Determination of cytarabine and uracil arabinoside in human plasma and cerebrospinal fluid by high-performance liquid chromatography.

A high-performance liquid chromatographic method for the determination of the antineoplastic agent cytarabine and its main metabolite uracil arabinoside in human plasma and cerebrospinal fluid is described. Complete separation from endogenous constituents was achieved by isocratic reversed-phase chromatography using phosphate buffer (0.05 M, pH 7.0) as the eluent. The limit of detection was 50 ng/ml. Day-to-day coefficients of variation were below 10%. The applicability of this rapid, simple and specific method for pharmacokinetic studies and monitoring of therapy was demonstrated.