted with base and the extract is injected into a high-performance liquid chromatograph. The substances are detected by a UV detector operating at 214 nm, amitriptyline being used as internal standard. Concentrations as low as 2 ng per sample can be measured.