Pentamethylmelamine (PMM) 80 mg/m2 was administered I.V. to 8 patients during surgical resection of intracerebral
tumors. PMM concentrations in
tumors were generally much higher than concurrent plasma concentrations, ranging from undetectable (less than .01 micrograms/g) to as high as 4.47 micrograms/g and were much higher in
malignant melanoma samples than in
astrocytoma samples. PMM was barely detectable or undetectable in most samples of edematous brain tissue adjacent to intracerebral
tumor and in temporalis muscle. The PMM metabolites tetramethylmelamine (TeMM), trimethylmelamine (TrMM), and dimethylmelamine (DMM) were each detectable in
tumor samples from one or two patients. Monomethylmelamine (MMM) was present in
tumor samples from all except one patient. MMM was noted in samples of edematous brain tissue adjacent to
tumor from 4 of 8 patients. It was the only PMM metabolite found in brain. TrMM, DMM, and MMM but not PMM, and TeMM were found in
tumor cyst fluid from a patient with an intracerebral
malignant melanoma. Two patients receiving therapeutic doses of PMM had biopsies taken of subcutaneous
malignant melanoma deposits. PMM was undetectable in samples from one patient but reached high concentrations in the other patient. In both patients, MMM was the major metabolite. There was no indication that PMM penetrated into extracerebral
tumors more readily than into intracerebral
tumors Cerebrospinal fluid (CSF) samples were obtained from one patient without neurological toxicity who received low doses of PMM and from 4 patients receiving high doses of PMM who had developed neurological toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)