Concentrations of VP16 and VM26 in human brain tumors.

VP16 and VM26 were determined by high pressure liquid chromatography in intracerebral tumors, adjacent normal brain tissue, plasma and CSF samples from 24 patients given the two drugs before surgical resection of the tumor. The drugs were administered at doses of 100-150 mg/m2 as a 1-hour i.v. infusion, between 1.5 and 12 hours before surgery. Concentrations of VP16 ranged between 1.05 and 3.28 micrograms/g in tumors in the series of patients who received the drug 1.5-3 hours before surgery and between less than 0.05 and 1.12 micrograms/g in four patients who received the drug 9-13 hours before surgery. Tumor concentrations of VM26 also varied, ranging from less than 0.05 to 1.68 micrograms/g between 1.5 and 12 hours before surgery. VP16 and VM26 in the apparently normal brain tissue surrounding the tumor were low or undetectable except in one patient who had received radiotherapy, in whom we found 3.1 micrograms/g.