Pharmacokinetics of nitrosoureas: levels of 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) in organs of normal and Walker 256/B carcinoma bearing rats after i.v. bolus.

The disappearance of 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU) from plasma, liver, kidney, lung, brain, spleen, tumor tissue and epididymal adipose tissue of Walker 256/B carcinoma-bearing rats and healthy animals was measured by differential pulse polarography after i.v. bolus of the drug. Only BCNU, not its decomposition products, was detected by the polarographic assay. Levels of BCNU in liver of tumor-bearing animals were significantly lower (about 10 times) than those on healthy rats. A bi-exponential fit was used to calculate the kinetics of BCNU in plasma, kidney, lung and brain, but no difference could be found between healthy and Walker tumor-bearing rats. BCNU disappeared faster from adipose tissue of tumor-bearing animals than from normals.