Determination of the antineoplastic agent methotrexate in body fluids by high-performance liquid chromatography with electrochemical detection.

Some preliminary data concerning the anodic behaviour of the antineoplastic agent methotrexate are reported, and a high-performance liquid chromatographic method with electrochemical detection for its determination in human serum and urine is described. The method uses a reversed-phase C18 column and isocratic elution with amperometric detection on glassy carbon at +0.95 V vs. Ag/AgCl reference electrode. Sample treatment consists of a simple deproteinization step (serum) or an extraction procedure on Sep-Pak C18 cartridges (serum) or Amberlite column (urine). The detection limit for methotrexate in serum is 2.2 nmol/l. The method should prove useful for the evaluation of the drug pharmacokinetics in patients undergoing anticancer therapy.