Measurement of antidepressants by liquid chromatography: a review of current methodology

Antidepressant measurement by liquid chromatography (LC) has enhanced the therapy of patients who are being treated with some of the first generation tricyclic antidepressants; the merits of routinely monitoring the other antidepressants await further study. Currently, the role of LC is changing from dominant to complementary as a result of the recent availability of monoclonal antibody immunoassays with increased specificity. For successful application of LC, considerations would include designing the sampling protocol and matching assay that together are uniquely suitable for a particular laboratory. The assay should be simple, the sample preparation manual (liquid-liquid, solid-phase extraction columns), semi-automated, or automated. Normal- or reversed-phase columns with functionalities such as C-18, CN, C-8, and phenyl are used. Other useful LC variables include particle size, capping, ion-pairing, and recycling. This survey of LC methods includes the first and second generations, and new antidepressants such as alprazolam, amoxapine, bupropion, maprotiline, trazodone, and selected metabolites. Potential chromatographic interference by (e.g.) benzodiazepines and neuroleptics is addressed, followed by proposed guidelines for their resolution. Future developments are discussed.