High-performance liquid chromatographic determination of cis-dichlorodiammineplatinum(II) in plasma ultrafiltrate

Abstract A reproducible, simple and sensitive high-performance liquid chromatographic method was described for the quantitative analysis of cis -diamminedichloroplatinum(II) (CDDP) in ultrafiltrate plasma in the presence of nickel chloride as internal standard. CDDP and the internal standard were chelated by exchange with diethyldithiocarbamate. After derivatization, the mixture was directly injected into the column. Chromatography was performed on an Ultrasphere column and the eluent measured spectrophotometrically at 260 nm for CDDP and at 250 nm for the internal standard. The peak area ratio of CDDP to the internal standard varied linearly with concentration over the range 0.05–10 μg ml −1 . Precision and reproducibility were both excellent and the limit of quantification was 0.03 μg ml −1 using only 0.5 ml of ultrafiltrate. The present method, without extraction, should be entirely automated. This assay may be suitable for therapeutic drug monitoring in patients receiving CDDP.