Pharmacokinetics of 11C-BCNU in experimental brain tumor.

Wistar rats implanted intracerebrally with AA ascites tumor were injected seven or eight days later with 11C-labelled BCNU. Radioactive compounds in samples of plasma, tumor, and contralateral brain were identified after injection at intervals by doing chloroform extraction and thin layer radiochromatography. At 60 min after injection radioactivity levels were 56% higher in the tumor than in contralateral brain. This increase was due mainly to 2-chlorethyl isocyanate, which binds to amino groups and/or nucleic acid. The results demonstrated both a higher concentration and a faster decomposition of BCNU in the tumor.