Variable oral absorption of hexamethylmelamine in man.

Plasma levels of hexamethylmelamine were measured by a sensitive and specific gas chromatographic assay in 11 patients after they received oral doses ranging from 120 to 300 mg/m2. Peak levels were reached in 0.5--3 hours and ranged from 0.2 to 20.8 micrograms/ml. The area under the curve ranged from 70.2 to 3606.6 micrograms/ml x minute. The half-life of the beta-phase of elimination also showed considerable variability, ranging between 4.66 and 10.2 hours. These parameters were not related to the dose administered. No plasma accumulation of the drug was observed after daily treatment with hexamethylmelamine for 14--21 days.