[Pharmacokinetic analysis of ACNU in brain tumors (author's transl)].

In order to establish the standard of administration of ACNU against brain tumors, pharmacokinetic analysis of ACNU in tumor tissue, cystic fluid, cerebrospinal fluid and blood was performed. The sample specimens were obtained sequentially after intravenous administration of 1--2 mg/kg/BW of ACNU and quantitatively analysed by high-performance liquid chromatography in 3 cases of glioblastoma and each one case of astrocytoma, meningioma and brain metastasis. Concentrations of ACNU in blood was calculated by two compartment open model and those in cystic fluid was calculated by one compartment model using BMDP-3R program. The half-time in blood was 2.6--4.1 min, and its distribution was very fast. The penetration of ACNU into the tumor tissue was sufficient, because the central compartment was 23% and the tissue compartment was 77%. The transmission rate constant into the cyst was 1.8 and the elimination rate constant was 0.96. The maximum concentration in the cystic fluid 42 min after intravenous injection of 2 mg/kg/BW of ACNU was 0.27--0. 35 mg/dl. In conclusion, 3--4 mg/kg/BW of ACNU should be injected intravenously at one time.