Comparison of the iv and ip routes of administration of cisplatin in dogs.

Cisplatin at a dose of 3 mg/kg was administered to dogs either iv or ip. Cisplatin concentrations in serum, urine, and tissues were measured with a radioisotope tracer method employing 195mPt cisplatin. Systemic toxicity was monitored by serial BUN, creatinine, and wbc and platelet counts. The mode of administration did not affect systemic toxicity since the changes in renal and bone marrow functions were identical in the two groups. Serum cisplatin levels following iv administration peaked at 13.5 micrograms/ml at 5 minutes and were biphasic with rapid initial decline and a prolonged elimination phase. In contrast, levels following ip administration increased rapidly to 1.5 micrograms/ml at 4 hours and then decreased with the iv levels. The amount of drug recovered in the urine was similar regardless of method of administration, with approximately 50% of the injected dose excreted by Day 4. The drug levels within the tissues on Days 4 and 8 were similar, with the exception of the tissues lining the peritoneal cavity. On Day 4 the tissues lining the peritoneal cavity had 2.5-8 times higher levels of drug after ip administration, and this difference was statistically significant (P less than 0.01). Local toxic effects encountered with ip administration consisted of bloody ascites on Day 4 (four of none dogs) and filmy adhesions on Day 8 (one of four dogs). It is concluded that ip cisplatin chemotherapy may increase the therapeutic index for small tumors which are confined to the peritoneal cavity.