[Pharmacokinetics following intraperitoneal infusion of cisplatinum with and without sodium thiosulfate rescue in carcinomatous peritonitis in advanced gastric cancers].

The pharmacokinetics of ip cisplatinum (100 mg/body) was studied in 10 patients with advanced gastric cancer. Five patients were administered ip-cisplatinum with STS and another 5 patients were given the same without STS. As a result, 1) the level of free-CDDP in ascites fluid was significantly elevated after administration, showing that free-CDDP possessing anti-tumor activity persisted in the ascites fluid for a long time and reached the peak concentration 30 minutes after administration. 2) The free-CDDP transferred into the blood after administration also persisted for a long time in parallel with changes in the free-CDDP level in the ascites fluid. 3) The AUC, MRT and VRT of the free-CDDP concentration in the peritoneal cavity after ip administration of CDDP were high, clearly indicating the direct effect on peritoneal concentration. 4) The AUC, MRT and VRT of free-CDDP in the venous phase after ip administration of CDDP were higher than after its iv administration, suggesting that effects equivalent to or greater than those of the iv route drug can be expected in the venous phase. 5) The frequency of side effects induced by the combination of STS was lower than that of side effects induced by the administration without combined STS. Much larger doses of CDDP may be given ip by combining with STS.