Pharmacokinetics of oxaliplatin in gastrointestinal cancer patients with malignant ascites.

The pharmacokinetics of oxaliplatin in plasma and ascitic fluid was investigated in 5 gastrointestinal cancer patients with malignant ascites. Oxaliplatin was administered at 85 mg/m² by 2-hour infusion in the FOLFOX4 regimen, and the concentrations of total and free platinum were measured. There was a trend of lower plasma C(max) values of total platinum in patients with a larger volume of ascitic fluid. The AUC(0-t) values of mean concentration curves of total plasma platinum, total ascites platinum, free plasma platinum, and free ascites platinum were 31.15, 7.96, 4.93 and 2.93 mg•h/ml, respectively. The concentrations of free ascites platinum were similar to those of free plasma platinum at the last sampling time of 26 h in each patient. The decrease or disappearance of ascitic fluid was observed in 4 patients. These results suggest that oxaliplatin exerted a beneficial effect in gastrointestinal cancer patients with malignant ascites, even when administered intravenously.