Biliary excretion of platinum in rats after administration of cisplatin and aqua(1,1-bis(aminomethyl)-cyclohexane)sulfatoplatinum(II) (spiroplatin, TNO-6).

Three groups of 6 rats were treated with cisplatin (3 mg/kg, bolus and 3-h infusion) and spiroplatin (3 mg/kg, bolus) by infusion in the right external jugular vein. The mean amounts of platinum +/- c.v. excreted in the bile during the first 6 h after the start of administration were 0.32 +/- 0.19% and 0.39 +/- 0.29% of the dose after bolus injection and 3-h infusion of cisplatin, respectively, and 3.77 +/- 3.32% of the dose after spiroplatin. The values were not significantly different between the 2 cisplatin administration modes (P greater than 0.05), but were between the spiroplatin and cisplatin bolus groups (Wilcoxon two-sided rank test, P less than 0.01). These data are related to pharmacokinetic parameters in man.