High-performance liquid chromatographic method for sensitive determinationof the alkylating agent CB1954 in human plasma

A high-performance liquid chromatography (HPLC) method is described for the measurement of the weak alkylating agent CB1954 in human plasma. CB1954 ca n be used as an innocuous prodrug designed for activation by bacterial nitr oreductases in strategies of gene-directed enzyme-prodrug therapy, and beco mes activated to a potent bifunctional alkylating agent. The HPLC method in volves precipitation and solvent extraction and uses Mitomycin C (MMC) as a n internal standard, with a retention time for MMC of 5.85+/-0.015 min, and for CB1954 of 10.72+/-0.063 min. The limit of detection for CB1954 is 2.9 ng/ml, and this compares favourably with systems involving direct analysis of plasma (limit of detection 600 ng/ml, approximately). The method is now being used for pharmacokinetic measurements in plasma samples from cancer p atients entering phase I clinical trials of CB1954. Results using serial pl asma samples from one patient are presented. The patient was treated intrav enously with CB1954 (6 mg/m(2)), and plasma clearance of the drug showed bi phasic kinetics with alpha half-life 14.6 min, and beta half-life 170.5 min . (C) 1999 Elsevier Science B.V. All rights reserved.