Determination of phosphonoformic acid in human plasma and urine by high-performance liquid chromatography with electrochemical detection.

Trisodium phosphonoformate (foscarnet) is used in the treatment of cytomegalovirus infections in immunocompromised patients, such as bone marrow and renal transplant recipients, as well as patients with the acquired immune deficiency syndrome. A simple high-performance liquid chromatographic assay is described using an electrochemical detector. The method is accurate, precise and reproducible. Hydrochlorothiazide is used as the internal standard. This assay allows measurement of foscarnet in biological fluids at concentrations as low as 33 microM. This method is being used for the analysis of samples in clinical trials and is important in the evaluation of the pharmacokinetic disposition of the drug.